Modeling Fluid Flow in Natural Systems, Model Validation and...
Modeling Fluid Flow in Natural Systems, Model Validation and Demonstration Modeling Fluid Flow in Natural Systems, Model Validation and Demonstration Clay and granitic units are ...
Transient Wellbore Fluid Flow Model
Energy Science and Technology Software Center (OSTI)
1982-04-06
WELBORE is a code to solve transient, one-dimensional two-phase or single-phase non-isothermal fluid flow in a wellbore. The primary thermodynamic variables used in solving the equations are the pressure and specific energy. An equation of state subroutine provides the density, quality, and temperature. The heat loss out of the wellbore is calculated by solving a radial diffusion equation for the temperature changes outside the bore. The calculation is done at each node point in themore » wellbore.« less
Modeling fluid flow in deformation bands with stabilized localization...
Office of Scientific and Technical Information (OSTI)
Modeling fluid flow in deformation bands with stabilized localization mixed finite elements. Citation Details In-Document Search Title: Modeling fluid flow in deformation bands...
Can We Accurately Model Fluid Flow in Shale?
U.S. Department of Energy (DOE) all webpages (Extended Search)
Can We Accurately Model Fluid Flow in Shale? Can We Accurately Model Fluid Flow in Shale? Print Thursday, 03 January 2013 00:00 Over 20 trillion cubic meters of natural gas are...
Monitoring and Modeling Fluid Flow in a Developing EGS Reservoir |
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Department of Energy EGS Reservoir Monitoring and Modeling Fluid Flow in a Developing EGS Reservoir Project objectives: Better understand and model fluid injection into a tight reservoir on the edges of a hydrothermal field. Use seismic data to constrain geomechanical/hydrologic/thermal model of reservoir. seismic_fehler_fluid_flow.pdf (1.15 MB) More Documents & Publications Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in EGS Reservoirs Detection and
Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
in EGS Reservoirs | Department of Energy Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in EGS Reservoirs Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in EGS Reservoirs Project objectives: Improve image resolution for microseismicimaging and time-lapse active seismic imaging; Enhance the prediction of fluid flow and temperature distributions and stress changes by coupling fracture flow simulations with reservoir flow simulations; and
Monitoring and Modeling Fluid Flow in a Developing EGS Reservoir...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
EGS Reservoir Monitoring and Modeling Fluid Flow in a Developing EGS Reservoir Project ... More Documents & Publications Imaging, Characterizing, and Modeling of Fracture Networks ...
Monitoring and Modeling Fluid Flow in a Developing Enhanced Geothermal...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Enhanced Geothermal System (EGS) Reservoir; 2010 Geothermal Technology Program Peer Review Report Monitoring and Modeling Fluid Flow in a Developing Enhanced Geothermal System ...
Two-fluid Hydrodynamic Model for Fluid-Flow Simulation in Fluid-Solids Systems
Energy Science and Technology Software Center (OSTI)
1994-06-20
FLUFIX is a two-dimensional , transient, Eulerian, and finite-difference program, based on a two-fluid hydrodynamic model, for fluid flow simulation in fluid-solids systems. The software is written in a modular form using the Implicit Multi-Field (IMF) numerical technique. Quantities computed are the spatial distribution of solids loading, gas and solids velocities, pressure, and temperatures. Predicted are bubble formation, bed frequencies, and solids recirculation. Applications include bubbling and circulating atmospheric and pressurized fluidized bed reactors, combustors,more » gasifiers, and FCC (Fluid Catalytic Cracker) reactors.« less
Monitoring and Modeling Fluid Flow in a Developing EGS
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
3 Peer Review Insert photo of your choice Monitoring and Modeling Fluid Flow in a Developing EGS Reservoir April 24, 2013 Michael Fehler Massachusetts Institute of Technology Monitoring and Monitoring Fluid Flow This presentation does not contain any proprietary confidential, or otherwise restricted information. Relevance/Impact of Research 2 | US DOE Geothermal Program eere.energy.gov Project Objective Use Chevron's high-quality data from a long-term injection in the Salak geothermal field to
A preliminary study to Assess Model Uncertainties in Fluid Flows
Marc Oliver Delchini; Jean C. Ragusa
2009-09-01
The goal of this study is to assess the impact of various flow models for a simplified primary coolant loop of a light water nuclear reactor. The various fluid flow models are based on the Euler equations with an additional friction term, gravity term, momentum source, and energy source. The geometric model is purposefully chosen simple and consists of a one-dimensional (1D) loop system in order to focus the study on the validity of various fluid flow approximations. The 1D loop system is represented by a rectangle; the fluid is heated up along one of the vertical legs and cooled down along the opposite leg. A pressurizer and a pump are included in the horizontal legs. The amount of energy transferred and removed from the system is equal in absolute value along the two vertical legs. The various fluid flow approximations are compressible vs. incompressible, and complete momentum equation vs. Darcys approximation. The ultimate goal is to compute the fluid flow models uncertainties and, if possible, to generate validity ranges for these models when applied to reactor analysis. We also limit this study to single phase flows with low-Mach numbers. As a result, sound waves carry a very small amount of energy in this particular case. A standard finite volume method is used for the spatial discretization of the system.
Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
in EGS Reservoirs; II: Full-Waveform Inversion of 3D-9C VSP data from Bradys EGS Site and Update of the Brady Reservoir Scale Model | Department of Energy Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in EGS Reservoirs; II: Full-Waveform Inversion of 3D-9C VSP data from Bradys EGS Site and Update of the Brady Reservoir Scale Model Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in EGS Reservoirs; II: Full-Waveform Inversion of 3D-9C
Monitoring and Modeling Fluid Flow in a Developing EGS | Department of
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Energy and Modeling Fluid Flow in a Developing EGS Monitoring and Modeling Fluid Flow in a Developing EGS Monitoring and Modeling Fluid Flow in a Developing EGS presentation at the April 2013 peer review meeting held in Denver, Colorado. modeling_fluid_flow_egs_peer2013.pdf (1.35 MB) More Documents & Publications Monitoring and Modeling Fluid Flow in a Developing EGS Reservoir Integration of Noise and Coda Correlation Data into Kinematic and Waveform Inversions
Monitoring and Modeling Fluid Flow in a Developing Enhanced Geothermal
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
System (EGS) Reservoir; 2010 Geothermal Technology Program Peer Review Report | Department of Energy Enhanced Geothermal System (EGS) Reservoir; 2010 Geothermal Technology Program Peer Review Report Monitoring and Modeling Fluid Flow in a Developing Enhanced Geothermal System (EGS) Reservoir; 2010 Geothermal Technology Program Peer Review Report DOE 2010 Geothermal Technologies Program Peer Review seismic_025_fehler.pdf (195.11 KB) More Documents & Publications Analysis of Geothermal
Draft: Modeling Two-Phase Flow in Porous Media Including Fluid-Fluid Interfacial Area
Crandall, Dustin; Niessner, Jennifer; Hassanizadeh, S Majid
2008-01-01
We present a new numerical model for macro-scale twophase flow in porous media which is based on a physically consistent theory of multi-phase flow.The standard approach for modeling the flow of two fluid phases in a porous medium consists of a continuity equation for each phase, an extended form of Darcy’s law as well as constitutive relationships for relative permeability and capillary pressure. This approach is known to have a number of important shortcomings and, in particular, it does not account for the presence and role of fluid - fluid interfaces. An alternative is to use an extended model which is founded on thermodynamic principles and is physically consistent. In addition to the standard equations, the model uses a balance equation for specific interfacial area. The constitutive relationship for capillary pressure involves not only saturation, but also specific interfacial area. We show how parameters can be obtained for the alternative model using experimental data from a new kind of flow cell and present results of a numerical modeling study
Modeling two-fluid-phase flow and species transport in porous...
Office of Scientific and Technical Information (OSTI)
Publisher's Accepted Manuscript: Modeling two-fluid-phase flow and species transport in porous media This content will become publicly available on March 3, 2017 Title: Modeling ...
Modeling Fluid Flow in Natural Systems, Model Validation and Demonstration
Office of Energy Efficiency and Renewable Energy (EERE)
Clay and granitic units are potential host media for future repositories for used nuclear fuel. The report addresses the representation and characterization of flow in these two media within...
Fluid Flow Model Development for Representative Geologic Media
Office of Energy Efficiency and Renewable Energy (EERE)
Clay and granitic geologic rock units are potential host media for future repositories for used nuclear fuel and high level waste. This report addresses the representation of flow in these two media within numerical process (discrete fracture network) models.
Modeling two-fluid-phase flow and species transport in porous...
Office of Scientific and Technical Information (OSTI)
Modeling two-fluid-phase flow and species transport in porous media Citation Details In-Document Search This content will become publicly available on March 3, 2017 Title: Modeling ...
Chang, F.C.; Hull, J.R.; Wang, Y.H.; Blazek, K.E.
1996-02-01
A computer model was developed to predict eddy currents and fluid flows in molten steel. The model was verified by comparing predictions with experimental results of liquid-metal containment and fluid flow in electromagnetic (EM) edge dams (EMDs) designed at Inland Steel for twin-roll casting. The model can optimize the EMD design so it is suitable for application, and minimize expensive, time-consuming full-scale testing. Numerical simulation was performed by coupling a three-dimensional (3-D) finite-element EM code (ELEKTRA) and a 3-D finite-difference fluids code (CaPS-EM) to solve heat transfer, fluid flow, and turbulence transport in a casting process that involves EM fields. ELEKTRA is able to predict the eddy- current distribution and the electromagnetic forces in complex geometries. CaPS-EM is capable of modeling fluid flows with free surfaces. Results of the numerical simulation compared well with measurements obtained from a static test.
Direct pore-level modeling of incompressible fluid flow in porous media
Ovaysi, Saeed; Piri, Mohammad
2010-09-20
We present a dynamic particle-based model for direct pore-level modeling of incompressible viscous fluid flow in disordered porous media. The model is capable of simulating flow directly in three-dimensional high-resolution micro-CT images of rock samples. It is based on moving particle semi-implicit (MPS) method. We modify this technique in order to improve its stability for flow in porous media problems. Using the micro-CT image of a rock sample, the entire medium, i.e., solid and fluid, is discretized into particles. The incompressible Navier-Stokes equations are then solved for each particle using the MPS summations. The model handles highly irregular fluid-solid boundaries effectively. An algorithm to split and merge fluid particles is also introduced. To handle the computational load, we present a parallel version of the model that runs on distributed memory computer clusters. The accuracy of the model is validated against the analytical, numerical, and experimental data available in the literature. The validated model is then used to simulate both unsteady- and steady-state flow of an incompressible fluid directly in a representative elementary volume (REV) size micro-CT image of a naturally-occurring sandstone with 3.398 {mu}m resolution. We analyze the quality and consistency of the predicted flow behavior and calculate absolute permeability using the steady-state flow rate.
Solution Algorithms for Effective-Field Models of Multi-Fluid Flows
Office of Scientific and Technical Information (OSTI)
(Technical Report) | SciTech Connect Technical Report: Solution Algorithms for Effective-Field Models of Multi-Fluid Flows Citation Details In-Document Search Title: Solution Algorithms for Effective-Field Models of Multi-Fluid Flows Authors: Robert Nourgaliev ; Mark Christon Publication Date: 2012-09-01 OSTI Identifier: 1058095 Report Number(s): INL/EXT-12-27187 DOE Contract Number: DE-AC07-05ID14517 Resource Type: Technical Report Research Org: Idaho National Laboratory (INL) Sponsoring
Billeter, Thomas R.; Philipp, Lee D.; Schemmel, Richard R.
1976-01-01
A microwave fluid flow meter is described utilizing two spaced microwave sensors positioned along a fluid flow path. Each sensor includes a microwave cavity having a frequency of resonance dependent upon the static pressure of the fluid at the sensor locations. The resonant response of each cavity with respect to a variation in pressure of the monitored fluid is represented by a corresponding electrical output which can be calibrated into a direct pressure reading. The pressure drop between sensor locations is then correlated as a measure of fluid velocity. In the preferred embodiment the individual sensor cavities are strategically positioned outside the path of fluid flow and are designed to resonate in two distinct frequency modes yielding a measure of temperature as well as pressure. The temperature response can then be used in correcting for pressure responses of the microwave cavity encountered due to temperature fluctuations.
Predictions of bubbly flows in vertical pipes using two-fluid models in CFDS-FLOW3D code
Banas, A.O.; Carver, M.B.; Unrau, D.
1995-09-01
This paper reports the results of a preliminary study exploring the performance of two sets of two-fluid closure relationships applied to the simulation of turbulent air-water bubbly upflows through vertical pipes. Predictions obtained with the default CFDS-FLOW3D model for dispersed flows were compared with the predictions of a new model (based on the work of Lee), and with the experimental data of Liu. The new model, implemented in the CFDS-FLOW3D code, included additional source terms in the {open_quotes}standard{close_quotes} {kappa}-{epsilon} transport equations for the liquid phase, as well as modified model coefficients and wall functions. All simulations were carried out in a 2-D axisymmetric format, collapsing the general multifluid framework of CFDS-FLOW3D to the two-fluid (air-water) case. The newly implemented model consistently improved predictions of radial-velocity profiles of both phases, but failed to accurately reproduce the experimental phase-distribution data. This shortcoming was traced to the neglect of anisotropic effects in the modelling of liquid-phase turbulence. In this sense, the present investigation should be considered as the first step toward the ultimate goal of developing a theoretically sound and universal CFD-type two-fluid model for bubbly flows in channels.
Can We Accurately Model Fluid Flow in Shale?
U.S. Department of Energy (DOE) all webpages (Extended Search)
The source of shale oil and gas is kerogen, an organic material in the shale, but until now kerogen hasn't been incorporated in mathematical models of shale gas reservoirs. Paulo ...
Magnetically stimulated fluid flow patterns
Martin, Jim; Solis, Kyle
2014-03-06
Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.
Magnetically stimulated fluid flow patterns
Martin, Jim; Solis, Kyle
2014-08-06
Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.
Optimization of a Two-Fluid Hydrodynamic Model of Churn-Turbulent Flow
Donna Post Guillen
2009-07-01
A hydrodynamic model of two-phase, churn-turbulent flows is being developed using the computational multiphase fluid dynamics (CMFD) code, NPHASE-CMFD. The numerical solutions obtained by this model are compared with experimental data obtained at the TOPFLOW facility of the Institute of Safety Research at the Forschungszentrum Dresden-Rossendorf. The TOPFLOW data is a high quality experimental database of upward, co-current air-water flows in a vertical pipe suitable for validation of computational fluid dynamics (CFD) codes. A five-field CMFD model was developed for the continuous liquid phase and four bubble size groups using mechanistic closure models for the ensemble-averaged Navier-Stokes equations. Mechanistic models for the drag and non-drag interfacial forces are implemented to include the governing physics to describe the hydrodynamic forces controlling the gas distribution. The closure models provide the functional form of the interfacial forces, with user defined coefficients to adjust the force magnitude. An optimization strategy was devised for these coefficients using commercial design optimization software. This paper demonstrates an approach to optimizing CMFD model parameters using a design optimization approach. Computed radial void fraction profiles predicted by the NPHASE-CMFD code are compared to experimental data for four bubble size groups.
Mukhopadhyay, S.; Tsang, Y.; Finsterle, S.
2009-01-15
A simple conceptual model has been recently developed for analyzing pressure and temperature data from flowing fluid temperature logging (FFTL) in unsaturated fractured rock. Using this conceptual model, we developed an analytical solution for FFTL pressure response, and a semianalytical solution for FFTL temperature response. We also proposed a method for estimating fracture permeability from FFTL temperature data. The conceptual model was based on some simplifying assumptions, particularly that a single-phase airflow model was used. In this paper, we develop a more comprehensive numerical model of multiphase flow and heat transfer associated with FFTL. Using this numerical model, we perform a number of forward simulations to determine the parameters that have the strongest influence on the pressure and temperature response from FFTL. We then use the iTOUGH2 optimization code to estimate these most sensitive parameters through inverse modeling and to quantify the uncertainties associated with these estimated parameters. We conclude that FFTL can be utilized to determine permeability, porosity, and thermal conductivity of the fracture rock. Two other parameters, which are not properties of the fractured rock, have strong influence on FFTL response. These are pressure and temperature in the borehole that were at equilibrium with the fractured rock formation at the beginning of FFTL. We illustrate how these parameters can also be estimated from FFTL data.
Moller, Nancy; Weare J. H.
2008-05-29
Successful exploitation of the vast amount of heat stored beneath the earth’s surface in hydrothermal and fluid-limited, low permeability geothermal resources would greatly expand the Nation’s domestic energy inventory and thereby promote a more secure energy supply, a stronger economy and a cleaner environment. However, a major factor limiting the expanded development of current hydrothermal resources as well as the production of enhanced geothermal systems (EGS) is insufficient knowledge about the chemical processes controlling subsurface fluid flow. With funding from past grants from the DOE geothermal program and other agencies, we successfully developed advanced equation of state (EOS) and simulation technologies that accurately describe the chemistry of geothermal reservoirs and energy production processes via their free energies for wide XTP ranges. Using the specific interaction equations of Pitzer, we showed that our TEQUIL chemical models can correctly simulate behavior (e.g., mineral scaling and saturation ratios, gas break out, brine mixing effects, down hole temperatures and fluid chemical composition, spent brine incompatibilities) within the compositional range (Na-K-Ca-Cl-SO4-CO3-H2O-SiO2-CO2(g)) and temperature range (T < 350°C) associated with many current geothermal energy production sites that produce brines with temperatures below the critical point of water. The goal of research carried out under DOE grant DE-FG36-04GO14300 (10/1/2004-12/31/2007) was to expand the compositional range of our Pitzer-based TEQUIL fluid/rock interaction models to include the important aluminum and silica interactions (T < 350°C). Aluminum is the third most abundant element in the earth’s crust; and, as a constituent of aluminosilicate minerals, it is found in two thirds of the minerals in the earth’s crust. The ability to accurately characterize effects of temperature, fluid mixing and interactions between major rock-forming minerals and hydrothermal and
Computational Modeling of Fluid Flow through a Fracture in Permeable Rock
Crandall, Dustin; Ahmadi, Goodarz; Smith, Duane H
2010-01-01
Laminar, single-phase, finite-volume solutions to the Navier–Stokes equations of fluid flow through a fracture within permeable media have been obtained. The fracture geometry was acquired from computed tomography scans of a fracture in Berea sandstone, capturing the small-scale roughness of these natural fluid conduits. First, the roughness of the two-dimensional fracture profiles was analyzed and shown to be similar to Brownian fractal structures. The permeability and tortuosity of each fracture profile was determined from simulations of fluid flow through these geometries with impermeable fracture walls. A surrounding permeable medium, assumed to obey Darcy’s Law with permeabilities from 0.2 to 2,000 millidarcies, was then included in the analysis. A series of simulations for flows in fractured permeable rocks was performed, and the results were used to develop a relationship between the flow rate and pressure loss for fractures in porous rocks. The resulting frictionfactor, which accounts for the fracture geometric properties, is similar to the cubic law; it has the potential to be of use in discrete fracture reservoir-scale simulations of fluid flow through highly fractured geologic formations with appreciable matrix permeability. The observed fluid flow from the surrounding permeable medium to the fracture was significant when the resistance within the fracture and the medium were of the same order. An increase in the volumetric flow rate within the fracture profile increased by more than 5% was observed for flows within high permeability-fractured porous media.
McKay, M.D.; Sweeney, C.E.; Spangler, B.S. Jr.
1993-11-30
A flow meter and temperature measuring device are described comprising a tube with a body centered therein for restricting flow and a sleeve at the upper end of the tube to carry several channels formed longitudinally in the sleeve to the appropriate axial location where they penetrate the tube to allow pressure measurements and temperature measurements with thermocouples. The high pressure measurement is made using a channel penetrating the tube away from the body and the low pressure measurement is made at a location at the widest part of the body. An end plug seals the end of the device and holes at its upper end allow fluid to pass from the interior of the tube into a plenum. The channels are made by cutting grooves in the sleeve, the grooves widened at the surface of the sleeve and then a strip of sleeve material is welded to the grooves closing the channels. Preferably the sleeve is packed with powdered graphite before cutting the grooves and welding the strips. 7 figures.
McKay, Mark D.; Sweeney, Chad E.; Spangler, Jr., B. Samuel
1993-01-01
A flow meter and temperature measuring device comprising a tube with a body centered therein for restricting flow and a sleeve at the upper end of the tube to carry several channels formed longitudinally in the sleeve to the appropriate axial location where they penetrate the tube to allow pressure measurements and temperature measurements with thermocouples. The high pressure measurement is made using a channel penetrating the tube away from the body and the low pressure measurement is made at a location at the widest part of the body. An end plug seals the end of the device and holes at its upper end allow fluid to pass from the interior of the tube into a plenum. The channels are made by cutting grooves in the sleeve, the grooves widened at the surface of the sleeve and then a strip of sleeve material is welded to the grooves closing the channels. Preferably the sleeve is packed with powdered graphite before cutting the grooves and welding the strips.
Acoustic concentration of particles in fluid flow
Ward, Michael D.; Kaduchak, Gregory
2010-11-23
An apparatus for acoustic concentration of particles in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.
Fluid Flow Phenomena during Welding
Zhang, Wei
2011-01-01
MOLTEN WELD POOLS are dynamic. Liquid in the weld pool in acted on by several strong forces, which can result in high-velocity fluid motion. Fluid flow velocities exceeding 1 m/s (3.3 ft/s) have been observed in gas tungsten arc (GTA) welds under ordinary welding conditions, and higher velocities have been measured in submerged arc welds. Fluid flow is important because it affects weld shape and is related to the formation of a variety of weld defects. Moving liquid transports heat and often dominates heat transport in the weld pool. Because heat transport by mass flow depends on the direction and speed of fluid motion, weld pool shape can differ dramatically from that predicted by conductive heat flow. Temperature gradients are also altered by fluid flow, which can affect weld microstructure. A number of defects in GTA welds have been attributed to fluid flow or changes in fluid flow, including lack of penetration, top bead roughness, humped beads, finger penetration, and undercutting. Instabilities in the liquid film around the keyhole in electron beam and laser welds are responsible for the uneven penetration (spiking) characteristic of these types of welds.
Fluid flow modeling of resin transfer molding for composite material wind turbine blade structures.
Cairns, Douglas S. (Montana State University, Bozeman, MT); Rossel, Scott M. (Montana State University, Bozeman, MT)
2004-06-01
Resin transfer molding (RTM) is a closed mold process for making composite materials. It has the potential to produce parts more cost effectively than hand lay-up or other methods. However, fluid flow tends to be unpredictable and parts the size of a wind turbine blade are difficult to engineer without some predictive method for resin flow. There were five goals of this study. The first was to determine permeabilities for three fabrics commonly used for RTM over a useful range of fiber volume fractions. Next, relations to estimate permeabilities in mixed fabric lay-ups were evaluated. Flow in blade substructures was analyzed and compared to predictions. Flow in a full-scale blade was predicted and substructure results were used to validate the accuracy of a full-scale blade prediction.
On the multidimensional modeling of fluid flow and heat transfer in SCWRS
Gallaway, T.; Antal, S. P.; Podowski, M. Z.
2012-07-01
The Supercritical Water Reactor (SCWR) has been proposed as one of the six Generation IV reactor design concepts under consideration. The key feature of the SCWR is that water at supercritical pressures is used as the reactor coolant. Although at such pressures, fluids do not undergo phase change as they are heated, the fluid properties experience dramatic variations throughout what is known as the pseudo-critical region. Highly nonuniform temperature and fluid property distributions are expected in the reactor core, which will have a significant impact on turbulence and heat transfer in future SCWRs. The goal of the present work has been to understand and predict the effects of these fluid property variations on turbulence and heat transfer throughout the reactor core. Spline-type property models have been formulated for water at supercritical pressures in order to include the dependence of properties on both temperature and pressure into a numerical solver. New models of turbulence and heat transfer for variable-property fluids have been developed and implemented into the NPHASE-CMFD software. The results for these models have been compared to experimental data from the Korea Atomic Energy Research Inst. (KAERI) for various heat transfer regimes. It is found that the Low-Reynolds {kappa}-{epsilon} model performs best at predicting the experimental data. (authors)
Insertable fluid flow passage bridgepiece and method
Jones, Daniel O.
2000-01-01
A fluid flow passage bridgepiece for insertion into an open-face fluid flow channel of a fluid flow plate is provided. The bridgepiece provides a sealed passage from a columnar fluid flow manifold to the flow channel, thereby preventing undesirable leakage into and out of the columnar fluid flow manifold. When deployed in the various fluid flow plates that are used in a Proton Exchange Membrane (PEM) fuel cell, bridgepieces of this invention prevent mixing of reactant gases, leakage of coolant or humidification water, and occlusion of the fluid flow channel by gasket material. The invention also provides a fluid flow plate assembly including an insertable bridgepiece, a fluid flow plate adapted for use with an insertable bridgepiece, and a method of manufacturing a fluid flow plate with an insertable fluid flow passage bridgepiece.
Fluid Flow Within Fractured Porous Media
Crandall, D.M.; Ahmadi, G.; Smith, D.H.; Bromhal, G.S.
2006-10-01
Fractures provide preferential flow paths to subterranean fluid flows. In reservoir scale modeling of geologic flows fractures must be approximated by fairly simple formulations. Often this is accomplished by assuming fractures are parallel plates subjected to an applied pressure gradient. This is known as the cubic law. An induced fracture in Berea sandstone has been digitized to perform numerical flow simulations. A commercially available computational fluid dynamics software package has been used to solve the flow through this model. Single phase flows have been compared to experimental works in the literature to evaluate the accuracy with which this model can be applied. Common methods of fracture geometry classification are also calculated and compared to experimentally obtained values. Flow through regions of the fracture where the upper and lower fracture walls meet (zero aperture) are shown to induce a strong channeling effect on the flow. This model is expanded to include a domain of surrounding porous media through which the flow can travel. The inclusion of a realistic permeability in this media shows that the regions of small and zero apertures contribute to the greatest pressure losses over the fracture length and flow through the porous media is most prevalent in these regions. The flow through the fracture is shown to be the largest contributor to the net flow through the media. From this work, a novel flow relationship is proposed for flow through fractured media.
Computational fluid dynamics modeling of two-phase flow in a BWR fuel assembly. Final CRADA Report.
Tentner, A.; Nuclear Engineering Division
2009-10-13
A direct numerical simulation capability for two-phase flows with heat transfer in complex geometries can considerably reduce the hardware development cycle, facilitate the optimization and reduce the costs of testing of various industrial facilities, such as nuclear power plants, steam generators, steam condensers, liquid cooling systems, heat exchangers, distillers, and boilers. Specifically, the phenomena occurring in a two-phase coolant flow in a BWR (Boiling Water Reactor) fuel assembly include coolant phase changes and multiple flow regimes which directly influence the coolant interaction with fuel assembly and, ultimately, the reactor performance. Traditionally, the best analysis tools for this purpose of two-phase flow phenomena inside the BWR fuel assembly have been the sub-channel codes. However, the resolution of these codes is too coarse for analyzing the detailed intra-assembly flow patterns, such as flow around a spacer element. Advanced CFD (Computational Fluid Dynamics) codes provide a potential for detailed 3D simulations of coolant flow inside a fuel assembly, including flow around a spacer element using more fundamental physical models of flow regimes and phase interactions than sub-channel codes. Such models can extend the code applicability to a wider range of situations, which is highly important for increasing the efficiency and to prevent accidents.
Effect of Compressibility on Hyperbolicity and Choke Flow Criterion of the Two-phase Two-fluid Model
Suneet Singh; Vincent A. Mousseau
2008-09-01
The standard two-phase two-fluid model lacks hyperbolicity which results in oscillations in the numerical solutions. For the incompressible two-phase flows an exact correction term can be derived which when added to the momentum equations makes the model hyperbolic. No such straightforward approach exists for the similar compressible flows. In the current work, the effect of the compressibility on the characteristic equation is analyzed. It is shown that the hyperbolicity of the system depends only on the slip velocity and not on the phasic velocities, independently. Moreover, a slip Mach number is defined and a non-dimensional characteristic equation is derived. It is shown that for the small values of slip Mach number the effect of the compressibility on the hyperbolicity can be ignored. To verify the above analysis, the characteristic equation for the two-phase compressible flows is numerically solved and results compared with the values obtained with the analytical solution for incompressible flows. Numerical solution of the two-phase two-fluid model for the benchmark problem is used to further verify the abovementioned analysis. Furthermore, the eigenvalues of the characteristic equation are obtained as a power series expansion about the point where the slip Mach number is zero. These eigenvalues are used to develop a choking criterion for the compressible two-phase flows.
Borehole Fluid Conductivity Model
Energy Science and Technology Software Center (OSTI)
2004-03-15
Dynamic wellbore electrical conductivity logs provide a valuable means to determine the flow characteristics of fractures intersectin a wellbore, in order to study the hydrologic behavior of fractured rocks. To expedite the analysis of log data, a computer program called BORE II has been deveoloped that considers multiple inflow or outflow points along the wellbore, including the case of horizontal flow across the wellbore, BORE II calculates the evolution of fluid electrical conducivity (FEC) profilesmorein a wellbore or wellbore section, which may be pumped at a low rate, and compares model results to log data in a variety of ways. FEC variations may arise from inflow under natural-state conditions or due to tracer injected in a neighboring well (interference tests). BORE II has an interactive, graphical user interface and runs on a personal computer under the Windows operating system. BORE II is a modification and extension of older codes called BORE and BOREXT, which considered inflow points only. Finite difference solution of the one-dimensional advection-diffusion equation with explicit time stepping; feed points treated as prescribed-mass sources or sinks; assume quadratic relationship between fluid electrical conductivity and ion consentration. Graphical user interface; interactive modification of model parameters and graphical display of model results and filed data in a variety of ways. Can examine horizontal flow or arbitarily complicated combination of upflow, downflow, and horizontal flow. Feed point flow rate and/or concentration may vary in time.less
General Transient Fluid Flow Algorithm
Energy Science and Technology Software Center (OSTI)
1992-03-12
SALE2D calculates two-dimensional fluid flows at all speeds, from the incompressible limit to highly supersonic. An implicit treatment of the pressure calculation similar to that in the Implicit Continuous-fluid Eulerian (ICE) technique provides this flow speed flexibility. In addition, the computing mesh may move with the fluid in a typical Lagrangian fashion, be held fixed in an Eulerian manner, or move in some arbitrarily specified way to provide a continuous rezoning capability. This latitude resultsmore » from use of an Arbitrary Lagrangian-Eulerian (ALE) treatment of the mesh. The partial differential equations solved are the Navier-Stokes equations and the mass and internal energy equations. The fluid pressure is determined from an equation of state and supplemented with an artificial viscous pressure for the computation of shock waves. The computing mesh consists of a two-dimensional network of quadrilateral cells for either cylindrical or Cartesian coordinates, and a variety of user-selectable boundary conditions are provided in the program.« less
Coupled reactive mass transport and fluid flow: Issues in model verification
Freedman, Vicky L.; Ibaraki, Motomu
2003-01-03
Model verification and validation are both important steps in the development of reactive transport models. In this paper, a distinction is made between verification and validation, and the focus is on codifying the issues of verification for a numerical, reactive transport flow model. First, the conceptual basis of model verification is reviewed, which shows that verification should be understood as a first step in model development, and be followed by a protocol that assures that the model accurately represents system behavior. Second, commonly used procedures and methods of model verification are presented. In the third part of this paper, an intercomparison of models is used to demonstrate that model verification can be performed despite differences in hydrogeochemical transport code formulations. Results of an example simulation of transport are presented in which the numerical model is tested against other hydrogeochemical codes. Different kinetic formulations between solid and aqueous phases used among numerical models complicates model verification. This test problem involves uranium transport under conditions of varying pH and oxidation potential, with reversible precipitation of calcium uranate and coffinite. Results between the different hydrogeochemical transport codes show differences in oxidation potentials, but similarities in mineral assemblages and aqueous transport patterns. Because model verification can be further complicated by differences in the approach for solving redox problems, a comparison of a fugacity approach to both the external approach (based on hypothetical electron activity) and effective internal approach (based on conservation of electrons) is performed. The comparison demonstrates that the oxygen fugacity approach produces different redox potentials and mineral assemblages than both the effective internal and external approaches.
Harvego, Edwin Allan; Siefken, Larry James
2000-04-01
The SCDAP/RELAP5 code is being developed at the Idaho National Engineering and Environmental Laboratory under the primary sponsorship of the U.S. Nuclear Regulatory Commission (NRC) to provide best-estimate transient simulations of light water reactor coolant systems during severe accidents. This paper describes the modeling approach used in the SCDAP/RELAP5 code to calculate fluid heat transfer and flow losses through porous debris that has accumulated in the vessel lower head and core regions during the latter stages of a severe accident. The implementation of heat transfer and flow loss correlations into the code is discussed, and calculations performed to assess the validity of the modeling approach are described. The different modes of heat transfer in porous debris include: (1) forced convection to liquid, (2) forced convection to gas, (3) nucleate boiling, (4) transition boiling, (5) film boiling, and (6) transition from film boiling to convection to vapor. The correlations for flow losses in porous debris include frictional and form losses. The correlations for flow losses were integrated into the momentum equations in the RELAP5 part of the code. Since RELAP5 is a very general non-homogeneous non-equilibrium thermal-hydraulics code, the resulting modeling methodology is applicable to a wide range of debris thermal-hydraulic conditions. Assessment of the SCDAP/RELAP5 debris bed thermal-hydraulic models included comparisons with experimental measurements and other models available in the open literature. The assessment calculations, described in the paper, showed that SCDAP/RELAP5 is capable of calculating the heat transfer and flow losses occurring in porous debris regions that may develop in a light water reactor during a severe accident.
E. A. Harvego; L. J. Siefken
2000-04-02
The SCDAP/RELAP5 code is being developed at the Idaho National Engineering and Environmental Laboratory under the primary sponsorship of the U.S. Nuclear Regulatory Commission (NRC) to provide best-estimate transient simulations of light water reactor coolant systems during severe accidents. This paper describes the modeling approach used in the SCDAP/RELAP5 code to calculate fluid heat transfer and flow losses through porous debris that has accumulated in the vessel lower head and core regions during the latter stages of a severe accident. The implementation of heat transfer and flow loss correlations into the code is discussed, and calculations performed to assess the validity of the modeling approach are described. The different modes of heat transfer in porous debris include: (1) forced convection to liquid, (2) forced convection to gas, (3) nucleate boiling, (4) transition boiling, (5) film boiling, and (6) transition from film boiling to convection to vapor. The correlations for flow losses in porous debris include frictional and form losses. The correlations for flow losses were integrated into the momentum equations in the RELAP5 part of the code. Since RELAP5 is a very general non-homogeneous non-equilibrium thermal-hydraulics code, the resulting modeling methodology is applicable to a wide range of debris thermal-hydraulic conditions. Assessment of the SCDAP/RELAP5 debris bed thermal-hydraulic models included comparisons with experimental measurements and other models available in the open literature. The assessment calculations, described in the paper, showed that SCDAP/RELAP5 is capable of calculating the heat transfer and flow losses occurring in porous debris regions that may develop in a light water reactor during a severe accident.
2-Phase Fluid Flow & Heat Transport
Energy Science and Technology Software Center (OSTI)
1993-03-13
GEOTHER is a three-dimensional, geothermal reservoir simulation code. The model describes heat transport and flow of a single component, two-phase fluid in porous media. It is based on the continuity equations for steam and water, which are reduced to two nonlinear partial differential equations in which the dependent variables are fluid pressure and enthalpy. GEOTHER can be used to simulate the fluid-thermal interaction in rock that can be approximated by a porous media representation. Itmorecan simulate heat transport and the flow of compressed water, two-phase mixtures, and superheated steam in porous media over a temperature range of 10 to 300 degrees C. In addition, it can treat the conversion from single to two-phase flow, and vice versa. It can be used for evaluation of a near repository spatial scale and a time scale of a few years to thousands of years. The model can be used to investigate temperature and fluid pressure changes in response to thermal loading by waste materials.less
2-Phase Fluid Flow & Heat Transport
Energy Science and Technology Software Center (OSTI)
1993-03-13
GEOTHER is a three-dimensional, geothermal reservoir simulation code. The model describes heat transport and flow of a single component, two-phase fluid in porous media. It is based on the continuity equations for steam and water, which are reduced to two nonlinear partial differential equations in which the dependent variables are fluid pressure and enthalpy. GEOTHER can be used to simulate the fluid-thermal interaction in rock that can be approximated by a porous media representation. Itmore » can simulate heat transport and the flow of compressed water, two-phase mixtures, and superheated steam in porous media over a temperature range of 10 to 300 degrees C. In addition, it can treat the conversion from single to two-phase flow, and vice versa. It can be used for evaluation of a near repository spatial scale and a time scale of a few years to thousands of years. The model can be used to investigate temperature and fluid pressure changes in response to thermal loading by waste materials.« less
Rakowski, Cynthia L.; Serkowski, John A.; Richmond, Marshall C.; Perkins, William A.
2010-12-01
In 2003, an extension of the existing ice and trash sluiceway was added at Bonneville Powerhouse 2 (B2). This extension started at the existing corner collector for the ice and trash sluiceway adjacent to Bonneville Powerhouse 2 and the new sluiceway was extended to the downstream end of Cascade Island. The sluiceway was designed to improve juvenile salmon survival by bypassing turbine passage at B2, and placing these smolt in downstream flowing water minimizing their exposure to fish and avian predators. In this study, a previously developed computational fluid dynamics model was modified and used to characterized tailrace hydraulics and sluiceway egress conditions for low total river flows and low levels of spillway flow. STAR-CD v4.10 was used for seven scenarios of low total river flow and low spill discharges. The simulation results were specifically examined to look at tailrace hydraulics at 5 ft below the tailwater elevation, and streamlines used to compare streamline pathways for streamlines originating in the corner collector outfall and adjacent to the outfall. These streamlines indicated that for all higher spill percentage cases (25% and greater) that streamlines from the corner collector did not approach the shoreline at the downstream end of Bradford Island. For the cases with much larger spill percentages, the streamlines from the corner collector were mid-channel or closer to the Washington shore as they moved downstream. Although at 25% spill at 75 kcfs total river, the total spill volume was sufficient to "cushion" the flow from the corner collector from the Bradford Island shore, areas of recirculation were modeled in the spillway tailrace. However, at the lowest flows and spill percentages, the streamlines from the B2 corner collector pass very close to the Bradford Island shore. In addition, the very flow velocity flows and large areas of recirculation greatly increase potential predator exposure of the spillway passed smolt. If there is
A Site-Scale Model For Fluid And Heat Flow In The Unsaturated...
Open Energy Information (Open El) [EERE & EIA]
surface infiltration, and geothermal conditions are incorporated into the model. The reliability and accuracy of the model have been the subject of a comprehensive model...
Value for controlling flow of cryogenic fluid
Knapp, Philip A.
1996-01-01
A valve is provided for accurately controlling the flow of cryogenic fluids such as liquid nitrogen. The valve comprises a combination of disc and needle valves affixed to a valve stem in such a manner that the disc and needle are free to rotate about the stem, but are constrained in lateral and vertical movements. This arrangement provides accurate and precise fluid flow control and positive fluid isolation.
Overview of heat transfer and fluid flow problem areas encountered in stirling engine modeling
Tew, R.C. Jr.
1988-02-01
NASA Lewis Research Center has been managing Stirling engine development programs for over a decade. In addition to contractual programs, this work has included in-house engine testing and development of engine computer models. Attempts to validate Stirling engine computer models with test data have demonstrated that engine thermodynamic losses need better characterization. Various Stirling engine thermodynamic losses and efforts that are underway to characterize these losses are discussed.
Fluid properties determine flow line blockage potential
Hunt, A.
1996-07-15
A thorough understanding of fluid properties helps in determining the potential of hydrates, paraffins, or asphaltenes to block subsea flow lines. Thermal, chemical, and mechanical methods are the main ways for preventing deposition. Already in both the North Sea and the Gulf of Mexico, blockages have led to significant losses in production and reserves recovery. This first article in a two-part series discusses thermal and chemical methods in overcoming fluid behavior problems caused by hydrate and other fluid constituents in subsea multiphase flow. The paper discusses subsea production, possible problems, nucleation, growth, deposition, preventing deposition, hydrate predictions, multiphase flow, and hydrate inhibition.
Method and device for measuring fluid flow
Atherton, Richard; Marinkovich, Phillip S.; Spadaro, Peter R.; Stout, J. Wilson
1976-11-23
This invention is a fluid flow measuring device for determining the coolant flow at the entrance to a specific nuclear reactor fuel region. The device comprises a plurality of venturis having the upstream inlet and throat pressure of each respectively manifolded together to provide one static pressure signal for each region monitored. The device provides accurate flow measurement with low pressure losses and uniform entrance and discharge flow distribution.
Fracture Propagation, Fluid Flow, and Geomechanics of Water-Based...
Office of Scientific and Technical Information (OSTI)
Conference: Fracture Propagation, Fluid Flow, and Geomechanics of Water-Based Hydraulic ... Title: Fracture Propagation, Fluid Flow, and Geomechanics of Water-Based Hydraulic ...
Temperature distribution and fluid flow in an enclosure with...
Office of Scientific and Technical Information (OSTI)
Temperature distribution and fluid flow in an enclosure with localized heating and cooling Citation Details In-Document Search Title: Temperature distribution and fluid flow in an ...
Fracture Propagation, Fluid Flow, and Geomechanics of Water-Based...
Office of Scientific and Technical Information (OSTI)
Conference: Fracture Propagation, Fluid Flow, and Geomechanics of Water-Based Hydraulic ... Citation Details In-Document Search Title: Fracture Propagation, Fluid Flow, and ...
Controlling Subsurface Fractures and Fluid Flow: A Basic Research...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda PDF icon BES Report Controlling ...
Application of Neutron Imaging and Scattering to Fluid Flow and...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Application of Neutron Imaging and Scattering to Fluid Flow and Fracture in EGS Environments Application of Neutron Imaging and Scattering to Fluid Flow and Fracture in EGS ...
Microfluidics: Kinetics of Hybridized DNA With Fluid Flow Variations...
Office of Scientific and Technical Information (OSTI)
Microfluidics: Kinetics of Hybridized DNA With Fluid Flow Variations. Citation Details In-Document Search Title: Microfluidics: Kinetics of Hybridized DNA With Fluid Flow ...
Apparatus for measuring fluid flow
Smith, Jack E.; Thomas, David G.
1984-01-01
Flow measuring apparatus includes a support loop having strain gages mounted thereon and a drag means which is attached to one end of the support loop and which bends the sides of the support loop and induces strains in the strain gages when a flow stream impacts thereon.
Apparatus for measuring fluid flow
Smith, J.E.; Thomas, D.G.
Flow measuring apparatus includes a support loop having strain gages mounted thereon and a drag means which is attached to one end of the support loop and which bends the sides of the support loop and induces strains in the strain gages when a flow stream impacts thereon.
Directed flow fluid rinse trough
Kempka, S.N.; Walters, R.N.
1996-07-02
Novel rinse troughs accomplish thorough uniform rinsing. The tanks are suitable for one or more essentially planar items having substantially the same shape. The troughs ensure that each surface is rinsed uniformly. The new troughs also require less rinse fluid to accomplish a thorough rinse than prior art troughs. 9 figs.
Directed flow fluid rinse trough
Kempka, Steven N.; Walters, Robert N.
1996-01-01
Novel rinse troughs accomplish thorough uniform rinsing. The tanks are suitable for one or more essentially planar items having substantially the same shape. The troughs ensure that each surface is rinsed uniformly. The new troughs also require less rinse fluid to accomplish a thorough rinse than prior art troughs.
The effect of fluid flow on coiled tubing reach
Bhalla, K.; Walton, I.C.
1996-12-31
A critical parameter to the success of many coiled tubing (CT) operations in highly deviated or horizontal wells is the depth penetration that can be attained before the CT buckles and locks up. Achieving a desired depth is always critical in CT operations and attaining an additional reach of a few hundred feet can be crucial. This paper addresses the effect of fluid flow in the CT and in the CT/wellbore annulus on the state of force and stress in the CT, and thereby predicts its effect on the reach attainable by the CT. The flow of fluid through the CT and annulus between the CT and borehole modifies the pressures and the effective force which governs the mechanical stability of the CT. The net force per unit length due to fluid flow in the coiled tubing and annulus between the coiled tubing casing/well is calculated in terms of the shear stress and its effect on the onset of buckling and lockup is determined. The model is then implemented in a full tubing forces calculation and the effect of flowing fluids and producing fluids on reach is analyzed. The new model is utilized in the design of commercial jobs. The exact analytic model shows that fluid flow inside the CT has zero impact on reach, that downward flow in the annulus has a favourable impact, and upward flow in the annulus reduces the maximum attainable reach. Using the full tubing forces model, a coiled tubing job can be designed taking into account the flow of a fluid with a specified rheology, density and flow rate. Thus the feasibility of attaining a given reach can be more accurately determined. Results are presented in the form of the surface weight for commercial wells and compared to field jobs.
Standardization of Thermo-Fluid Modeling in Modelica.Fluid
Franke, Rudiger; Casella, Francesco; Sielemann, Michael; Proelss, Katrin; Otter, Martin; Wetter, Michael
2009-09-01
This article discusses the Modelica.Fluid library that has been included in the Modelica Standard Library 3.1. Modelica.Fluid provides interfaces and basic components for the device-oriented modeling of onedimensional thermo-fluid flow in networks containing vessels, pipes, fluid machines, valves and fittings. A unique feature of Modelica.Fluid is that the component equations and the media models as well as pressure loss and heat transfer correlations are decoupled from each other. All components are implemented such that they can be used for media from the Modelica.Media library. This means that an incompressible or compressible medium, a single or a multiple substance medium with one or more phases might be used with one and the same model as long as the modeling assumptions made hold. Furthermore, trace substances are supported. Modeling assumptions can be configured globally in an outer System object. This covers in particular the initialization, uni- or bi-directional flow, and dynamic or steady-state formulation of mass, energy, and momentum balance. All assumptions can be locally refined for every component. While Modelica.Fluid contains a reasonable set of component models, the goal of the library is not to provide a comprehensive set of models, but rather to provide interfaces and best practices for the treatment of issues such as connector design and implementation of energy, mass and momentum balances. Applications from various domains are presented.
Drift flux model as approximation of two fluid model for two phase dispersed and slug flow in tube
Nigmatulin, R.I.
1995-09-01
The analysis of one-dimensional schematizing for non-steady two-phase dispersed and slug flow in tube is presented. Quasi-static approximation, when inertia forces because of the accelerations of the phases may be neglected, is considered. Gas-liquid bubbly and slug vertical upward flows are analyzed. Non-trivial theoretical equations for slip velocity for these flows are derived. Juxtaposition of the derived equations for slip velocity with the famous Zuber-Findlay correlation as cross correlation coefficients is criticized. The generalization of non-steady drift flux Wallis theory taking into account influence of wall friction on the bubbly or slug flows for kinematical waves is considered.
MEANS FOR VISUALIZING FLUID FLOW PATTERNS
Lynch, F.E.; Palmer, L.D.; Poppendick, H.F.; Winn, G.M.
1961-05-16
An apparatus is given for determining both the absolute and relative velocities of a phosphorescent fluid flowing through a transparent conduit. The apparatus includes a source for exciting a narrow trsnsverse band of the fluid to phosphorescence, detecting means such as a camera located downstream from the exciting source to record the shape of the phosphorescent band as it passes, and a timer to measure the time elapsed between operation of the exciting source and operation of the camera.
Grant, C.W.; Goggin, D.J.; Harris, P.M. )
1994-01-01
Vertical and horizontal transects were sampled from core and outcrop of the San Andres Formation at Lawyer Canyon, Guadalupe Mountains, New Mexico, to assess permeability variation in a geologic framework of upward-shallowing carbonate cycles and to show the potential effect these variations have on viscous-dominated flow behavior in analogous reservoirs. These cycles occur in a ramp-crest facies, tract, are 3-13 m (10-45 ft) thick, and contain both vertical and lateral variation of lithofacies. Thicker cycles consist of a basal dolomudstone, which is overlain by burrowed dolomudstone, and capped by bar-flank ooid-peloid dolograinstone and bar-crest ooid dolograinstones. In vertical transects, permeability is extremely variable about the mean, yet upward-increasing trends coinciding with the succession of lithofacies typify a given cycle. Semi-variance analysis shows permeability to be uncorrelated vertically at distances greater than 5.5 m (18 ft), which is the average cycle thickness, suggesting that the cycles may equate to fluid-flow unit in a reservoir. Semi-variance analysis of measurements collected along a horizontal transect within bar-crest dolograinstones of a single cycle show permeability is uncorrelated at distances greater than 3.6 m (12 ft). This correlation distance appears to be controlled by alternating porous and tightly cemented zones that formed during dolomitization. Vertical and lateral variogram models were fit to the spatial parameters to generate a variety of conditionally simulated permeability fields. Fluid-flow simulations show viscous-dominated flow behavior is compartmentalized by both the individual cycles and groups of cycles. The basal dolomudstones are potential baffles to flow crossover between cycles, but poorly developed cycles (i.e., those that are mud rich and lack well-developed bar-flank and bar-crest facies) result in the greatest compartmentalization of fluid flow within a succession of cycles.
Method and apparatus for controlling fluid flow
Miller, J.R.
1980-06-27
A method and apparatus for precisely controlling the rate (and hence amount) of fluid flow are given. The controlled flow rate is finely adjustable, can be extremely small (on the order of microliter-atmospheres per second), can be adjusted to zero (flow stopped), and is stable to better than 1% with time. The dead volume of the valve can be made arbitrarily small, in fact essentially zero. The valve employs no wearing mechanical parts (including springs, stems, or seals). The valve is finely adjustable, has a flow rate dynamic range of many decades, can be made compatible with any fluid, and is suitable for incorporation into an open or closed loop servo-control system.
Understanding heat and fluid flow in linear GTA welds
Zacharia, T.; David, S.A.; Vitek, J.M.
1992-12-31
A transient heat flow and fluid flow model was used to predict the development of gas tungsten arc (GTA) weld pools in 1.5 mm thick AISI 304 SS. The welding parameters were chosen so as to correspond to an earlier experimental study which produced high-resolution surface temperature maps. The motivation of the present study was to verify the predictive capability of the computational model. Comparison of the numerical predictions and experimental observations indicate good agreement.
Understanding heat and fluid flow in linear GTA welds
Zacharia, T.; David, S.A.; Vitek, J.M.
1992-01-01
A transient heat flow and fluid flow model was used to predict the development of gas tungsten arc (GTA) weld pools in 1.5 mm thick AISI 304 SS. The welding parameters were chosen so as to correspond to an earlier experimental study which produced high-resolution surface temperature maps. The motivation of the present study was to verify the predictive capability of the computational model. Comparison of the numerical predictions and experimental observations indicate good agreement.
International Collaborations on Fluid Flows in Fractured Crystalline...
Office of Scientific and Technical Information (OSTI)
International Collaborations on Fluid Flows in Fractured Crystalline Rocks: FY14 Progress Report. Citation Details In-Document Search Title: International Collaborations on Fluid ...
Carrillo, Jose-Antonio Goudon, Thierry Lafitte, Pauline
2008-08-10
In this work, we propose asymptotic preserving numerical schemes for the bubbling and flowing regimes of particles immersed in a fluid treated by two-phase flow models. The description comprises compressible Euler equations for the dense phase (fluid) and a kinetic Fokker-Planck equation for the disperse phase (particles) coupled through friction terms. We show numerical simulations in the relevant case of gravity in the one-dimensional case demonstrating the overall behavior of the schemes.
Ultrasonic fluid flow measurement method and apparatus
Kronberg, James W.
1993-01-01
An apparatus for measuring the flow of a fluid in a pipe using ultrasonic waves. The apparatus comprises an ultrasonic generator, a lens for focusing the sound energy produced by the generator, and means for directing the focused energy into the side of the pipe through an opening and in a direction close to parallel to the long axis of the pipe. A cone carries the sound energy to the lens from the generator. Depending on the choice of materials, there may be a quarter-wave, acoustic impedance matching section between the generator and the cone to reduce the reflections of energy at the cone boundary. The lens material has an acoustic impedance similar to that of the cone material but a different sonic velocity so that the lens can converge the sound waves in the fluid. A transition section between the lens and the fluid helps to couple the energy to the fluid and assures it is directed as close to parallel to the fluid flow direction as possible.
Ultrasonic fluid flow measurement method and apparatus
Kronberg, J.W.
1993-10-12
An apparatus for measuring the flow of a fluid in a pipe using ultrasonic waves. The apparatus comprises an ultrasonic generator, a lens for focusing the sound energy produced by the generator, and means for directing the focused energy into the side of the pipe through an opening and in a direction close to parallel to the long axis of the pipe. A cone carries the sound energy to the lens from the generator. Depending on the choice of materials, there may be a quarter-wave, acoustic impedance matching section between the generator and the cone to reduce the reflections of energy at the cone boundary. The lens material has an acoustic impedance similar to that of the cone material but a different sonic velocity so that the lens can converge the sound waves in the fluid. A transition section between the lens and the fluid helps to couple the energy to the fluid and assures it is directed as close to parallel to the fluid flow direction as possible. 3 figures.
Boles, James R.; Garven, Grant
2015-08-04
Our studies have had an important impact on societal issues. Experimental and field observations show that CO_{2} degassing, such as might occur from stored CO_{2} reservoir gas, can result in significant stable isotopic disequilibrium. In the offshore South Ellwood field of the Santa Barbara channel, we show how oil production has reduced natural seep rates in the area, thereby reducing greenhouse gases. Permeability is calculated to be ~20-30 millidarcys for km-scale fault-focused fluid flow, using changes in natural gas seepage rates from well production, and poroelastic changes in formation pore-water pressure. In the Los Angeles (LA) basin, our characterization of formation water chemistry, including stable isotopic studies, allows the distinction between deep and shallow formations waters. Our multiphase computational-based modeling of petroleum migration demonstrates the important role of major faults on geological-scale fluid migration in the LA basin, and show how petroleum was dammed up against the Newport-Inglewood fault zone in a “geologically fast” interval of time (less than 0.5 million years). Furthermore, these fluid studies also will allow evaluation of potential cross-formational mixing of formation fluids. Lastly, our new study of helium isotopes in the LA basin shows a significant leakage of mantle helium along the Newport Inglewood fault zone (NIFZ), at flow rates up to 2 cm/yr. Crustal-scale fault permeability (~60 microdarcys) and advective versus conductive heat transport rates have been estimated using the observed helium isotopic data. The NIFZ is an important deep-seated fault that may crosscut a proposed basin decollement fault in this heavily populated area, and appears to allow seepage of helium from the mantle sources about 30 km beneath Los Angeles. The helium study has been widely cited in recent weeks by the news media, both in radio and on numerous web sites.
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
I: Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in EGS Reservoirs; II: Full-Waveform Inversion of 3D-9C VSP data from Brady's EGS Site and Update of the Brady Reservoir Scale Model Lianjie Huang Los Alamos National Laboratory Fluid Imaging Project Officer: Lauren Boyd Total Project Funding: Part I: $855,430 (LANL), $1M (NETL); Part II: $250,000 (LANL) April 22-25, 2013 This presentation does not contain any proprietary confidential, or otherwise restricted
Solution Algorithms for Effective-Field Models of Multi-Fluid...
Office of Scientific and Technical Information (OSTI)
Solution Algorithms for Effective-Field Models of Multi-Fluid Flows Citation Details In-Document Search Title: Solution Algorithms for Effective-Field Models of Multi-Fluid Flows ...
Fracture Network and Fluid Flow Imaging for EGS Applications from
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Multi-Dimensional Electrical Resistivity Structure | Department of Energy Network and Fluid Flow Imaging for EGS Applications from Multi-Dimensional Electrical Resistivity Structure Fracture Network and Fluid Flow Imaging for EGS Applications from Multi-Dimensional Electrical Resistivity Structure Fracture Network and Fluid Flow Imaging for EGS Applications from Multi-Dimensional Electrical Resistivity Structure presentation at the April 2013 peer review meeting held in Denver, Colorado.
Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda |
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Department of Energy Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda BES Report Controlling Subsurface Fractures and Fluid Flow.pdf (815.56 KB) More Documents & Publications AGU SubTER Town Hall Presentation 2015 SubTER Grand Challenge Roundtable: Imaging Geophysical and Geochemical Signals in the Subsurface SubTER Jason Report
Fluid flow plate for decreased density of fuel cell assembly
Vitale, N.G.
1999-11-09
A fluid flow plate includes first and second outward faces. Each of the outward faces has a flow channel thereon for carrying respective fluid. At least one of the fluids serves as reactant fluid for a fuel cell of a fuel cell assembly. One or more pockets are formed between the first and second outward faces for decreasing density of the fluid flow plate. A given flow channel can include one or more end sections and an intermediate section. An interposed member can be positioned between the outward faces at an interface between an intermediate section, of one of the outward faces, and an end section, of that outward face. The interposed member can serve to isolate the reactant fluid from the opposing outward face. The intermediate section(s) of flow channel(s) on an outward face are preferably formed as a folded expanse.
Fluid flow plate for decreased density of fuel cell assembly
Vitale, Nicholas G.
1999-01-01
A fluid flow plate includes first and second outward faces. Each of the outward faces has a flow channel thereon for carrying respective fluid. At least one of the fluids serves as reactant fluid for a fuel cell of a fuel cell assembly. One or more pockets are formed between the first and second outward faces for decreasing density of the fluid flow plate. A given flow channel can include one or more end sections and an intermediate section. An interposed member can be positioned between the outward faces at an interface between an intermediate section, of one of the outward faces, and an end section, of that outward face. The interposed member can serve to isolate the reactant fluid from the opposing outward face. The intermediate section(s) of flow channel(s) on an outward face are preferably formed as a folded expanse.
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
EIN Cash Flow Model Energy Independence Now (EIN) Objectives Identify financial risks in early hydrogen infrastructure systems and illustrate hydrogen station cash flows under a ...
Method and apparatus for chemically altering fluids in continuous flow
Heath, W.O.; Virden, J.W. Jr.; Richardson, R.L.; Bergsman, T.M.
1993-10-19
The present invention relates to a continuous flow fluid reactor for chemically altering fluids. The reactor operates on standard frequency (50 to 60 Hz) electricity. The fluid reactor contains particles that are energized by the electricity to form a corona throughout the volume of the reactor and subsequently a non-equilibrium plasma that interacts with the fluid. Particles may form a fixed bed or a fluid bed. Electricity may be provided through electrodes or through an inductive coil. Fluids include gases containing exhaust products and organic fuels requiring oxidation. 4 figures.
Method and apparatus for chemically altering fluids in continuous flow
Heath, William O.; Virden, Jr., Judson W.; Richardson, R. L.; Bergsman, Theresa M.
1993-01-01
The present invention relates to a continuous flow fluid reactor for chemically altering fluids. The reactor operates on standard frequency (50 to 60 Hz) electricity. The fluid reactor contains particles that are energized by the electricity to form a corona throughout the volume of the reactor and subsequently a non-equilibrium plasma that interacts with the fluid. Particles may form a fixed bed or a fluid bed. Electricity may be provided through electrodes or through an inductive coil. Fluids include gases containing exhaust products and organic fuels requiring oxidation.
A Model For The Transient Temperature Effects Of Horizontal Fluid...
Open Energy Information (Open El) [EERE & EIA]
Transient Temperature Effects Of Horizontal Fluid Flow In Geothermal Systems Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A Model For The...
Friction-Induced Fluid Heating in Nanoscale Helium Flows
Li Zhigang [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)
2010-05-21
We investigate the mechanism of friction-induced fluid heating in nanoconfinements. Molecular dynamics simulations are used to study the temperature variations of liquid helium in nanoscale Poiseuille flows. It is found that the fluid heating is dominated by different sources of friction as the external driving force is changed. For small external force, the fluid heating is mainly caused by the internal viscous friction in the fluid. When the external force is large and causes fluid slip at the surfaces of channel walls, the friction at the fluid-solid interface dominates over the internal friction in the fluid and is the major contribution to fluid heating. An asymmetric temperature gradient in the fluid is developed in the case of nonidentical walls and the general temperature gradient may change sign as the dominant heating factor changes from internal to interfacial friction with increasing external force.
Stress and Fluid-Flow Interaction for the Coso Geothermal Field...
Open Energy Information (Open El) [EERE & EIA]
Fluid-Flow Interaction for the Coso Geothermal Field Derived from 3D Numerical Models Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Proceedings:...
Feedback regulated induction heater for a flowing fluid
Migliori, A.; Swift, G.W.
1984-06-13
A regulated induction heater for heating a stream of flowing fluid to a predetermined desired temperature. The heater includes a radiofrequency induction coil which surrounds a glass tube through which the fluid flows. A heating element consisting of a bundle of approximately 200 stainless steel capillary tubes located within the glass tube couples the output of the induction coil to the fluid. The temperature of the fluid downstream from the heating element is sensed with a platinum resistance thermometer, the output of which is applied to an adjustable porportional and integral feedback control circuit which regulates the power applied to the induction coil. The heater regulates the fluid temperature to within 0.005/sup 0/C at a flow rate of 50 cm/sup 3//sec with a response time of less than 0.1 second, and can accommodate changes in heat load up to 1500 watts.
Feedback regulated induction heater for a flowing fluid
Migliori, Albert; Swift, Gregory W.
1985-01-01
A regulated induction heater for heating a stream of flowing fluid to a predetermined desired temperature. The heater includes a radiofrequency induction coil which surrounds a glass tube through which the fluid flows. A heating element consisting of a bundle of approximately 200 stainless steel capillary tubes located within the glass tube couples the output of the induction coil to the fluid. The temperature of the fluid downstream from the heating element is sensed with a platinum resistance thermometer, the output of which is applied to an adjustable proportional and integral feedback control circuit which regulates the power applied to the induction coil. The heater regulates the fluid temperature to within 0.005.degree. C. at a flow rate of 50 cm.sup.3 /second with a response time of less than 0.1 second, and can accommodate changes in heat load up to 1500 watts.
Apparatus for irradiating a continuously flowing stream of fluid
Speir, Leslie G.; Adams, Edwin L.
1984-01-01
An apparatus for irradiating a continuously flowing stream of fluid is diosed. The apparatus consists of a housing having a spherical cavity and a spherical moderator containing a radiation source positioned within the spherical cavity. The spherical moderator is of lesser diameter than the spherical cavity so as to define a spherical annular volume around the moderator. The housing includes fluid intake and output conduits which open onto the spherical cavity at diametrically opposite positions. Fluid flows through the cavity around the spherical moderator and is uniformly irradiated due to the 4.pi. radiation geometry. The irradiation source, for example a .sup.252 CF neutron source, is removable from the spherical moderator through a radial bore which extends outwardly to an opening on the outside of the housing. The radiation source may be routinely removed without interrupting the flow of fluid or breaching the containment of the fluid.
Fluid mechanics experiments in oscillatory flow. Volume 1
Seume, J.; Friedman, G.; Simon, T.W.
1992-03-01
Results of a fluid mechanics measurement program is oscillating flow within a circular duct are present. The program began with a survey of transition behavior over a range of oscillation frequency and magnitude and continued with a detailed study at a single operating point. Such measurements were made in support of Stirling engine development. Values of three dimensionless parameters, Re{sub max}, Re{sub W}, and A{sub R}, embody the velocity amplitude, frequency of oscillation and mean fluid displacement of the cycle, respectively. Measurements were first made over a range of these parameters which included operating points of all Stirling engines. Next, a case was studied with values of these parameters that are representative of the heat exchanger tubes in the heater section of NASA`s Stirling cycle Space Power Research Engine (SPRE). Measurements were taken of the axial and radical components of ensemble-averaged velocity and rms-velocity fluctuation and the dominant Reynolds shear stress, at various radial positions for each of four axial stations. In each run, transition from laminar to turbulent flow, and in reverse, were identified and sufficient data was gathered to propose the transition mechanism. Models of laminar and turbulent boundary layers were used to process the data into wall coordinates and to evaluate skin friction coefficients. Such data aids in validating computational models and is useful in comparing oscillatory flow characteristics to those of fully-developed steady flow. Data were taken with a contoured entry to each end of the test section and with flush square inlets so that the effects of test section inlet geometry on transition and turbulence are documented. The following is presented in two-volumes. Volume I contains the text of the report including figures and supporting appendices. Volume II contains data reduction program listings and tabulated data (including its graphical presentation).
Fluid flow structure around the mixer in a reactor with mechanical mixing
Lecheva, A.; Zheleva, I.
2015-10-28
Fluid flow structure around the mixer in a cylindrical reactor with mechanical mixing is studied and numerical results are presented in this article. The model area is complex because of the presence of convex corners of the mixer in the fluid flow. Proper boundary conditions for the vorticity calculated on the base of the stream function values near solid boundaries of the examined area are presented. The boundary value problem of motion of swirling incompressible viscous fluid in a vertical tank reactor with a mixer is solved numerically. The calculations are made by a computer code, written in MATLAB. The complex structure of the flow around the mixing disk is described and commented.
Flow regimes for fluid injection into a confined porous medium
Zheng, Zhong; Guo, Bo; Christov, Ivan C.; Celia, Michael A.; Stone, Howard A.
2015-02-24
We report theoretical and numerical studies of the flow behaviour when a fluid is injected into a confined porous medium saturated with another fluid of different density and viscosity. For a two-dimensional configuration with point source injection, a nonlinear convectiondiffusion equation is derived to describe the time evolution of the fluidfluid interface. In the early time period, the fluid motion is mainly driven by the buoyancy force and the governing equation is reduced to a nonlinear diffusion equation with a well-known self-similar solution. In the late time period, the fluid flow is mainly driven by the injection, and the governing equation is approximated by a nonlinear hyperbolic equation that determines the global spreading rate; a shock solution is obtained when the injected fluid is more viscous than the displaced fluid, whereas a rarefaction wave solution is found when the injected fluid is less viscous. In the late time period, we also obtain analytical solutions including the diffusive term associated with the buoyancy effects (for an injected fluid with a viscosity higher than or equal to that of the displaced fluid), which provide the structure of the moving front. Numerical simulations of the convectiondiffusion equation are performed; the various analytical solutions are verified as appropriate asymptotic limits, and the transition processes between the individual limits are demonstrated.
Collapsible sheath fluid reservoirs for flow cytometers
Mark, Graham A. (Los Alamos, NM)
2000-01-01
The present invention is a container in the form of a single housing for holding fluid, including a first collapsible reservoir having a first valve. The first reservoir initially contains a volume of fluid. The container also includes a second reservoir, initially empty (or substantially empty), expandable to a second volume. The second reservoir has a second valve. As the volume of said first reservoir decreases, the volume of the second reservoir proportionally increases.
Fracture Network and Fluid Flow Imaging for EGS Applications from
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Multi-Dimensional Electrical Resistivity Structure | Department of Energy Network and Fluid Flow Imaging for EGS Applications from Multi-Dimensional Electrical Resistivity Structure Fracture Network and Fluid Flow Imaging for EGS Applications from Multi-Dimensional Electrical Resistivity Structure Project objectives: Develop a 3-D code for simulating EM responses at the surface of the earth with topographic variations. To start; two platform choices will be pursued to determine the superior
Flow regimes for fluid injection into a confined porous medium
Zheng, Zhong; Guo, Bo; Christov, Ivan C.; Celia, Michael A.; Stone, Howard A.
2015-02-24
We report theoretical and numerical studies of the flow behaviour when a fluid is injected into a confined porous medium saturated with another fluid of different density and viscosity. For a two-dimensional configuration with point source injection, a nonlinear convection–diffusion equation is derived to describe the time evolution of the fluid–fluid interface. In the early time period, the fluid motion is mainly driven by the buoyancy force and the governing equation is reduced to a nonlinear diffusion equation with a well-known self-similar solution. In the late time period, the fluid flow is mainly driven by the injection, and the governing equation is approximated by a nonlinear hyperbolic equation that determines the global spreading rate; a shock solution is obtained when the injected fluid is more viscous than the displaced fluid, whereas a rarefaction wave solution is found when the injected fluid is less viscous. In the late time period, we also obtain analytical solutions including the diffusive term associated with the buoyancy effects (for an injected fluid with a viscosity higher than or equal to that of the displaced fluid), which provide the structure of the moving front. Numerical simulations of the convection–diffusion equation are performed; the various analytical solutions are verified as appropriate asymptotic limits, and the transition processes between the individual limits are demonstrated.
Flow regimes for fluid injection into a confined porous medium
Zheng, Zhong; Guo, Bo; Christov, Ivan C.; Celia, Michael A.; Stone, Howard A.
2015-02-24
We report theoretical and numerical studies of the flow behaviour when a fluid is injected into a confined porous medium saturated with another fluid of different density and viscosity. For a two-dimensional configuration with point source injection, a nonlinear convection–diffusion equation is derived to describe the time evolution of the fluid–fluid interface. In the early time period, the fluid motion is mainly driven by the buoyancy force and the governing equation is reduced to a nonlinear diffusion equation with a well-known self-similar solution. In the late time period, the fluid flow is mainly driven by the injection, and the governingmore » equation is approximated by a nonlinear hyperbolic equation that determines the global spreading rate; a shock solution is obtained when the injected fluid is more viscous than the displaced fluid, whereas a rarefaction wave solution is found when the injected fluid is less viscous. In the late time period, we also obtain analytical solutions including the diffusive term associated with the buoyancy effects (for an injected fluid with a viscosity higher than or equal to that of the displaced fluid), which provide the structure of the moving front. Numerical simulations of the convection–diffusion equation are performed; the various analytical solutions are verified as appropriate asymptotic limits, and the transition processes between the individual limits are demonstrated.« less
System and method measuring fluid flow in a conduit
Ortiz, M.G.; Kidd, T.G.
1999-05-18
A system is described for measuring fluid mass flow in a conduit in which there exists a pressure differential in the fluid between at least two spaced-apart locations in the conduit. The system includes a first pressure transducer disposed in the side of the conduit at a first location for measuring pressure of fluid at that location, a second or more pressure transducers disposed in the side of the conduit at a second location, for making multiple measurements of pressure of fluid in the conduit at that location, and a computer for computing the average pressure of the multiple measurements at the second location and for computing flow rate of fluid in the conduit from the pressure measurement by the first pressure transducer and from the average pressure calculation of the multiple measurements. 3 figs.
System and method measuring fluid flow in a conduit
Ortiz, Marcos German; Kidd, Terrel G.
1999-01-01
A system for measuring fluid mass flow in a conduit in which there exists a pressure differential in the fluid between at least two spaced-apart locations in the conduit. The system includes a first pressure transducer disposed in the side of the conduit at a first location for measuring pressure of fluid at that location, a second or more pressure transducers disposed in the side of the conduit at a second location, for making multiple measurements of pressure of fluid in the conduit at that location, and a computer for computing the average pressure of the multiple measurements at the second location and for computing flow rate of fluid in the conduit from the pressure measurement by the first pressure transducer and from the average pressure calculation of the multiple measurements.
Signatures in flowing fluid electric conductivity logs (Journal...
Office of Scientific and Technical Information (OSTI)
including analysis of natural regional flowin the permeable layer. A numerical model simulates flow and transport inthe wellbore during flowing FEC logging, and fracture ...
Modeling shrouded stator cavity flows in axial-flow compressors
Wellborn, S.R.; Tolchinsky, I.; Okiishi, T.H.
2000-01-01
Experiments and computational analyses were completed to understand the nature of shrouded stator cavity flows. From this understanding, a one-dimensional model of the flow through shrouded stator cavities was developed. This model estimates the leakage mass flow, temperature rise, and angular momentum increase through the cavity, given geometry parameters and the flow conditions at the interface between the cavity and primary flow path. This cavity model consists of two components, one that estimates the flow characteristics through the labyrinth seals and the other that predicts the transfer of momentum due to windage. A description of the one-dimensional model is given. The incorporation and use of the one-dimensional model in a multistage compressor primary flow analysis tool is described. The combination of this model and the primary flow solver was used to reliably simulate the significant impact on performance of the increase of hub seal leakage in a twelve-stage axial-flow compressor. Observed higher temperatures of the hub region fluid, different stage matching, and lower overall efficiencies and core flow than expected could be correctly linked to increased hub seal clearance with this new technique. The importance of including these leakage flows in compressor simulations is shown.
Method, apparatus and system for controlling fluid flow
McMurtrey, Ryan D.; Ginosar, Daniel M.; Burch, Joesph V.
2007-10-30
A system, apparatus and method of controlling the flow of a fluid are provided. In accordance with one embodiment of the present invention, a flow control device includes a valve having a flow path defined therethrough and a valve seat in communication with the flow path with a valve stem disposed in the valve seat. The valve stem and valve seat are cooperatively configured to cause mutual relative linear displacement thereof in response to rotation of the valve stem. A gear member is coupled with the rotary stem and a linear positioning member includes a portion which complementarily engages the gear member. Upon displacement of the linear positioning member along a first axis, the gear member and rotary valve stem are rotated about a second axis and the valve stem and valve seat are mutually linearly displaced to alter the flow of fluid through the valve.
Computerized tomographic analysis of fluid flow in fractured tuff
Felice, C.W.; Sharer, J.C.; Springer, E.P.
1992-05-01
The purpose of this summary is to demonstrate the usefulness of X-ray computerized tomography to observe fluid flow down a fracture and rock matrix imbibition in a sample of Bandelier tuff. This was accomplished by using a tuff sample 152.4 mm long and 50.8 mm in diameter. A longitudinal fracture was created by cutting the core with a wire saw. The fractured piece was then coupled to its adjacent section to that the fracture was not expected. Water was injected into a dry sample at five flow rates and CT scanning performed at set intervals during the flow. Cross sectional images and longitudinal reconstructions were built and saturation profiles calculated for the sample at each time interval at each flow rate. The results showed that for the test conditions, the fracture was not a primary pathway of fluid flow down the sample. At a slow fluid injection rate into the dry sample, the fluid was imbibed into the rock uniformly down the length of the core. With increasing injection rates, the flow remained uniform over the core cross section through complete saturation.
Computerized tomographic analysis of fluid flow in fractured tuff
Felice, C.W.; Sharer, J.C. ); Springer, E.P. )
1992-01-01
The purpose of this summary is to demonstrate the usefulness of X-ray computerized tomography to observe fluid flow down a fracture and rock matrix imbibition in a sample of Bandelier tuff. This was accomplished by using a tuff sample 152.4 mm long and 50.8 mm in diameter. A longitudinal fracture was created by cutting the core with a wire saw. The fractured piece was then coupled to its adjacent section to that the fracture was not expected. Water was injected into a dry sample at five flow rates and CT scanning performed at set intervals during the flow. Cross sectional images and longitudinal reconstructions were built and saturation profiles calculated for the sample at each time interval at each flow rate. The results showed that for the test conditions, the fracture was not a primary pathway of fluid flow down the sample. At a slow fluid injection rate into the dry sample, the fluid was imbibed into the rock uniformly down the length of the core. With increasing injection rates, the flow remained uniform over the core cross section through complete saturation.
Solution Algorithms for Effective-Field Models of Multi-Fluid...
Office of Scientific and Technical Information (OSTI)
Citation Details In-Document Search Title: Solution Algorithms for Effective-Field Models of Multi-Fluid Flows Authors: Robert Nourgaliev ; Mark Christon Publication Date: ...
Apparatus for controlling fluid flow in a conduit wall
Glass, S. Jill; Nicolaysen, Scott D.; Beauchamp, Edwin K.
2003-05-13
A frangible rupture disk and mounting apparatus for use in blocking fluid flow, generally in a fluid conducting conduit such as a well casing, a well tubing string or other conduits within subterranean boreholes. The disk can also be utilized in above-surface pipes or tanks where temporary and controllable fluid blockage is required. The frangible rupture disk is made from a pre-stressed glass with controllable rupture properties wherein the strength distribution has a standard deviation less than approximately 5% from the mean strength. The frangible rupture disk has controllable operating pressures and rupture pressures.
L3:MPO.CRUD.P8.02 Two-Phase Fluid Flow
U.S. Department of Energy (DOE) all webpages (Extended Search)
CRUD.P8.02 Two-Phase Fluid Flow Modeling in CRUD using MAMBA-BDM Miaomiao Jina and Michael Short Massachusetts Institute of Technology February 17, 2014 CASL-U-2014-0143-000 Two-Phase Fluid Flow Modeling in CRUD using MAMBA-BDM Miaomiao Jin a , Prof. Michael Short a,∗ a Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 Abstract CRUD is a CASL challenge problem with a significant component in the Materials Performance and Optimization (MPO) focus area. CRUD
Noninvasive characterization of a flowing multiphase fluid using ultrasonic interferometry
Sinha, Dipen N.
2007-06-12
An apparatus for noninvasively monitoring the flow and/or the composition of a flowing liquid using ultrasound is described. The position of the resonance peaks for a fluid excited by a swept-frequency ultrasonic signal have been found to change frequency both in response to a change in composition and in response to a change in the flow velocity thereof. Additionally, the distance between successive resonance peaks does not change as a function of flow, but rather in response to a change in composition. Thus, a measurement of both parameters (resonance position and resonance spacing), once calibrated, permits the simultaneous determination of flow rate and composition using the apparatus and method of the present invention.
Noninvasive characterization of a flowing multiphase fluid using ultrasonic interferometry
Sinha, Dipen N.
2003-11-11
An apparatus for noninvasively monitoring the flow and/or the composition of a flowing liquid using ultrasound is described. The position of the resonance peaks for a fluid excited by a swept-frequency ultrasonic signal have been found to change frequency both in response to a change in composition and in response to a change in the flow velocity thereof. Additionally, the distance between successive resonance peaks does not change as a function of flow, but rather in response to a change in composition. Thus, a measurement of both parameters (resonance position and resonance spacing), once calibrated, permits the simultaneous determination of flow rate and composition using the apparatus and method of the present invention.
Noninvasive Characterization Of A Flowing Multiphase Fluid Using Ultrasonic Interferometry
Sinha, Dipen N.
2005-05-10
An apparatus for noninvasively monitoring the flow and/or the composition of a flowing liquid using ultrasound is described. The position of the resonance peaks for a fluid excited by a swept-frequency ultrasonic signal have been found to change frequency both in response to a change in composition and in response to a change in the flow velocity thereof. Additionally, the distance between successive resonance peaks does not change as a function of flow, but rather in response to a change in composition. Thus, a measurement of both parameters (resonance position and resonance spacing), once calibrated, permits the simultaneous determination of flow rate and composition using the apparatus and method of the present invention.
Fully Coupled Well Models for Fluid Injection and Production
White, Mark D.; Bacon, Diana H.; White, Signe K.; Zhang, Z. F.
2013-08-05
Wells are the primary engineered component of geologic sequestration systems with deep subsurface reservoirs. Wells provide a conduit for injecting greenhouse gases and producing reservoirs fluids, such as brines, natural gas, and crude oil, depending on the target reservoir. Well trajectories, well pressures, and fluid flow rates are parameters over which well engineers and operators have control during the geologic sequestration process. Current drilling practices provided well engineers flexibility in designing well trajectories and controlling screened intervals. Injection pressures and fluids can be used to purposely fracture the reservoir formation or to purposely prevent fracturing. Numerical simulation of geologic sequestration processes involves the solution of multifluid transport equations within heterogeneous geologic media. These equations that mathematically describe the flow of fluid through the reservoir formation are nonlinear in form, requiring linearization techniques to resolve. In actual geologic settings fluid exchange between a well and reservoir is a function of local pressure gradients, fluid saturations, and formation characteristics. In numerical simulators fluid exchange between a well and reservoir can be specified using a spectrum of approaches that vary from totally ignoring the reservoir conditions to fully considering reservoir conditions and well processes. Well models are a numerical simulation approach that account for local conditions and gradients in the exchange of fluids between the well and reservoir. As with the mathematical equations that describe fluid flow in the reservoir, variation in fluid properties with temperature and pressure yield nonlinearities in the mathematical equations that describe fluid flow within the well. To numerically simulate the fluid exchange between a well and reservoir the two systems of nonlinear multifluid flow equations must be resolved. The spectrum of numerical approaches for resolving
Michael R. Gross; Kajari Ghosh; Alex K. Manda; Sumanjit Aich
2006-05-08
The theory behind how chemically reactive tracers are used to characterize the velocity and temperature distribution in steady flowing systems is reviewed. Kinetic parameters are established as a function of reservoir temperatures and fluid residence times for selecting appropriate reacting systems. Reactive tracer techniques are applied to characterize the temperature distribution in a laminar-flow heat exchanger. Models are developed to predict reactive tracer behavior in fractured geothermal reservoirs of fixed and increasing size.
Device and method for measuring multi-phase fluid flow in a conduit using an elbow flow meter
Ortiz, M.G.; Boucher, T.J.
1997-06-24
A system is described for measuring fluid flow in a conduit. The system utilizes pressure transducers disposed generally in line upstream and downstream of the flow of fluid in a bend in the conduit. Data from the pressure transducers is transmitted to a microprocessor or computer. The pressure differential measured by the pressure transducers is then used to calculate the fluid flow rate in the conduit. Control signals may then be generated by the microprocessor or computer to control flow, total fluid dispersed, (in, for example, an irrigation system), area of dispersal or other desired effect based on the fluid flow in the conduit. 2 figs.
Device and method for measuring multi-phase fluid flow in a conduit using an elbow flow meter
Ortiz, Marcos G.; Boucher, Timothy J.
1997-01-01
A system for measuring fluid flow in a conduit. The system utilizes pressure transducers disposed generally in line upstream and downstream of the flow of fluid in a bend in the conduit. Data from the pressure transducers is transmitted to a microprocessor or computer. The pressure differential measured by the pressure transducers is then used to calculate the fluid flow rate in the conduit. Control signals may then be generated by the microprocessor or computer to control flow, total fluid dispersed, (in, for example, an irrigation system), area of dispersal or other desired effect based on the fluid flow in the conduit.
Highly simplified lateral flow-based nucleic acid sample preparation and passive fluid flow control
Cary, Robert E.
2015-12-08
Highly simplified lateral flow chromatographic nucleic acid sample preparation methods, devices, and integrated systems are provided for the efficient concentration of trace samples and the removal of nucleic acid amplification inhibitors. Methods for capturing and reducing inhibitors of nucleic acid amplification reactions, such as humic acid, using polyvinylpyrrolidone treated elements of the lateral flow device are also provided. Further provided are passive fluid control methods and systems for use in lateral flow assays.
Jong Chull Jo; Myung Jo Jhung; Woong Sik Kim; Hho Jung Kim
2004-07-01
This study investigates the fluid-elastic instability characteristics of steam generator helical type tubes in operating nuclear power plants. The thermal-hydraulic conditions of both tube side and shell side flow fields are predicted by a general purpose computational fluid dynamics code employing the finite volume element modeling. To get the natural frequency, corresponding mode shape and participation factor, modal analyses are performed for helical type tubes with various conditions. Investigated are the effects of the helix angle, the number of supports and the status of the inner fluid on the modal, and fluid-elastic instability characteristics of the tubes, which are expressed in terms of the natural frequency, corresponding mode shape, and stability ratio. (authors)
Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda
Pyrak-Nolte, Laura J; DePaolo, Donald J.; Pietraß, Tanja
2015-05-22
. In response, the Office of Science, through its Office of Basic Energy Science (BES), convened a roundtable consisting of 15 national lab, university and industry geoscience experts to brainstorm basic research areas that underpin the SubTER goals but are currently underrepresented in the BES research portfolio. Held in Germantown, Maryland on May 22, 2015, the round-table participants developed a basic research agenda that is detailed in this report. Highlights include the following: -A grand challenge calling for advanced imaging of stress and geological processes to help understand how stresses and chemical substances are distributed in the subsurface—knowledge that is critical to all aspects of subsurface engineering; -A priority research direction aimed at achieving control of fluid flow through fractured media; -A priority research direction aimed at better understanding how mechanical and geochemical perturbations to subsurface rock systems are coupled through fluid and mineral interactions; -A priority research direction aimed at studying the structure, permeability, reactivity and other properties of nanoporous rocks, like shale, which have become critical energy materials and exhibit important hallmarks of mesoscale materials; -A cross-cutting theme that would accelerate development of advanced computational methods to describe heterogeneous time-dependent geologic systems that could, among other potential benefits, provide new and vastly improved models of hydraulic fracturing and its environmental impacts; -A cross-cutting theme that would lead to the creation of “geo-architected materials” with controlled repeatable heterogeneity and structure that can be tested under a variety of thermal, hydraulic, chemical and mechanical conditions relevant to subsurface systems; -A cross-cutting theme calling for new laboratory studies on both natural and geo-architected subsurface materials that deploy advanced high-resolution 3D imaging and chemical analysis
Tracking interface and common curve dynamics for two-fluid flow in porous media
Mcclure, James E.; Miller, Cass T.; Gray, W. G.; Berrill, Mark A.
2016-04-29
Pore-scale studies of multiphase flow in porous medium systems can be used to understand transport mechanisms and quantitatively determine closure relations that better incorporate microscale physics into macroscale models. Multiphase flow simulators constructed using the lattice Boltzmann method provide a means to conduct such studies, including both the equilibrium and dynamic aspects. Moving, storing, and analyzing the large state space presents a computational challenge when highly-resolved models are applied. We present an approach to simulate multiphase flow processes in which in-situ analysis is applied to track multiphase flow dynamics at high temporal resolution. We compute a comprehensive set of measuresmore » of the phase distributions and the system dynamics, which can be used to aid fundamental understanding and inform closure relations for macroscale models. The measures computed include microscale point representations and macroscale averages of fluid saturations, the pressure and velocity of the fluid phases, interfacial areas, interfacial curvatures, interface and common curve velocities, interfacial orientation tensors, phase velocities and the contact angle between the fluid-fluid interface and the solid surface. Test cases are studied to validate the approach and illustrate how measures of system state can be obtained and used to inform macroscopic theory.« less
A compendium of fracture flow models, 1994
Diodato, D.M.
1994-11-01
The report is designed to be used as a decision-making aid for individuals who need to simulate fluid flow in fractured porous media. Fracture flow codes of varying capability in the public and private domain were identified in a survey of government, academia, and industry. The selection and use of an appropriate code requires conceptualization of the geology, physics, and chemistry (for transport) of the fracture flow problem to be solved. Conceptual models that have been invoked to describe fluid flow in fractured porous media include explicit discrete fracture, dual continuum (porosity and/or permeability), discrete fracture network, multiple interacting continua, multipermeability/multiporosity, and single equivalent continuum. The explicit discrete-fracture model is a ``near-field`` representation, the single equivalent continuum model is a ``far-field`` representation, and the dual-continuum model is intermediate to those end members. Of these, the dual-continuum model is the most widely employed. The concept of multiple interacting continua has been applied in a limited number of examples. Multipermeability/multiporosity provides a unified conceptual model. The ability to accurately describe fracture flow phenomena will continue to improve as a result of advances in fracture flow research and computing technology. This improvement will result in enhanced capability to protect the public environment, safety, and health.
DYNAMIC MODELING STRATEGY FOR FLOW REGIME TRANSITION IN GAS-LIQUID TWO-PHASE FLOWS
X. Wang; X. Sun; H. Zhao
2011-09-01
In modeling gas-liquid two-phase flows, the concept of flow regime has been used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are often flow regime dependent. Currently, the determination of the flow regimes is primarily based on flow regime maps or transition criteria, which are developed for steady-state, fully-developed flows and widely applied in nuclear reactor system safety analysis codes, such as RELAP5. As two-phase flows are observed to be dynamic in nature (fully-developed two-phase flows generally do not exist in real applications), it is of importance to model the flow regime transition dynamically for more accurate predictions of two-phase flows. The present work aims to develop a dynamic modeling strategy for determining flow regimes in gas-liquid two-phase flows through the introduction of interfacial area transport equations (IATEs) within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation and destruction of the interfacial area, such as the fluid particle (bubble or liquid droplet) disintegration, boiling and evaporation; and fluid particle coalescence and condensation, respectively. For the flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shape (which are correlated), namely small bubbles and large bubbles. A preliminary approach to dynamically identifying the flow regimes is provided, in which discriminators are based on the predicted information, such as the void fraction and interfacial area concentration of small bubble and large bubble groups. This method is expected to be applied to computer codes to improve their predictive capabilities of gas-liquid two-phase flows, in particular for the applications in
Crandall, Dustin; Bromhal, Grant; Karpyn, Zuleima T.
2010-07-01
Understanding how fracture wall-roughness affects fluid flow is important when modeling many subsurface transport problems. Computed tomography scanning provides a unique view of rock fractures, allowing the measurement of fracture wall-roughness, without destroying the initial rock sample. For this computational fluid dynamics study, we used several different methods to obtain three-dimensional meshes of a computed tomography scanned fracture in Berea sandstone. These volumetric meshes had different wall-roughnesses, which we characterized using the Joint Roughness Coefficient and the fractal dimension of the fracture profiles. We then related these macroscopic roughness parameters to the effective flow through the fractures, as determined from Navier-Stokes numerical models. Thus, we used our fracture meshes to develop relationships between the observed roughness properties of the fracture geometries and flow parameters that are of importance for modeling flow through fractures in field scale models. Fractures with high Joint Roughness Coefficients and fractal dimensions were shown to exhibit tortuous flow paths, be poorly characterized by the mean geometric aperture, and have a fracture transmissivity 35 times smaller than the smoother modeled fracture flows.
Schroth, Martin H.; Oostrom, Mart; Dobson, Richard; Zeyer, Josef
2008-08-01
Fluid/fluid interfacial areas are important in controlling the rate of mass and energy transfer between fluid phases in porous media. We present a modified thermodynamically based model (TBM) to predict fluid/fluid interfacial areas in porous media for arbitrary drainage/imbibition sequences. The TBM explicitly distinguishes between interfacial areas associated with continuous (free) and isolated (entrapped) nonwetting fluids. The model is restricted to two-fluid systems in which (1) no significant conversion of mechanical work into heat occurs, (2) the wetting fluid completely wets the porous mediums solid surfaces, and (3) no changes in interfacial area due to mass transfer between phases occur. We show example calculations for two different drainage/imbibition sequences in two porous media: a highly uniform silica sand and a well-graded silt. The TBMs predictions for interfacial area associated with free nonwetting-fluid are identical to those of a previously published geometry-based model (GBM). However, predictions for interfacial area associated with entrapped nonwetting-fluid are consistently larger in the TBM than in the GBM. Although a comparison of model predictions with experimental data is currently only possible to a limited extent, good general agreement was found for the TBM. As required model parameters are commonly used as inputs for or tracked during multifluid-flow simulations, the modified TBM may be easily incorporated in numerical codes.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Nicole Lautze
2015-01-01
Groundwater flow model for the island of Oahu. Data is from the following sources: Rotzoll, K., A.I. El-Kadi. 2007. Numerical Ground-Water Flow Simulation for Red Hill Fuel Storage Facilities, NAVFAC Pacific, Oahu, Hawaii - Prepared TEC, Inc. Water Resources Research Center, University of Hawaii, Honolulu.; Whittier, R.B., K. Rotzoll, S. Dhal, A.I. El-Kadi, C. Ray, G. Chen, and D. Chang. 2004. Hawaii Source Water Assessment Program Report – Volume VII – Island of Oahu Source Water Assessment Program Report. Prepared for the Hawaii Department of Health, Safe Drinking Water Branch. University of Hawaii, Water Resources Research Center. Updated 2008.; and Whittier, R. and A.I. El-Kadi. 2009. Human and Environmental Risk Ranking of Onsite Sewage Disposal Systems – Final. Prepared by the University of Hawaii, Dept. of Geology and Geophysics for the State of Hawaii Dept. of Health, Safe Drinking Water Branch. December 2009.
Computational Fluid Dynamics Modeling of Diesel Engine Combustion...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Computational Fluid Dynamics Modeling of Diesel Engine Combustion and Emissions Computational Fluid Dynamics Modeling of Diesel Engine Combustion and Emissions 2005 Diesel Engine ...
Reduced order modeling of fluid/structure interaction.
Barone, Matthew Franklin; Kalashnikova, Irina; Segalman, Daniel Joseph; Brake, Matthew Robert
2009-11-01
This report describes work performed from October 2007 through September 2009 under the Sandia Laboratory Directed Research and Development project titled 'Reduced Order Modeling of Fluid/Structure Interaction.' This project addresses fundamental aspects of techniques for construction of predictive Reduced Order Models (ROMs). A ROM is defined as a model, derived from a sequence of high-fidelity simulations, that preserves the essential physics and predictive capability of the original simulations but at a much lower computational cost. Techniques are developed for construction of provably stable linear Galerkin projection ROMs for compressible fluid flow, including a method for enforcing boundary conditions that preserves numerical stability. A convergence proof and error estimates are given for this class of ROM, and the method is demonstrated on a series of model problems. A reduced order method, based on the method of quadratic components, for solving the von Karman nonlinear plate equations is developed and tested. This method is applied to the problem of nonlinear limit cycle oscillations encountered when the plate interacts with an adjacent supersonic flow. A stability-preserving method for coupling the linear fluid ROM with the structural dynamics model for the elastic plate is constructed and tested. Methods for constructing efficient ROMs for nonlinear fluid equations are developed and tested on a one-dimensional convection-diffusion-reaction equation. These methods are combined with a symmetrization approach to construct a ROM technique for application to the compressible Navier-Stokes equations.
Dynamic Modeling Strategy for Flow Regime Transition in Gas-Liquid Two-Phase Flows
Xia Wang; Xiaodong Sun; Benjamin Doup; Haihua Zhao
2012-12-01
In modeling gas-liquid two-phase flows, the concept of flow regimes has been widely used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are flow regime dependent. Current nuclear reactor safety analysis codes, such as RELAP5, classify flow regimes using flow regime maps or transition criteria that were developed for steady-state, fully-developed flows. As twophase flows are dynamic in nature, it is important to model the flow regime transitions dynamically to more accurately predict the two-phase flows. The present work aims to develop a dynamic modeling strategy to determine flow regimes in gas-liquid two-phase flows through introduction of interfacial area transport equations (IATEs) within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation of the interfacial area, fluid particle (bubble or liquid droplet) disintegration, boiling and evaporation, and the destruction of the interfacial area, fluid particle coalescence and condensation. For flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shapes, namely group-1 and group-2 bubbles. A preliminary approach to dynamically identify the flow regimes is discussed, in which discriminator s are based on the predicted information, such as the void fraction and interfacial area concentration. The flow regime predicted with this method shows good agreement with the experimental observations.
General single phase wellbore flow model
Ouyang, Liang-Biao; Arbabi, S.; Aziz, K.
1997-02-05
A general wellbore flow model, which incorporates not only frictional, accelerational and gravitational pressure drops, but also the pressure drop caused by inflow, is presented in this report. The new wellbore model is readily applicable to any wellbore perforation patterns and well completions, and can be easily incorporated in reservoir simulators or analytical reservoir inflow models. Three dimensionless numbers, the accelerational to frictional pressure gradient ratio R{sub af}, the gravitational to frictional pressure gradient ratio R{sub gf}, and the inflow-directional to accelerational pressure gradient ratio R{sub da}, have been introduced to quantitatively describe the relative importance of different pressure gradient components. For fluid flow in a production well, it is expected that there may exist up to three different regions of the wellbore: the laminar flow region, the partially-developed turbulent flow region, and the fully-developed turbulent flow region. The laminar flow region is located near the well toe, the partially-turbulent flow region lies in the middle of the wellbore, while the fully-developed turbulent flow region is at the downstream end or the heel of the wellbore. Length of each region depends on fluid properties, wellbore geometry and flow rate. As the distance from the well toe increases, flow rate in the wellbore increases and the ratios R{sub af} and R{sub da} decrease. Consequently accelerational and inflow-directional pressure drops have the greatest impact in the toe region of the wellbore. Near the well heel the local wellbore flow rate becomes large and close to the total well production rate, here R{sub af} and R{sub da} are small, therefore, both the accelerational and inflow-directional pressure drops can be neglected.
Reducing or stopping the uncontrolled flow of fluid such as oil from a well
Hermes, Robert E
2014-02-18
The uncontrolled flow of fluid from an oil or gas well may be reduced or stopped by injecting a composition including 2-cyanoacrylate ester monomer into the fluid stream. Injection of the monomer results in a rapid, perhaps instantaneous, polymerization of the monomer within the flow stream of the fluid. This polymerization results in formation of a solid plug that reduces or stops the flow of additional fluid from the well.
Carter, K.E.; Dworkin, S.I. )
1990-08-01
Geochemical and petrographic studies of the Triassic Portoro limestone of the Tuscan nappe in Liguria, Italy, indicate that fluid flow was channeled through interlayered bedding-parallel shear zones during Miocene shearing and low-grade metamorphism. Carbon, oxygen, and strontium isotopic compositions and trace element concentrations in the Portoro indicate that it was precipitated from normal marine waters. In sheared and unsheared layers these isotopic compositions are indistinguishable, yet sheared layers of microspar contain less than half the amount of strontium preserved in undeformed layers. Wavy grain boundaries and a dimensional preferred orientation of elongated grains indicate that calcite within sheared zones was dynamically recrystallized. On the basis of these observations we suggest that during burial, extraformational fluids were buffered into oxygen isotopic, but not strontium-concentration, equilibrium with the Portoro. These syndeformational fluids were channeled through discrete 1- to 15-cm-thick shear zones in which strontium was expelled from calcite and incorporated into grain-boundary fluids during dynamic recrystallization.
Hydrostatic bearings for a turbine fluid flow metering device
Fincke, J.R.
1982-05-04
A rotor assembly fluid metering device has been improved by development of a hydrostatic bearing fluid system which provides bearing fluid at a common pressure to rotor assembly bearing surfaces. The bearing fluid distribution system produces a uniform film of fluid between bearing surfaces and allows rapid replacement of bearing fluid between bearing surfaces, thereby minimizing bearing wear and corrosion. 3 figs.
Hydrostatic bearings for a turbine fluid flow metering device
Fincke, James R.
1982-01-01
A rotor assembly fluid metering device has been improved by development of a hydrostatic bearing fluid system which provides bearing fluid at a common pressure to rotor assembly bearing surfaces. The bearing fluid distribution system produces a uniform film of fluid between bearing surfaces and allows rapid replacement of bearing fluid between bearing surfaces, thereby minimizing bearing wear and corrosion.
PArallel Reacting Multiphase FLOw Computational Fluid Dynamic Analysis
Energy Science and Technology Software Center (OSTI)
2002-06-01
PARMFLO is a parallel multiphase reacting flow computational fluid dynamics (CFD) code. It can perform steady or unsteady simulations in three space dimensions. It is intended for use in engineering CFD analysis of industrial flow system components. Its parallel processing capabilities allow it to be applied to problems that use at least an order of magnitude more computational cells than the number that can be used on a typical single processor workstation (about 106 cellsmore » in parallel processing mode versus about io cells in serial processing mode). Alternately, by spreading the work of a CFD problem that could be run on a single workstation over a group of computers on a network, it can bring the runtime down by an order of magnitude or more (typically from many days to less than one day). The software was implemented using the industry standard Message-Passing Interface (MPI) and domain decomposition in one spatial direction. The phases of a flow problem may include an ideal gas mixture with an arbitrary number of chemical species, and dispersed droplet and particle phases. Regions of porous media may also be included within the domain. The porous media may be packed beds, foams, or monolith catalyst supports. With these features, the code is especially suited to analysis of mixing of reactants in the inlet chamber of catalytic reactors coupled to computation of product yields that result from the flow of the mixture through the catalyst coaled support structure.« less
A review of interaction mechanisms in fluid-solid flows
Johnson, G.; Rajagopal, K.R. . Dept. of Mechanical Engineering); Massoudi, M. )
1990-09-01
Multiphase flows have become the subject of considerable attention because of their importance in many industrial applications, such as fluidized beds, pneumatic transport of solids, coal combustion, etc. Fundamental research into the nature of pneumatic transport has made significant progress in identifying key parameters controlling the characteristics of these processes. The emphasis of this study is on a mixture composed of spherical particles of uniform size and a linearly viscous fluid. Section 1 introduces our approach and the importance of this study. In Section 2, the dynamics of a single particle as studied in classical hydrodynamics and fluid dynamics is presented. This has been a subject of study for more than 200 years. In Section 3, we review the literature for the constitutive relations as given in multiphase studies, i.e., generalization of single particle and as given in literature concerning the continuum theories of mixtures or multicomponent systems. In Section 4, a comparison between these representations and the earlier approach, i.e., forces acting on a single particle will be made. The importance of flow regimes, particle concentration, particle size and shape, rotation of the particle, effect of solid walls, etc. are discussed. 141 refs.
Production of Natural Gas and Fluid Flow in Tight Sand Reservoirs
Maria Cecilia Bravo
2006-06-30
This document reports progress of this research effort in identifying relationships and defining dependencies between macroscopic reservoir parameters strongly affected by microscopic flow dynamics and production well performance in tight gas sand reservoirs. These dependencies are investigated by identifying the main transport mechanisms at the pore scale that should affect fluids flow at the reservoir scale. A critical review of commercial reservoir simulators, used to predict tight sand gas reservoir, revealed that many are poor when used to model fluid flow through tight reservoirs. Conventional simulators ignore altogether or model incorrectly certain phenomena such as, Knudsen diffusion, electro-kinetic effects, ordinary diffusion mechanisms and water vaporization. We studied the effect of Knudsen's number in Klinkenberg's equation and evaluated the effect of different flow regimes on Klinkenberg's parameter b. We developed a model capable of explaining the pressure dependence of this parameter that has been experimentally observed, but not explained in the conventional formalisms. We demonstrated the relevance of this, so far ignored effect, in tight sands reservoir modeling. A 2-D numerical simulator based on equations that capture the above mentioned phenomena was developed. Dynamic implications of new equations are comprehensively discussed in our work and their relative contribution to the flow rate is evaluated. We performed several simulation sensitivity studies that evidenced that, in general terms, our formalism should be implemented in order to get more reliable tight sands gas reservoirs' predictions.
Y. Wu
2004-11-01
The purpose of this report is to document the unsaturated zone (UZ) flow models and submodels, as well as the flow fields that have been generated using the UZ flow model(s) of Yucca Mountain, Nevada. In this report, the term ''UZ model'' refers to the UZ flow model and the several submodels, which include tracer transport, temperature or ambient geothermal, pneumatic or gas flow, and geochemistry (chloride, calcite, and strontium) submodels. The term UZ flow model refers to the three-dimensional models used for calibration and simulation of UZ flow fields. This work was planned in the ''Technical Work Plan (TWP) for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Section 1.2.7). The table of included Features, Events, and Processes (FEPs), Table 6.2-11, is different from the list of included FEPs assigned to this report in the ''Technical Work Plan for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Table 2.1.5-1), as discussed in Section 6.2.6. The UZ model has revised, updated, and enhanced the previous UZ model (BSC 2001 [DIRS 158726]) by incorporating the repository design with new grids, recalibration of property sets, and more comprehensive validation effort. The flow fields describe fracture-fracture, matrix-matrix, and fracture-matrix liquid flow rates, and their spatial distributions as well as moisture conditions in the UZ system. These three-dimensional UZ flow fields are used directly by Total System Performance Assessment (TSPA). The model and submodels evaluate important hydrogeologic processes in the UZ as well as geochemistry and geothermal conditions. These provide the necessary framework to test hypotheses of flow and transport at different scales, and predict flow and transport behavior under a variety of climatic conditions. In addition, the limitations of the UZ model are discussed in Section 8.11.
Hydrostatic bearings for a turbine fluid flow metering device
Fincke, J.R.
1980-05-02
A rotor assembly fluid metering device has been improved by development of a hydrostatic bearing fluid system which provides bearing fluid at a common pressure to rotor assembly bearing surfaces. The bearing fluid distribution system produces a uniform film of fluid distribution system produces a uniform film of fluid between bearing surfaces and allows rapid replacement of bearing fluid between bearing surfaces, thereby minimizing bearing wear and corrosion.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Nicole Lautze
2015-01-01
Groundwater flow model for Kauai. Data is from the following sources: Whittier, R. and A.I. El-Kadi. 2014. Human and Environmental Risk Ranking of Onsite Sewage Disposal Systems For the Hawaiian Islands of Kauai, Molokai, Maui, and Hawaii – Final. Prepared by the University of Hawaii, Dept. of Geology and Geophysics for the State of Hawaii Dept. of Health, Safe Drinking Water Branch. September 2014.; and Whittier, R.B., K. Rotzoll, S. Dhal, A.I. El-Kadi, C. Ray, G. Chen, and D. Chang. 2004. Hawaii Source Water Assessment Program Report – Volume IV – Island of Kauai Source Water Assessment Program Report. Prepared for the Hawaii Department of Health, Safe Drinking Water Branch. University of Hawaii, Water Resources Research Center. Updated 2015.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Nicole Lautze
2015-01-01
Groundwater flow model for Kauai. Data is from the following sources: Whittier, R. and A.I. El-Kadi. 2014. Human and Environmental Risk Ranking of Onsite Sewage Disposal Systems For the Hawaiian Islands of Kauai, Molokai, Maui, and Hawaii Final. Prepared by the University of Hawaii, Dept. of Geology and Geophysics for the State of Hawaii Dept. of Health, Safe Drinking Water Branch. September 2014.; and Whittier, R.B., K. Rotzoll, S. Dhal, A.I. El-Kadi, C. Ray, G. Chen, and D. Chang. 2004. Hawaii Source Water Assessment Program Report Volume IV Island of Kauai Source Water Assessment Program Report. Prepared for the Hawaii Department of Health, Safe Drinking Water Branch. University of Hawaii, Water Resources Research Center. Updated 2015.
Aoki, Shigehisa; Ikeda, Satoshi; Takezawa, Toshiaki; Kishi, Tomoya; Makino, Junichi; Uchihashi, Kazuyoshi; Matsunobu, Aki; Noguchi, Mitsuru; Sugihara, Hajime; Toda, Shuji
2011-12-16
Highlights: Black-Right-Pointing-Pointer Late-onset peritoneal fibrosis leading to EPS remains to be elucidated. Black-Right-Pointing-Pointer Fluid streaming is a potent factor for peritoneal fibrosis in PD. Black-Right-Pointing-Pointer We focused on the prolonged effect of fluid streaming on mesothelial cell kinetics. Black-Right-Pointing-Pointer A history of fluid streaming exposure promoted mesothelial proliferative activity. Black-Right-Pointing-Pointer We have thus identified a potent new factor for late-onset peritoneal fibrosis. -- Abstract: Encapsulating peritoneal sclerosis (EPS) often develops after transfer to hemodialysis and transplantation. Both termination of peritoneal dialysis (PD) and transplantation-related factors are risks implicated in post-PD development of EPS, but the precise mechanism of this late-onset peritoneal fibrosis remains to be elucidated. We previously demonstrated that fluid flow stress induced mesothelial proliferation and epithelial-mesenchymal transition via mitogen-activated protein kinase (MAPK) signaling. Therefore, we speculated that the prolonged bioactive effect of fluid flow stress may affect mesothelial cell kinetics after cessation of fluid streaming. To investigate how long mesothelial cells stay under the bioactive effect brought on by fluid flow stress after removal of the stress, we initially cultured mesothelial cells under fluid flow stress and then cultured the cells under static conditions. Mesothelial cells exposed to fluid flow stress for a certain time showed significantly high proliferative activity compared with static conditions after stoppage of fluid streaming. The expression levels of protein phosphatase 2A, which dephosphorylates MAPK, in mesothelial cells changed with time and showed a biphasic pattern that was dependent on the duration of exposure to fluid flow stress. There were no differences in the fluid flow stress-related bioactive effects on mesothelial cells once a certain time had passed
TOUGH Simulations of the Updegraff's Set of Fluid and Heat Flow Problems
Moridis, G.J.; Pruess , K.
1992-11-01
The TOUGH code [Pruess, 1987] for two-phase flow of water, air, and heat in penneable media has been exercised on a suite of test problems originally selected and simulated by C. D. Updegraff [1989]. These include five 'verification' problems for which analytical or numerical solutions are available, and three 'validation' problems that model laboratory fluid and heat flow experiments. All problems could be run without any code modifications (*). Good and efficient numerical performance, as well as accurate results were obtained throughout. Additional code verification and validation problems from the literature are briefly summarized, and suggestions are given for proper applications of TOUGH and related codes.
On fluid flow in a heterogeneous medium under nonisothermal conditions
D.W., Vasco
2010-11-01
An asymptotic technique, valid in the presence of smoothly-varying heterogeneity, provides explicit expressions for the velocity of a propagating pressure and temperature disturbance. The governing equations contain nonlinear terms due to the presence of temperature-dependent coefficients and due to the advection of fluids with differing temperatures. Two cases give well-defined expressions in terms of the parameters of the porous medium: the uncoupled propagation of a pressure disturbance and the propagation of a fully coupled temperature and pressure disturbance. The velocity of the coupled disturbance or front, depends upon the medium parameters and upon the change in temperature and pressure across the front. For uncoupled flow, the semi-analytic expression for the front velocity reduces to that associated with a linear diffusion equation. A comparison of the asymptotic travel time estimates with calculations from a numerical simulator indicates reasonably good agreement for both uncoupled and coupled disturbances.
System and method for bidirectional flow and controlling fluid flow in a conduit
Ortiz, Marcos German
1999-01-01
A system for measuring bidirectional flow, including backflow, of fluid in a conduit. The system utilizes a structural mechanism to create a pressure differential in the conduit. Pressure sensors are positioned upstream from the mechanism, at the mechanism, and downstream from the mechanism. Data from the pressure sensors are transmitted to a microprocessor or computer, and pressure differential detected between the pressure sensors is then used to calculate the backflow. Control signals may then be generated by the microprocessor or computer to shut off valves located in the conduit, upon the occurrence of backflow, or to control flow, total material dispersed, etc. in the conduit.
System and method for bidirectional flow and controlling fluid flow in a conduit
Ortiz, M.G.
1999-03-23
A system for measuring bidirectional flow, including backflow, of fluid in a conduit is disclosed. The system utilizes a structural mechanism to create a pressure differential in the conduit. Pressure sensors are positioned upstream from the mechanism, at the mechanism, and downstream from the mechanism. Data from the pressure sensors are transmitted to a microprocessor or computer, and pressure differential detected between the pressure sensors is then used to calculate the backflow. Control signals may then be generated by the microprocessor or computer to shut off valves located in the conduit, upon the occurrence of backflow, or to control flow, total material dispersed, etc. in the conduit. 3 figs.
Application of Neutron Imaging and Scattering to Fluid Flow and Fracture in
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
EGS Environments | Department of Energy Application of Neutron Imaging and Scattering to Fluid Flow and Fracture in EGS Environments Application of Neutron Imaging and Scattering to Fluid Flow and Fracture in EGS Environments Application of Neutron Imaging and Scattering to Fluid Flow and Fracture in EGS Environments presentation at the April 2013 peer review meeting held in Denver, Colorado. neutrons_peer2013.pdf (1.51 MB) More Documents & Publications Development of a Geological and
de Stadler, M; Chand, K
2007-11-12
Gas centrifuges exhibit very complex flows. Within the centrifuge there is a rarefied region, a transition region, and a region with an extreme density gradient. The flow moves at hypersonic speeds and shock waves are present. However, the flow is subsonic in the axisymmetric plane. The analysis may be simplified by treating the flow as a perturbation of wheel flow. Wheel flow implies that the fluid is moving as a solid body. With the very large pressure gradient, the majority of the fluid is located very close to the rotor wall and moves at an azimuthal velocity proportional to its distance from the rotor wall; there is no slipping in the azimuthal plane. The fluid can be modeled as incompressible and subsonic in the axisymmetric plane. By treating the centrifuge as long, end effects can be appropriately modeled without performing a detailed boundary layer analysis. Onsager's pancake approximation is used to construct a simulation to model fluid flow in a gas centrifuge. The governing 6th order partial differential equation is broken down into an equivalent coupled system of three equations and then solved numerically. In addition to a discussion on the baseline solution, known problems and future work possibilities are presented.
Nearby-fluids equilibria. II. Zonal flows in a high-{beta}, self-organized plasma experiment
Steinhauer, L.C.; Guo, H.Y.
2006-05-15
The field and flow structure observed in a high-{beta} field reversed configuration (FRC) produced in the translation, confinement, and sustainment (TCS) experiment are modeled using the newly developed nearby-fluids equilibrium model. These results are the first evidence that experimental FRCs have complex flows, that is nonrigid rotational flow and poloidal flow, both with maximum speeds nearly half the Alfven speed. The interpretive approach is an innovative 'backwards' method using the nearby-fluids platform for two-fluid equilibria. The most remarkable outcome is the prediction of a poloidal flow structure with significant zonal features. The poloidal flow has never been directly measured in FRCs; thus this discovery results from applying the flowing equilibrium model as an interpretive tool. The poloidal flows explain the unusual toroidal field structure observed in TCS. Zonal features in the rotational flow are also inferred from the unfolding of chord-integrated measurements. The results also indicated that a broad core of the FRC is very close to a minimum energy state.
U.S. Department of Energy (DOE) all webpages (Extended Search)
scour-tracc-cfd TRACC RESEARCH Computational Fluid Dynamics Computational Structural Mechanics Transportation Systems Modeling Computational Fluid Dynamics Overview of CFD: Video Clip with Audio Computational fluid dynamics (CFD) research uses mathematical and computational models of flowing fluids to describe and predict fluid response in problems of interest, such as the flow of air around a moving vehicle or the flow of water and sediment in a river. Coupled with appropriate and prototypical
STRUCTURAL HETEROGENEITIES AND PALEO FLUID FLOW IN AN ANALOG SANDSTONE RESERVOIR 2001-2004
Pollard, David; Aydin, Atilla
2005-02-22
Fractures and faults are brittle structural heterogeneities that can act both as conduits and barriers with respect to fluid flow in rock. This range in the hydraulic effects of fractures and faults greatly complicates the challenges faced by geoscientists working on important problems: from groundwater aquifer and hydrocarbon reservoir management, to subsurface contaminant fate and transport, to underground nuclear waste isolation, to the subsurface sequestration of CO2 produced during fossil-fuel combustion. The research performed under DOE grant DE-FG03-94ER14462 aimed to address these challenges by laying a solid foundation, based on detailed geological mapping, laboratory experiments, and physical process modeling, on which to build our interpretive and predictive capabilities regarding the structure, patterns, and fluid flow properties of fractures and faults in sandstone reservoirs. The material in this final technical report focuses on the period of the investigation from July 1, 2001 to October 31, 2004. The Aztec Sandstone at the Valley of Fire, Nevada, provides an unusually rich natural laboratory in which exposures of joints, shear deformation bands, compaction bands and faults at scales ranging from centimeters to kilometers can be studied in an analog for sandstone aquifers and reservoirs. The suite of structures there has been documented and studied in detail using a combination of low-altitude aerial photography, outcrop-scale mapping and advanced computational analysis. In addition, chemical alteration patterns indicative of multiple paleo fluid flow events have been mapped at outcrop, local and regional scales. The Valley of Fire region has experienced multiple episodes of fluid flow and this is readily evident in the vibrant patterns of chemical alteration from which the Valley of Fire derives its name. We have successfully integrated detailed field and petrographic observation and analysis, process-based mechanical modeling, and numerical
Scaled Experimental Modeling of VHTR Plenum Flows
ICONE 15
2007-04-01
Abstract The Very High Temperature Reactor (VHTR) is the leading candidate for the Next Generation Nuclear Power (NGNP) Project in the U.S. which has the goal of demonstrating the production of emissions free electricity and hydrogen by 2015. Various scaled heated gas and water flow facilities were investigated for modeling VHTR upper and lower plenum flows during the decay heat portion of a pressurized conduction-cooldown scenario and for modeling thermal mixing and stratification (thermal striping) in the lower plenum during normal operation. It was concluded, based on phenomena scaling and instrumentation and other practical considerations, that a heated water flow scale model facility is preferable to a heated gas flow facility and to unheated facilities which use fluids with ranges of density to simulate the density effect of heating. For a heated water flow lower plenum model, both the Richardson numbers and Reynolds numbers may be approximately matched for conduction-cooldown natural circulation conditions. Thermal mixing during normal operation may be simulated but at lower, but still fully turbulent, Reynolds numbers than in the prototype. Natural circulation flows in the upper plenum may also be simulated in a separate heated water flow facility that uses the same plumbing as the lower plenum model. However, Reynolds number scaling distortions will occur at matching Richardson numbers due primarily to the necessity of using a reduced number of channels connected to the plenum than in the prototype (which has approximately 11,000 core channels connected to the upper plenum) in an otherwise geometrically scaled model. Experiments conducted in either or both facilities will meet the objectives of providing benchmark data for the validation of codes proposed for NGNP designs and safety studies, as well as providing a better understanding of the complex flow phenomena in the plenums.
DOE Fundamentals Handbook: Thermodynamics, Heat Transfer, and Fluid Flow, Volume 2
Not Available
1992-06-01
The Thermodynamics, Heat Transfer, and Fluid Flow Fundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of the thermal sciences. The handbook includes information on thermodynamics and the properties of fluids; the three modes of heat transfer -- conduction, convection, and radiation; and fluid flow, and the energy relationships in fluid systems. This information will provide personnel with a foundation for understanding the basic operation of various types of DOE nuclear facility fluid systems.
DOE Fundamentals Handbook: Thermodynamics, Heat Transfer, and Fluid Flow, Volume 1
Not Available
1992-06-01
The Thermodynamics, Heat Transfer, and Fluid Flow Fundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of the thermal sciences. The handbook includes information on thermodynamics and the properties of fluids; the three modes of heat transfer -- conduction, convection, and radiation; and fluid flow, and the energy relationships in fluid systems. This information will provide personnel with a foundation for understanding the basic operation of various types of DOE nuclear facility fluid systems.
DOE Fundamentals Handbook: Thermodynamics, Heat Transfer, and Fluid Flow, Volume 3
Not Available
1992-06-01
The Thermodynamics, Heat Transfer, and Fluid Flow Fundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of the thermal sciences. The handbook includes information on thermodynamics and the properties of fluids; the three modes of heat transfer -- conduction, convection, and radiation; and fluid flow, and the energy relationships in fluid systems. This information will provide personnel with a foundation for understanding the basic operation of various types of DOE nuclear facility fluid systems.
Device and method for measuring fluid flow in a conduit having a gradual bend
Ortiz, M.G.; Boucher, T.J.
1998-11-10
A system is described for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow. 1 fig.
Device and method for measuring fluid flow in a conduit having a gradual bend
Ortiz, Marcos German; Boucher, Timothy J
1998-01-01
A system for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.
Mutiscale Modeling of Segregation in Granular Flows
Jin Sun
2007-08-03
Modeling and simulation of segregation phenomena in granular flows are investigated. Computational models at different scales ranging from particle level (microscale) to continuum level (macroscale) are employed in order to determine the important microscale physics relevant to macroscale modeling. The capability of a multi-fluid model to capture segregation caused by density difference is demonstrated by simulating grain-chaff biomass flows in a laboratory-scale air column and in a combine harvester. The multi-fluid model treats gas and solid phases as interpenetrating continua in an Eulerian frame. This model is further improved by incorporating particle rotation using kinetic theory for rapid granular flow of slightly frictional spheres. A simplified model is implemented without changing the current kinetic theory framework by introducing an effective coefficient of restitution to account for additional energy dissipation due to frictional collisions. The accuracy of predicting segregation rate in a gas-fluidized bed is improved by the implementation. This result indicates that particle rotation is important microscopic physics to be incorporated into the hydrodynamic model. Segregation of a large particle in a dense granular bed of small particles under vertical. vibration is studied using molecular dynamics simulations. Wall friction is identified as a necessary condition for the segregation. Large-scale force networks bearing larger-than-average forces are found with the presence of wall friction. The role of force networks in assisting rising of the large particle is analyzed. Single-point force distribution and two-point spatial force correlation are computed. The results show the heterogeneity of forces and a short-range correlation. The short correlation length implies that even dense granular flows may admit local constitutive relations. A modified minimum spanning tree (MST) algorithm is developed to asymptotically recover the force statistics in the
Computational fluid dynamic modeling of fluidized-bed polymerization reactors
Rokkam, Ram
2012-01-01
Polyethylene is one of the most widely used plastics, and over 60 million tons are produced worldwide every year. Polyethylene is obtained by the catalytic polymerization of ethylene in gas and liquid phase reactors. The gas phase processes are more advantageous, and use fluidized-bed reactors for production of polyethylene. Since they operate so close to the melting point of the polymer, agglomeration is an operational concern in all slurry and gas polymerization processes. Electrostatics and hot spot formation are the main factors that contribute to agglomeration in gas-phase processes. Electrostatic charges in gas phase polymerization fluidized bed reactors are known to influence the bed hydrodynamics, particle elutriation, bubble size, bubble shape etc. Accumulation of electrostatic charges in the fluidized-bed can lead to operational issues. In this work a first-principles electrostatic model is developed and coupled with a multi-fluid computational fluid dynamic (CFD) model to understand the effect of electrostatics on the dynamics of a fluidized-bed. The multi-fluid CFD model for gas-particle flow is based on the kinetic theory of granular flows closures. The electrostatic model is developed based on a fixed, size-dependent charge for each type of particle (catalyst, polymer, polymer fines) phase. The combined CFD model is first verified using simple test cases, validated with experiments and applied to a pilot-scale polymerization fluidized-bed reactor. The CFD model reproduced qualitative trends in particle segregation and entrainment due to electrostatic charges observed in experiments. For the scale up of fluidized bed reactor, filtered models are developed and implemented on pilot scale reactor.
Fluid-structure interactions in compressible cavity flows
Wagner, Justin L.; Casper, Katya Marie; Beresh, Steven J.; Hunter, Patrick S.; Spillers, Russell Wayne; Henfling, John F.; Mayes, Randall L.
2015-06-08
Experiments were performed to understand the complex fluid-structure interactions that occur during aircraft internal store carriage. A cylindrical store was installed in a rectangular cavity having a length-to-depth ratio of 3.33 and a length-to-width ratio of 1. The Mach number ranged from 0.6 to 2.5 and the incoming boundary layer was turbulent. Fast-response pressure measurements provided aeroacoustic loading in the cavity, while triaxial accelerometers provided simultaneous store response. Despite occupying only 6% of the cavity volume, the store significantly altered the cavity acoustics. The store responded to the cavity flow at its natural structural frequencies, and it exhibited a directionallymore » dependent response to cavity resonance. Specifically, cavity tones excited the store in the streamwise and wall-normal directions consistently, whereas a spanwise response was observed only occasionally. Also, the streamwise and wall-normal responses were attributed to the longitudinal pressure waves and shear layer vortices known to occur during cavity resonance. Although the spanwise response to cavity tones was limited, broadband pressure fluctuations resulted in significant spanwise accelerations at store natural frequencies. As a result, the largest vibrations occurred when a cavity tone matched a structural natural frequency, although energy was transferred more efficiently to natural frequencies having predominantly streamwise and wall-normal motions.« less
Fluid-structure interactions in compressible cavity flows
Wagner, Justin L.; Casper, Katya Marie; Beresh, Steven J.; Hunter, Patrick S.; Spillers, Russell Wayne; Henfling, John F.; Mayes, Randall L.
2015-06-08
Experiments were performed to understand the complex fluid-structure interactions that occur during aircraft internal store carriage. A cylindrical store was installed in a rectangular cavity having a length-to-depth ratio of 3.33 and a length-to-width ratio of 1. The Mach number ranged from 0.6 to 2.5 and the incoming boundary layer was turbulent. Fast-response pressure measurements provided aeroacoustic loading in the cavity, while triaxial accelerometers provided simultaneous store response. Despite occupying only 6% of the cavity volume, the store significantly altered the cavity acoustics. The store responded to the cavity flow at its natural structural frequencies, and it exhibited a directionally dependent response to cavity resonance. Specifically, cavity tones excited the store in the streamwise and wall-normal directions consistently, whereas a spanwise response was observed only occasionally. Also, the streamwise and wall-normal responses were attributed to the longitudinal pressure waves and shear layer vortices known to occur during cavity resonance. Although the spanwise response to cavity tones was limited, broadband pressure fluctuations resulted in significant spanwise accelerations at store natural frequencies. As a result, the largest vibrations occurred when a cavity tone matched a structural natural frequency, although energy was transferred more efficiently to natural frequencies having predominantly streamwise and wall-normal motions.
Two-phase flow modeling with discrete particles
Mortensen, G.A.; Trapp, J.A. |
1992-03-23
The design of efficient heat exchangers in which the working fluid changes phase requires accurate modeling of two-phase fluid flow. The local Navier-Stokes equations form the basic continuum equations for this flow situation. However, the local instantaneous model using these equations is intractable for afl but the simplest problems. AH the practical models for two-phase flow analysis are based on equations that have been averaged over control volumes. These models average out the detailed description within the control volumes and rely on flow regime maps to determine the distribution of the two phases within a control volume. Flow regime maps depend on steady state models and probably are not correct for dynamic models. Numerical simulations of the averaged two-phase flow models are usually performed using a two-fluid Eulerian description for the two phases. Eulerian descriptions have the advantage of having simple boundary conditions, but the disadvantage of introducing numerical diffusion, i.e., sharp interfaces are not maintained as the flow develops, but are diffused. Lagrangian descriptions have the advantage of being able to track sharp interfaces without diffusion, but they have the disadvantage of requiring more complicated boundary conditions. This paper describes a numerical scheme and attendant computer program, DISCON2, for the calculation of two-phase flows that does not require the use of flow regime maps. This model is intermediate between the intractable local instantaneous and the averaged two-fluid model. This new model uses a combination of an Eulerian and a Lagrangian representation of the two phases. The dispersed particles (bubbles or drops) are modeled individually using a large representative number of particles, each with their own Lagrangian description. The continuous phases (liquid or gas) use an Eulerian description.
Othman, M. N. K. E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Zuradzman, M. Razlan E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Hazry, D. E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Khairunizam, Wan E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Shahriman, A. B. E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Yaacob, S. E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; Ahmed, S. Faiz E-mail: zuradzman@unimap.edu.my E-mail: khairunizam@unimap.edu.my E-mail: s.yaacob@unimap.edu.my E-mail: abadal@unimap.edu.my; and others
2014-12-04
This paper explain the analysis of internal air flow velocity of a bladeless vertical takeoff and landing (VTOL) Micro Aerial Vehicle (MAV) hemisphere body. In mechanical design, before produce a prototype model, several analyses should be done to ensure the product's effectiveness and efficiency. There are two types of analysis method can be done in mechanical design; mathematical modeling and computational fluid dynamic. In this analysis, I used computational fluid dynamic (CFD) by using SolidWorks Flow Simulation software. The idea came through to overcome the problem of ordinary quadrotor UAV which has larger size due to using four rotors and the propellers are exposed to environment. The bladeless MAV body is designed to protect all electronic parts, which means it can be used in rainy condition. It also has been made to increase the thrust produced by the ducted propeller compare to exposed propeller. From the analysis result, the air flow velocity at the ducted area increased to twice the inlet air. This means that the duct contribute to the increasing of air velocity.
Multiscale Simulation Framework for Coupled Fluid Flow and Mechanical Deformation
Tchelepi, Hamdi
2014-11-14
A multiscale linear-solver framework for the pressure equation associated with flow in highly heterogeneous porous formations was developed. The multiscale based approach is cast in a general algebraic form, which facilitates integration of the new scalable linear solver in existing flow simulators. The Algebraic Multiscale Solver (AMS) is employed as a preconditioner within a multi-stage strategy. The formulations investigated include the standard MultiScale Finite-Element (MSFE) andMultiScale Finite-Volume (MSFV) methods. The local-stage solvers include incomplete factorization and the so-called Correction Functions (CF) associated with the MSFV approach. Extensive testing of AMS, as an iterative linear solver, indicate excellent convergence rates and computational scalability. AMS compares favorably with advanced Algebraic MultiGrid (AMG) solvers for highly detailed three-dimensional heterogeneous models. Moreover, AMS is expected to be especially beneficial in solving time-dependent problems of coupled multiphase flow and transport in large-scale subsurface formations.
Tartakovsky, Alexandre M.
2010-06-24
A new Lagrangian particle model based on smoothed particle hydrodynamics (SPH) was developed and used to simulate Darcy scale flow and transport in porous media. The proposed numerical method has excellent conservation properties and treats advection exactly. The method was used in stochastic analysis of miscible density driven fluid flows. It was found that heterogeneity significantly increases dispersion and slows development of Rayleigh-Taylor instability. The presented numerical examples illustrate the advantages of Lagrangian methods for stochastic transport simulations.
Flow Of Mantle Fluids Through The Ductile Lower Crust- Helium...
Open Energy Information (Open El) [EERE & EIA]
ratios and active transtensional deformation indicates a deformation-enhanced permeability and that mantle fluids can penetrate the ductile lithosphere, even in regions where...
Multiphase Fluid Flow in Deformable Variable-Aperture Fractures - Final Report
Detwiler, Russell
2014-04-30
Fractures provide flow paths that can potentially lead to fast migration of fluids or contaminants. A number of energy-?related applications involve fluid injections that significantly perturb both the pressures and chemical composition of subsurface fluids. These perturbations can cause both mechanical deformation and chemical alteration of host rocks with potential for significant changes in permeability. In fractured rock subjected to coupled chemical and mechanical stresses, it can be difficult to predict the sign of permeability changes, let alone the magnitude. This project integrated experimental and computational studies to improve mechanistic understanding of these coupled processes and develop and test predictive models and monitoring techniques. The project involved three major components: (1) study of two-?phase flow processes involving mass transfer between phases and dissolution of minerals along fracture surfaces (Detwiler et al., 2009; Detwiler, 2010); (2) study of fracture dissolution in fractures subjected to normal stresses using experimental techniques (Ameli, et al., 2013; Elkhoury et al., 2013; Elkhoury et al., 2014) and newly developed computational models (Ameli, et al., 2014); (3) evaluation of electrical resistivity tomography (ERT) as a method to detect and quantify gas leakage through a fractured caprock (Breen et al., 2012; Lochbuhler et al., 2014). The project provided support for one PhD student (Dr. Pasha Ameli; 2009-?2013) and partially supported a post-?doctoral scholar (Dr. Jean Elkhoury; 2010-?2013). In addition, the project provided supplemental funding to support collaboration with Dr. Charles Carrigan at Lawrence Livermore National Laboratory in connection with (3) and supported one MS student (Stephen Breen; 2011-?2013). Major results from each component of the project include the following: (1) Mineral dissolution in fractures occupied by two fluid phases (e.g., oil-?water or water-?CO{sub 2}) causes changes in local
Fluid Flow and Infiltration in Structured Fibrous Porous Media
Papathanasiou, Thanasis D.
2006-08-09
Present the results of an extensive computational investigation of flow through structured fibrous media.
Method and apparatus for measuring the mass flow rate of a fluid
Evans, Robert P.; Wilkins, S. Curtis; Goodrich, Lorenzo D.; Blotter, Jonathan D.
2002-01-01
A non invasive method and apparatus is provided to measure the mass flow rate of a multi-phase fluid. An accelerometer is attached to a pipe carrying a multi-phase fluid. Flow related measurements in pipes are sensitive to random velocity fluctuations whose magnitude is proportional to the mean mass flow rate. An analysis of the signal produced by the accelerometer shows a relationship between the mass flow of a fluid and the noise component of the signal of an accelerometer. The noise signal, as defined by the standard deviation of the accelerometer signal allows the method and apparatus of the present invention to non-intrusively measure the mass flow rate of a multi-phase fluid.
Marc Cremer; Zumao Chen; Dave Wang; Paul Wolff
2004-06-01
This is the extended second Semiannual Technical Report for DOE Cooperative Agreement No: DE-FC26-02NT41580. The goal of this project is to systematically assess the sensitivity of furnace operational conditions to burner air and fuel flows in coal fired utility boilers. Our approach is to utilize existing baseline furnace models that have been constructed using Reaction Engineering International's (REI) computational fluid dynamics (CFD) software. Using CFD analyses provides the ability to carry out a carefully controlled virtual experiment to characterize the sensitivity of NOx emissions, unburned carbon (UBC), furnace exit CO (FECO), furnace exit temperature (FEGT), and waterwall deposition to burner flow controls. The Electric Power Research Institute (EPRI) is providing co-funding for this program, and instrument and controls experts from EPRI's Instrument and Controls (I&C) Center are active participants in this project. This program contains multiple tasks and good progress is being made on all fronts.
Oort, E. van; Hale, A.H.; Mody, F.K.
1995-12-31
Coupled osmotic flows have been studied as a means of stabilising shales exposed to water-based muds. The prime factor that governs the magnitude of chemical osmotic flow, i.e. the shale-fluid membrane efficiency, was investigated in detail. Its dependence on shale parameters, fluid parameters and external conditions was quantified. Membrane efficiency was found to increase with an increase in (hydrated) solute-to-pore-size ratio, with an increase in the shale`s high-surface area clay content and with a decrease shale permeability when increasing effective confining stress. Moreover, new drilling fluid chemistries for improving the efficiencies of low- and non-selective shale-fluid systems were identified. Induced osmotic flow with optimised shale-fluid membrane efficiencies in water-based environments is presented as a new strategy for improving wellbore stability in shales.
Apparatus for irradiating a continuously flowing stream of fluid. [For neutron activation analysis
Speir, L.G.; Adams, E.L.
1982-05-13
An apparatus for irradiating a continuously flowing stream of fluid is disclosed. The apparatus consists of a housing having a spherical cavity and a spherical moderator containing a radiation source positioned within the spherical cavity. The spherical moderator is of lesser diameter than the spherical cavity so as to define a spherical annular volume around the moderator. The housing includes fluid intake and output conduits which open onto the spherical cavity at diametrically opposite positions. Fluid flows through the cavity around the spherical moderator and is uniformly irradiated due to the 4..pi.. radiation geometry. The irradiation source, for example a /sup 252/Cf neutron source, is removable from the spherical moderator through a radial bore which extends outwardly to an opening on the outside of the housing. The radiation source may be routinely removed without interrupting the flow of fluid or breaching the containment of the fluid.
Inhomogeneity of fluid flow in Stirling engine regenerators
Jones, J.D. )
1989-10-01
The literature relating to inhomogeneity of flow regenerators is briefly reviewed. It is noted that, in contrast to other applications of regenerators, relatively little attention has been paid to the consequences of flow inhomogeneity for thermal regeneration in Stirling cycle machines. The construction of regenerator capsules for a large stationary Stirling engine is described. A test rig is developed to measure the gas velocity profile across the face of the packed regenerator capsules under steady flow conditions. Measured flow profiles for a number of different matrix materials and construction techniques are presented, and it is noted that stacked-mesh regenerator matrices tend to display marked inhomogeneities of flow. The consequences of flow inhomogeneity for flow friction and regenerator effectiveness are analyzed theoretically, and approximate formulae deduced. One method for reducing flow inhomogeneity in stacked-screen matrice
Tracking interface and common curve dynamics for two-fluid flow...
Office of Scientific and Technical Information (OSTI)
Tracking interface and common curve dynamics for two-fluid flow in porous media This content will become publicly available on April 29, 2017 Title: Tracking interface and common ...
Similarity Solution for Multi-Phase Fluid and Heat Flow in Radial Geometry
Energy Science and Technology Software Center (OSTI)
1994-12-02
SIMSOL calculates transient fluid and heat flow for a uniform geologic medium containing water (in both liquid and vapor phases) and air, surrounding a constant-strength linear heat source.
IN SITU STRESS, FRACTURE, AND FLUID FLOW ANALYSIS IN WELL 38C...
Open Energy Information (Open El) [EERE & EIA]
FRACTURE, AND FLUID FLOW ANALYSIS IN WELL 38C-9:AN ENHANCED GEOTHERMAL SYSTEM IN THE COSO GEOTHERMAL FIELD Jump to: navigation, search OpenEI Reference LibraryAdd to library...
Multi-material incompressible flow simulation using the moment-of-fluid method
Garimella, R V; Schofield, S P; Lowrie, R B; Swartz, B K; Christon, M A; Dyadechko, V
2009-01-01
The Moment-of-Fluid interface reconstruction technique is implemented in a second order accurate, unstructured finite element variable density incompressible Navier-Stokes solver. For flows with multiple materials, MOF significantly outperforms existing first and second order interface reconstruction techniques. For two material flows, the performance of MOF is similar to other interface reconstruction techniques. For strongly driven bouyant flows, the errors in the flow solution dominate and all the interface reconstruction techniques perform similarly.
Temperature distribution in a flowing fluid heated in a microwave resonant cavity
Thomas, J.R. Jr. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States); Nelson, E.M.; Kares, R.J.; Stringfield, R.M. [Los Alamos National Lab., NM (United States)
1996-04-01
This paper presents results of an analytical study of microwave heating of a fluid flowing through a tube situated along the axis of a cylindrical microwave applicator. The interaction of the microwave field pattern and the fluid velocity profiles is illustrated for both laminar and turbulent flow. Resulting temperature profiles are compared with those generated by conventional heating through a surface heat flux. It is found that microwave heating offers several advantages over conventional heating.
Application of Neutron Imaging and Scattering to Fluid Flow and Fracture in EGS Environments
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Application of Neutron Imaging and Scattering to Fluid Flow and Fracture in EGS Environments Yarom Polsky Oak Ridge National Laboratory Track Name Project Officer: Greg Stillman Total Project Funding: $300K April 23, 2013 This presentation does not contain any proprietary confidential, or otherwise restricted information. 2 | US DOE Geothermal Office eere.energy.gov Relevance/Impact of Research Goals: 1) Develop an experimental capability to image/characterize fluid flow through fractures 2)
Fracture Network and Fluid Flow Imaging for EGS Applications...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Structure FRAC-STIM: A Physics-Based Fracture Simulation, reservoir Flow and Heat Transport Simulator(aka FALCON) Integration of Noise and Coda Correlation Data into ...
Use of Geophysical Techniques to Characterize Fluid Flow in a...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Project objectives: Joint inversion of geophysical data for ground water flow imaging; ... More Documents & Publications Time-lapse Joint Inversion of Geophysical Data and its ...
Controls on Fault-Hosted Fluid Flow: Preliminary Results from...
Open Energy Information (Open El) [EERE & EIA]
Flow: Preliminary Results from the Coso Geothermal Field, CA Abstract cap rock, permeability, fault, fracture, clay, Coso Authors Davatzes, N.C.; Hickman and S.H. Published...
Dispersed Fluid Flow in Fractured Reservoirs- an Analysis of...
Open Energy Information (Open El) [EERE & EIA]
Reservoirs- an Analysis of Tracer-Determined Residence Time Distributions Abstract A methodology for analyzing the internal flow characteristics of a fractured geothermal reservoir...
Tao, Y.B.; He, Y.L.
2010-10-15
A unified two-dimensional numerical model was developed for the coupled heat transfer process in parabolic solar collector tube, which includes nature convection, forced convection, heat conduction and fluid-solid conjugate problem. The effects of Rayleigh number (Ra), tube diameter ratio and thermal conductivity of the tube wall on the heat transfer and fluid flow performance were numerically analyzed. The distributions of flow field, temperature field, local Nu and local temperature gradient were examined. The results show that when Ra is larger than 10{sup 5}, the effects of nature convection must be taken into account. With the increase of tube diameter ratio, the Nusselt number in inner tube (Nu{sub 1}) increases and the Nusselt number in annuli space (Nu{sub 2}) decreases. With the increase of tube wall thermal conductivity, Nu{sub 1} decreases and Nu{sub 2} increases. When thermal conductivity is larger than 200 W/(m K), it would have little effects on Nu and average temperatures. Due to the effect of the nature convection, along the circumferential direction (from top to down), the temperature in the cross-section decreases and the temperature gradient on inner tube surface increases at first. Then, the temperature and temperature gradients would present a converse variation at {theta} near {pi}. The local Nu on inner tube outer surface increases along circumferential direction until it reaches a maximum value then it decreases again. (author)
Method of measuring the mass flow rate of a substance entering a cocurrent fluid stream
Cochran, Jr., Henry D.
1978-04-11
This invention relates to an improved method of monitoring the mass flow rate of a substance entering a cocurrent fluid stream. The method very basically consists of heating equal sections of the fluid stream above and below the point of entry of the substance to be monitored, and measuring and comparing the resulting change in temperature of the sections. Advantage is taken of the difference in thermal characteristics of the fluid and the substance to be measured to correlate temperature differences in the sections above and below the substance feed point for providing an indication of the mass flow rate of the substance.
Computational fluid dynamics modeling of proton exchange membrane fuel cells
UM,SUKKEE; WANG,C.Y.; CHEN,KEN S.
2000-02-11
A transient, multi-dimensional model has been developed to simulate proton exchange membrane (PEM) fuel cells. The model accounts simultaneously for electrochemical kinetics, current distribution, hydrodynamics and multi-component transport. A single set of conservation equations valid for flow channels, gas-diffusion electrodes, catalyst layers and the membrane region are developed and numerically solved using a finite-volume-based computational fluid dynamics (CFD) technique. The numerical model is validated against published experimental data with good agreement. Subsequently, the model is applied to explore hydrogen dilution effects in the anode feed. The predicted polarization cubes under hydrogen dilution conditions are found to be in qualitative agreement with recent experiments reported in the literature. The detailed two-dimensional electrochemical and flow/transport simulations further reveal that in the presence of hydrogen dilution in the fuel stream, hydrogen is depleted at the reaction surface resulting in substantial kinetic polarization and hence a lower current density that is limited by hydrogen transport from the fuel stream to the reaction site.
Multiscale modeling for fluid transport in nanosystems.
Lee, Jonathan W.; Jones, Reese E.; Mandadapu, Kranthi Kiran; Templeton, Jeremy Alan; Zimmerman, Jonathan A.
2013-09-01
Atomistic-scale behavior drives performance in many micro- and nano-fluidic systems, such as mircrofludic mixers and electrical energy storage devices. Bringing this information into the traditionally continuum models used for engineering analysis has proved challenging. This work describes one such approach to address this issue by developing atomistic-to-continuum multi scale and multi physics methods to enable molecular dynamics (MD) representations of atoms to incorporated into continuum simulations. Coupling is achieved by imposing constraints based on fluxes of conserved quantities between the two regions described by one of these models. The impact of electric fields and surface charges are also critical, hence, methodologies to extend finite-element (FE) MD electric field solvers have been derived to account for these effects. Finally, the continuum description can have inconsistencies with the coarse-grained MD dynamics, so FE equations based on MD statistics were derived to facilitate the multi scale coupling. Examples are shown relevant to nanofluidic systems, such as pore flow, Couette flow, and electric double layer.
A Two-length Scale Turbulence Model for Single-phase Multi-fluid Mixing
Schwarzkopf, J. D.; Livescu, D.; Baltzer, J. R.; Gore, R. A.; Ristorcelli, J. R.
2015-09-08
A two-length scale, second moment turbulence model (Reynolds averaged Navier-Stokes, RANS) is proposed to capture a wide variety of single-phase flows, spanning from incompressible flows with single fluids and mixtures of different density fluids (variable density flows) to flows over shock waves. The two-length scale model was developed to address an inconsistency present in the single-length scale models, e.g. the inability to match both variable density homogeneous Rayleigh-Taylor turbulence and Rayleigh-Taylor induced turbulence, as well as the inability to match both homogeneous shear and free shear flows. The two-length scale model focuses on separating the decay and transport length scales, as the two physical processes are generally different in inhomogeneous turbulence. This allows reasonable comparisons with statistics and spreading rates over such a wide range of turbulent flows using a common set of model coefficients. The specific canonical flows considered for calibrating the model include homogeneous shear, single-phase incompressible shear driven turbulence, variable density homogeneous Rayleigh-Taylor turbulence, Rayleigh-Taylor induced turbulence, and shocked isotropic turbulence. The second moment model shows to compare reasonably well with direct numerical simulations (DNS), experiments, and theory in most cases. The model was then applied to variable density shear layer and shock tube data and shows to be in reasonable agreement with DNS and experiments. Additionally, the importance of using DNS to calibrate and assess RANS type turbulence models is highlighted.
Kim, Jihoon; Um, Evan; Moridis, George
2014-12-01
We investigate fracture propagation induced by hydraulic fracturing with water injection, using numerical simulation. For rigorous, full 3D modeling, we employ a numerical method that can model failure resulting from tensile and shear stresses, dynamic nonlinear permeability, leak-off in all directions, and thermo-poro-mechanical effects with the double porosity approach. Our numerical results indicate that fracture propagation is not the same as propagation of the water front, because fracturing is governed by geomechanics, whereas water saturation is determined by fluid flow. At early times, the water saturation front is almost identical to the fracture tip, suggesting that the fracture is mostly filled with injected water. However, at late times, advance of the water front is retarded compared to fracture propagation, yielding a significant gap between the water front and the fracture top, which is filled with reservoir gas. We also find considerable leak-off of water to the reservoir. The inconsistency between the fracture volume and the volume of injected water cannot properly calculate the fracture length, when it is estimated based on the simple assumption that the fracture is fully saturated with injected water. As an example of flow-geomechanical responses, we identify pressure fluctuation under constant water injection, because hydraulic fracturing is itself a set of many failure processes, in which pressure consistently drops when failure occurs, but fluctuation decreases as the fracture length grows. We also study application of electromagnetic (EM) geophysical methods, because these methods are highly sensitive to changes in porosity and pore-fluid properties due to water injection into gas reservoirs. Employing a 3D finite-element EM geophysical simulator, we evaluate the sensitivity of the crosswell EM method for monitoring fluid movements in shaly reservoirs. For this sensitivity evaluation, reservoir models are generated through the coupled flow
Ortiz, M.G.; Boucher, T.J.
1998-10-27
A system is described for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow. 1 fig.
Ortiz, Marcos German; Boucher, Timothy J.
1998-01-01
A system for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.
Grossman, S.A.; Trump, D.L.; Chen, D.C.; Thompson, G.; Camargo, E.E.
1982-11-01
Cerebrospinal fluid flow dynamics were evaluated by /sup 111/In-diethylenetriamine pentaacetic acid (/sup 111/In-DTPA) ventriculography in 27 patients with neoplastic meningitis. Nineteen patients (70 percent) had evidence of cerebrospinal fluid flow disturbances. These occurred as ventricular outlet obstructions, abnormalities of flow in the spinal canal, or flow distrubances over the cortical convexities. Tumor histology, physical examination, cerebrospinal fluid analysis, myelograms, and computerized axial tomographic scans were not sufficient to predict cerebrospinal fluid flow patterns. These data indicate that cerebrospinal fluid flow abnormalities are common in patients with neoplastic meningitis and that /sup 111/In-DTPA cerebrospinal fluid flow imaging is useful in characterizing these abnormalities. This technique provides insight into the distribution of intraventricularly administered chemotherapy and may provide explanations for treatment failure and drug-induced neurotoxicity in patients with neoplastic meningitis.
Computational Methods for Analyzing Fluid Flow Dynamics from Digital Imagery
Luttman, A.
2012-03-30
The main goal (long term) of this work is to perform computational dynamics analysis and quantify uncertainty from vector fields computed directly from measured data. Global analysis based on observed spatiotemporal evolution is performed by objective function based on expected physics and informed scientific priors, variational optimization to compute vector fields from measured data, and transport analysis proceeding with observations and priors. A mathematical formulation for computing flow fields is set up for computing the minimizer for the problem. An application to oceanic flow based on sea surface temperature is presented.
U-Sr isotopic speedometer: Fluid flow and chemical weatheringrates inaquifers
Maher, Kate; DePaolo, Donald J.; Christensen, John N.
2005-12-27
Both chemical weathering rates and fluid flow are difficultto measure in natural systems. However, these parameters are critical forunderstanding the hydrochemical evolution of aquifers, predicting thefate and transport of contaminants, and for water resources/water qualityconsiderations. 87Sr/86Sr and (234U/238U) activity ratios are sensitiveindicators of water-rock interaction, and thus provide a means ofquantifying both flow and reactivity. The 87Sr/86Sr values in groundwaters are controlled by the ratio of the dissolution rate to the flowrate. Similarly, the (234U/238U) ratio of natural ground waters is abalance between the flow rate and the dissolution of solids, andalpha-recoil loss of 234U from the solids. By coupling these two isotopesystems it is possible to constrain both the long-term (ca. 100's to1000's of years) flow rate and bulk dissolution rate along the flow path.Previous estimates of the ratio of the dissolution rate to theinfiltration flux from Sr isotopes (87Sr/86Sr) are combined with a modelfor (234U/238U) to constrain the infiltration flux and dissolution ratefor a 70-m deep vadose zone core from Hanford, Washington. The coupledmodel for both (234U/238U) ratios and the 87Sr/86Sr data suggests aninfiltration flux of 5+-2 mm/yr, and bulk silicate dissolution ratesbetween 10-15.7 and 10-16.5 mol/m2/s. The process of alpha-recoilenrichment, while primarily responsible for the observed variation in(234U/238U) of natural systems, is difficult to quantify. However, therate of this process in natural systems affects the interpretation ofmost U-series data. Models for quantifying the alpha-recoil loss fractionbased on geometric predictions, surface area constraints, and chemicalmethods are also presented. The agreement between the chemical andtheoretical methods, such as direct measurement of (234U/238U) of thesmall grain size fraction and geometric calculations for that sizefraction, is quite good.
Modelling of multiphase flow in ironmaking blast furnace
Dong, X.F.; Yu, A.B.; Burgess, J.M.; Pinson, D.; Chew, S.; Zulli, P.
2009-01-15
A mathematical model for the four-phase (gas, powder, liquid, and solids) flow in a two-dimensional ironmaking blast furnace is presented by extending the existing two-fluid flow models. The model describes the motion of gas, solid, and powder phases, based on the continuum approach, and implements the so-called force balance model for the flow of liquids, such as metal and slag in a blast furnace. The model results demonstrate a solid stagnant zone and dense powder hold-up region, as well as a dense liquid flow region that exists in the lower part of a blast furnace, which are consistent with the experimental observations reported in the literature. The simulation is extended to investigate the effects of packing properties and operational conditions on the flow and the volume fraction distribution of each phase in a blast furnace. It is found that solid movement has a significant effect on powder holdup distribution. Small solid particles and low porosity distribution are predicted to affect the fluid flow considerably, and this can cause deterioration in bed permeability. The dynamic powder holdup in a furnace increases significantly with the increase of powder diameter. The findings should be useful to better understand and control blast furnace operations.
Stochastic models for turbulent reacting flows
Kerstein, A.
1993-12-01
The goal of this program is to develop and apply stochastic models of various processes occurring within turbulent reacting flows in order to identify the fundamental mechanisms governing these flows, to support experimental studies of these flows, and to further the development of comprehensive turbulent reacting flow models.
Magnetohydrodynamic pump with a system for promoting flow of fluid in one direction
Lemoff, Asuncion V.; Lee, Abraham P.
2010-07-13
A magnetohydrodynamic pump for pumping a fluid. The pump includes a microfluidic channel for channeling the fluid, a MHD electrode/magnet system operatively connected to the microfluidic channel, and a system for promoting flow of the fluid in one direction in the microfluidic channel. The pump has uses in the medical and biotechnology industries for blood-cell-separation equipment, biochemical assays, chemical synthesis, genetic analysis, drug screening, an array of antigen-antibody reactions, combinatorial chemistry, drug testing, medical and biological diagnostics, and combinatorial chemistry. The pump also has uses in electrochromatography, surface micromachining, laser ablation, inkjet printers, and mechanical micromilling.
Hamel, William R.
1984-01-01
This invention relates to a new method and new apparatus for determining fluid mass flowrate and density. In one aspect of the invention, the fluid is passed through a straight cantilevered tube in which transient oscillation has been induced, thus generating Coriolis damping forces on the tube. The decay rate and frequency of the resulting damped oscillation are measured, and the fluid mass flowrate and density are determined therefrom. In another aspect of the invention, the fluid is passed through the cantilevered tube while an electrically powered device imparts steady-state harmonic excitation to the tube. This generates Coriolis tube-damping forces which are dependent on the mass flowrate of the fluid. Means are provided to respond to incipient flow-induced changes in the amplitude of vibration by changing the power input to the excitation device as required to sustain the original amplitude of vibration. The fluid mass flowrate and density are determined from the required change in power input. The invention provides stable, rapid, and accurate measurements. It does not require bending of the fluid flow.
Computational Fluid Dynamics Modeling of Diesel Engine Combustion and
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Emissions | Department of Energy Computational Fluid Dynamics Modeling of Diesel Engine Combustion and Emissions Computational Fluid Dynamics Modeling of Diesel Engine Combustion and Emissions 2005 Diesel Engine Emissions Reduction (DEER) Conference Presentations and Posters 2005_deer_reitz.pdf (682.47 KB) More Documents & Publications Experiments and Modeling of Two-Stage Combustion in Low-Emissions Diesel Engines Comparison of Conventional Diesel and Reactivity Controlled Compression
Dynamics of a confined dusty fluid in a sheared ion flow
Laishram, Modhuchandra; Sharma, Devendra; Kaw, Predhiman K. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
2014-07-15
Dynamics of an isothermally driven dust fluid is analyzed which is confined in an azimuthally symmetric cylindrical setup by an effective potential and is in equilibrium with an unconfined sheared flow of a streaming plasma. Cases are analyzed where the confining potential constitutes a barrier for the driven fluid, limiting its spatial extension and boundary velocity. The boundary effects entering the formulation are characterized by applying the appropriate boundary conditions and a range of solutions exhibiting single and multiple vortex are obtained. The equilibrium solutions considered in the cylindrical setup feature a transition from single to multiple vortex state of the driven flow. Effects of (i) the variation in dust viscosity, (ii) coupling between the driving and the driven fluid, and (iii) a friction determining the equilibrium dynamics of the driven system are characterized.
Flow of mantle fluids through the ductile lower crust: Heliumisotope trends
Kennedy, B. Mack; van Soest, Matthijs C.
2007-10-07
Heat and mass are injected into the shallow crust when mantle fluids are able to flow through the ductile lower crust. Minimum 3He/4He ratios in surface fluids from the northern Basin and Range province, western North America increase systematically from low, crustal values in the east to high, mantle values in the west, a regional trend that correlates with the rates of active crustal deformation. The highest ratios occur where the extension and shear strain rates are greatest. The correspondence of helium isotope ratios and active trans-tensional deformation indicates a deformation enhanced permeability and that mantle fluids can penetrate the ductile lithosphere in regions even where there is no significant magmatism. Superimposed on the regional trend are local, high-{sup 3}He/{sup 4}He anomalies signifying hidden magmatic activity and/or deep fluid production with locally enhanced permeability, identifying zones with high resource potential, particularly for geothermal energy development.
East Maui Groundwater Flow Model
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Nicole Lautze
2015-01-01
Groundwater flow model for East Maui. Data is from the following sources: Whittier, R. and A.I. El-Kadi. 2014. Human and Environmental Risk Ranking of Onsite Sewage Disposal Systems For the Hawaiian Islands of Kauai, Molokai, Maui, and Hawaii – Final. Prepared by the University of Hawaii, Dept. of Geology and Geophysics for the State of Hawaii Dept. of Health, Safe Drinking Water Branch. September 2014; and Whittier, R.B., K. Rotzoll, S. Dhal, A.I. El-Kadi, C. Ray, G. Chen, and D. Chang. 2004. Hawaii Source Water Assessment Program Report – Volume V – Island of Maui Source Water Assessment Program Report. Prepared for the Hawaii Department of Health, Safe Drinking Water Branch. University of Hawaii, Water Resources Research Center. Updated 2008.
Hawaii Island Groundwater Flow Model
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Nicole Lautze
2015-01-01
Groundwater flow model for Hawaii Island. Data is from the following sources: Whittier, R.B., K. Rotzoll, S. Dhal, A.I. El-Kadi, C. Ray, G. Chen, and D. Chang. 2004. Hawaii Source Water Assessment Program Report – Volume II – Island of Hawaii Source Water Assessment Program Report. Prepared for the Hawaii Department of Health, Safe Drinking Water Branch. University of Hawaii, Water Resources Research Center. Updated 2008; and Whittier, R. and A.I. El-Kadi. 2014. Human and Environmental Risk Ranking of Onsite Sewage Disposal Systems For the Hawaiian Islands of Kauai, Molokai, Maui, and Hawaii – Final. Prepared by the University of Hawaii, Dept. of Geology and Geophysics for the State of Hawaii Dept. of Health, Safe Drinking Water Branch. September 2014.
West Maui Groundwater Flow Model
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Nicole Lautze
2015-01-01
Groundwater flow model for West Maui. Data is from the following sources: Whittier, R. and A.I. El-Kadi. 2014. Human and Environmental Risk Ranking of Onsite Sewage Disposal Systems For the Hawaiian Islands of Kauai, Molokai, Maui, and Hawaii – Final. Prepared by the University of Hawaii, Dept. of Geology and Geophysics for the State of Hawaii Dept. of Health, Safe Drinking Water Branch. September 2014; and Whittier, R.B., K. Rotzoll, S. Dhal, A.I. El-Kadi, C. Ray, G. Chen, and D. Chang. 2004. Hawaii Source Water Assessment Program Report – Volume V – Island of Maui Source Water Assessment Program Report. Prepared for the Hawaii Department of Health, Safe Drinking Water Branch. University of Hawaii, Water Resources Research Center. Updated 2008.
West Maui Groundwater Flow Model
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Nicole Lautze
2015-01-01
Groundwater flow model for West Maui. Data is from the following sources: Whittier, R. and A.I. El-Kadi. 2014. Human and Environmental Risk Ranking of Onsite Sewage Disposal Systems For the Hawaiian Islands of Kauai, Molokai, Maui, and Hawaii Final. Prepared by the University of Hawaii, Dept. of Geology and Geophysics for the State of Hawaii Dept. of Health, Safe Drinking Water Branch. September 2014; and Whittier, R.B., K. Rotzoll, S. Dhal, A.I. El-Kadi, C. Ray, G. Chen, and D. Chang. 2004. Hawaii Source Water Assessment Program Report Volume V Island of Maui Source Water Assessment Program Report. Prepared for the Hawaii Department of Health, Safe Drinking Water Branch. University of Hawaii, Water Resources Research Center. Updated 2008.
Device and method for measuring multi-phase fluid flow in a conduit having an abrupt gradual bend
Ortiz, M.G.
1998-02-10
A system is described for measuring fluid flow in a conduit having an abrupt bend. The system includes pressure transducers, one disposed in the conduit at the inside of the bend and one or more disposed in the conduit at the outside of the bend but spaced a distance therefrom. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow. 1 fig.
Device and method for measuring multi-phase fluid flow in a conduit having an abrupt gradual bend
Ortiz, Marcos German
1998-01-01
A system for measuring fluid flow in a conduit having an abrupt bend. The system includes pressure transducers, one disposed in the conduit at the inside of the bend and one or more disposed in the conduit at the outside of the bend but spaced a distance therefrom. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.
Gen Purpose 1-D Finite Element Network Fluid Flow Heat Transfer System Simulator
Energy Science and Technology Software Center (OSTI)
1993-08-02
SAFSIM (System Analysis Flow Simulator) is a FORTRAN computer program to simulate the integrated performance of systems involving fluid mechanics, heat transfer, and reactor dynamics. SAFSIM provides sufficient versatility to allow the engineering simulation of almost any system, from a backyard sprinkler system to a clustered nuclear reactor propulsion system. In addition to versatility, speed and robustness are primary SAFSIM development goals. SAFSIM contains three basic physics modules: (1) a one-dimensional finite element fluid mechanicsmore » module with multiple flow network capability; (2) a one-dimensional finite element structure heat transfer module with multiple convection and radiation exchange capability; and (3) a point reactor dynamics module with reactivity feedback and decay heat capability. SAFSIM can be used for compressible and incompressible, single-phase, multicomponent flow systems.« less
Armstrong, William D.; Naughton, Jonathan; Lindberg, William R.
2008-09-02
A shear stress sensor for measuring fluid wall shear stress on a test surface is provided. The wall shear stress sensor is comprised of an active sensing surface and a sensor body. An elastic mechanism mounted between the active sensing surface and the sensor body allows movement between the active sensing surface and the sensor body. A driving mechanism forces the shear stress sensor to oscillate. A measuring mechanism measures displacement of the active sensing surface relative to the sensor body. The sensor may be operated under periodic excitation where changes in the nature of the fluid properties or the fluid flow over the sensor measurably changes the amplitude or phase of the motion of the active sensing surface, or changes the force and power required from a control system in order to maintain constant motion. The device may be operated under non-periodic excitation where changes in the nature of the fluid properties or the fluid flow over the sensor change the transient motion of the active sensor surface or change the force and power required from a control system to maintain a specified transient motion of the active sensor surface.
Non-Invasive Characterization Of A Flowing Multi-Phase Fluid Using Ultrasonic Interferometry
Sinha, Dipen N.
2005-11-01
An apparatus for noninvasively monitoring the flow and/or the composition of a flowing liquid using ultrasound is described. The position of the resonance peaks for a fluid excited by a swept-frequency ultrasonic signal have been found to change frequency both in response to a change in composition and in response to a change in the flow velocity thereof. Additionally, the distance between successive resonance peaks does not change as a function of flow, but rather in response to a change in composition. Thus, a measurement of both parameters (resonance position and resonance spacing), once calibrated, permits the simultaneous determination of flow rate and composition using the apparatus and method of the present invention.
SALE: a simplified ALE computer program for fluid flow at all speeds
Amsden, A.A.; Ruppel, H.M.; Hirt, C.W.
1980-06-01
A simplified numerical fluid-dynamics computing technique is presented for calculating two-dimensional fluid flows at all speeds. It combines an implicit treatment of the pressure equation similar to that in the Implicit Continuous-fluid Eulerian (ICE) technique with the grid rezoning philosophy of the Arbitrary Lagrangian-Eulerian (ALE) method. As a result, it can handle flow speeds from supersonic to the incompressible limit in a grid that may be moved with the fluid in typical Lagrangian fashion, or held fixed in an Eulerian manner, or moved in some arbitrary way to give a continuous rezoning capability. The report describes the combined (ICEd-ALE) technique in the framework of the SALE (Simplified ALE) computer program, for which a general flow diagram and complete FORTRAN listing are included. A set of sample problems show how to use or modify the basic code for a variety of applications. Numerical listings are provided for a sample problem run with the SALE program.
Scalability of preconditioners as a strategy for parallel computation of compressible fluid flow
Hansen, G.A.
1996-05-01
Parallel implementations of a Newton-Krylov-Schwarz algorithm are used to solve a model problem representing low Mach number compressible fluid flow over a backward-facing step. The Mach number is specifically selected to result in a numerically {open_quote}stiff{close_quotes} matrix problem, based on an implicit finite volume discretization of the compressible 2D Navier-Stokes/energy equations using primitive variables. Newton`s method is used to linearize the discrete system, and a preconditioned Krylov projection technique is used to solve the resulting linear system. Domain decomposition enables the development of a global preconditioner via the parallel construction of contributions derived from subdomains. Formation of the global preconditioner is based upon additive and multiplicative Schwarz algorithms, with and without subdomain overlap. The degree of parallelism of this technique is further enhanced with the use of a matrix-free approximation for the Jacobian used in the Krylov technique (in this case, GMRES(k)). Of paramount interest to this study is the implementation and optimization of these techniques on parallel shared-memory hardware, namely the Cray C90 and SGI Challenge architectures. These architectures were chosen as representative and commonly available to researchers interested in the solution of problems of this type. The Newton-Krylov-Schwarz solution technique is increasingly being investigated for computational fluid dynamics (CFD) applications due to the advantages of full coupling of all variables and equations, rapid non-linear convergence, and moderate memory requirements. A parallel version of this method that scales effectively on the above architectures would be extremely attractive to practitioners, resulting in efficient, cost-effective, parallel solutions exhibiting the benefits of the solution technique.
A Two-length Scale Turbulence Model for Single-phase Multi-fluid Mixing
Schwarzkopf, J. D.; Livescu, D.; Baltzer, J. R.; Gore, R. A.; Ristorcelli, J. R.
2015-09-08
A two-length scale, second moment turbulence model (Reynolds averaged Navier-Stokes, RANS) is proposed to capture a wide variety of single-phase flows, spanning from incompressible flows with single fluids and mixtures of different density fluids (variable density flows) to flows over shock waves. The two-length scale model was developed to address an inconsistency present in the single-length scale models, e.g. the inability to match both variable density homogeneous Rayleigh-Taylor turbulence and Rayleigh-Taylor induced turbulence, as well as the inability to match both homogeneous shear and free shear flows. The two-length scale model focuses on separating the decay and transport length scales,more » as the two physical processes are generally different in inhomogeneous turbulence. This allows reasonable comparisons with statistics and spreading rates over such a wide range of turbulent flows using a common set of model coefficients. The specific canonical flows considered for calibrating the model include homogeneous shear, single-phase incompressible shear driven turbulence, variable density homogeneous Rayleigh-Taylor turbulence, Rayleigh-Taylor induced turbulence, and shocked isotropic turbulence. The second moment model shows to compare reasonably well with direct numerical simulations (DNS), experiments, and theory in most cases. The model was then applied to variable density shear layer and shock tube data and shows to be in reasonable agreement with DNS and experiments. Additionally, the importance of using DNS to calibrate and assess RANS type turbulence models is highlighted.« less
Viscous quark-gluon plasma model through fluid QCD approach
Djun, T. P.; Soegijono, B.; Mart, T.; Handoko, L. T. E-mail: Laksana.tri.handoko@lipi.go.id
2014-09-25
A Lagrangian density for viscous quark-gluon plasma has been constructed within the fluid-like QCD framework. Gauge symmetry is preserved for all terms inside the Lagrangian, except for the viscous term. The transition mechanism from point particle field to fluid field, and vice versa, are discussed. The energy momentum tensor that is relevant to the gluonic plasma having the nature of fluid bulk of gluon sea is derived within the model. By imposing conservation law in the energy momentum tensor, shear viscosity appears as extractable from the equation.
Nelson, John Stuart; Milner, Thomas Edward; Chen, Zhongping
1999-01-01
Optical Doppler tomography permits imaging of fluid flow velocity in highly scattering media. The tomography system combines Doppler velocimetry with high spatial resolution of partially coherent optical interferometry to measure fluid flow velocity at discrete spatial locations. Noninvasive in vivo imaging of blood flow dynamics and tissue structures with high spatial resolutions of the order of 2 to 10 microns is achieved in biological systems. The backscattered interference signals derived from the interferometer may be analyzed either through power spectrum determination to obtain the position and velocity of each particle in the fluid flow sample at each pixel, or the interference spectral density may be analyzed at each frequency in the spectrum to obtain the positions and velocities of the particles in a cross-section to which the interference spectral density corresponds. The realized resolutions of optical Doppler tomography allows noninvasive in vivo imaging of both blood microcirculation and tissue structure surrounding the vessel which has significance for biomedical research and clinical applications.
Site-Scale Saturated Zone Flow Model
G. Zyvoloski
2003-12-17
The purpose of this model report is to document the components of the site-scale saturated-zone flow model at Yucca Mountain, Nevada, in accordance with administrative procedure (AP)-SIII.lOQ, ''Models''. This report provides validation and confidence in the flow model that was developed for site recommendation (SR) and will be used to provide flow fields in support of the Total Systems Performance Assessment (TSPA) for the License Application. The output from this report provides the flow model used in the ''Site-Scale Saturated Zone Transport'', MDL-NBS-HS-000010 Rev 01 (BSC 2003 [162419]). The Site-Scale Saturated Zone Transport model then provides output to the SZ Transport Abstraction Model (BSC 2003 [164870]). In particular, the output from the SZ site-scale flow model is used to simulate the groundwater flow pathways and radionuclide transport to the accessible environment for use in the TSPA calculations. Since the development and calibration of the saturated-zone flow model, more data have been gathered for use in model validation and confidence building, including new water-level data from Nye County wells, single- and multiple-well hydraulic testing data, and new hydrochemistry data. In addition, a new hydrogeologic framework model (HFM), which incorporates Nye County wells lithology, also provides geologic data for corroboration and confidence in the flow model. The intended use of this work is to provide a flow model that generates flow fields to simulate radionuclide transport in saturated porous rock and alluvium under natural or forced gradient flow conditions. The flow model simulations are completed using the three-dimensional (3-D), finite-element, flow, heat, and transport computer code, FEHM Version (V) 2.20 (software tracking number (STN): 10086-2.20-00; LANL 2003 [161725]). Concurrently, process-level transport model and methodology for calculating radionuclide transport in the saturated zone at Yucca Mountain using FEHM V 2.20 are being
Energy flow in passive and active 3D cochlear model
Wang, Yanli; Steele, Charles; Puria, Sunil
2015-12-31
Energy flow in the cochlea is an important characteristic of the cochlear traveling wave, and many investigators, such as von Békésy and Lighthill, have discussed this phenomenon. Particularly after the discovery of the motility of the outer hair cells (OHCs), the nature of the power gain of the cochlea has been a fundamental research question. In the present work, direct three-dimensional (3D) calculations of the power on cross sections of the cochlea and on the basilar membrane are performed based on a box model of the mouse cochlea. The distributions of the fluid pressure and fluid velocity in the scala vestibuli are presented. The power output from the OHCs and the power loss due to fluid viscous damping are calculated along the length of the cochlea. This work provides a basis for theoretical calculations of the power gain of the OHCs from mechanical considerations.
Shock Desensitization Experiments and Reactive Flow Modeling...
Office of Scientific and Technical Information (OSTI)
Shock Desensitization Experiments and Reactive Flow Modeling on Self-Sustaining LX-17 Detonation Waves Citation Details In-Document Search Title: Shock Desensitization Experiments ...
Computational fluid dynamics modeling of coal gasification in a pressurized spout-fluid bed
Zhongyi Deng; Rui Xiao; Baosheng Jin; He Huang; Laihong Shen; Qilei Song; Qianjun Li
2008-05-15
Computational fluid dynamics (CFD) modeling, which has recently proven to be an effective means of analysis and optimization of energy-conversion processes, has been extended to coal gasification in this paper. A 3D mathematical model has been developed to simulate the coal gasification process in a pressurized spout-fluid bed. This CFD model is composed of gas-solid hydrodynamics, coal pyrolysis, char gasification, and gas phase reaction submodels. The rates of heterogeneous reactions are determined by combining Arrhenius rate and diffusion rate. The homogeneous reactions of gas phase can be treated as secondary reactions. A comparison of the calculated and experimental data shows that most gasification performance parameters can be predicted accurately. This good agreement indicates that CFD modeling can be used for complex fluidized beds coal gasification processes. 37 refs., 7 figs., 5 tabs.
Xu, Ben; Li, Peiwen; Waller, Peter; Huesemann, Michael H.
2015-02-27
This paper analyzes and evaluates the flow mixing in an open channel algal raceway for biofuel production. The flow mixing governs the frequency of how algae cells are exposed to sunlight, due to the fluid movement between the surface and the bottom of the algal raceway, thereby affecting algal growth rate. In this work, we investigated the flow mixing performance in a table-sized model of the High Velocity Algae Raceway Integrated Design (ARID-HV). Various geometries of the raceway channels and dams were considered in both the CFD analysis and experimental flowvisualization. In the CFD simulation, the pathlines of fluid particleswere analyzed to obtain the distribution of the number of times that particles passed across a critical water depth, Dc, defined as a cycle count. In addition, the distribution of the time period fraction that the fluid particles stayed in the zones above and below Dc was recorded. Such information was used to evaluate the flow mixing in the raceway. The CFD evaluation of the flow mixing was validated using experimental flow visualization, which showed a good qualitative agreement with the numerical results. In conclusion, this CFD-based evaluation methodology is recommended for flow field optimization for open channel algal raceways, as well as for other engineering applications in which flow mixing is an important concern.
Use of Geophysical Techniques to Characterize Fluid Flow in a Geothermal
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Reservoir; 2010 Geothermal Technology Program Peer Review Report | Department of Energy Reservoir; 2010 Geothermal Technology Program Peer Review Report Use of Geophysical Techniques to Characterize Fluid Flow in a Geothermal Reservoir; 2010 Geothermal Technology Program Peer Review Report DOE 2010 Geothermal Technologies Program Peer Review reservoir_029_revil.pdf (195.46 KB) More Documents & Publications Detection and Characterization of Natural and Induced Fractures for the
Marc Cremer; Dave Wang; Connie Senior; Andrew Chiodo; Steven Hardy; Paul Wolff
2005-07-01
This is the Final Technical Report for DOE Cooperative Agreement No: DE-FC26-02NT41580. The goal of this project was to systematically assess the sensitivity of furnace operational conditions to burner air and fuel flows in coal fired utility boilers. The focus of this project was to quantify the potential impacts of ''fine level'' controls rather than that of ''coarse level'' controls (i.e. combustion tuning). Although it is well accepted that combustion tuning will generally improve efficiency and emissions of an ''out of tune'' boiler, it is not as well understood what benefits can be derived through active multiburner measurement and control systems in boiler that has coarse level controls. The approach used here was to utilize existing baseline furnace models that have been constructed using Reaction Engineering International's (REI) computational fluid dynamics (CFD) software. Using CFD analyses provides the ability to carry out a carefully controlled virtual experiment to characterize the sensitivity of NOx emissions, unburned carbon (UBC), furnace exit CO (FECO), furnace exit temperature (FEGT), and waterwall deposition to burner air and fuel flow rates. The Electric Power Research Institute (EPRI) provided co-funding for this program, and instrument and controls experts from EPRI's Instrument and Controls (I&C) Center have been active participants in this project. CFD simulations were completed for five coal fired boilers as planned: (1) 150 MW wall fired, (2) 500 MW opposed wall fired, (3) 600 MW T-Fired, (4) 330 MW cyclone-fired, and (5) 200 MW T-Fired Twin Furnace. In all cases, the unit selections were made in order to represent units that were descriptive of the utility industry as a whole. For each unit, between 25 and 44 furnace simulations were completed in order to evaluate impacts of burner to burner variations in: (1) coal and primary air flow rate, and (2) secondary air flow rate. The parametric matrices of cases that were completed were
Approximate Model for Turbulent Stagnation Point Flow.
Dechant, Lawrence
2016-01-01
Here we derive an approximate turbulent self-similar model for a class of favorable pressure gradient wedge-like flows, focusing on the stagnation point limit. While the self-similar model provides a useful gross flow field estimate this approach must be combined with a near wall model is to determine skin friction and by Reynolds analogy the heat transfer coefficient. The combined approach is developed in detail for the stagnation point flow problem where turbulent skin friction and Nusselt number results are obtained. Comparison to the classical Van Driest (1958) result suggests overall reasonable agreement. Though the model is only valid near the stagnation region of cylinders and spheres it nonetheless provides a reasonable model for overall cylinder and sphere heat transfer. The enhancement effect of free stream turbulence upon the laminar flow is used to derive a similar expression which is valid for turbulent flow. Examination of free stream enhanced laminar flow suggests that the rather than enhancement of a laminar flow behavior free stream disturbance results in early transition to turbulent stagnation point behavior. Excellent agreement is shown between enhanced laminar flow and turbulent flow behavior for high levels, e.g. 5% of free stream turbulence. Finally the blunt body turbulent stagnation results are shown to provide realistic heat transfer results for turbulent jet impingement problems.
Doughty, C.; Pruess, K.
1991-06-01
Over the past few years the authors have developed a semianalytical solution for transient two-phase water, air, and heat flow in a porous medium surrounding a constant-strength linear heat source, using a similarity variable {eta} = r/{radical}t. Although the similarity transformation approach requires a simplified geometry, all the complex physical mechanisms involved in coupled two-phase fluid and heat flow can be taken into account in a rigorous way, so that the solution may be applied to a variety of problems of current interest. The work was motivated by adverse to predict the thermohydrological response to the proposed geologic repository for heat-generating high-level nuclear wastes at Yucca Mountain, Nevada, in a partially saturated, highly fractured volcanic formation. The paper describes thermal and hydrologic conditions near the heat source; new features of the model; vapor pressure lowering; and the effective-continuum representation of a fractured/porous medium.
Thermodynamic micellization model of asphaltene precipitation from petroleum fluids
Victorov, A.I.; Firoozabadi, A.
1996-06-01
A thermodynamic micellization model is proposed for the description of asphaltene precipitation from petroleum fluids. It describes the solubilization of asphaltene polar species by resin bipolar molecules in the micelles. A simple form of the standard Gibbs free energy of micellization is used. The petroleum fluid is assumed to be a dilute solution with respect to the monomeric asphaltenes, resins, and micelles. The Peng-Robinson equation of state (PR-EOS) is applied to describe the fugacity of monomeric asphaltene in the bulk of the petroleum fluid. Intermicellar interactions as well as osmotic pressure effects are neglected. The proposed model shows promising results to describe asphaltene deposition from crude mixtures. It predicts the change in precipitation power of different alkane precipitants and the effect of pressure on asphaltene precipitation. The amount and the onset of predicted asphaltene precipitation are sensitive to the amount of resins in the crude. All these results are in line with laboratory observations and oil-field data.
Donald M. McEligot; Stefan Becker; Hugh M. McIlroy, Jr.
2010-07-01
In recent international collaboration, INL and Uni. Erlangen have developed large MIR flow systems which can be ideal for joint graduate student education and research. The benefit of the MIR technique is that it permits optical measurements to determine flow characteristics in complex passages and around objects to be obtained without locating a disturbing transducer in the flow field and without distortion of the optical paths. The MIR technique is not new itself; others employed it earlier. The innovation of these MIR systems is their large size relative to previous experiments, yielding improved spatial and temporal resolution. This report will discuss the benefits of the technique, characteristics of the systems and some examples of their applications to complex situations. Typically their experiments have provided new fundamental understanding plus benchmark data for assessment and possible validation of computational thermal fluid dynamic codes.
Fakcharoenphol, Perapon; Xiong, Yi; Hu, Litang; Winterfeld, Philip H.; Xu, Tianfu; Wu, Yu-Shu
2013-05-01
TOUGH2-EGS is a numerical simulation program coupling geomechanics and chemical reactions for fluid and heat flows in porous media and fractured reservoirs of enhanced geothermal systems. The simulator includes the fully-coupled geomechanical (THM) module, the fully-coupled geochemical (THC) module, and the sequentially coupled reactive geochemistry (THMC) module. The fully-coupled flow-geomechanics model is developed from the linear elastic theory for the thermo-poro-elastic system and is formulated with the mean normal stress as well as pore pressure and temperature. The chemical reaction is sequentially coupled after solution of flow equations, which provides the flow velocity and phase saturation for the solute transport calculation at each time step. In addition, reservoir rock properties, such as porosity and permeability, are subjected to change due to rock deformation and chemical reactions. The relationships between rock properties and geomechanical and chemical effects from poro-elasticity theories and empirical correlations are incorporated into the simulator. This report provides the user with detailed information on both mathematical models and instructions for using TOUGH2-EGS for THM, THC or THMC simulations. The mathematical models include the fluid and heat flow equations, geomechanical equation, reactive geochemistry equations, and discretization methods. Although TOUGH2-EGS has the capability for simulating fluid and heat flows coupled with both geomechanical and chemical effects, it is up to the users to select the specific coupling process, such as THM, THC, or THMC in a simulation. There are several example problems illustrating the applications of this program. These example problems are described in details and their input data are presented. The results demonstrate that this program can be used for field-scale geothermal reservoir simulation with fluid and heat flow, geomechanical effect, and chemical reaction in porous and fractured media.
Boles, James
2013-05-24
Our study targets recent (Plio-Pleistocene) faults and young (Tertiary) petroleum fields in southern California. Faults include the Refugio Fault in the Transverse Ranges, the Ellwood Fault in the Santa Barbara Channel, and most recently the Newport- Inglewood in the Los Angeles Basin. Subsurface core and tubing scale samples, outcrop samples, well logs, reservoir properties, pore pressures, fluid compositions, and published structural-seismic sections have been used to characterize the tectonic/diagenetic history of the faults. As part of the effort to understand the diagenetic processes within these fault zones, we have studied analogous processes of rapid carbonate precipitation (scaling) in petroleum reservoir tubing and manmade tunnels. From this, we have identified geochemical signatures in carbonate that characterize rapid CO2 degassing. These data provide constraints for finite element models that predict fluid pressures, multiphase flow patterns, rates and patterns of deformation, subsurface temperatures and heat flow, and geochemistry associated with large fault systems.
State-of-the-art review of computational fluid dynamics modeling for fluid-solids systems
Lyczkowski, R.W.; Bouillard, J.X.; Ding, J.; Chang, S.L.; Burge, S.W.
1994-05-12
As the result of 15 years of research (50 staff years of effort) Argonne National Laboratory (ANL), through its involvement in fluidized-bed combustion, magnetohydrodynamics, and a variety of environmental programs, has produced extensive computational fluid dynamics (CFD) software and models to predict the multiphase hydrodynamic and reactive behavior of fluid-solids motions and interactions in complex fluidized-bed reactors (FBRS) and slurry systems. This has resulted in the FLUFIX, IRF, and SLUFIX computer programs. These programs are based on fluid-solids hydrodynamic models and can predict information important to the designer of atmospheric or pressurized bubbling and circulating FBR, fluid catalytic cracking (FCC) and slurry units to guarantee optimum efficiency with minimum release of pollutants into the environment. This latter issue will become of paramount importance with the enactment of the Clean Air Act Amendment (CAAA) of 1995. Solids motion is also the key to understanding erosion processes. Erosion rates in FBRs and pneumatic and slurry components are computed by ANL`s EROSION code to predict the potential metal wastage of FBR walls, intervals, feed distributors, and cyclones. Only the FLUFIX and IRF codes will be reviewed in the paper together with highlights of the validations because of length limitations. It is envisioned that one day, these codes with user-friendly pre and post-processor software and tailored for massively parallel multiprocessor shared memory computational platforms will be used by industry and researchers to assist in reducing and/or eliminating the environmental and economic barriers which limit full consideration of coal, shale and biomass as energy sources, to retain energy security, and to remediate waste and ecological problems.
Obied Allah, M. H.
2013-04-15
In this work, a viscous potential flow analysis is used to investigate capillary surface waves between two horizontal finite fluid layers. The two layers have finite conductivities and admit mass and heat transfer. A general dispersion relation is derived. The presence of finite conductivities together with the dielectric permeabilities makes the horizontal electric field play a dual role in the stability criterion. The phenomenon of negative viscosity is observed. A new growth rate parameter, depending on the kinematical viscosity of the lower fluid layer, is found and has a stabilizing effect on the unstable modes. The growth rates and neutral stability curve are given and applied to air-water interface. The effects of various parameters are discussed for the Kelvin-Helmholtz and the Rayleigh-Taylor instabilities.
Multiphase flow modeling based on the hyperbolic thermodynamically compatible systems theory
Romenski, E.
2015-03-10
An application of the theory of thermodynamically compatible hyperbolic systems to design a multiphase compressible flow models is discussed. With the use of such approach the governing equations are derived from the first principles, formulated in a divergent form and can be transformed to a symmetric hyperbolic system in the sense of Friedrichs. A usage of the proposed approach is described for the development of multiphase compressible fluid models, including two-phase flow models.
Rutqvist, J.
2010-06-01
This paper presents recent advancement in and applications of TOUGH-FLAC, a simulator for multiphase fluid flow and geomechanics. The TOUGH-FLAC simulator links the TOUGH family multiphase fluid and heat transport codes with the commercial FLAC{sup 3D} geomechanical simulator. The most significant new TOUGH-FLAC development in the past few years is a revised architecture, enabling a more rigorous and tight coupling procedure with improved computational efficiency. The applications presented in this paper are related to modeling of crustal deformations caused by deep underground fluid movements and pressure changes as a result of both industrial activities (the In Salah CO{sub 2} Storage Project and the Geysers Geothermal Field) and natural events (the 1960s Matsushiro Earthquake Swarm). Finally, the paper provides some perspectives on the future of TOUGH-FLAC in light of its applicability to practical problems and the need for high-performance computing capabilities for field-scale problems, such as industrial-scale CO{sub 2} storage and enhanced geothermal systems. It is concluded that despite some limitations to fully adapting a commercial code such as FLAC{sup 3D} for some specialized research and computational needs, TOUGH-FLAC is likely to remain a pragmatic simulation approach, with an increasing number of users in both academia and industry.
Direct numerical simulations of fluid flow, heat transfer and phase changes
Juric, D.; Tryggvason, G.; Han, J.
1997-04-01
Direct numerical simulations of fluid flow, heat transfer, and phase changes are presented. The simulations are made possible by a recently developed finite difference/front tracking method based on the one-field formulation of the governing equations where a single set of conservation equations is written for all the phases involved. The conservation equations are solved on a fixed rectangular grid, but the phase boundaries are kept sharp by tracking them explicitly by a moving grid of lower dimension. The method is discussed and applications to boiling heat transfer and the solidification of drops colliding with a wall are shown.
The Properties of Confined Water and Fluid Flow at the Nanoscale
Schwegler, E; Reed, J; Lau, E; Prendergast, D; Galli, G; Grossman, J C; Cicero, G
2009-03-09
This project has been focused on the development of accurate computational tools to study fluids in confined, nanoscale geometries, and the application of these techniques to probe the structural and electronic properties of water confined between hydrophilic and hydrophobic substrates, including the presence of simple ions at the interfaces. In particular, we have used a series of ab-initio molecular dynamics simulations and quantum Monte Carlo calculations to build an understanding of how hydrogen bonding and solvation are modified at the nanoscale. The properties of confined water affect a wide range of scientific and technological problems - including protein folding, cell-membrane flow, materials properties in confined media and nanofluidic devices.
A Landau fluid model for dissipative trapped electron modes
Hedrick, C.L.; Leboeuf, J.N.; Sidikman, K.L.
1995-09-01
A Landau fluid model for dissipative trapped electron modes is developed which focuses on an improved description of the ion dynamics. The model is simple enough to allow nonlinear calculations with many harmonics for the times necessary to reach saturation. The model is motivated by a discussion that starts with the gyro-kinetic equation and emphasizes the importance of simultaneously including particular features of magnetic drift resonance, shear, and Landau effects. To ensure that these features are simultaneously incorporated in a Landau fluid model with only two evolution equations, a new approach to determining the closure coefficients is employed. The effect of this technique is to reduce the matching of fluid and kinetic responses to a single variable, rather than two, and to allow focusing on essential features of the fluctuations in question, rather than features that are only important for other types of fluctuations. Radially resolved nonlinear calculations of this model, advanced in time to reach saturation, are presented to partially illustrate its intended use. These calculations have a large number of poloidal and toroidal harmonics to represent the nonlinear dynamics in a converged steady state which includes cascading of energy to both short and long wavelengths.
A computational model for thermal fluid design analysis of nuclear thermal rockets
Given, J.A.; Anghaie, S.
1997-01-01
A computational model for simulation and design analysis of nuclear thermal propulsion systems has been developed. The model simulates a full-topping expander cycle engine system and the thermofluid dynamics of the core coolant flow, accounting for the real gas properties of the hydrogen propellant/coolant throughout the system. Core thermofluid studies reveal that near-wall heat transfer models currently available may not be applicable to conditions encountered within some nuclear rocket cores. Additionally, the possibility of a core thermal fluid instability at low mass fluxes and the effects of the core power distribution are investigated. Results indicate that for tubular core coolant channels, thermal fluid instability is not an issue within the possible range of operating conditions in these systems. Findings also show the advantages of having a nonflat centrally peaking axial core power profile from a fluid dynamic standpoint. The effects of rocket operating conditions on system performance are also investigated. Results show that high temperature and low pressure operation is limited by core structural considerations, while low temperature and high pressure operation is limited by system performance constraints. The utility of these programs for finding these operational limits, optimum operating conditions, and thermal fluid effects is demonstrated.
Fuel cell assembly fluid flow plate having conductive fibers and rigidizing material therein
Walsh, Michael M.
2000-01-01
A fluid flow plate is preferably formed with three initial sections, for instance, two layers of conductive (e.g., metal) fibers and a barrier material (e.g., metal foil) which is interposed between the two layers. For example, sintering of these three sections can provide electrical path(s) between outer faces of the two layers. Then, the sintered sections can be, for instance, placed in a mold for forming of flow channel(s) into one or more of the outer faces. Next, rigidizing material (e.g., resin) can be injected into the mold, for example, to fill and/or seal space(s) about a conductive matrix of the electrical path(s). Preferably, abrading of surface(s) of the outer face(s) serves to expose electrical contact(s) to the electrical path(s).
Dr. Chenn Zhou
2008-10-15
Pulverized coal injection (PCI) into the blast furnace (BF) has been recognized as an effective way to decrease the coke and total energy consumption along with minimization of environmental impacts. However, increasing the amount of coal injected into the BF is currently limited by the lack of knowledge of some issues related to the process. It is therefore important to understand the complex physical and chemical phenomena in the PCI process. Due to the difficulty in attaining trus BF measurements, Computational fluid dynamics (CFD) modeling has been identified as a useful technology to provide such knowledge. CFD simulation is powerful for providing detailed information on flow properties and performing parametric studies for process design and optimization. In this project, comprehensive 3-D CFD models have been developed to simulate the PCI process under actual furnace conditions. These models provide raceway size and flow property distributions. The results have provided guidance for optimizing the PCI process.
Paul Meakin; Zhijie Xu
2008-06-01
Particle methods are much less computationally efficient than grid based numerical solution of the Navier Stokes equation, and they have been used much less extensively, particularly for engineering applications. However, they have important advantages for some applications. These advantages include rigorous mast conservation, momentum conservation and isotropy. In addition, there is no need for explicit interface tracking/capturing. Code development effort is relatively low, and it is relatively simple to simulate flows with moving boundaries. In addition, it is often quite easy to include coupling of fluid flow with other physical phenomena such a phase separation. Here we describe the application of three particle methods: molecular dynamics, dissipative particle dynamics and smoothed particle hydrodynamics. While these methods were developed to simulate fluids and other materials on three quite different scales the molecular, meso and continuum scales, they are very closely related from a computational point of view. The mesoscale (between the molecular and continuum scales) dissipative particle dynamics method can be used to simulate systems that are too large to simulate using molecular dynamics but small enough for thermal fluctuations to play an important role. Important examples include polymer solutions, gels, small particle suspensions and membranes. In these applications inter particle and intra molecular hydrodynamic interactions are automatically included
Potential Hydraulic Modelling Errors Associated with Rheological Data Extrapolation in Laminar Flow
Shadday, Martin A., Jr.
1997-03-20
The potential errors associated with the modelling of flows of non-Newtonian slurries through pipes, due to inadequate rheological models and extrapolation outside of the ranges of data bases, are demonstrated. The behaviors of both dilatant and pseudoplastic fluids with yield stresses, and the errors associated with treating them as Bingham plastics, are investigated.
PROBABILISTIC SIMULATION OF SUBSURFACE FLUID FLOW: A STUDY USING A NUMERICAL SCHEME
Buscheck, Timothy Eric
1980-03-01
There has been an increasing interest in probabilistic modeling of hydrogeologic systems. The classical approach to groundwater modeling has been deterministic in nature, where individual layers and formations are assumed to be uniformly homogeneous. Even in the case of complex heterogeneous systems, the heterogeneities describe the differences in parameter values between various layers, but not within any individual layer. In a deterministic model a single-number is assigned to each hydrogeologic parameter, given a particular scale of interest. However, physically there is no such entity as a truly uniform and homogeneous unit. Single-number representations or deterministic predictions are subject to uncertainties. The approach used in this work models such uncertainties with probabilistic parameters. The resulting statistical distributions of output variables are analyzed. A numerical algorithm, based on axiomatic principles of probability theory, performs arithmetic operations between probability distributions. Two subroutines are developed from the algorithm and incorporated into the computer program TERZAGI, which solves groundwater flow problems in saturated, multi-dimensional systems. The probabilistic computer program is given the name, PROGRES. The algorithm has been applied to study the following problems: one-dimensional flow through homogeneous media, steady-state and transient flow conditions, one-dimensional flow through heterogeneous media, steady-state and transient flow conditions, and two-dimensional steady-stte flow through heterogeneous media. The results are compared with those available in the literature.
Modeling interfacial area transport in multi-fluid systems
Yarbro, S.L.
1996-11-01
Many typical chemical engineering operations are multi-fluid systems. They are carried out in distillation columns (vapor/liquid), liquid-liquid contactors (liquid/liquid) and other similar devices. An important parameter is interfacial area concentration, which determines the rate of interfluid heat, mass and momentum transfer and ultimately, the overall performance of the equipment. In many cases, the models for determining interfacial area concentration are empirical and can only describe the cases for which there is experimental data. In an effort to understand multiphase reactors and the mixing process better, a multi-fluid model has been developed as part of a research effort to calculate interfacial area transport in several different types of in-line static mixers. For this work, the ensemble-averaged property conservation equations have been derived for each fluid and for the mixture. These equations were then combined to derive a transport equation for the interfacial area concentration. The final, one-dimensional model was compared to interfacial area concentration data from two sizes of Kenics in-line mixer, two sizes of concurrent jet and a Tee mixer. In all cases, the calculated and experimental data compared well with the highest scatter being with the Tee mixer comparison.
Mukhopadhyay, Sumit; Tsang, Yvonne W.
2008-08-01
Flowing fluid temperature logging (FFTL) has been recently proposed as a method to locate flowing fractures. We argue that FFTL, backed up by data from high-precision distributed temperature sensors, can be a useful tool in locating flowing fractures and in estimating the transport properties of unsaturated fractured rocks. We have developed the theoretical background needed to analyze data from FFTL. In this paper, we present a simplified conceptualization of FFTL in unsaturated fractured rock, and develop a semianalytical solution for spatial and temporal variations of pressure and temperature inside a borehole in response to an applied perturbation (pumping of air from the borehole). We compare the semi-analytical solution with predictions from the TOUGH2 numerical simulator. Based on the semi-analytical solution, we propose a method to estimate the permeability of the fracture continuum surrounding the borehole. Using this proposed method, we estimated the effective fracture continuum permeability of the unsaturated rock hosting the Drift Scale Test (DST) at Yucca Mountain, Nevada. Our estimate compares well with previous independent estimates for fracture permeability of the DST host rock. The conceptual model of FFTL presented in this paper is based on the assumptions of single-phase flow, convection-only heat transfer, and negligible change in system state of the rock formation. In a sequel paper [Mukhopadhyay et al., 2008], we extend the conceptual model to evaluate some of these assumptions. We also perform inverse modeling of FFTL data to estimate, in addition to permeability, other transport parameters (such as porosity and thermal conductivity) of unsaturated fractured rocks.
Xiong, Yi; Fakcharoenphol, Perapon; Wang, Shihao; Winterfeld, Philip H.; Zhang, Keni; Wu, Yu-Shu
2013-12-01
TOUGH2-EGS-MP is a parallel numerical simulation program coupling geomechanics with fluid and heat flow in fractured and porous media, and is applicable for simulation of enhanced geothermal systems (EGS). TOUGH2-EGS-MP is based on the TOUGH2-MP code, the massively parallel version of TOUGH2. In TOUGH2-EGS-MP, the fully-coupled flow-geomechanics model is developed from linear elastic theory for thermo-poro-elastic systems and is formulated in terms of mean normal stress as well as pore pressure and temperature. Reservoir rock properties such as porosity and permeability depend on rock deformation, and the relationships between these two, obtained from poro-elasticity theories and empirical correlations, are incorporated into the simulation. This report provides the user with detailed information on the TOUGH2-EGS-MP mathematical model and instructions for using it for Thermal-Hydrological-Mechanical (THM) simulations. The mathematical model includes the fluid and heat flow equations, geomechanical equation, and discretization of those equations. In addition, the parallel aspects of the code, such as domain partitioning and communication between processors, are also included. Although TOUGH2-EGS-MP has the capability for simulating fluid and heat flows coupled with geomechanical effects, it is up to the user to select the specific coupling process, such as THM or only TH, in a simulation. There are several example problems illustrating applications of this program. These example problems are described in detail and their input data are presented. Their results demonstrate that this program can be used for field-scale geothermal reservoir simulation in porous and fractured media with fluid and heat flow coupled with geomechanical effects.
Review and selection of unsaturated flow models
Reeves, M.; Baker, N.A.; Duguid, J.O.
1994-04-04
Since the 1960`s, ground-water flow models have been used for analysis of water resources problems. In the 1970`s, emphasis began to shift to analysis of waste management problems. This shift in emphasis was largely brought about by site selection activities for geologic repositories for disposal of high-level radioactive wastes. Model development during the 1970`s and well into the 1980`s focused primarily on saturated ground-water flow because geologic repositories in salt, basalt, granite, shale, and tuff were envisioned to be below the water table. Selection of the unsaturated zone at Yucca Mountain, Nevada, for potential disposal of waste began to shift model development toward unsaturated flow models. Under the US Department of Energy (DOE), the Civilian Radioactive Waste Management System Management and Operating Contractor (CRWMS M&O) has the responsibility to review, evaluate, and document existing computer models; to conduct performance assessments; and to develop performance assessment models, where necessary. This document describes the CRWMS M&O approach to model review and evaluation (Chapter 2), and the requirements for unsaturated flow models which are the bases for selection from among the current models (Chapter 3). Chapter 4 identifies existing models, and their characteristics. Through a detailed examination of characteristics, Chapter 5 presents the selection of models for testing. Chapter 6 discusses the testing and verification of selected models. Chapters 7 and 8 give conclusions and make recommendations, respectively. Chapter 9 records the major references for each of the models reviewed. Appendix A, a collection of technical reviews for each model, contains a more complete list of references. Finally, Appendix B characterizes the problems used for model testing.
Charge flow model for atomic ordering in nonisovalent alloys...
Office of Scientific and Technical Information (OSTI)
Charge flow model for atomic ordering in nonisovalent alloys Title: Charge flow model for atomic ordering in nonisovalent alloys Authors: Wang, Shuzhi ; Wang, Lin-Wang Publication ...
A Multidimensional Eulerian Model for Simulating Gas-Solids Flow
Energy Science and Technology Software Center (OSTI)
1993-12-13
FORCE2 is a fundamentally based three-dimensional numerical model for simulating fluid-bed hydrodynamics for a wide range of fluid beds, from laboratory to plant scale. It is based upon the ''two-fluid'' modeling approach and includes surface permeabilities, volume porosities, and distributed resistances.
A model for transonic plasma flow
Guazzotto, Luca; Hameiri, Eliezer
2014-02-15
A linear, two-dimensional model of a transonic plasma flow in equilibrium is constructed and given an explicit solution in the form of a complex Laplace integral. The solution indicates that the transonic state can be solved as an elliptic boundary value problem, as is done in the numerical code FLOW [Guazzotto et al., Phys. Plasmas 11, 604 (2004)]. Moreover, the presence of a hyperbolic region does not necessarily imply the presence of a discontinuity or any other singularity of the solution.
Lopez, A.R.; Gritzo, L.A.; Hassan, B.
1997-06-01
For the purposes of designing improved Halon-alternative fire suppression strategies for aircraft applications, Computational Fluid Dynamics (CFD) simulations of the air flow, suppressant transport, and air-suppressant mixing within an uncluttered F18 engine nacelle were performed. The release of inert gases from a Solid Propellant Gas Generator (SPGG) was analyzed at two different injection locations in order to understand the effect of injection position on the flow patterns and the mixing of air and suppression agent. An uncluttered engine nacelle was simulated to provide insight into the global flow features as well as to promote comparisons with previous nacelle fire tests and recent water tunnel tests which included little or no clutter. Oxygen concentration levels, fuel/air residence times that would exist if a small fuel leak were present, velocity contours, and streamline patterns are presented inside the engine nacelle. The numerical results show the influence of the gent release location on regions of potential flame extinction due to oxygen inerting and high flame strain. The occurrence of inflow through the exhaust ducts on the aft end of the nacelle is also predicted. As expected, the predicted oxygen concentration levels were consistently higher than the measured levels since a fire was not modeled in this analysis. Despite differences in the conditions of these simulations and the experiments, good agreement was obtained between the CFD predictions and the experimental measurements.
Multiparticle imaging technique for two-phase fluid flows using pulsed laser speckle velocimetry
Hassan, T.A.
1992-12-01
The practical use of Pulsed Laser Velocimetry (PLV) requires the use of fast, reliable computer-based methods for tracking numerous particles suspended in a fluid flow. Two methods for performing tracking are presented. One method tracks a particle through multiple sequential images (minimum of four required) by prediction and verification of particle displacement and direction. The other method, requiring only two sequential images uses a dynamic, binary, spatial, cross-correlation technique. The algorithms are tested on computer-generated synthetic data and experimental data which was obtained with traditional PLV methods. This allowed error analysis and testing of the algorithms on real engineering flows. A novel method is proposed which eliminates tedious, undersirable, manual, operator assistance in removing erroneous vectors. This method uses an iterative process involving an interpolated field produced from the most reliable vectors. Methods are developed to allow fast analysis and presentation of sets of PLV image data. Experimental investigation of a two-phase, horizontal, stratified, flow regime was performed to determine the interface drag force, and correspondingly, the drag coefficient. A horizontal, stratified flow test facility using water and air was constructed to allow interface shear measurements with PLV techniques. The experimentally obtained local drag measurements were compared with theoretical results given by conventional interfacial drag theory. Close agreement was shown when local conditions near the interface were similar to space-averaged conditions. However, theory based on macroscopic, space-averaged flow behavior was shown to give incorrect results if the local gas velocity near the interface as unstable, transient, and dissimilar from the average gas velocity through the test facility.
Wind Turbine Modeling for Computational Fluid Dynamics: December 2010 - December 2012
Tossas, L. A. M.; Leonardi, S.
2013-07-01
With the shortage of fossil fuel and the increasing environmental awareness, wind energy is becoming more and more important. As the market for wind energy grows, wind turbines and wind farms are becoming larger. Current utility-scale turbines extend a significant distance into the atmospheric boundary layer. Therefore, the interaction between the atmospheric boundary layer and the turbines and their wakes needs to be better understood. The turbulent wakes of upstream turbines affect the flow field of the turbines behind them, decreasing power production and increasing mechanical loading. With a better understanding of this type of flow, wind farm developers could plan better-performing, less maintenance-intensive wind farms. Simulating this flow using computational fluid dynamics is one important way to gain a better understanding of wind farm flows. In this study, we compare the performance of actuator disc and actuator line models in producing wind turbine wakes and the wake-turbine interaction between multiple turbines. We also examine parameters that affect the performance of these models, such as grid resolution, the use of a tip-loss correction, and the way in which the turbine force is projected onto the flow field.
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Joint inversion of electrical and seismic data for Fracture char. and Imaging of Fluid Flow in Geothermal Systems Michael Batzle, PI Colorado School of Mines Track Name: Fluid Imaging Project Officer: Eric Hess Total Project Funding: $1,246, 579 April 22, 2013 This presentation does not contain any proprietary confidential, or otherwise restricted information. 2 | US DOE Geothermal Office eere.energy.gov Relevance/Impact of Research Project objectives * Use combined inversion of geophysical data
Slurry fired heater cold-flow modelling
Moujaes, S.F.
1983-07-01
This report summarizes the experimental and theoretical work leading to the scale-up of the SRC-I Demonstration Plant slurry fired heater. The scale-up involved a theoretical model using empirical relations in the derivation, and employed variables such as flow conditions, liquid viscosity, and slug frequency. Such variables have been shown to affect the heat transfer characteristics ofthe system. The model assumes that, if all other variables remain constant, the heat transfer coefficient can be scaled up proportional to D/sup -2/3/ (D = inside diameter of the fired heater tube). All flow conditions, liquid viscosities, and pipe inclinations relevant to the demonstration plant have indicated a slug flow regime in the slurry fired heater. The annular and stratified flow regimes should be avoided to minimize the potential for excessive pipe erosion and to decrease temperature gradients along the pipe cross section leading to coking and thermal stresses, respectively. Cold-flow studies in 3- and 6.75-in.-inside-diameter (ID) pipes were conducted to determine the effect of scale-up on flow regime, slug frequency, and slug dimensions. The developed model assumes that conduction heat transfer occurs through the liquid film surrounding the gas slug and laminar convective heat transfer to the liquid slug. A weighted average of these two heat transfer mechanisms gives a value for the average pipe heat transfer coefficient. The cold-flow work showed a decrease in the observed slug frequency between the 3- and 6.75-ID pipes. Data on the ratio of gas to liquid slug length in the 6.75-in. pipe are not yet complete, but are expected to yield generally lower values than those obtained in the 3-in. pipe; this will probably affect the scale-up to demonstration plant conditions. 5 references, 15 figures, 7 tables.
Spane, Frank A.
2013-04-29
Preliminary Analysis of Grande Ronde Basalt Formation Flow Top Transmissivity as it Relates to Assessment and Site Selection Applications for Fluid/Energy Storage and Sequestration Projects
Microtomography and pore-scale modeling of two-phase Fluid Distribution
Silin, D.; Tomutsa, L.; Benson, S.; Patzek, T.
2010-10-19
Synchrotron-based X-ray microtomography (micro CT) at the Advanced Light Source (ALS) line 8.3.2 at the Lawrence Berkeley National Laboratory produces three-dimensional micron-scale-resolution digital images of the pore space of the reservoir rock along with the spacial distribution of the fluids. Pore-scale visualization of carbon dioxide flooding experiments performed at a reservoir pressure demonstrates that the injected gas fills some pores and pore clusters, and entirely bypasses the others. Using 3D digital images of the pore space as input data, the method of maximal inscribed spheres (MIS) predicts two-phase fluid distribution in capillary equilibrium. Verification against the tomography images shows a good agreement between the computed fluid distribution in the pores and the experimental data. The model-predicted capillary pressure curves and tomography-based porosimetry distributions compared favorably with the mercury injection data. Thus, micro CT in combination with modeling based on the MIS is a viable approach to study the pore-scale mechanisms of CO{sub 2} injection into an aquifer, as well as more general multi-phase flows.
Carrington, David Bradley; Monayem, A. K. M.; Mazumder, H.; Heinrich, Juan C.
2015-03-05
A three-dimensional finite element method for the numerical simulations of fluid flow in domains containing moving rigid objects or boundaries is developed. The method falls into the general category of Arbitrary Lagrangian Eulerian methods; it is based on a fixed mesh that is locally adapted in the immediate vicinity of the moving interfaces and reverts to its original shape once the moving interfaces go past the elements. The moving interfaces are defined by separate sets of marker points so that the global mesh is independent of interface movement and the possibility of mesh entanglement is eliminated. The results is a fully robust formulation capable of calculating on domains of complex geometry with moving boundaries or devises that can also have a complex geometry without danger of the mesh becoming unsuitable due to its continuous deformation thus eliminating the need for repeated re-meshing and interpolation. Moreover, the boundary conditions on the interfaces are imposed exactly. This work is intended to support the internal combustion engines simulator KIVA developed at Los Alamos National Laboratories. The model's capabilities are illustrated through application to incompressible flows in different geometrical settings that show the robustness and flexibility of the technique to perform simulations involving moving boundaries in a three-dimensional domain.
The handbook of fluid dynamics
Johnson, R.W.
1998-07-01
This book provides professionals in the field of fluid dynamics with a comprehensive guide and resource. The book balances three traditional areas of fluid mechanics--theoretical, computational, and experimental--and expounds on basic science and engineering techniques. Each chapter introduces a topic, discusses the primary issues related to this subject, outlines approaches taken by experts, and supplies references for further information. Topics discussed include: (1) basic engineering fluid dynamics; (2) classical fluid dynamics; (3) turbulence modeling; (4) reacting flows; (5) multiphase flows; (6) flow and porous media; (7) high Reynolds number asymptotic theories; (8) finite difference method; (9) finite volume method; (10) finite element methods; (11) spectral element methods for incompressible flows; (12) experimental methods, such as hot-wire anemometry, laser-Doppler velocimetry, and flow visualization; and (13) applications, such as axial-flow compressor and fan aerodynamics, turbomachinery, airfoils and wings, atmospheric flows, and mesoscale oceanic flows.
Real-time fluid flow model for control of solidification
Kraftick, K.; Sholl, P.
1985-07-01
The Atomic Vapor Laser Isotope Separation (AVLIS) process is an advanced uranium enrichment technology being developed by the Lawrence Livermore National Laboratory. This process is designed to increase the concentration of /sup 235/U in uranium from 0.7% as found in nature to approximately 3% as required for light water nuclear reactor fuel. Separation is accomplished by vaporizing uranium, selectively ionizing /sup 235/U atoms and electromagnetically collecting these ions. The electromagnetic collector system utilizes resistance heaters to maintain a temperature range defined by the melting point of the metal product and tails collected and the materials compatibility limits between the liquid metal and the structure. If temperatures are not within these bounds, metal freezing or structural damage may occur which disrupts the process. Additionally, inappropriate heater usage could result in heater burn-out or overheating.
TOUGH +: Modeling Fluid and Heat Flow in Porous and Fractured...
U.S. Department of Energy (DOE) all webpages (Extended Search)
Contact LBL About This Technology Technology Marketing SummaryTOUGH+ is a general-purpose ... For more information or to license TOUGH + software go to: http:esd.lbl.govTOUGHPLUS...
CFD modeling of entrained-flow coal gasifiers with improved physical and chemical sub-models
Ma, J.; Zitney, S.
2012-01-01
Optimization of an advanced coal-fired integrated gasification combined cycle system requires an accurate numerical prediction of gasifier performance. While the turbulent multiphase reacting flow inside entrained-flow gasifiers has been modeled through computational fluid dynamic (CFD), the accuracy of sub-models requires further improvement. Built upon a previously developed CFD model for entrained-flow gasification, the advanced physical and chemical sub-models presented here include a moisture vaporization model with consideration of high mass transfer rate, a coal devolatilization model with more species to represent coal volatiles and heating rate effect on volatile yield, and careful selection of global gas phase reaction kinetics. The enhanced CFD model is applied to simulate two typical oxygen-blown entrained-flow configurations including a single-stage down-fired gasifier and a two-stage up-fired gasifier. The CFD results are reasonable in terms of predicted carbon conversion, syngas exit temperature, and syngas exit composition. The predicted profiles of velocity, temperature, and species mole fractions inside the entrained-flow gasifier models show trends similar to those observed in a diffusion-type flame. The predicted distributions of mole fractions of major species inside both gasifiers can be explained by the heterogeneous combustion and gasification reactions and the homogeneous gas phase reactions. It was also found that the syngas compositions at the CFD model exits are not in chemical equilibrium, indicating the kinetics for both heterogeneous and gas phase homogeneous reactions are important. Overall, the results achieved here indicate that the gasifier models reported in this paper are reliable and accurate enough to be incorporated into process/CFD co-simulations of IGCC power plants for systemwide design and optimization.
Matzen, G.W.
1997-01-01
Three-dimensional creeping flow around single, axisymmetric protrusions is studied numerically using the boundary-integral technique. Emphasis is placed upon cylindrical protrusions on plane walls for various height-to-radius (h-to-a) aspect ratios, but cones and sections of spheres protruding from plane walls are also briefly examined. The presented items include shear-stress distributions, shear-stress contours, extents of the fluid-flow disturbance, total forces and torques on the cylinders, streamlines, and skin-friction lines. Also included is a discussion of flow topology around axisymmetric geometries. No flow reversal is observed for cylindrical protrusions with aspect ratios greater than 2.4 to 2.6. At higher aspect ratios, the fluid tends to be swept around cylindrical protrusions with little vertical motion. At lower aspect ratios, the strength of the recirculation increases, and the recirculation region becomes wider in the transverse direction and narrower in the flow direction. Also, the recirculation pattern begins to resemble the closed streamline patterns in two-dimensional flow over square ridges. However, unlike two-dimensional flow, closed streamline patterns are not observed. For arbitrary axisymmetric geometries, the extent of the fluid-flow disturbance can be estimated with the total force that is exerted on the protrusion. When the same force is exerted on protrusions with different aspect ratios, the protrusion with the higher aspect ratio tends to have a greater disturbance in the flow direction and a smaller disturbance in the transverse direction. The total force exerted on cylindrical protrusions with rounded corners is only slightly lower than the total force exerted on cylindrical protrusions with sharp corners.
FLUID-STRUCTURE INTERACTION MODELS OF THE MITRAL VALVE: FUNCTION IN NORMAL AND PATHOLOGIC STATES
Kunzelman, K. S.; Einstein, Daniel R.; Cochran, R. P.
2007-08-29
Successful mitral valve repair is dependent upon a full understanding of normal and abnormal mitral valve anatomy and function. Computational analysis is one such method that can be applied to simulate mitral valve function in order to analyze the roles of individual components, and evaluate proposed surgical repair. We developed the first three-dimensional, finite element (FE) computer model of the mitral valve including leaflets and chordae tendineae, however, one critical aspect that has been missing until the last few years was the evaluation of fluid flow, as coupled to the function of the mitral valve structure. We present here our latest results for normal function and specific pathologic changes using a fluid-structure interaction (FSI) model. Normal valve function was first assessed, followed by pathologic material changes in collagen fiber volume fraction, fiber stiffness, fiber splay, and isotropic stiffness. Leaflet and chordal stress and strain, and papillary muscle force was determined. In addition, transmitral flow, time to leaflet closure, and heart valve sound were assessed. Model predictions in the normal state agreed well with a wide range of available in-vivo and in-vitro data. Further, pathologic material changes that preserved the anisotropy of the valve leaflets were found to preserve valve function. By contrast, material changes that altered the anisotropy of the valve were found to profoundly alter valve function. The addition of blood flow and an experimentally driven microstructural description of mitral tissue represent significant advances in computational studies of the mitral valve, which allow further insight to be gained. This work is another building block in the foundation of a computational framework to aid in the refinement and development of a truly noninvasive diagnostic evaluation of the mitral valve. Ultimately, it represents the basis for simulation of surgical repair of pathologic valves in a clinical and educational
Zou, Ling; Zhao, Haihua; Zhang, Hongbin
2016-03-09
This work represents a first-of-its-kind successful application to employ advanced numerical methods in solving realistic two-phase flow problems with two-fluid six-equation two-phase flow model. These advanced numerical methods include high-resolution spatial discretization scheme with staggered grids (high-order) fully implicit time integration schemes, and Jacobian-free Newton–Krylov (JFNK) method as the nonlinear solver. The computer code developed in this work has been extensively validated with existing experimental flow boiling data in vertical pipes and rod bundles, which cover wide ranges of experimental conditions, such as pressure, inlet mass flux, wall heat flux and exit void fraction. Additional code-to-code benchmark with the RELAP5-3Dmore » code further verifies the correct code implementation. The combined methods employed in this work exhibit strong robustness in solving two-phase flow problems even when phase appearance (boiling) and realistic discrete flow regimes are considered. Transitional flow regimes used in existing system analysis codes, normally introduced to overcome numerical difficulty, were completely removed in this work. As a result, this in turn provides the possibility to utilize more sophisticated flow regime maps in the future to further improve simulation accuracy.« less
Lee, S. W.; Park, S. D.; Kang, S.; Kim, S. M.; Seo, H.; Lee, D. W.; Bang, I. C.
2012-07-01
Critical heat flux (CHF) is the thermal limit of a phenomenon in which a phase change occurs during heating (such as bubbles forming on a metal surface used to heat water), which suddenly decreases the heat transfer efficiency, thus causing localized overheating of the heating surface. The enhancement of CHF can increase the safety margins and allow operation at higher heat fluxes; thus, it can increase the economy. A very interesting characteristics of nano-fluids is their ability to significantly enhance the CHF. nano-fluids are nano-technology-based colloidal dispersions engineered through stable suspending of nanoparticles. All experiments were performed in round tubes with an inner diameter of 0.01041 m and a length of 0.5 m under low pressure and low flow (LPLF) conditions at a fixed inlet temperature using water, 0.01 vol. % Al{sub 2}O{sub 3}/water and SiC/water nano-fluids. It was found that the CHF of the nano-fluids was enhanced and the CHF of the SiC/water nano-fluid was more enhanced than that of the Al{sub 2}O{sub 3}/water nano-fluid. (authors)
High vacuum measurements and calibrations, molecular flow fluid transient effects
Leishear, Robert A.; Gavalas, Nickolas A.
2015-04-29
High vacuum pressure measurements and calibrations below 1 × 10^{-8} Torr are problematic. Specifically, measurement accuracies change drastically for vacuum gauges when pressures are suddenly lowered in vacuum systems. How can gauges perform like this? A brief system description is first required to answer this question. Calibrations were performed using a vacuum calibration chamber with attached vacuum gauges. To control chamber pressures, vacuum pumps decreased the chamber pressure while nitrogen tanks increased the chamber pressure. By balancing these opposing pressures, equilibrium in the chamber was maintained at selected set point pressures to perform calibrations. When pressures were suddenly decreased during set point adjustments, a sudden rush of gas from the chamber also caused a surge of gas from the gauges to decrease the pressures in those gauges. Gauge pressures did not return to equilibrium as fast as chamber pressures due to the sparse distribution of gas molecules in the system. This disparity in the rate of pressure changes caused the pressures in different gauges to be different than expected. This discovery was experimentally proven to show that different gauge designs return to equilibrium at different rates, and that gauge accuracies vary for different gauge designs due to fluid transients in molecular flow.
High vacuum measurements and calibrations, molecular flow fluid transient effects
Leishear, Robert A.; Gavalas, Nickolas A.
2015-04-29
High vacuum pressure measurements and calibrations below 1 × 10-8 Torr are problematic. Specifically, measurement accuracies change drastically for vacuum gauges when pressures are suddenly lowered in vacuum systems. How can gauges perform like this? A brief system description is first required to answer this question. Calibrations were performed using a vacuum calibration chamber with attached vacuum gauges. To control chamber pressures, vacuum pumps decreased the chamber pressure while nitrogen tanks increased the chamber pressure. By balancing these opposing pressures, equilibrium in the chamber was maintained at selected set point pressures to perform calibrations. When pressures were suddenly decreased duringmore » set point adjustments, a sudden rush of gas from the chamber also caused a surge of gas from the gauges to decrease the pressures in those gauges. Gauge pressures did not return to equilibrium as fast as chamber pressures due to the sparse distribution of gas molecules in the system. This disparity in the rate of pressure changes caused the pressures in different gauges to be different than expected. This discovery was experimentally proven to show that different gauge designs return to equilibrium at different rates, and that gauge accuracies vary for different gauge designs due to fluid transients in molecular flow.« less
High vacuum measurements and calibrations, molecular flow fluidtransient effects
Leishear, Robert A.; Gavalas, Nickolas A.
2015-04-29
High vacuum pressure measurements and calibrations below 1 10^{-8} Torr are problematic. Specifically, measurement accuracies change drastically for vacuum gauges when pressures are suddenly lowered in vacuum systems. How can gauges perform like this? A brief system description is first required to answer this question. Calibrations were performed using a vacuum calibration chamber with attached vacuum gauges. To control chamber pressures, vacuum pumps decreased the chamber pressure while nitrogen tanks increased the chamber pressure. By balancing these opposing pressures, equilibrium in the chamber was maintained at selected set point pressures to perform calibrations. When pressures were suddenly decreased during set point adjustments, a sudden rush of gas from the chamber also caused a surge of gas from the gauges to decrease the pressures in those gauges. Gauge pressures did not return to equilibrium as fast as chamber pressures due to the sparse distribution of gas molecules in the system. This disparity in the rate of pressure changes caused the pressures in different gauges to be different than expected. This discovery was experimentally proven to show that different gauge designs return to equilibrium at different rates, and that gauge accuracies vary for different gauge designs due to fluid transients in molecular flow.
A Smoothed Particle Hydrodynamics-Based Fluid Model With a Spatially
U.S. Department of Energy (DOE) all webpages (Extended Search)
Dependent Viscosity | Argonne Leadership Computing Facility Smoothed Particle Hydrodynamics-Based Fluid Model With a Spatially Dependent Viscosity Authors: Martys, N.S., George, W.L., Chun, B., Lootens, D. A smoothed particle hydrodynamics approach is utilized to model a non-Newtonian fluid with a spatially varying viscosity. In the limit of constant viscosity, this approach recovers an earlier model for Newtonian fluids of Espa Publication Date: September, 2010 Name of Publication Source:
Williams, P.T.
1993-09-01
As the field of computational fluid dynamics (CFD) continues to mature, algorithms are required to exploit the most recent advances in approximation theory, numerical mathematics, computing architectures, and hardware. Meeting this requirement is particularly challenging in incompressible fluid mechanics, where primitive-variable CFD formulations that are robust, while also accurate and efficient in three dimensions, remain an elusive goal. This dissertation asserts that one key to accomplishing this goal is recognition of the dual role assumed by the pressure, i.e., a mechanism for instantaneously enforcing conservation of mass and a force in the mechanical balance law for conservation of momentum. Proving this assertion has motivated the development of a new, primitive-variable, incompressible, CFD algorithm called the Continuity Constraint Method (CCM). The theoretical basis for the CCM consists of a finite-element spatial semi-discretization of a Galerkin weak statement, equal-order interpolation for all state-variables, a 0-implicit time-integration scheme, and a quasi-Newton iterative procedure extended by a Taylor Weak Statement (TWS) formulation for dispersion error control. Original contributions to algorithmic theory include: (a) formulation of the unsteady evolution of the divergence error, (b) investigation of the role of non-smoothness in the discretized continuity-constraint function, (c) development of a uniformly H{sup 1} Galerkin weak statement for the Reynolds-averaged Navier-Stokes pressure Poisson equation, (d) derivation of physically and numerically well-posed boundary conditions, and (e) investigation of sparse data structures and iterative methods for solving the matrix algebra statements generated by the algorithm.
U.S. Department of Energy (DOE) all webpages (Extended Search)
Fascinating Fluids Fascinating Fluids From liquids to gases, we take on this most fascinating compound with hands-on activities for children and adults alike. We are made of fluids, mostly water, arguably the most interesting compound in the universe. Think About This Liquids Fluids are amazing. Fluids flow. Liquids have variable shapes but almost constant volumes. Gases Gases take the shape of their containers and can be squeezed and stretched relatively easily. Sand What is fine sand? It is a
Observing and modeling Earths energy flows
Stevens B.; Schwartz S.
2012-05-11
This article reviews, from the authors perspective, progress in observing and modeling energy flows in Earth's climate system. Emphasis is placed on the state of understanding of Earth's energy flows and their susceptibility to perturbations, with particular emphasis on the roles of clouds and aerosols. More accurate measurements of the total solar irradiance and the rate of change of ocean enthalpy help constrain individual components of the energy budget at the top of the atmosphere to within {+-}2 W m{sup -2}. The measurements demonstrate that Earth reflects substantially less solar radiation and emits more terrestrial radiation than was believed even a decade ago. Active remote sensing is helping to constrain the surface energy budget, but new estimates of downwelling surface irradiance that benefit from such methods are proving difficult to reconcile with existing precipitation climatologies. Overall, the energy budget at the surface is much more uncertain than at the top of the atmosphere. A decade of high-precision measurements of the energy budget at the top of the atmosphere is providing new opportunities to track Earth's energy flows on timescales ranging from days to years, and at very high spatial resolution. The measurements show that the principal limitation in the estimate of secular trends now lies in the natural variability of the Earth system itself. The forcing-feedback-response framework, which has developed to understand how changes in Earth's energy flows affect surface temperature, is reviewed in light of recent work that shows fast responses (adjustments) of the system are central to the definition of the effective forcing that results from a change in atmospheric composition. In many cases, the adjustment, rather than the characterization of the compositional perturbation (associated, for instance, with changing greenhouse gas concentrations, or aerosol burdens), limits accurate determination of the radiative forcing. Changes in clouds
Modeling of Immiscible, Two-Phase Flows in a Natural Rock Fracture
Crandall, Dustin; Ahmadi, Goodarz; Smith, Duane H
2009-01-01
One potential method of geologically sequestering carbon dioxide (CO2) is to inject the gas into brine-filled, subsurface formations. Within these low-permeability rocks, fractures exist that can act as natural fluid conduits. Understanding how a less viscous fluid moves when injected into an initially saturated rock fracture is important for the prediction of CO2 transport within fractured rocks. Our study examined experimentally and numerically the motion of immiscible fluids as they were transported through models of a fracture in Berea sandstone. The natural fracture geometry was initially scanned using micro-computerized tomography (CT) at a fine volume-pixel (voxel) resolution by Karpyn et al. [1]. This CT scanned fracture was converted into a numerical mesh for two-phase flow calculations using the finite-volume solver FLUENT® and the volume-of-fluid method. Additionally, a translucent experimental model was constructed using stereolithography. The numerical model was shown to agree well with experiments for the case of a constant rate injection of air into the initially water-saturated fracture. The invading air moved intermittently, quickly invading large-aperture regions of the fracture. Relative permeability curves were developed to describe the fluid motion. These permeability curves can be used in reservoir-scale discrete fracture models for predictions of fluid motion within fractured geological formations. The numerical model was then changed to better mimic the subsurface conditions at which CO2 will move into brine saturated fractures. The different fluid properties of the modeled subsurface fluids were shown to increase the amount of volume the less-viscous invading gas would occupy while traversing the fracture.
Chang, S. L.
1998-08-25
Fluid Catalytic Cracking (FCC) technology is the most important process used by the refinery industry to convert crude oil to valuable lighter products such as gasoline. New and modified processes are constantly developed by refinery companies to improve their global competitiveness and meet more stringent environmental regulations. Short residence time FCC riser reactor is one of the advanced processes that the refining industry is actively pursuing because it can improve the yield selectivity and efficiency of an FCC unit. However, as the residence time becomes shorter, the impact of the mixing between catalyst and feed oil at the feed injection region on the product yield becomes more significant. Currently, most FCC computer models used by the refineries perform sophisticated kinetic calculations on simplified flow field and can not be used to evaluate the impact of fluid mixing on the performance of an FCC unit. Argonne National Laboratory (AFL) is developing a computational fluid dynamic (CFD) code ICRKFLO for FCC riser flow modeling. The code, employing hybrid hydrodynamic-chemical kinetic coupling techniques, is used to investigate the effect of operating and design conditions on the product yields of FCC riser reactors. Numerical calculations were made using the code to examine the impacts of the operating and design conditions on the product yields. The controlling parameters under investigation include the residence time, reaction temperature, and catalyst/oil ratio. This paper describes the CFD code, presents computation results, and discusses the effects of operating conditions on the performance of short residence time FCC riser reactors.
U.S. Department of Energy (DOE) all webpages (Extended Search)
Characterization of Experimental Fracture Alteration and Fluid Flow in Fractured Natural Seals 25 August 2014 Office of Fossil Energy NRAP-TRS-III-003-2014 Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any
Boundary layer modeling of reactive flow over a porous surface with angled injection
Liu, Shiling; Fotache, Catalin G.; Hautman, Donald J.; Ochs, Stuart S. [United Technologies Research Center, MS 129-29, 411 Silver Lane, East Hartford, CT 06108 (United States); Chao, Beei-Huan [Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)
2008-08-15
An analytical model was developed to investigate the dynamics of nonpremixed flames in a shear layer established between a mainstream flow of fuel-rich combustion products and a porous surface with an angled injection of air. In the model, a one-step overall chemical reaction was employed, together with boundary layer conservation equations solved using similarity solutions. Parametric studies were performed to understand the effects of equivalence ratio, temperature, and mass flow rate of the fuel and air streams on the flame standoff distance, surface temperature, and heat flux at the surface. The analytical model predictions were compared with computational fluid dynamics results obtained using the FLUENT commercial code for both the laminar and the turbulent flow models. Qualitative agreement in surface temperature was observed. Finally, the flame stability limits predicted by the model were compared with available experimental data and found to agree qualitatively, as well. (author)
Swirling structure for mixing two concentric fluid flows at nozzle outlet
Mensink, Daniel L.
1993-01-01
A nozzle device for causing two fluids to mix together. In particular, a spray nozzle comprise two hollow, concentric housings, an inner housing and an outer housing. The inner housing has a channel formed therethrough for a first fluid. Its outer surface cooperates with the interior surface of the outer housing to define the second channel for a second fluid. The outer surface of the inner housing and the inner surface of the outer housing each carry a plurality of vanes that interleave but do not touch, each vane of one housing being between two vanes of the other housing. The vanes are curved and the inner surface of the outer housing and the outer surface of the inner housing converge to narrow the second channel. The shape of second channel results in a swirling, accelerating second fluid that will impact the first fluid just past the end of the nozzle where mixing will take place.
Swirling structure for mixing two concentric fluid flows at nozzle outlet
Mensink, D.L.
1993-07-20
A nozzle device is described for causing two fluids to mix together. In particular, a spray nozzle comprises two hollow, concentric housings, an inner housing and an outer housing. The inner housing has a channel formed therethrough for a first fluid. Its outer surface cooperates with the interior surface of the outer housing to define the second channel for a second fluid. The outer surface of the inner housing and the inner surface of the outer housing each carry a plurality of vanes that interleave but do not touch, each vane of one housing being between two vanes of the other housing. The vanes are curved and the inner surface of the outer housing and the outer surface of the inner housing converge to narrow the second channel. The shape of second channel results in a swirling, accelerating second fluid that will impact the first fluid just past the end of the nozzle where mixing will take place.
Modeling high gradient magnetic separation from biological fluids.
Bockenfeld, D.; Chen, H.; Rempfer, D.; Kaminski, M. D.; Rosengart, A. J.; Chemical Engineering; Illinois Inst. of Tech.; Univ. of Chicago, Pritzker School of Medicine
2006-01-01
A proposed portable magnetic separator consists of an array of biocompatible capillary tubing and magnetizable wires immersed in an externally applied homogeneous magnetic field. While subject to the homogeneous magnetic field, the wires create high magnetic field gradients, which aid in the collection of blood-borne magnetic nanospheres from blood flow. In this study, a 3-D numerical model was created using COMSOL Multiphysics 3.2 software to determine the configuration of the wire-tubing array from two possible configurations, one being an array with rows alternating between wires and tubing, and the other being an array where wire and tubing alternate in two directions. The results demonstrated that the second configuration would actually capture more of the magnetic spheres. Experimental data obtained by our group support this numerical result.
L3:THM.CFD.P6.01 Report: Newton-Krylov Based P2 Projection Solver for Fluid Flows
U.S. Department of Energy (DOE) all webpages (Extended Search)
1 Report: Newton-Krylov Based P2 Projection Solver for Fluid Flows J. Bakosi, M.A. Christon, LANL R.R. Nourgaliev, INL February 12, 2013 CASL-U-2013-0288-000-b CASL-U-2013-0288-000-b INL/EXT-13-28278 Newton-Krylov based P2 Projection Solver for Fluid Flows Robert Nourgaliev, Mark Christon, Jozsef Bakosi February 12, 2013 CASL-U-2013-0288-000-b This Page is Intentionally Left Blank CASL-U-2013-0288-000-b I Newton-Krylov based P2 Projection Solver for Fluid Flows ROBERT NOURGALIEV ⋆ , MARK
Physical Model Development and Benchmarking for MHD Flows in Blanket Design
Ramakanth Munipalli; P.-Y.Huang; C.Chandler; C.Rowell; M.-J.Ni; N.Morley; S.Smolentsev; M.Abdou
2008-06-05
An advanced simulation environment to model incompressible MHD flows relevant to blanket conditions in fusion reactors has been developed at HyPerComp in research collaboration with TEXCEL. The goals of this phase-II project are two-fold: The first is the incorporation of crucial physical phenomena such as induced magnetic field modeling, and extending the capabilities beyond fluid flow prediction to model heat transfer with natural convection and mass transfer including tritium transport and permeation. The second is the design of a sequence of benchmark tests to establish code competence for several classes of physical phenomena in isolation as well as in select (termed here as canonical,) combinations. No previous attempts to develop such a comprehensive MHD modeling capability exist in the literature, and this study represents essentially uncharted territory. During the course of this Phase-II project, a significant breakthrough was achieved in modeling liquid metal flows at high Hartmann numbers. We developed a unique mathematical technique to accurately compute the fluid flow in complex geometries at extremely high Hartmann numbers (10,000 and greater), thus extending the state of the art of liquid metal MHD modeling relevant to fusion reactors at the present time. These developments have been published in noted international journals. A sequence of theoretical and experimental results was used to verify and validate the results obtained. The code was applied to a complete DCLL module simulation study with promising results.
Robert Podgorney; Chuan Lu; Hai Huang
2012-01-01
Development of enhanced geothermal systems (EGS) will require creation of a reservoir of sufficient volume to enable commercial-scale heat transfer from the reservoir rocks to the working fluid. A key assumption associated with reservoir creation/stimulation is that sufficient rock volumes can be hydraulically fractured via both tensile and shear failure, and more importantly by reactivation of naturally existing fractures (by shearing), to create the reservoir. The advancement of EGS greatly depends on our understanding of the dynamics of the intimately coupled rock-fracture-fluid-heat system and our ability to reliably predict how reservoirs behave under stimulation and production. Reliable performance predictions of EGS reservoirs require accurate and robust modeling for strongly coupled thermal-hydrological-mechanical (THM) processes. Conventionally, these types of problems have been solved using operator-splitting methods, usually by coupling a subsurface flow and heat transport simulators with a solid mechanics simulator via input files. An alternative approach is to solve the system of nonlinear partial differential equations that govern multiphase fluid flow, heat transport, and rock mechanics simultaneously, using a fully coupled, fully implicit solution procedure, in which all solution variables (pressure, enthalpy, and rock displacement fields) are solved simultaneously. This paper describes numerical simulations used to investigate the poro- and thermal- elastic effects of working fluid injection and thermal energy extraction on the properties of the fractures and rock matrix of a hypothetical EGS reservoir, using a novel simulation software FALCON (Podgorney et al., 2011), a finite element based simulator solving fully coupled multiphase fluid flow, heat transport, rock deformation, and fracturing using a global implicit approach. Investigations are also conducted on how these poro- and thermal-elastic effects are related to fracture permeability
Shi, Xing; Lin, Guang; Zou, Jianfeng; Fedosov, Dmitry A.
2013-07-20
To model red blood cell (RBC) deformation in flow, the recently developed LBM-DLM/FD method ([Shi and Lim, 2007)29], derived from the lattice Boltzmann method and the distributed Lagrange multiplier/fictitious domain methodthe fictitious domain method, is extended to employ the mesoscopic network model for simulations of red blood cell deformation. The flow is simulated by the lattice Boltzmann method with an external force, while the network model is used for modeling red blood cell deformation and the fluid-RBC interaction is enforced by the Lagrange multiplier. To validate parameters of the RBC network model, sThe stretching numerical tests on both coarse and fine meshes are performed and compared with the corresponding experimental data to validate the parameters of the RBC network model. In addition, RBC deformation in pipe flow and in shear flow is simulated, revealing the capacity of the current method for modeling RBC deformation in various flows.
Pan, Dongqing; Chien Jen, Tien [Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201 (United States); Li, Tao [School of Mechanical Engineering, Dalian University of Technology, Dalian 116024 (China); Yuan, Chris, E-mail: cyuan@uwm.edu [Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, Wisconsin 53211 (United States)
2014-01-15
This paper characterizes the carrier gas flow in the atomic layer deposition (ALD) vacuum reactor by introducing Lattice Boltzmann Method (LBM) to the ALD simulation through a comparative study of two LBM models. Numerical models of gas flow are constructed and implemented in two-dimensional geometry based on lattice BhatnagarGrossKrook (LBGK)-D2Q9 model and two-relaxation-time (TRT) model. Both incompressible and compressible scenarios are simulated and the two models are compared in the aspects of flow features, stability, and efficiency. Our simulation outcome reveals that, for our specific ALD vacuum reactor, TRT model generates better steady laminar flow features all over the domain with better stability and reliability than LBGK-D2Q9 model especially when considering the compressible effects of the gas flow. The LBM-TRT is verified indirectly by comparing the numerical result with conventional continuum-based computational fluid dynamics solvers, and it shows very good agreement with these conventional methods. The velocity field of carrier gas flow through ALD vacuum reactor was characterized by LBM-TRT model finally. The flow in ALD is in a laminar steady state with velocity concentrated at the corners and around the wafer. The effects of flow fields on precursor distributions, surface absorptions, and surface reactions are discussed in detail. Steady and evenly distributed velocity field contribute to higher precursor concentration near the wafer and relatively lower particle velocities help to achieve better surface adsorption and deposition. The ALD reactor geometry needs to be considered carefully if a steady and laminar flow field around the wafer and better surface deposition are desired.
Numerical simulation model for vertical flow in geothermal wells
Tachimori, M.
1982-01-01
A numerical simulation model for vertical flow in geothermal wells is presented. The model consists of equations for the conservation of mass, momentum, and energy, for thermodynamic state of water, for friction losses, for slip velocity relations, and of the criteria for various flow regimes. A new set of correlations and criteria is presented for two-phase flow to improve the accuracy of predictions; bubbly flow - Griffith and Wallis correlation, slug flow - Nicklin et al. one, annular-mist flow - Inoue and Aoki and modified by the author. The simulation method was verified by data from actual wells.
SCDAP/RELAP5 Modeling of Heat Transfer and Flow Losses in Lower Head Porous Debris
Siefken, Larry James; Coryell, Eric Wesley; Paik, Seungho; Kuo, Han Hsiung
1999-07-01
Designs are described for implementing models for calculating the heat transfer and flow losses in porous debris in the lower head of a reactor vessel. The COUPLE model in SCDAP/RELAP5 represents both the porous and nonporous debris that results from core material slumping into the lower head. Currently, the COUPLE model has the capability to model convective and radiative heat transfer from the surfaces of nonporous debris in a detailed manner and to model only in a simplistic manner the heat transfer from porous debris. In order to advance beyond the simplistic modeling for porous debris, designs are developed for detailed calculations of heat transfer and flow losses in porous debris. Correlations are identified for convective heat transfer in porous debris for the following modes of heat transfer; (1) forced convection to liquid, (2) forced convection to gas, (3) nucleate boiling, (4) transition boiling, and (5) film boiling. Interphase heat transfer is modeled in an approximate manner. Designs are described for models to calculate the flow losses and interphase drag of fluid flowing through the interstices of the porous debris, and to apply these variables in the momentum equations in the RELAP5 part of the code. Since the models for heat transfer and flow losses in porous debris in the lower head are designed for general application, a design is also described for implementation of these models to the analysis of porous debris in the core region. A test matrix is proposed for assessing the capability of the implemented models to calculate the heat transfer and flow losses in porous debris. The implementation of the models described in this report is expected to improve the COUPLE code calculation of the temperature distribution in porous debris and in the lower head that supports the debris. The implementation of these models is also expected to improve the calculation of the temperature and flow distribution in porous debris in the core region.
Cihan, Abdullah; Birkholzer, Jens; Trevisan, Luca; Bianchi, Marco; Zhou, Quanlin; Illangasekare, Tissa
2014-12-31
During CO_{2} injection and storage in deep reservoirs, the injected CO_{2} enters into an initially brine saturated porous medium, and after the injection stops, natural groundwater flow eventually displaces the injected mobile-phase CO_{2}, leaving behind residual non-wetting fluid. Accurate modeling of two-phase flow processes are needed for predicting fate and transport of injected CO_{2}, evaluating environmental risks and designing more effective storage schemes. The entrapped non-wetting fluid saturation is typically a function of the spatially varying maximum saturation at the end of injection. At the pore-scale, distribution of void sizes and connectivity of void space play a major role for the macroscopic hysteresis behavior and capillary entrapment of wetting and non-wetting fluids. This paper presents development of an approach based on the connectivity of void space for modeling hysteretic capillary pressure-saturation-relative permeability relationships. The new approach uses void-size distribution and a measure of void space connectivity to compute the hysteretic constitutive functions and to predict entrapped fluid phase saturations. Two functions, the drainage connectivity function and the wetting connectivity function, are introduced to characterize connectivity of fluids in void space during drainage and wetting processes. These functions can be estimated through pore-scale simulations in computer-generated porous media or from traditional experimental measurements of primary drainage and main wetting curves. The hysteresis model for saturation-capillary pressure is tested successfully by comparing the model-predicted residual saturation and scanning curves with actual data sets obtained from column experiments found in the literature. A numerical two-phase model simulator with the new hysteresis functions is tested against laboratory experiments conducted in a quasi-two-dimensional flow cell (91.4cm5.6cm61cm
Cihan, Abdullah; Birkholzer, Jens; Trevisan, Luca; Bianchi, Marco; Zhou, Quanlin; Illangasekare, Tissa
2014-12-31
During CO2 injection and storage in deep reservoirs, the injected CO2 enters into an initially brine saturated porous medium, and after the injection stops, natural groundwater flow eventually displaces the injected mobile-phase CO2, leaving behind residual non-wetting fluid. Accurate modeling of two-phase flow processes are needed for predicting fate and transport of injected CO2, evaluating environmental risks and designing more effective storage schemes. The entrapped non-wetting fluid saturation is typically a function of the spatially varying maximum saturation at the end of injection. At the pore-scale, distribution of void sizes and connectivity of void space play a major role formore » the macroscopic hysteresis behavior and capillary entrapment of wetting and non-wetting fluids. This paper presents development of an approach based on the connectivity of void space for modeling hysteretic capillary pressure-saturation-relative permeability relationships. The new approach uses void-size distribution and a measure of void space connectivity to compute the hysteretic constitutive functions and to predict entrapped fluid phase saturations. Two functions, the drainage connectivity function and the wetting connectivity function, are introduced to characterize connectivity of fluids in void space during drainage and wetting processes. These functions can be estimated through pore-scale simulations in computer-generated porous media or from traditional experimental measurements of primary drainage and main wetting curves. The hysteresis model for saturation-capillary pressure is tested successfully by comparing the model-predicted residual saturation and scanning curves with actual data sets obtained from column experiments found in the literature. A numerical two-phase model simulator with the new hysteresis functions is tested against laboratory experiments conducted in a quasi-two-dimensional flow cell (91.4cm×5.6cm×61cm), packed with homogeneous and
Modeling of Gas-Liquid Flow Through An Interconnected Channel Matrix
Crandall, Dustin; Ahmadi, Goodarz; Smith, Duane.H
2009-01-01
The motion of a less viscous, non-wetting gas into a liquid-saturated porous medium is known as drainage. Drainage is an important process in environmental applications, such as enhanced oil recovery and geologic CO2 sequestration. Understanding what conditions will increase the volume of gas that can saturate an initially water-saturated porous medium is of importance for predictions of the total CO2 volume that can be sequestered in known geologic formations. To further the understanding of how drainage flow properties are related to different injection flow-rates, a porous medium consisting of interconnected channels and pores was manufactured to perform bench-top experiments of drainage. Additionally, a finite-volume model of this interconnected channel matrix was constructed. Numerical simulations of constant-rate injection into the model porous medium are first shown to compare favorably to the bench-top experiments. The fluid and injection properties of the drainage process were then varied to evaluate the flow conditions which would maximize the volume of gas trapped within the porous medium. In particular, CO2 displacing brine within the porous medium was modeled, with representative subsurface temperatures and fluid properties. It was shown with these fluid conditions a higher final saturation of the invading less-viscous CO2 was obtained, as compared to air into water experiments at similar injection rates.
Binary fish passage models for uniform and nonuniform flows
Neary, Vincent S
2011-01-01
Binary fish passage models are considered by many fisheries managers to be the best 21 available practice for culvert inventory assessments and for fishway and barrier design. 22 Misunderstandings between different binary passage modeling approaches often arise, 23 however, due to differences in terminology, application and presentation. In this paper 24 one-dimensional binary fish passage models are reviewed and refined to clarify their 25 origins and applications. For uniform flow, a simple exhaustion-threshold (ET) model 26 equation is derived that predicts the flow speed threshold in a fishway or velocity barrier 27 that causes exhaustion at a given maximum distance of ascent. Flow speeds at or above 28 the threshold predict failure to pass (exclusion). Flow speeds below the threshold predict 29 passage. The binary ET model is therefore intuitive and easily applied to predict passage 30 or exclusion. It is also shown to be consistent with the distance-maximizing model. The 31 ET model s limitation to uniform flow is addressed by deriving a passage model that 32 accounts for nonuniform flow conditions more commonly found in the field, including 33 backwater profiles and drawdown curves. Comparison of these models with 34 experimental observations of volitional passage for Gambusia affinis in uniform and 35 nonuniform flows indicates reasonable prediction of binary outcomes (passage or 36 exclusion) if the flow speed is not near the threshold flow velocity. More research is 37 needed on fish behavior, passage strategies under nonuniform flow regimes and 38 stochastic methods that account for individual differences in swimming performance at or 39 near the threshold flow speed. Future experiments should track and measure ground 40 speeds of ascending fish to test nonuniform flow passage strategies and to improve model 41 predictions. Stochastic models, such as Monte-Carlo techniques, that account for 42 different passage performance among individuals and allow
Wang, Liang Germaschewski, K.; Hakim, Ammar H.; Bhattacharjee, A.
2015-01-15
We introduce an extensible multi-fluid moment model in the context of collisionless magnetic reconnection. This model evolves full Maxwell equations and simultaneously moments of the Vlasov-Maxwell equation for each species in the plasma. Effects like electron inertia and pressure gradient are self-consistently embedded in the resulting multi-fluid moment equations, without the need to explicitly solving a generalized Ohm's law. Two limits of the multi-fluid moment model are discussed, namely, the five-moment limit that evolves a scalar pressures for each species and the ten-moment limit that evolves the full anisotropic, non-gyrotropic pressure tensor for each species. We first demonstrate analytically and numerically that the five-moment model reduces to the widely used Hall magnetohydrodynamics (Hall MHD) model under the assumptions of vanishing electron inertia, infinite speed of light, and quasi-neutrality. Then, we compare ten-moment and fully kinetic particle-in-cell (PIC) simulations of a large scale Harris sheet reconnection problem, where the ten-moment equations are closed with a local linear collisionless approximation for the heat flux. The ten-moment simulation gives reasonable agreement with the PIC results regarding the structures and magnitudes of the electron flows, the polarities and magnitudes of elements of the electron pressure tensor, and the decomposition of the generalized Ohm's law. Possible ways to improve the simple local closure towards a nonlocal fully three-dimensional closure are also discussed.
Use of Geophysical Techniques to Characterize Fluid Flow in a Geothermal Reservoir
Project objectives: Joint inversion of geophysical data for ground water flow imaging; Reduced the cost in geothermal exploration and monitoring; & Combined passive and active geophysical methods.
Liquid-fluidized-bed heat exchanger flow distribution models...
Office of Scientific and Technical Information (OSTI)
One contains a horizontal bundle and the other a vertical tube bundle. Plexiglass construction allowed visual observation of flow patterns. The vertical model proved to have more ...
Double Shock Experiments and Reactive Flow Modeling of High Pressure...
Office of Scientific and Technical Information (OSTI)
Double Shock Experiments and Reactive Flow Modeling of High Pressure LX-17 Detonation Reaction Product States Citation Details In-Document Search Title: Double Shock Experiments ...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
1-92 JUNE 1992 DOE FUNDAMENTALS HANDBOOK THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Volume 1 of 3 U.S. Department of Energy FSC-6910 Washington, D.C. 20585 Distribution Statement A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information. P. O. Box 62, Oak Ridge, TN 37831; (615) 576-8401. Available to the public from the National
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
2-92 JUNE 1992 DOE FUNDAMENTALS HANDBOOK THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Volume 2 of 3 U.S. Department of Energy FSC-6910 Washington, D.C. 20585 Distribution Statement A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information. P. O. Box 62, Oak Ridge, TN 37831; prices available from (615) 576- 8401. FTS 626-8401.
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
3-92 JUNE 1992 DOE FUNDAMENTALS HANDBOOK THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Volume 3 of 3 U.S. Department of Energy FSC-6910 Washington, D.C. 20585 Distribution Statement A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information. P. O. Box 62, Oak Ridge, TN 37831; prices available from (615) 576- 8401. FTS 626-8401.
Continuum-kinetic-microscopic model of lung clearance due to core-annular fluid entrainment
Mitran, Sorin
2013-07-01
The human lung is protected against aspirated infectious and toxic agents by a thin liquid layer lining the interior of the airways. This airway surface liquid is a bilayer composed of a viscoelastic mucus layer supported by a fluid film known as the periciliary liquid. The viscoelastic behavior of the mucus layer is principally due to long-chain polymers known as mucins. The airway surface liquid is cleared from the lung by ciliary transport, surface tension gradients, and airflow shear forces. This work presents a multiscale model of the effect of airflow shear forces, as exerted by tidal breathing and cough, upon clearance. The composition of the mucus layer is complex and variable in time. To avoid the restrictions imposed by adopting a viscoelastic flow model of limited validity, a multiscale computational model is introduced in which the continuum-level properties of the airway surface liquid are determined by microscopic simulation of long-chain polymers. A bridge between microscopic and continuum levels is constructed through a kinetic-level probability density function describing polymer chain configurations. The overall multiscale framework is especially suited to biological problems due to the flexibility afforded in specifying microscopic constituents, and examining the effects of various constituents upon overall mucus transport at the continuum scale.
Code System to Calculate Transient 2-Dimensional 2-Fluid Flow Dynamics.
Energy Science and Technology Software Center (OSTI)
1999-07-19
Version 00 The transient dynamics of two-dimensional, two-phase flow with interfacial exchange are calculated at all flow speeds. Each phase is described in terms of its own density, velocity, and temperature. Separate sets of field equations govern the gas and liquid phase dynamics. The six field equations for the two phases couple through mass, momentum, and energy exchange.
Validation of Numerical Two-Fluid and Kinetic Plasma Models
Daniel Barnes
2011-03-25
This was a four year grant commencing October 1, 2003 and finishing September 30, 2007. The funding was primarily used to support the work of the Principal Investigator, who collaborated with Profs. Scott Parker and John Cary at U. Colorado, and with two students, N. Xiang and J. Cheng also of U. Colorado. The technical accomplishments of this grant can be found in the publications listed in the final Section here. The main accomplishments of the grant work were: (1) Development and implementation of time-implicit two-fluid simulation methods in collaboration with the NIMROD team; and (2) Development and testing of a new time-implicit delta-f, energy-conserving method The basic two-fluid method, with many improvements is used in present NIMROD calculations. The energy-conserving delta-f method is under continuing development under contract between Coronado Consulting, a New Mexico sole proprietorship and the Oak Ridge National Laboratory.
Alfvn wave coupled with flow-driven fluid instability in interpenetrating plasmas
Vranjes, J.
2015-05-15
The Alfvn wave is analyzed in case of one quasineutral plasma propagating with some constant speed v{sub 0} through another static quasineutral plasma. A dispersion equation is derived describing the Alfvn wave coupled with the flow driven mode ?=kv{sub 0} and solutions are discussed analytically and numerically. The usual solutions for two oppositely propagating Alfvn waves are substantially modified due to the flowing plasma. More profound is modification of the solution propagating in the negative direction with respect to the magnetic field and the plasma flow. For a large enough flow speed (exceeding the Alfvn speed in the static plasma), this negative solution may become non-propagating, with frequency equal to zero. In this case, it represents a spatial variation of the electromagnetic field. For greater flow speed it becomes a forward mode, and it may merge with the positive one. This merging of the two modes represents the starting point for a flow-driven instability, with two complex-conjugate solutions. The Alfvn wave in interpenetrating plasmas is thus modified and coupled with the flow-driven mode and this coupled mode is shown to be growing when the flow speed is large enough. The energy for the instability is macroscopic kinetic energy of the flowing plasma. The dynamics of plasma particles caused by such a coupled wave still remains similar to the ordinary Alfvn wave. This means that well-known stochastic heating by the Alfvn wave may work, and this should additionally support the potential role of the Alfvn wave in the coronal heating.
A Mechanical Fluid-Dynamical Model For Ground Movements At Campi...
Open Energy Information (Open El) [EERE & EIA]
Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Caldera Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A Mechanical...
Imaging, Characterizing, and Modeling of Fracture Networks and...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Reservoirs Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in ... and integrating imaging into modeling. seismicityhuangfracturenetworks.pdf ...
Fluid Flow In The Resurgent Dome Of Long Valley Caldera- Implications...
Open Energy Information (Open El) [EERE & EIA]
Flow In The Resurgent Dome Of Long Valley Caldera- Implications From Thermal Data And Deep Electrical Sounding Jump to: navigation, search OpenEI Reference LibraryAdd to library...
Digital control of working fluid flow rate for an OTEC plant
Nakamura, M.; Egashira, N.; Uehara, H.
1986-05-01
The role of control in operating an OTEC plant efficiently is of great importance. This paper describes digital control of working fluid rate based on an adaptive control theory for the ''Imari2'' OTEC plant at Saga University. Provisions have been made for linkage between the software of the adaptive control theory and the hardware of the OTEC plant. The authors can obtain satisfactory control performance using this digital control system.
Electrochemical Model of the Fe/V Redox Flow Battery
Stephenson, David E.; Kim, Soowhan; Chen, Feng; Thomsen, Edwin C.; Viswanathan, Vilayanur V.; Wang, Wei; Sprenkle, Vincent L.
2012-11-05
This paper presents a mathematical model for the new Fe/V redox flow battery chemistry. The model is designed to be useful for stack development and cost analysis purposes.
Solyndra Facts vs. Fiction: Cash Flow Modeling
Questions have been raised about a quote selectively pulled from an Aug. 20, 2009 email to make it look like Solyndra would run out of cash by Sept. 2011. To be clear, the analysis addressed in that email did not refer to Solyndra’s corporate cash flow, but rather the cash flow for a subsidiary of Solyndra – the “Fab 2 Project Company.
User's manual for the Sandia Waste-Isolation Flow and Transport model (SWIFT).
Reeves, Mark; Cranwell, Robert M.
1981-11-01
This report describes a three-dimensional finite-difference model (SWIFT) which is used to simulate flow and transport processes in geologic media. The model was developed for use by the Nuclear Regulatory Commission in the analysis of deep geologic nuclear waste-disposal facilities. This document, as indicated by the title, is a user's manual and is intended to facilitate the use of the SWIFT simulator. Mathematical equations, submodels, application notes, and a description of the program itself are given herein. In addition, a complete input data guide is given along with several appendices which are helpful in setting up a data-input deck. Computer code SWIFT (Sandia Waste Isolation, Flow and Transport Model) is a fully transient, three-dimensional model which solves the coupled equations for transport in geologic media. The processes considered are: (1) fluid flow; (2) heat transport; (3) dominant-species miscible displacement; and (4) trace-species miscible displacement. The first three processes are coupled via fluid density and viscosity. Together they provide the velocity field on which the fourth process depends.
Measurement of Flow Phenomena in a Lower Plenum Model of a Prismatic Gas-Cooled Reactor
Hugh M. McIlroy, Jr.; Donald M. McEligot; Robert J. Pink
2008-05-01
Mean-velocity-field and turbulence data are presented that measure turbulent flow phenomena in an approximately 1:7 scale model of a region of the lower plenum of a typical prismatic gas-cooled reactor (GCR) similar to a General Atomics Gas-Turbine-Modular Helium Reactor (GTMHR) design. The data were obtained in the Matched-Index-of-Refraction (MIR) facility at Idaho National Laboratory (INL) and are offered for assessing computational fluid dynamics (CFD) software. This experiment has been selected as the first Standard Problem endorsed by the Generation IV International Forum. This paper reviews the experimental apparatus and procedures, presents a sample of the data set, and reviews the INL Standard Problem. Results concentrate on the region of the lower plenum near its far reflector wall (away from the outlet duct). The flow in the lower plenum consists of multiple jets injected into a confined cross flow - with obstructions. The model consists of a row of full circular posts along its centerline with half-posts on the two parallel walls to approximate flow scaled to that expected from the staggered parallel rows of posts in the reactor design. The model is fabricated from clear, fused quartz to match the refractive-index of the mineral oil working fluid so that optical techniques may be employed for the measurements. The benefit of the MIR technique is that it permits optical measurements to determine flow characteristics in complex passages in and around objects to be obtained without locating intrusive transducers that will disturb the flow field and without distortion of the optical paths. An advantage of the INL system is its large size, leading to improved spatial and temporal resolution compared to similar facilities at smaller scales. A three-dimensional (3-D) Particle Image Velocimetry (PIV) system was used to collect the data. Inlet jet Reynolds numbers (based on the jet diameter and the time-mean average flow rate) are approximately 4,300 and 12
JACKSON VL
2011-08-31
The primary purpose of the tank mixing and sampling demonstration program is to mitigate the technical risks associated with the ability of the Hanford tank farm delivery and celtification systems to measure and deliver a uniformly mixed high-level waste (HLW) feed to the Waste Treatment and Immobilization Plant (WTP) Uniform feed to the WTP is a requirement of 24590-WTP-ICD-MG-01-019, ICD-19 - Interface Control Document for Waste Feed, although the exact definition of uniform is evolving in this context. Computational Fluid Dynamics (CFD) modeling has been used to assist in evaluating scaleup issues, study operational parameters, and predict mixing performance at full-scale.
Formulation, Implementation and Validation of a Two-Fluid model in a Fuel Cell CFD Code
Kunal Jain, Vernon Cole, Sanjiv Kumar and N. Vaidya
2008-11-01
Water management is one of the main challenges in PEM Fuel Cells. While water is essential for membrane electrical conductivity, excess liquid water leads to ooding of catalyst layers. Despite the fact that accurate prediction of two-phase transport is key for optimal water management, understanding of the two-phase transport in fuel cells is relatively poor. Wang et. al. [1], [2] have studied the two-phase transport in the channel and diffusion layer separately using a multiphase mixture model. The model fails to accurately predict saturation values for high humidity inlet streams. Nguyen et. al. [3] developed a two-dimensional, two-phase, isothermal, isobaric, steady state model of the catalyst and gas diffusion layers. The model neglects any liquid in the channel. Djilali et. al. [4] developed a three-dimensional two-phase multicomponent model. The model is an improvement over previous models, but neglects drag between the liquid and the gas phases in the channel. In this work, we present a comprehensive two- fluid model relevant to fuel cells. Models for two-phase transport through Channel, Gas Diffusion Layer (GDL) and Channel-GDL interface, are discussed. In the channel, the gas and liquid pressures are assumed to be same. The surface tension effects in the channel are incorporated using the continuum surface force (CSF) model. The force at the surface is expressed as a volumetric body force and added as a source to the momentum equation. In the GDL, the gas and liquid are assumed to be at different pressures. The difference in the pressures (capillary pressure) is calculated using an empirical correlations. At the Channel-GDL interface, the wall adhesion affects need to be taken into account. SIMPLE-type methods recast the continuity equation into a pressure-correction equation, the solution of which then provides corrections for velocities and pressures. However, in the two-fluid model, the presence of two phasic continuity equations gives more freedom and
Sundar, Sita; Das, Amita; Kaw, Predhiman [Institute for Plasma Research, Bhat, Gandhinagar-382428 (India)
2012-05-15
In the interaction of intense lasers with matter/plasma, energetic electrons having relativistic energies get created. These energetic electrons can often have sheared flow profiles as they propagate through the plasma medium. In an earlier study [Phys. Plasmas 17, 022101 (2010)], it was shown that a relativistic sheared electron flow modifies the growth rate and threshold condition of the conventional Kelvin-Helmholtz instability. A perturbative analytic treatment for the case of weakly relativistic regime has been provided here. It provides good agreement with the numerical results obtained earlier.
Ostermann, Lars; Seidel, Christian
2015-03-10
The numerical analysis of hydro power stations is an important method of the hydraulic design and is used for the development and optimisation of hydro power stations in addition to the experiments with the physical submodel of a full model in the hydraulic laboratory. For the numerical analysis, 2D and 3D models are appropriate and commonly used.The 2D models refer mainly to the shallow water equations (SWE), since for this flow model a large experience on a wide field of applications for the flow analysis of numerous problems in hydraulic engineering already exists. Often, the flow model is verified by in situ measurements. In order to consider 3D flow phenomena close to singularities like weirs, hydro power stations etc. the development of a hybrid fluid model is advantageous to improve the quality and significance of the global model. Here, an extended hybrid flow model based on the principle of the SWE is presented. The hybrid flow model directly links the numerical model with the experimental data, which may originate from physical full models, physical submodels and in-situ measurements. Hence a wide field of application of the hybrid model emerges including the improvement of numerical models and the strong coupling of numerical and experimental analysis.
Hassan, T.A.
1992-12-01
The practical use of Pulsed Laser Velocimetry (PLV) requires the use of fast, reliable computer-based methods for tracking numerous particles suspended in a fluid flow. Two methods for performing tracking are presented. One method tracks a particle through multiple sequential images (minimum of four required) by prediction and verification of particle displacement and direction. The other method, requiring only two sequential images uses a dynamic, binary, spatial, cross-correlation technique. The algorithms are tested on computer-generated synthetic data and experimental data which was obtained with traditional PLV methods. This allowed error analysis and testing of the algorithms on real engineering flows. A novel method is proposed which eliminates tedious, undersirable, manual, operator assistance in removing erroneous vectors. This method uses an iterative process involving an interpolated field produced from the most reliable vectors. Methods are developed to allow fast analysis and presentation of sets of PLV image data. Experimental investigation of a two-phase, horizontal, stratified, flow regime was performed to determine the interface drag force, and correspondingly, the drag coefficient. A horizontal, stratified flow test facility using water and air was constructed to allow interface shear measurements with PLV techniques. The experimentally obtained local drag measurements were compared with theoretical results given by conventional interfacial drag theory. Close agreement was shown when local conditions near the interface were similar to space-averaged conditions. However, theory based on macroscopic, space-averaged flow behavior was shown to give incorrect results if the local gas velocity near the interface as unstable, transient, and dissimilar from the average gas velocity through the test facility.
A General Nonlinear Fluid Model for Reacting Plasma-Neutral Mixtures
Meier, E T; Shumlak, U
2012-04-06
A generalized, computationally tractable fluid model for capturing the effects of neutral particles in plasmas is derived. The model derivation begins with Boltzmann equations for singly charged ions, electrons, and a single neutral species. Electron-impact ionization, radiative recombination, and resonant charge exchange reactions are included. Moments of the reaction collision terms are detailed. Moments of the Boltzmann equations for electron, ion, and neutral species are combined to yield a two-component plasma-neutral fluid model. Separate density, momentum, and energy equations, each including reaction transfer terms, are produced for the plasma and neutral equations. The required closures for the plasma-neutral model are discussed.
Glenn E McCreery; Keith G Condie
2006-09-01
The Very High Temperature Reactor (VHTR) is the leading candidate for the Next Generation Nuclear Power (NGNP) Project in the U.S. which has the goal of demonstrating the production of emissions free electricity and hydrogen by 2015. The present document addresses experimental modeling of flow and thermal mixing phenomena of importance during normal or reduced power operation and during a loss of forced reactor cooling (pressurized conduction cooldown) scenario. The objectives of the experiments are, 1), provide benchmark data for assessment and improvement of codes proposed for NGNP designs and safety studies, and, 2), obtain a better understanding of related phenomena, behavior and needs. Physical models of VHTR vessel upper and lower plenums which use various working fluids to scale phenomena of interest are described. The models may be used to both simulate natural convection conditions during pressurized conduction cooldown and turbulent lower plenum flow during normal or reduced power operation.
Imaging Fluid Flow in Geothermal Wells Using Distributed Thermal Perturbation Sensing
Project objective: A New Geothermal Well Imaging Tool. 1.To develop a robust and easily deployable DTPS for monitoring in geothermal wells; and 2. Develop the associated analysis methodology for flow imaging; andwhen possible by wellbore conditionsto determine in situthermal conductivity and basal heat flux.
Modeling and Algorithmic Approaches to Constitutively-Complex, Micro-structured Fluids
Forest, Mark Gregory
2014-05-06
The team for this Project made significant progress on modeling and algorithmic approaches to hydrodynamics of fluids with complex microstructure. Our advances are broken down into modeling and algorithmic approaches. In experiments a driven magnetic bead in a complex fluid accelerates out of the Stokes regime and settles into another apparent linear response regime. The modeling explains the take-off as a deformation of entanglements, and the longtime behavior is a nonlinear, far-from-equilibrium property. Furthermore, the model has predictive value, as we can tune microstructural properties relative to the magnetic force applied to the bead to exhibit all possible behaviors. Wave-theoretic probes of complex fluids have been extended in two significant directions, to small volumes and the nonlinear regime. Heterogeneous stress and strain features that lie beyond experimental capability were studied. It was shown that nonlinear penetration of boundary stress in confined viscoelastic fluids is not monotone, indicating the possibility of interlacing layers of linear and nonlinear behavior, and thus layers of variable viscosity. Models, algorithms, and codes were developed and simulations performed leading to phase diagrams of nanorod dispersion hydrodynamics in parallel shear cells and confined cavities representative of film and membrane processing conditions. Hydrodynamic codes for polymeric fluids are extended to include coupling between microscopic and macroscopic models, and to the strongly nonlinear regime.
DENSE MULTIPHASE FLOW SIMULATION: CONTINUUM MODEL FOR POLY-DISPERSED SYSTEMS USING KINETIC THEORY
Moses Bogere
2011-08-31
The overall objective of the project was to verify the applicability of the FCMOM approach to the kinetic equations describing the particle flow dynamics. For monodispersed systems the fundamental equation governing the particle flow dynamics is the Boltzmann equation. During the project, the FCMOM was successfully applied to several homogeneous and in-homogeneous problems in different flow regimes, demonstrating that the FCMOM has the potential to be used to solve efficiently the Boltzmann equation. However, some relevant issues still need to be resolved, i.e. the homogeneous cooling problem (inelastic particles cases) and the transition between different regimes. In this report, the results obtained in homogeneous conditions are discussed first. Then a discussion of the validation results for in-homogeneous conditions is provided. And finally, a discussion will be provided about the transition between different regimes. Alongside the work on development of FCMOM approach studies were undertaken in order to provide insights into anisotropy or particles kinetics in riser hydrodynamics. This report includes results of studies of multiphase flow with unequal granular temperatures and analysis of momentum re-distribution in risers due to particle-particle and fluid-particle interactions. The study of multiphase flow with unequal granular temperatures entailed both simulation and experimental studies of two particles sizes in a riser and, a brief discussion of what was accomplished will be provided. And finally, a discussion of the analysis done on momentum re-distribution of gas-particles flow in risers will be provided. In particular a discussion of the remaining work needed in order to improve accuracy and predictability of riser hydrodynamics based on two-fluid models and how they can be used to model segregation in risers.
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
The Center for Computational Sciences and Engineering (CCSE) develops and applies advanced computational methodologies to solve large-scale scientific and engineering problems arising in the Department of Energy (DOE) mission areas involving energy, environmental, and industrial technology. The primary focus is in the application of structured-grid finite difference methods on adaptive grid hierarchies for compressible, incompressible, and low Mach number flows. The diverse range of scientific applications that drive the research typically involve a large range of spatial and temporal scales (e.g. turbulent reacting flows) and require the use of extremely large computing hardware, such as the 153,000-core computer, Hopper, at NERSC. The CCSE approach to these problems centers on the development and application of advanced algorithms that exploit known separations in scale; for many of the application areas this results in algorithms are several orders of magnitude more efficient than traditional simulation approaches.
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda DOE Roundtable Report May 22, 2015 Germantown, MD 1 Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda Report of a Roundtable Convened to Consider Foundational Research Relevant to Subsurface Technology and Engineering RD&D May 22, 2015 Germantown, MD Organizing Committee Laura J. Pyrak-Nolte (Chair), Purdue University Donald
Numerical Modeling At Coso Geothermal Area (2006) | Open Energy...
Open Energy Information (Open El) [EERE & EIA]
transport and exchange analysis Notes Finite element models of single-phase, variable-density fluid flow, conductive- convective heat transfer, fluid-rock isotope exchange, and...
Entropy analysis on non-equilibrium two-phase flow models
Karwat, H.; Ruan, Y.Q.
1995-09-01
A method of entropy analysis according to the second law of thermodynamics is proposed for the assessment of a class of practical non-equilibrium two-phase flow models. Entropy conditions are derived directly from a local instantaneous formulation for an arbitrary control volume of a structural two-phase fluid, which are finally expressed in terms of the averaged thermodynamic independent variables and their time derivatives as well as the boundary conditions for the volume. On the basis of a widely used thermal-hydraulic system code it is demonstrated with practical examples that entropy production rates in control volumes can be numerically quantified by using the data from the output data files. Entropy analysis using the proposed method is useful in identifying some potential problems in two-phase flow models and predictions as well as in studying the effects of some free parameters in closure relationships.
Modeling and Algorithmic Approaches to Constitutively-Complex, Microstructured Fluids
Miller, Gregory H.; Forest, Gregory
2011-12-22
We present a new multiscale model for complex uids based on three scales: microscopic, kinetic, and continuum. We choose the microscopic level as Kramers' bead-rod model for polymers, which we describe as a system of stochastic di#11;erential equations with an implicit constraint formulation. The associated Fokker-Planck equation is then derived, and adiabatic elimination removes the fast momentum coordinates. Approached in this way, the kinetic level reduces to a dispersive drift equation. The continuum level is modeled with a #12;nite volume Godunov-projection algorithm. We demonstrate computation of viscoelastic stress divergence using this multiscale approach.
Analysis of fluid fuel flow to the neutron kinetics on molten salt reactor FUJI-12
Aji, Indarta Kuncoro; Waris, Abdul Permana, Sidik
2015-09-30
Molten Salt Reactor is a reactor are operating with molten salt fuel flowing. This condition interpret that the neutron kinetics of this reactor is affected by the flow rate of the fuel. This research analyze effect by the alteration velocity of the fuel by MSR type Fuji-12, with fuel composition LiF-BeF{sub 2}-ThF{sub 4}-{sup 233}UF{sub 4} respectively 71.78%-16%-11.86%-0.36%. Calculation process in this study is performed numerically by SOR and finite difference method use C programming language. Data of reactivity, neutron flux, and the macroscopic fission cross section for calculation process obtain from SRAC-CITATION (Standard thermal Reactor Analysis Code) and JENDL-4.0 data library. SRAC system designed and developed by JAEA (Japan Atomic Energy Agency). This study aims to observe the effect of the velocity of fuel salt to the power generated from neutron precursors at fourth year of reactor operate (last critical condition) with number of multiplication effective; 1.0155.
Modeling of Time Varying Slag Flow in Coal Gasifiers
Pilli, Siva Prasad; Johnson, Kenneth I.; Williford, Ralph E.; Sundaram, S. K.; Korolev, Vladimir N.; Crum, Jarrod V.
2008-08-30
There is considerable interest within government agencies and the energy industries across the globe to further advance the clean and economical conversion of coal into liquid fuels to reduce our dependency on imported oil. To date, advances in these areas have been largely based on experimental work. Although there are some detailed systems level performance models, little work has been done on numerical modeling of the component level processes. If accurate models are developed, then significant R&D time might be saved, new insights into the process might be gained, and some good predictions of process or performance can be made. One such area is the characterization of slag deposition and flow on the gasifier walls. Understanding slag rheology and slag-refractory interactions is critical to design and operation of gasifiers with extended refractory lifetimes and also to better control of operating parameters so that the overall gasifier performance with extended service life can be optimized. In the present work, the literature on slag flow modeling was reviewed and a model similar to Seggiani’s was developed to simulate the time varying slag accumulation and flow on the walls of a Prenflo coal gasifier. This model was further extended and modified to simulate a refractory wall gasifier including heat transfer through the refractory wall with flowing slag in contact with the refractory. The model was used to simulate temperature dependent slag flow using rheology data from our experimental slag testing program. These modeling results as well as experimental validation are presented.
Srinivasan, B.; Shumlak, U.
2011-09-15
The 5-moment two-fluid plasma model uses Euler equations to describe the ion and electron fluids and Maxwell's equations to describe the electric and magnetic fields. Two-fluid physics becomes significant when the characteristic spatial scales are on the order of the ion skin depth and characteristic time scales are on the order of the ion cyclotron period. The full two-fluid plasma model has disparate characteristic speeds ranging from the ion and electron speeds of sound to the speed of light. Two asymptotic approximations are applied to the full two-fluid plasma to arrive at the Hall-MHD model, namely negligible electron inertia and infinite speed of light. The full two-fluid plasma model and the Hall-MHD model are studied for applications to an electromagnetic plasma shock, geospace environmental modeling (GEM challenge) magnetic reconnection, an axisymmetric Z-pinch, and an axisymmetric field reversed configuration (FRC).
Dividing phases in two-phase flow and modeling of interfacial drag
Narumo, T.; Rajamaeki, M.
1997-07-01
Different models intended to describe one-dimensional two-phase flow are considered in this paper. The following models are introduced: conventional six-equation model, conventional model equipped with terms taking into account nonuniform transverse velocity distribution of the phases, several virtual mass models and a model in which the momentum equations have been derived by using the principles of Separation of the Flow According to Velocity (SFAV). The dynamics of the models have been tested by comparing their characteristic velocities to each other and against experimental data. The results show that the SFAV-model makes a hyperbolic system and predicts the propagation velocities of disturbances with the same order of accuracy as the best tested virtual mass models. Furthermore, the momentum interaction terms for the SFAV-model are considered. These consist of the wall friction terms and the interfacial friction term. The authors model wall friction with two independent terms describing the effect of each fluid on the wall separately. In the steady state, a relationship between the slip velocity and friction coefficients can be derived. Hence, the friction coefficients for the SFAV-model can be calculated from existing correlations, viz. from a drift-flux correlation and a wall friction correlation. The friction model was tested by searching steady-state distributions in a partial BWR fuel channel and comparing the relaxed values with the drift-flux correlation, which agreed very well with each other. In addition, response of the flow to a sine-wave disturbance in the water inlet flux was calculated as function of frequency. The results of the models differed from each other already with frequency of order 5 Hz, while the time constant for the relaxation, obtained from steady-state distribution calculation, would have implied significant differences appear not until with frequency of order 50 Hz.
Van Dam, Jeremy Daniel; Turnquist, Norman Arnold; Raminosoa, Tsarafidy; Shah, Manoj Ramprasad; Shen, Xiaochun
2015-09-29
An electric machine is presented. The electric machine includes a hollow rotor; and a stator disposed within the hollow rotor, the stator defining a flow channel. The hollow rotor includes a first end portion defining a fluid inlet, a second end portion defining a fluid outlet; the fluid inlet, the fluid outlet, and the flow channel of the stator being configured to allow passage of a fluid from the fluid inlet to the fluid outlet via the flow channel; and wherein the hollow rotor is characterized by a largest cross-sectional area of hollow rotor, and wherein the flow channel is characterized by a smallest cross-sectional area of the flow channel, wherein the smallest cross-sectional area of the flow channel is at least about 25% of the largest cross-sectional area of the hollow rotor. An electric fluid pump and a power generation system are also presented.
Dynamic mesoscale model of dipolar fluids via fluctuating hydrodynamics
Persson, Rasmus A. X.; Chu, Jhih-Wei, E-mail: jwchu@nctu.edu.tw [Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsinchu 30068, Taiwan (China); Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 30068, Taiwan (China); Voulgarakis, Nikolaos K. [Department of Mathematics, Washington State University, Richland, Washington 99372 (United States)
2014-11-07
Fluctuating hydrodynamics (FHD) is a general framework of mesoscopic modeling and simulation based on conservational laws and constitutive equations of linear and nonlinear responses. However, explicit representation of electrical forces in FHD has yet to appear. In this work, we devised an Ansatz for the dynamics of dipole moment densities that is linked with the Poisson equation of the electrical potential ? in coupling to the other equations of FHD. The resulting ?-FHD equations then serve as a platform for integrating the essential forces, including electrostatics in addition to hydrodynamics, pressure-volume equation of state, surface tension, and solvent-particle interactions that govern the emergent behaviors of molecular systems at an intermediate scale. This unique merit of ?-FHD is illustrated by showing that the water dielectric function and ion hydration free energies in homogeneous and heterogenous systems can be captured accurately via the mesoscopic simulation. Furthermore, we show that the field variables of ?-FHD can be mapped from the trajectory of an all-atom molecular dynamics simulation such that model development and parametrization can be based on the information obtained at a finer-grained scale. With the aforementioned multiscale capabilities and a spatial resolution as high as 5 , the ?-FHD equations represent a useful semi-explicit solvent model for the modeling and simulation of complex systems, such as biomolecular machines and nanofluidics.
Fluid-Structure Interaction Modeling of High-Aspect Ratio Nuclear Fuel Plates Using COMSOL
Curtis, Franklin G [ORNL] [ORNL; Ekici, Kivanc [ORNL] [ORNL; Freels, James D [ORNL] [ORNL
2013-01-01
The High Flux Isotope Reactor at the Oak Ridge National Lab is in the research stage of converting its fuel from high-enriched uranium to low-enriched uranium. Due to different physical properties of the new fuel and changes to the internal fuel plate design, the current safety basis must be re-evaluated through rigorous computational analyses. One of the areas being explored is the fluid-structure interaction phenomenon due to the interaction of thin fuel plates (50 mils thickness) and the cooling fluid (water). Detailed computational fluid dynamics and fluid-structure interaction simulations have only recently become feasible due to improved numerical algorithms and advancements in computing technology. For many reasons including the already built-in fluid-structure interaction module, COMSOL has been chosen for this complex problem. COMSOL's ability to solve multiphysics problems using a fully-coupled and implicit solution algorithm is crucial in obtaining a stable and accurate solution. Our initial findings show that COMSOL can accurately model such problems due to its ability to closely couple the fluid dynamics and the structural dynamics problems.
Computational fluid dynamics in oil burner design
Butcher, T.A.
1997-09-01
In Computational Fluid Dynamics, the differential equations which describe flow, heat transfer, and mass transfer are approximately solved using a very laborious numerical procedure. Flows of practical interest to burner designs are always turbulent, adding to the complexity of requiring a turbulence model. This paper presents a model for burner design.
Rafatov, I.; Bogdanov, E. A.; Kudryavtsev, A. A.
2012-09-15
We developed and tested a simple hybrid model for a glow discharge, which incorporates nonlocal ionization by fast electrons into the 'simple' and 'extended' fluid frameworks. Calculations have been performed for an argon gas. Comparison with the experimental data as well as with the hybrid (particle) and fluid modelling results demonstated good applicability of the proposed model.
Cost and Performance Model for Redox Flow Batteries
Viswanathan, Vilayanur V.; Crawford, Aladsair J.; Stephenson, David E.; Kim, Soowhan; Wang, Wei; Li, Bin; Coffey, Greg W.; Thomsen, Edwin C.; Graff, Gordon L.; Balducci, Patrick J.; Kintner-Meyer, Michael CW; Sprenkle, Vincent L.
2014-02-01
A cost model was developed for all vanadium and iron-vanadium redox flow batteries. Electrochemical performance modeling was done to estimate stack performance at various power densities as a function of state of charge. This was supplemented with a shunt current model and a pumping loss model to estimate actual system efficiency. The operating parameters such as power density, flow rates and design parameters such as electrode aspect ratio, electrolyte flow channel dimensions were adjusted to maximize efficiency and minimize capital costs. Detailed cost estimates were obtained from various vendors to calculate cost estimates for present, realistic and optimistic scenarios. The main drivers for cost reduction for various chemistries were identified as a function of the energy to power ratio of the storage system. Levelized cost analysis further guided suitability of various chemistries for different applications.
Wetting and free surface flow modeling for potting and encapsulation.
Brooks, Carlton, F.; Brooks, Michael J.; Graham, Alan Lyman; Noble, David F. ); Notz, Patrick K.; Hopkins, Matthew Morgan; Castaneda, Jaime N.; Mahoney, Leo James; Baer, Thomas A.; Berchtold, Kathryn; Adolf, Douglas Brian; Wilkes, Edward Dean; Rao, Rekha Ranjana; Givler, Richard C.; Sun, Amy Cha-Tien; Cote, Raymond O.; Mondy, Lisa Ann; Grillet, Anne Mary; Kraynik, Andrew Michael
2007-06-01
As part of an effort to reduce costs and improve quality control in encapsulation and potting processes the Technology Initiative Project ''Defect Free Manufacturing and Assembly'' has completed a computational modeling study of flows representative of those seen in these processes. Flow solutions are obtained using a coupled, finite-element-based, numerical method based on the GOMA/ARIA suite of Sandia flow solvers. The evolution of the free surface is solved with an advanced level set algorithm. This approach incorporates novel methods for representing surface tension and wetting forces that affect the evolution of the free surface. In addition, two commercially available codes, ProCAST and MOLDFLOW, are also used on geometries representing encapsulation processes at the Kansas City Plant. Visual observations of the flow in several geometries are recorded in the laboratory and compared to the models. Wetting properties for the materials in these experiments are measured using a unique flowthrough goniometer.
Fluid dynamic modeling of nano-thermite reactions
Martirosyan, Karen S.; Zyskin, Maxim; Jenkins, Charles M.; Horie, Yasuyuki
2014-03-14
This paper presents a direct numerical method based on gas dynamic equations to predict pressure evolution during the discharge of nanoenergetic materials. The direct numerical method provides for modeling reflections of the shock waves from the reactor walls that generates pressure-time fluctuations. The results of gas pressure prediction are consistent with the experimental evidence and estimates based on the self-similar solution. Artificial viscosity provides sufficient smoothing of shock wave discontinuity for the numerical procedure. The direct numerical method is more computationally demanding and flexible than self-similar solution, in particular it allows study of a shock wave in its early stage of reaction and allows the investigation of “slower” reactions, which may produce weaker shock waves. Moreover, numerical results indicate that peak pressure is not very sensitive to initial density and reaction time, providing that all the material reacts well before the shock wave arrives at the end of the reactor.
Global nuclear material flow/control model
Dreicer, J.S.; Rutherford, D.S.; Fasel, P.K.; Riese, J.M.
1997-10-01
This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The nuclear danger can be reduced by a system for global management, protection, control, and accounting as part of an international regime for nuclear materials. The development of an international fissile material management and control regime requires conceptual research supported by an analytical and modeling tool which treats the nuclear fuel cycle as a complete system. The prototype model developed visually represents the fundamental data, information, and capabilities related to the nuclear fuel cycle in a framework supportive of national or an international perspective. This includes an assessment of the global distribution of military and civilian fissile material inventories, a representation of the proliferation pertinent physical processes, facility specific geographic identification, and the capability to estimate resource requirements for the management and control of nuclear material. The model establishes the foundation for evaluating the global production, disposition, and safeguards and security requirements for fissile nuclear material and supports the development of other pertinent algorithmic capabilities necessary to undertake further global nuclear material related studies.
Self-Assembling Sup-porosity: The Effect On Fluid Flow And Seismic Wave Propagation
Pyrak-Nolte, Laura J.
2013-04-27
Fractures and joints in the field often contain debris within the void spaces. Debris originates from many different mechanisms: organic and/or inorganic chemical reactions/mineralization, sediment transport, formation of a fracture, mechanical weathering or combinations of these processes. In many cases, the presence of debris forms a âsub-porosityâ within the fracture void space. This sub-porosity often is composed of material that differs from the fracture walls in mineralogy and morphology. The âsub-porosityâ may partially fill voids that are on the order of hundreds of microns and thereby reduce the local porosity to lengths scales on the order of sub-microns to tens of microns. It is quite clear that a sub-porosity affects fracture porosity, permeability and storativity. What is not known is how the existence/formation of a sub-porosity affects seismic wave propagation and consequently our ability to probe changes in the subsurface caused by the formation or alteration of a sub-porosity. If seismic techniques are to be developed to monitor the injection and containment of phases in sequestration reservoirs or the propping of hydraulically induced fracture to enhance oil & gas production, it is important to understand how a sub-porosity within a fracture affects macroscopic seismic and hydraulic measurements. A sub-porosity will directly affect the interrelationship between the seismic and hydraulic properties of a fracture. This reports contains the results of the three main topics of research that were performed (1) to determine the effect of a sub-porosity composed of spherical grains on seismic wave propagation across fractures, (2) to determine the effect of biofilm growth in pores and between grains on seismic wave propagation in sediment, and (3) to determine the effect of the scale of observation (field-of-view) on monitoring alteration the pore space within a fracture caused by reactive flow. A brief summary of the results for each
Comparison of Mesomechanical and Continuum Granular Flow Models for Ceramics
Curran, D. R.
2006-07-28
Constitutive models for the shear strength of ceramics undergoing fracture are needed for modeling long rod and shaped-charge jet penetration events in ceramic armor. The ceramic material ahead of the penetrator has been observed to be finely comminuted material that flows around the nose of the eroding penetrator (Shockey et al.). The most-used continuum models are of the Drucker-Prager type with an upper cutoff, or of the Mohr-Coulomb type with strain rate dependence and strain softening. A disadvantage of such models is that they have an unclear connection to the actual microscopic processes of granular flow and comminution. An alternate approach is to use mesomechanical models that describe the dynamics of the granular flow, as well as containing a description of the granular comminution and resultant material softening. However, a disadvantage of the mesomechanical models is that they are computationally more burdensome to apply. In the present paper, we compare the behaviors of a mesomechanical model, FRAGBED2, with the Walker and Johnson-Holmquist continuum models, where the granular material is subjected to simple strain histories under various confining pressures and strain rates. We conclude that the mesomechanical model can provide valuable input to the continuum models, both in interpretation of the continuum models' parameters and in suggesting their range of applicability.
Multiphase Flow Modeling of Biofuel Production Processes
D. Gaston; D. P. Guillen; J. Tester
2011-06-01
As part of the Idaho National Laboratory's (INL's) Secure Energy Initiative, the INL is performing research in areas that are vital to ensuring clean, secure energy supplies for the future. The INL Hybrid Energy Systems Testing (HYTEST) Laboratory is being established to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence on foreign petroleum. HYTEST involves producing liquid fuels in a Hybrid Energy System (HES) by integrating carbon-based (i.e., bio-mass, oil-shale, etc.) with non-carbon based energy sources (i.e., wind energy, hydro, geothermal, nuclear, etc.). Advances in process development, control and modeling are the unifying vision for HES. This paper describes new modeling tools and methodologies to simulate advanced energy processes. Needs are emerging that require advanced computational modeling of multiphase reacting systems in the energy arena, driven by the 2007 Energy Independence and Security Act, which requires production of 36 billion gal/yr of biofuels by 2022, with 21 billion gal of this as advanced biofuels. Advanced biofuels derived from microalgal biomass have the potential to help achieve the 21 billion gal mandate, as well as reduce greenhouse gas emissions. Production of biofuels from microalgae is receiving considerable interest due to their potentially high oil yields (around 600 gal/acre). Microalgae have a high lipid content (up to 50%) and grow 10 to 100 times faster than terrestrial plants. The use of environmentally friendly alternatives to solvents and reagents commonly employed in reaction and phase separation processes is being explored. This is accomplished through the use of hydrothermal technologies, which are chemical and physical transformations in high-temperature (200-600 C), high-pressure (5-40 MPa) liquid or supercritical water. Figure 1 shows a simplified diagram of the production of biofuels from algae. Hydrothermal processing has significant
Lee, S. N.; Tak, N. I.; Kim, M. H.; Noh, J. M.
2012-07-01
The existing study of Spall et al. shows that only {nu}{sup 2}-f turbulence model well matches with the experimental data of Shehata and McEligot which were obtained under strongly heated gas flows. Significant over-predictions in those literatures were observed in the convective heat transfer with the other famous turbulence models such as the k-{epsilon} and k-{omega} models. In spite of such good evidence about the performance of the{nu}{sup 2}-f model, the application of the {nu}{sup 2}-f model to the thermo-fluid analysis of a prismatic core is very rare. In this paper, therefore, the convective heat transfer of the coolant flow in a prismatic core has been investigated using the {nu}{sup 2}-f model. Computational fluid dynamics (CFD) calculations have been carried out for the typical unit cell geometry of a prismatic fuel column with typical operating conditions of prismatic designs. The tested Reynolds numbers of the coolant flow are 10,000, 20,000, 30,000 and 50,000. The predicted Nusselt numbers with the {nu}{sup 2}-f model are compared with the results by the other turbulence models (k-{epsilon} and SST) as well as the empirical correlations. (authors)
Remarks on a model of thermal transport in nanofluids (Journal...
Office of Scientific and Technical Information (OSTI)
of Publication: United States Language: English Subject: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; HEAT TRANSFER; FLOW MODELS; FLUIDS; NANOSTRUCTURES...
MODELING COUPLED PROCESSES OF MULTIPHASE FLOW AND HEAT TRANSFER IN UNSATURATED FRACTURED ROCK
Y. Wu; S. Mukhopadhyay; K. Zhang; G.S. Bodvarsson
2006-02-28
A mountain-scale, thermal-hydrologic (TH) numerical model is developed for investigating unsaturated flow behavior in response to decay heat from the radioactive waste repository at Yucca Mountain, Nevada, USA. The TH model, consisting of three-dimensional (3-D) representations of the unsaturated zone, is based on the current repository design, drift layout, and thermal loading scenario under estimated current and future climate conditions. More specifically, the TH model implements the current geological framework and hydrogeological conceptual models, and incorporates the most updated, best-estimated input parameters. This mountain-scale TH model simulates the coupled TH processes related to mountain-scale multiphase fluid flow, and evaluates the impact of radioactive waste heat on the hydrogeological system, including thermally perturbed liquid saturation, gas- and liquid-phase fluxes, and water and rock temperature elevations, as well as the changes in water flux driven by evaporation/condensation processes and drainage between drifts. For a better description of the ambient geothermal condition of the unsaturated zone system, the TH model is first calibrated against measured borehole temperature data. The ambient temperature calibration provides the necessary surface and water table boundary as well as initial conditions. Then, the TH model is used to obtain scientific understanding of TH processes in the Yucca Mountain unsaturated zone under the designed schedule of repository thermal load.
SCDAP/RELAP5 modeling of heat transfer and flow losses in lower head porous debris. Revision 1
Siefken, L.J.; Coryell, E.W.; Paik, S.; Kuo, H.
1999-05-01
Designs are described for implementing models for calculating the heat transfer and flow losses in porous debris in the lower head of a reactor vessel. The COUPLE model in SCDAP/RELAP5 represents both the porous and nonporous debris that results from core material slumping into the lower head. Currently, the COUPLE model has the capability to model convective and radiative heat transfer from the surfaces of nonporous debris in a detailed manner and to model only in a simplistic manner the heat transfer from porous debris. In order to advance beyond the simplistic modeling for porous debris, designs are developed for detailed calculations of heat transfer and flow losses in porous debris. Correlations are identified for convective heat transfer in porous debris for the following modes of heat transfer; (1) forced convection to liquid, (2) forced convection to gas, (3) nucleate boiling, (4) transition boiling, and (5) film boiling. Interphase heat transfer is modeled in an approximate ma nner. Designs are described for models to calculate the flow losses and interphase drag of fluid flowing through the interstices of the porous debris, and to apply these variables in the momentum equations in the RELAP5 part of the code. Since the models for heat transfer and flow losses in porous debris in the lower head are designed for general application, a design is also described for implementation of these models to the analysis of porous debris in the core region. A test matrix is proposed for assessing the capability of the implemented models to calculate the heat transfer and flow losses in porous debris. The implementation of the models described in this report is expected to improve the COUPLE code calculation of the temperature distribution in porous debris and in the lower head that supports the debris. The implementation of these models is also expected to improve the calculation of the temperature and flow distribution in porous debris in the core region.
CFD modeling of commercial-scale entrained-flow coal gasifiers
Ma, J.; Zitney, S.
2012-01-01
Optimization of an advanced coal-fired integrated gasification combined cycle system requires an accurate numerical prediction of gasifier performance. Computational fluid dynamics (CFD) has been used to model the turbulent multiphase reacting flow inside commercial-scale entrained-flow coal gasifiers. Due to the complexity of the physical and chemical processes involved, the accuracy of sub-models requires further improvement. Built upon a previously developed CFD model for entrained-flow gasification, the advanced physical and chemical sub-models presented in this paper include a moisture vaporization model with consideration of high mass transfer rate and a coal devolatilization model with more species to represent coal volatiles and the heating rate effect on volatile yield. The global gas phase reaction kinetics is also carefully selected. To predict a reasonable peak temperature of the coal/O{sub 2} flame inside an entrained-flow gasifier, the reserve reaction of H{sub 2} oxidation is included in the gas phase reaction model. The enhanced CFD model is applied to simulate two typical commercial-scale oxygen-blown entrained-flow configurations including a single-stage down-fired gasifier and a two-stage up-fired gasifier. The CFD results are reasonable in terms of predicted carbon conversion, syngas exit temperature, and syngas exit composition. The predicted profiles of velocity, temperature, and species mole fractions inside the entrained-flow gasifier models show trends similar to those observed in a diffusion-type flame. The predicted distributions of mole fractions of major species inside both gasifiers can be explained by the heterogeneous combustion and gasification reactions and the homogeneous gas phase reactions. It was also found that the syngas compositions at the CFD model exits are not in chemical equilibrium, indicating the kinetics for both heterogeneous and gas phase homogeneous reactions are important. Overall, the results achieved here
Numerical modeling of an all vanadium redox flow battery.
Clausen, Jonathan R.; Brunini, Victor E.; Moffat, Harry K.; Martinez, Mario J.
2014-01-01
We develop a capability to simulate reduction-oxidation (redox) flow batteries in the Sierra Multi-Mechanics code base. Specifically, we focus on all-vanadium redox flow batteries; however, the capability is general in implementation and could be adopted to other chemistries. The electrochemical and porous flow models follow those developed in the recent publication by [28]. We review the model implemented in this work and its assumptions, and we show several verification cases including a binary electrolyte, and a battery half-cell. Then, we compare our model implementation with the experimental results shown in [28], with good agreement seen. Next, a sensitivity study is conducted for the major model parameters, which is beneficial in targeting specific features of the redox flow cell for improvement. Lastly, we simulate a three-dimensional version of the flow cell to determine the impact of plenum channels on the performance of the cell. Such channels are frequently seen in experimental designs where the current collector plates are borrowed from fuel cell designs. These designs use a serpentine channel etched into a solid collector plate.
A flowing plasma model to describe drift waves in a cylindrical helicon discharge
Chang, L.; Hole, M. J.; Corr, C. S.
2011-04-15
A two-fluid model developed originally to describe wave oscillations in the vacuum arc centrifuge, a cylindrical, rapidly rotating, low temperature, and confined plasma column, is applied to interpret plasma oscillations in a RF generated linear magnetized plasma [WOMBAT (waves on magnetized beams and turbulence)], with similar density and field strength. Compared to typical centrifuge plasmas, WOMBAT plasmas have slower normalized rotation frequency, lower temperature, and lower axial velocity. Despite these differences, the two-fluid model provides a consistent description of the WOMBAT plasma configuration and yields qualitative agreement between measured and predicted wave oscillation frequencies with axial field strength. In addition, the radial profile of the density perturbation predicted by this model is consistent with the data. Parameter scans show that the dispersion curve is sensitive to the axial field strength and the electron temperature, and the dependence of oscillation frequency with electron temperature matches the experiment. These results consolidate earlier claims that the density and floating potential oscillations are a resistive drift mode, driven by the density gradient. To our knowledge, this is the first detailed physics model of flowing plasmas in the diffusion region away from the RF source. Possible extensions to the model, including temperature nonuniformity and magnetic field oscillations, are also discussed.
Plastic flow modeling in glassy polymers
Clements, Brad
2010-12-13
developed glassy polymer model. While polymers are well known for their non-equilibrium deviatoric behavior we have found the need for incorporating both equilibrium and non-equilibrium volumetric behavior into our theory. Experimental evidence supporting the notion of non-equilibrium volumetric behavior will be summarized. Our polymer yield model accurately captures the stress plateau, softening and hardening and its yield stress predictions agree well with measured values for several glassy polymers including PMMA, PC, and an epoxy resin. We then apply our theory to plate impact experiments in an attempt to address the questions associated with high rate polymer yield in uniaxial strain configurations.
Interfacial shear modeling in two-phase annular flow
Kumar, R.; Edwards, D.P.
1996-07-01
A new interfacial shear stress model called the law of the interface model, based on the law of the wall approach in turbulent flows, has been developed and locally applied in a fully developed, adiabatic, two-phase annular flow in a duct. Numerical results have been obtained using this model in conjunction with other models available in the literature that are required for the closure of the continuity and momentum equations. These results have been compared with droplet velocity data (using laser Doppler velocimetry and hot film anemometry), void fraction data (using gamma densitometry) and pressure drop data obtained in a R-134A refrigerant test facility. Droplet velocity results match the experimental data well, however, the prediction of the void fraction is less accurate. The poor prediction of void fraction, especially for the low void fraction cases, appears to be due to the lack of a good mechanistic model for entrainment.
Abbott, Mark W.
2013-07-01
Throughout power generation, delivery and waste remediation, the ability to control process streams in difficult or impossible locations becomes increasingly necessary as the complexity of processes increases. Example applications include radioactive environments, inside concrete installations, buried in dirt, or inside a shielded or insulated pipe. In these situations, it is necessary to implement innovative solutions to tackle such issues as valve maintenance, valve control from remote locations, equipment cleaning in hazardous environments, and flow stream analysis. The Extended Sleeve family of products provides a scalable solution to tackle some of the most challenging applications in hazardous environments which require flow stream control and monitoring. The Extended Sleeve family of products is defined in three groups: Extended Sleeve (ESV), Extended Bonnet (EBV) and Instrument Enclosure (IE). Each of the products provides a variation on the same requirements: to provide access to the internals of a valve, or to monitor the fluid passing through the pipeline through shielding around the process pipe. The shielding can be as simple as a grout filled pipe covering a process pipe or as complex as a concrete deck protecting a room in which the valves and pipes pass through at varying elevations. Extended Sleeves are available between roughly 30 inches and 18 feet of distance between the pipeline centerline and the top of the surface to which it mounts. The Extended Sleeve provides features such as ± 1.5 inches of adjustment between the pipeline and deck location, internal flush capabilities, automatic alignment of the internal components during assembly and integrated actuator mounting pads. The Extended Bonnet is a shorter fixed height version of the Extended Sleeve which has a removable deck flange to facilitate installation through walls, and is delivered fully assembled. The Instrument Enclosure utilizes many of the same components as an Extended Sleeve
Goldberg, L.F.
1990-08-01
The activities described in this report do not constitute a continuum but rather a series of linked smaller investigations in the general area of one- and two-dimensional Stirling machine simulation. The initial impetus for these investigations was the development and construction of the Mechanical Engineering Test Rig (METR) under a grant awarded by NASA to Dr. Terry Simon at the Department of Mechanical Engineering, University of Minnesota. The purpose of the METR is to provide experimental data on oscillating turbulent flows in Stirling machine working fluid flow path components (heater, cooler, regenerator, etc.) with particular emphasis on laminar/turbulent flow transitions. Hence, the initial goals for the grant awarded by NASA were, broadly, to provide computer simulation backup for the design of the METR and to analyze the results produced. This was envisaged in two phases: First, to apply an existing one-dimensional Stirling machine simulation code to the METR and second, to adapt a two-dimensional fluid mechanics code which had been developed for simulating high Rayleigh number buoyant cavity flows to the METR. The key aspect of this latter component was the development of an appropriate turbulence model suitable for generalized application to Stirling simulation. A final-step was then to apply the two-dimensional code to an existing Stirling machine for which adequate experimental data exist. The work described herein was carried out over a period of three years on a part-time basis. Forty percent of the first year`s funding was provided as a match to the NASA funds by the Underground Space Center, University of Minnesota, which also made its computing facilities available to the project at no charge.
First status report on regional groundwater flow modeling for the Palo Duro Basin, Texas
Andrews, R.W.
1984-12-01
Regional groundwater flow within the principal hydrogeological units of the Palo Duro Basin is evaluated by developing a conceptual model of the flow regime in the shallow aquifers and the deep-basin brine aquifers and testing these models using a three-dimensional, finite-difference flow code. Semiquantitative sensitivity analysis (a limited parametric study) is conducted to define the system response to changes in hydrologic properties or boundary conditions. Adjoint sensitivity analysis is applied to the conceptualized flow regime in the Wolfcamp carbonate aquifer. All steps leading to the final results and conclusions are incorporated in this report. The available data utilized in this study are summarized. The specific conceptual models, defining the areal and vertical averaging of lithologic units, aquifer properties, fluid properties, and hydrologic boundary conditions, are described in detail. The results are delineated by the simulated potentiometric surfaces and tables summarizing areal and vertical boundary fluxes, Darcy velocities at specific points, and groundwater travel paths. Results from the adjoint sensitivity analysis included importance functions and sensitivity coefficients, using heads or the average Darcy velocities as the performance measures. The reported work is the first stage of an ongoing evaluation of two areas within the Palo Duro Basin as potantial repositories for high-level radioactive wastes. The results and conclusions should thus be considered preliminary and subject to modification with the collection of additional data. However, this report does provide a useful basis for describing the sensitivity and, to a lesser extent, the uncertainty of the present conceptualization of groundwater flow within the Palo Duro Basin.
Dalkilic, A.S. [Heat and Thermodynamics Division, Department of Mechanical Engineering, Yildiz Technical University, Yildiz, Besiktas, Istanbul 34349 (Turkey); Wongwises, S. [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)
2010-09-15
In the present study, new experimental data are presented for literature on the prediction of film thickness and identification of flow regime during the co-current downward condensation in a vertical smooth copper tube having an inner diameter of 8.1 mm and a length of 500 mm. R134a and water are used as working fluids in the tube side and annular side of a double tube heat exchanger, respectively. Condensation experiments are done at mass fluxes of 300 and 515 kg m{sup -2} s{sup -1}. The condensing temperatures are between 40 and 50 C; heat fluxes are between 12.65 and 66.61 kW m{sup -2}. The average experimental heat transfer coefficient of the refrigerant HFC-134a is calculated by applying an energy balance based on the energy transferred from the test section. A mathematical model by Barnea et al. based on the momentum balance of liquid and vapor phases is used to determine the condensation film thickness of R134a. The comparative film thickness values are determined indirectly using relevant measured data together with various void fraction models and correlations reported in the open literature. The effects of heat flux, mass flux, and condensation temperature on the film thickness and condensation heat transfer coefficient are also discussed for the laminar and turbulent flow conditions. There is a good agreement between the film thickness results obtained from the theoretical model and those obtained from six of 35 void fraction models in the high mass flux region of R134a. In spite of their different valid conditions, six well-known flow regime maps from the literature are found to be predictive for the annular flow conditions in the test tube in spite of their different operating conditions. (author)
Linden, D.S.
1993-05-01
The traditional two-fluid model of superconducting conductivity was modified to make it accurate, while remaining fast, for designing and simulating microwave devices. The modification reflects the BCS coherence effects in the conductivity of a superconductor, and is incorporated through the ratio of normal to superconducting electrons. This modified ratio is a simple analytical expression which depends on frequency, temperature and material parameters. This modified two-fluid model allows accurate and rapid calculation of the microwave surface impedance of a superconductor in the clean and dirty limits and in the weak- and strong-coupled regimes. The model compares well with surface resistance data for Nb and provides insight into Nb3Sn and Y1Ba2Cu3O(7-delta). Numerical calculations with the modified two-fluid model are an order of magnitude faster than the quasi-classical program by Zimmermann (1), and two to five orders of magnitude faster than Halbritter's BCS program (2) for surface resistance.
Nichols, B.D.; Mueller, C.; Necker, G.A.; Travis, J.R.; Spore, J.W.; Lam, K.L.; Royl, P.; Redlinger, R.; Wilson, T.L.
1998-10-01
Los Alamos National Laboratory (LANL) and Forschungszentrum Karlsruhe (FzK) are developing GASFLOW, a three-dimensional (3D) fluid dynamics field code as a best-estimate tool to characterize local phenomena within a flow field. Examples of 3D phenomena include circulation patterns; flow stratification; hydrogen distribution mixing and stratification; combustion and flame propagation; effects of noncondensable gas distribution on local condensation and evaporation; and aerosol entrainment, transport, and deposition. An analysis with GASFLOW will result in a prediction of the gas composition and discrete particle distribution in space and time throughout the facility and the resulting pressure and temperature loadings on the walls and internal structures with or without combustion. A major application of GASFLOW is for predicting the transport, mixing, and combustion of hydrogen and other gases in nuclear reactor containments and other facilities. It has been applied to situations involving transporting and distributing combustible gas mixtures. It has been used to study gas dynamic behavior (1) in low-speed, buoyancy-driven flows, as well as sonic flows or diffusion dominated flows; and (2) during chemically reacting flows, including deflagrations. The effects of controlling such mixtures by safety systems can be analyzed. The code version described in this manual is designated GASFLOW 2.1, which combines previous versions of the United States Nuclear Regulatory Commission code HMS (for Hydrogen Mixing Studies) and the Department of Energy and FzK versions of GASFLOW. The code was written in standard Fortran 90. This manual comprises three volumes. Volume I describes the governing physical equations and computational model. Volume II describes how to use the code to set up a model geometry, specify gas species and material properties, define initial and boundary conditions, and specify different outputs, especially graphical displays. Sample problems are included
François, Marianne M.
2015-05-28
A review of recent advances made in numerical methods and algorithms within the volume tracking framework is presented. The volume tracking method, also known as the volume-of-fluid method has become an established numerical approach to model and simulate interfacial flows. Its advantage is its strict mass conservation. However, because the interface is not explicitly tracked but captured via the material volume fraction on a fixed mesh, accurate estimation of the interface position, its geometric properties and modeling of interfacial physics in the volume tracking framework remain difficult. Several improvements have been made over the last decade to address these challenges.more » In this study, the multimaterial interface reconstruction method via power diagram, curvature estimation via heights and mean values and the balanced-force algorithm for surface tension are highlighted.« less
Electron collisions in the trapped gyro-Landau fluid transport model
Staebler, G. M.; Kinsey, J. E.
2010-12-15
Accurately modeling electron collisions in the trapped gyro-Landau fluid (TGLF) equations has been a major challenge. Insights gained from numerically solving the gyrokinetic equation have lead to a significant improvement of the low order TGLF model. The theoretical motivation and verification of this model with the velocity-space gyrokinetic code GYRO[J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] will be presented. The improvement in the fidelity of TGLF to GYRO is shown to also lead to better prediction of experimental temperature profiles by TGLF for a dedicated collision frequency scan.
Wang, J.S.Y.; Narasimhan, T.N.
1993-06-01
This report discusses conceptual models and mathematical equations, analyzes distributions and correlations among hydrological parameters of soils and tuff, introduces new path integration approaches, and outlines scaling procedures to model potential-driven fluid flow in heterogeneous media. To properly model the transition from fracture-dominated flow under saturated conditions to matrix-dominated flow under partially saturated conditions, characteristic curves and permeability functions for fractures and matrix need to be improved and validated. Couplings from two-phase flow, heat transfer, solute transport, and rock deformation to liquid flow are also important. For stochastic modeling of alternating units of welded and nonwelded tuff or formations bounded by fault zones, correlations and constraints on average values of saturated permeability and air entry scaling factor between different units need to be imposed to avoid unlikely combinations of parameters and predictions. Large-scale simulations require efficient and verifiable numerical algorithms. New path integration approaches based on postulates of minimum work and mass conservation to solve flow geometry and potential distribution simultaneously are introduced. This verifiable integral approach, together with fractal scaling procedures to generate statistical realizations with parameter distribution, correlation, and scaling taken into account, can be used to quantify uncertainties and generate the cumulative distribution function for groundwater travel times.
Extinction properties of single-walled carbon nanotubes: Two-fluid model
Moradi, Afshin
2014-03-15
The extinction spectra of a single-walled carbon nanotube are investigated, within the framework of the vector wave function method in conjunction with the hydrodynamic model. Both polarizations of the incident plane wave (TE and TM with respect to the x-z plane) are treated. Electronic excitations on the nanotube surface are modeled by an infinitesimally thin layer of a two-dimensional electron gas represented by two interacting fluids, which takes into account the different nature of the σ and π electrons. Numerical results show that strong interaction between the fluids gives rise to the splitting of the extinction spectra into two peaks in quantitative agreement with the π and σ + π plasmon energies.
Lee, S. Y.; Park, C. E.; Hibiki, T.; Ishii, M.; Ransom, V. H.
2012-07-01
The well-posedness, convergence and the stability of the two-fluid code has been studied for a long time. Most of the investigations concern the semi-implicit upwind solution scheme for the six equation two-fluid model such as used in RELAP5 3 or TRACE 21. Since the system code, SPACE 2, adopts one more field, a droplet field, it consists of nine equations (3 mass, 3 momentum and 3 energy balance equations) and thus more involved investigations are necessary to confirm the stability and convergence. For this objective, the old issue of the well-posedness, convergence and the stability is revisited and some general guidelines to develop a well-posed numerical multi-fluid model are derived as follows; (1) Hyperbolicity of the corresponding system of partial differential equations is not a necessary condition for the development of a numerical model for multi-phase flow, but whether or not it is hyperbolic can provide guidance relative to initial conditions, boundary conditions, and expected high frequency behavior of the model. (2) A necessary condition for a well-posed numerical model is stability in the von Neumann sense, i.e. growth factor less than 1.0 for the shortest wave-length, 2{Delta}x. (3) The smallest node size used for convergence studies should be of the order of the characteristic dimension of the average description, i.e. smaller nodes can be used so long as they do not result in unphysical growth of wave-lengths less than the characteristic dimension. The usual mathematical definition of convergence i.e. the behavior of the solution as the node size approaches zero, is not appropriate for the discrete averaged numerical model, since there is diminished physical meaning to behavior at wavelengths less than the characteristic dimension of the average description. Under these guidelines, dispersion analysis and von Neumann stability analysis are performed for the three field multi-fluid, semi-implicit, upwind numerical model to show that the necessary
Technical Review of the CENWP Computational Fluid Dynamics Model of the John Day Dam Forebay
Rakowski, Cynthia L.; Serkowski, John A.; Richmond, Marshall C.
2010-12-01
The US Army Corps of Engineers Portland District (CENWP) has developed a computational fluid dynamics (CFD) model of the John Day forebay on the Columbia River to aid in the development and design of alternatives to improve juvenile salmon passage at the John Day Project. At the request of CENWP, Pacific Northwest National Laboratory (PNNL) Hydrology Group has conducted a technical review of CENWP's CFD model run in CFD solver software, STAR-CD. PNNL has extensive experience developing and applying 3D CFD models run in STAR-CD for Columbia River hydroelectric projects. The John Day forebay model developed by CENWP is adequately configured and validated. The model is ready for use simulating forebay hydraulics for structural and operational alternatives. The approach and method are sound, however CENWP has identified some improvements that need to be made for future models and for modifications to this existing model.
Recent results and persisting problems in modeling flow induced coalescence
Forteln, I. E-mail: juza@imc.cas.cz; Jza, J. E-mail: juza@imc.cas.cz
2014-05-15
The contribution summarizes recent results of description of the flow induced coalescence in immiscible polymer blends and addresses problems that call for which solving. The theory of coalescence based on the switch between equations for matrix drainage between spherical or deformed droplets provides a good agreement with more complicated modeling and available experimental data for probability, P{sub c}, that the collision of droplets will be followed by their fusion. A new equation for description of the matrix drainage between deformed droplets, applicable to the whole range of viscosity ratios, p, of the droplets and matrixes, is proposed. The theory facilitates to consider the effect of the matrix elasticity on coalescence. P{sub c} decreases with the matrix relaxation time but this decrease is not pronounced for relaxation times typical of most commercial polymers. Modeling of the flow induced coalescence in concentrated systems is needed for prediction of the dependence of coalescence rate on volume fraction of droplets. The effect of the droplet anisometry on P{sub c} should be studied for better understanding the coalescence in flow field with high and moderate deformation rates. A reliable description of coalescence in mixing and processing devices requires proper modeling of complex flow fields.
Branch Flow Model: Relaxations and Convexification-Part II
Farivar, M; Low, SH
2013-08-01
We propose a branch flow model for the analysis and optimization of mesh as well as radial networks. The model leads to a new approach to solving optimal power flow (OPF) that consists of two relaxation steps. The first step eliminates the voltage and current angles and the second step approximates the resulting problem by a conic program that can be solved efficiently. For radial networks, we prove that both relaxation steps are always exact, provided there are no upper bounds on loads. For mesh networks, the conic relaxation is always exact but the angle relaxation may not be exact, and we provide a simple way to determine if a relaxed solution is globally optimal. We propose convexification of mesh networks using phase shifters so that OPF for the convexified network can always be solved efficiently for an optimal solution. We prove that convexification requires phase shifters only outside a spanning tree of the network and their placement depends only on network topology, not on power flows, generation, loads, or operating constraints. Part I introduces our branch flow model, explains the two relaxation steps, and proves the conditions for exact relaxation. Part II describes convexification of mesh networks, and presents simulation results.
Branch Flow Model: Relaxations and Convexification-Part I
Farivar, M; Low, SH
2013-08-01
We propose a branch flow model for the analysis and optimization of mesh as well as radial networks. The model leads to a new approach to solving optimal power flow (OPF) that consists of two relaxation steps. The first step eliminates the voltage and current angles and the second step approximates the resulting problem by a conic program that can be solved efficiently. For radial networks, we prove that both relaxation steps are always exact, provided there are no upper bounds on loads. For mesh networks, the conic relaxation is always exact but the angle relaxation may not be exact, and we provide a simple way to determine if a relaxed solution is globally optimal. We propose convexification of mesh networks using phase shifters so that OPF for the convexified network can always be solved efficiently for an optimal solution. We prove that convexification requires phase shifters only outside a spanning tree of the network and their placement depends only on network topology, not on power flows, generation, loads, or operating constraints. Part I introduces our branch flow model, explains the two relaxation steps, and proves the conditions for exact relaxation. Part II describes convexification of mesh networks, and presents simulation results.
Final Report - Advanced Conceptual Models for Unsaturated and Two-Phase Flow in Fractured Rock
Nicholl, Michael J.
2006-07-10
The Department of Energy Environmental Management Program is faced with two major issues involving two-phase flow in fractured rock; specifically, transport of dissolved contaminants in the Vadose Zone, and the fate of Dense Nonaqueous Phase Liquids (DNAPLs) below the water table. Conceptual models currently used to address these problems do not correctly include the influence of the fractures, thus leading to erroneous predictions. Recent work has shown that it is crucial to understand the topology, or ''structure'' of the fluid phases (air/water or water/DNAPL) within the subsurface. It has also been shown that even under steady boundary conditions, the influence of fractures can lead to complex and dynamic phase structure that controls system behavior, with or without the presence of a porous rock matrix. Complicated phase structures within the fracture network can facilitate rapid transport, and lead to a sparsely populated and widespread distribution of concentrated contaminants; these qualities are highly difficult to describe with current conceptual models. The focus of our work is to improve predictive modeling through the development of advanced conceptual models for two-phase flow in fractured rock.
An algebraic model for a zinc/bromine flow cell
Simpson, G.D.; White, R.E. . Dept. of Chemical Engineering)
1989-08-01
An algebraic model for a parallel plate, zinc/bromine flow cell is presented and used to predict various performance quantities, which are compared to those predicted by using previously published differential equation models. The results presented compare well with previous work. The model is based on the concept of using well-mixed zones and linear concentration and potential profiles for the diffusion layers and the separator. The Butler-Volmer equation is used for the electro chemical reactions, and the homogeneous reaction between bromine and bromide is included.
Sub-grid drag models for horizontal cylinder arrays immersed in gas-particle multiphase flows
Sarkar, Avik; Sun, Xin; Sundaresan, Sankaran
2013-09-08
Immersed cylindrical tube arrays often are used as heat exchangers in gas-particle fluidized beds. In multiphase computational fluid dynamics (CFD) simulations of large fluidized beds, explicit resolution of small cylinders is computationally infeasible. Instead, the cylinder array may be viewed as an effective porous medium in coarse-grid simulations. The cylinders' influence on the suspension as a whole, manifested as an effective drag force, and on the relative motion between gas and particles, manifested as a correction to the gas-particle drag, must be modeled via suitable sub-grid constitutive relationships. In this work, highly resolved unit-cell simulations of flow around an array of horizontal cylinders, arranged in a staggered configuration, are filtered to construct sub-grid, or `filtered', drag models, which can be implemented in coarse-grid simulations. The force on the suspension exerted by the cylinders is comprised of, as expected, a buoyancy contribution, and a kinetic component analogous to fluid drag on a single cylinder. Furthermore, the introduction of tubes also is found to enhance segregation at the scale of the cylinder size, which, in turn, leads to a reduction in the filtered gas-particle drag.
An Evaluation of Unsaturated Flow Models in an Arid Climate
Dixon, J.
1999-12-01
The objective of this study was to evaluate the effectiveness of two unsaturated flow models in arid regions. The area selected for the study was the Area 5 Radioactive Waste Management Site (RWMS) at the Nevada Test Site in Nye County, Nevada. The two models selected for this evaluation were HYDRUS-1D [Simunek et al., 1998] and the SHAW model [Flerchinger and Saxton, 1989]. Approximately 5 years of soil-water and atmospheric data collected from an instrumented weighing lysimeter site near the RWMS were used for building the models with actual initial and boundary conditions representative of the site. Physical processes affecting the site and model performance were explored. Model performance was based on a detailed sensitivity analysis and ultimately on storage comparisons. During the process of developing descriptive model input, procedures for converting hydraulic parameters for each model were explored. In addition, the compilation of atmospheric data collected at the site became a useful tool for developing predictive functions for future studies. The final model results were used to evaluate the capacities of the HYDRUS and SHAW models for predicting soil-moisture movement and variable surface phenomena for bare soil conditions in the arid vadose zone. The development of calibrated models along with the atmospheric and soil data collected at the site provide useful information for predicting future site performance at the RWMS.
Pruess, Karsten
2005-03-22
Leakage of CO2 from a hypothetical geologic storage reservoir along an idealized fault zone has been simulated, including transitions between supercritical, liquid, and gaseous CO2. We find strong non-isothermal effects due to boiling and Joule-Thomson cooling of expanding CO2. Leakage fluxes are limited by limitations in conductive heat transfer to the fault zone. The interplay between multiphase flow and heat transfer effects produces non-monotonic leakage behavior.
Ng, Jonathan; Huang, Yi -Min; Hakim, Ammar; Bhattacharjee, A.; Stanier, Adam; Daughton, William; Wang, Liang; Germaschewski, Kai
2015-11-05
As modeling of collisionless magnetic reconnection in most space plasmas with realistic parameters is beyond the capability of today's simulations, due to the separation between global and kinetic length scales, it is important to establish scaling relations in model problems so as to extrapolate to realistic scales. Furthermore, large scale particle-in-cell simulations of island coalescence have shown that the time averaged reconnection rate decreases with system size, while fluid systems at such large scales in the Hall regime have not been studied. Here, we perform the complementary resistive magnetohydrodynamic (MHD), Hall MHD, and two fluid simulations using a ten-moment model with the same geometry. In contrast to the standard Harris sheet reconnection problem, Hall MHD is insufficient to capture the physics of the reconnection region. Additionally, motivated by the results of a recent set of hybrid simulations which show the importance of ion kinetics in this geometry, we evaluate the efficacy of the ten-moment model in reproducing such results.
Ng, Jonathan; Huang, Yi-Min; Hakim, Ammar; Bhattacharjee, A.; Stanier, Adam; Daughton, William; Wang, Liang; Germaschewski, Kai
2015-11-15
As modeling of collisionless magnetic reconnection in most space plasmas with realistic parameters is beyond the capability of today's simulations, due to the separation between global and kinetic length scales, it is important to establish scaling relations in model problems so as to extrapolate to realistic scales. Recently, large scale particle-in-cell simulations of island coalescence have shown that the time averaged reconnection rate decreases with system size, while fluid systems at such large scales in the Hall regime have not been studied. Here, we perform the complementary resistive magnetohydrodynamic (MHD), Hall MHD, and two fluid simulations using a ten-moment model with the same geometry. In contrast to the standard Harris sheet reconnection problem, Hall MHD is insufficient to capture the physics of the reconnection region. Additionally, motivated by the results of a recent set of hybrid simulations which show the importance of ion kinetics in this geometry, we evaluate the efficacy of the ten-moment model in reproducing such results.
Aniel-Buchheit, Sylvie; Podowski, Michael Z.
2006-07-01
The purpose of this paper is to discuss the development in progress of a complete space- and time-dependent model of the coupled neutron kinetic and reactor thermal-hydraulics. The neutron kinetics model is based on two-group diffusion equations with Doppler and void reactivity feedback effects. This model is coupled with the model of two-phase flow and heat transfer in parallel coolant channels. The modeling concepts considered for this purpose include one-dimensional drift flux and two-fluid models, as well a CFD model implemented in the NPHASE advanced computational multiphase fluid dynamics (CMFD) computer code. Two methods of solution for the overall model are proposed. One is based on direct numerical integration of the spatially-discretized governing equations. The other approach is based on a quasi-analytical modal approach to the neutronics model, in which a complete set of eigenvectors is found for step-wise temporal changes of the cross-sections of core materials (fuel and coolant/moderator). The issues investigated in the paper include details of model formulation, as well as the results of calculations for neutronically-coupled density-wave oscillations. (authors)
Effective permittivity of single-walled carbon nanotube composites: Two-fluid model
Moradi, Afshin; Zangeneh, Hamid Reza; Moghadam, Firoozeh Karimi
2015-12-15
We develop an effective medium theory to obtain effective permittivity of a composite of two-dimensional (2D) aligned single-walled carbon nanotubes. Electronic excitations on each nanotube surface are modeled by an infinitesimally thin layer of a 2D electron gas represented by two interacting fluids, which takes into account different nature of the σ and π electrons. Calculations of both real and imaginary parts of the effective dielectric function of the system are presented, for different values of the filling factor and radius of carbon nanotubes.
Ng, Jonathan; Huang, Yi -Min; Hakim, Ammar; Bhattacharjee, A.; Stanier, Adam; Daughton, William; Wang, Liang; Germaschewski, Kai
2015-11-05
As modeling of collisionless magnetic reconnection in most space plasmas with realistic parameters is beyond the capability of today's simulations, due to the separation between global and kinetic length scales, it is important to establish scaling relations in model problems so as to extrapolate to realistic scales. Furthermore, large scale particle-in-cell simulations of island coalescence have shown that the time averaged reconnection rate decreases with system size, while fluid systems at such large scales in the Hall regime have not been studied. Here, we perform the complementary resistive magnetohydrodynamic (MHD), Hall MHD, and two fluid simulations using a ten-moment modelmore » with the same geometry. In contrast to the standard Harris sheet reconnection problem, Hall MHD is insufficient to capture the physics of the reconnection region. Additionally, motivated by the results of a recent set of hybrid simulations which show the importance of ion kinetics in this geometry, we evaluate the efficacy of the ten-moment model in reproducing such results.« less
McHugh, P.R.
1995-10-01
Fully coupled, Newton-Krylov algorithms are investigated for solving strongly coupled, nonlinear systems of partial differential equations arising in the field of computational fluid dynamics. Primitive variable forms of the steady incompressible and compressible Navier-Stokes and energy equations that describe the flow of a laminar Newtonian fluid in two-dimensions are specifically considered. Numerical solutions are obtained by first integrating over discrete finite volumes that compose the computational mesh. The resulting system of nonlinear algebraic equations are linearized using Newton`s method. Preconditioned Krylov subspace based iterative algorithms then solve these linear systems on each Newton iteration. Selected Krylov algorithms include the Arnoldi-based Generalized Minimal RESidual (GMRES) algorithm, and the Lanczos-based Conjugate Gradients Squared (CGS), Bi-CGSTAB, and Transpose-Free Quasi-Minimal Residual (TFQMR) algorithms. Both Incomplete Lower-Upper (ILU) factorization and domain-based additive and multiplicative Schwarz preconditioning strategies are studied. Numerical techniques such as mesh sequencing, adaptive damping, pseudo-transient relaxation, and parameter continuation are used to improve the solution efficiency, while algorithm implementation is simplified using a numerical Jacobian evaluation. The capabilities of standard Newton-Krylov algorithms are demonstrated via solutions to both incompressible and compressible flow problems. Incompressible flow problems include natural convection in an enclosed cavity, and mixed/forced convection past a backward facing step.
Miller, Jan D; Hupka, Jan; Aranowski, Robert
2012-11-20
A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.
Hoff, Brian D.; Johnson, Kris William; Algrain, Marcelo C.; Akasam, Sivaprasad
2006-06-06
A method of controlling the delivery of fluid to an engine includes receiving a fuel flow rate signal. An electric pump is arranged to deliver fluid to the engine. The speed of the electric pump is controlled based on the fuel flow rate signal.
Trabold, T.A.; Kumar, R.
1999-07-01
In Part 1, detailed measurements were made in a high pressure, adiabatic (boiled at the inlet) annular flow in a narrow, high aspect ratio duct using a gamma densitometer, hot-film anemometer and high-speed video photography. Measurements of void fraction, droplet frequency, velocity, drop size, and interfacial area concentration have been made to support the three field computational capability. An important aspect of this testing is the use of a modeling fluid (R-134a) in a vertical duct which permits visual access in annular flow. This modeling fluid accurately simulates the low liquid-to-vapor density ratio of steam-water flows at high pressures. These measurements have been taken in a narrow duct of hydraulic diameter 4.85 mm, and a cross-section aspect ratio of 22.5. However, the flow displays profiles of various shapes not only in the narrow dimension, but also in the width dimension. In particular, the shape of the droplet profiles depends on the entrained droplet flux from the edges in the vapor core. The average diameter from these profiles compare well with the models developed in the literature. Interfacial area concentration for these low density ratio flows is higher than the highest concentration reported for air-water flows. Video records show that along with the bow-shaped waves, three-dimensional {lambda}-shaped waves appear in annular flows for high flow rates. Part 2 outlines the development of a three-field modeling approach in annular flow and the predictive capability of an analysis code. Models have been developed here or adapted from the literature for the thin film near the wall as well as the droplets in the vapor core, and have been locally applied in a fully developed, two-phase adiabatic boiling annular flow in a duct heated at the inlet at high pressure. Numerical results have been obtained using these models that are required for the closure of the continuity and momentum equations. The two-dimensional predictions are compared with
Numerical modeling of immiscible two-phase flow in micro-models using a commercial CFD code
Crandall, Dustin; Ahmadia, Goodarz; Smith, Duane H.
2009-01-01
Off-the-shelf CFD software is being used to analyze everything from flow over airplanes to lab-on-a-chip designs. So, how accurately can two-phase immiscible flow be modeled flowing through some small-scale models of porous media? We evaluate the capability of the CFD code FLUENT{trademark} to model immiscible flow in micro-scale, bench-top stereolithography models. By comparing the flow results to experimental models we show that accurate 3D modeling is possible.
Ashraf, M. Bilal; Hayat, T.; Shehzad, S. A.; Alsaedi, A.
2015-02-15
Three dimensional radiative flow of Maxwell fluid over an inclined stretching surface with convective boundary condition is investigated. Heat and mass transfer analysis is taken into account with thermophoresis effects. Similarity transformations are utilized to reduce the partial differential equations into ordinary differential equations. Series solutions of velocity, temperature and concentration are developed. Influence of different parameters Biot number, therrmophoretic parameter, Deborah number, ratio parameter, inclined stretching angle, radiation parameter, mixed convection parameter and concentration buoyancy parameter on the non-dimensional velocity components, temperature and concentration are plotted and discussed in detail. Physical quantities of interests are tabulated and examined.
Ortega, Jesus; Khivsara, Sagar; Christian, Joshua; Ho, Clifford; Yellowhair, Julius; Dutta, Pradip
2016-05-30
In single phase performance and appealing thermo-physical properties supercritical carbon dioxide (s-CO2) make a good heat transfer fluid candidate for concentrating solar power (CSP) technologies. The development of a solar receiver capable of delivering s-CO2 at outlet temperatures ~973 K is required in order to merge CSP and s-CO2 Brayton cycle technologies. A coupled optical and thermal-fluid modeling effort for a tubular receiver is undertaken to evaluate the direct tubular s-CO2 receiver’s thermal performance when exposed to a concentrated solar power input of ~0.3–0.5 MW. Ray tracing, using SolTrace, is performed to determine the heat flux profiles on the receivermore » and computational fluid dynamics (CFD) determines the thermal performance of the receiver under the specified heating conditions. Moreover, an in-house MATLAB code is developed to couple SolTrace and ANSYS Fluent. CFD modeling is performed using ANSYS Fluent to predict the thermal performance of the receiver by evaluating radiation and convection heat loss mechanisms. Understanding the effects of variation in heliostat aiming strategy and flow configurations on the thermal performance of the receiver was achieved through parametric analyses. Finally, a receiver thermal efficiency ~85% was predicted and the surface temperatures were observed to be within the allowable limit for the materials under consideration.« less
Hammond, Glenn E.; Lichtner, Peter C.; Lu, Chuan
2007-08-01
Numerical modeling has become a critical tool to the Department of Energy for evaluating the environmental impact of alternative energy sources and remediation strategies for legacy waste sites. Unfortunately, the physical and chemical complexity of many sites overwhelms the capabilities of even most state of the art groundwater models. Of particular concern are the representation of highly-heterogeneous stratified rock/soil layers in the subsurface and the biological and geochemical interactions of chemical species within multiple fluid phases. Clearly, there is a need for higher-resolution modeling (i.e. more spatial, temporal, and chemical degrees of freedom) and increasingly mechanistic descriptions of subsurface physicochemical processes. We present research being performed in the development of PFLOTRAN, a parallel multiphase flow and multicomponent reactive transport model. Written in Fortran90, PFLOTRAN is founded upon PETSc data structures and solvers and has exhibited impressive strong scalability on up to 4000 processors on the ORNL Cray XT3. We are employing PFLOTRAN in the simulation of uranium transport at the Hanford 300 Area, a contaminated site of major concern to the Department of Energy, the State of Washington, and other government agencies where overly-simplistic historical modeling erroneously predicted decade removal times for uranium by ambient groundwater flow. By leveraging the billions of degrees of freedom available through high-performance computation using tens of thousands of processors, we can better characterize the release of uranium into groundwater and its subsequent transport to the Columbia River, and thereby better understand and evaluate the effectiveness of various proposed remediation strategies.
A generic model for transport in turbulent shear flows
Newton, Andrew P. L.; Kim, Eun-Jin [Department of Applied Mathematics, University of Sheffield, Sheffield, S3 7RH (United Kingdom)
2011-05-15
Turbulence regulation by large-scale shear flows is crucial for a predictive modeling of transport in plasma. In this paper the suppression of turbulent transport by large-scale flows is studied numerically by measuring the turbulent diffusion D{sub t} and scalar amplitude
Engineered Barrier System Degradation, Flow, and Transport Process Model Report
E.L. Hardin
2000-07-17
The Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is one of nine PMRs supporting the Total System Performance Assessment (TSPA) being developed by the Yucca Mountain Project for the Site Recommendation Report (SRR). The EBS PMR summarizes the development and abstraction of models for processes that govern the evolution of conditions within the emplacement drifts of a potential high-level nuclear waste repository at Yucca Mountain, Nye County, Nevada. Details of these individual models are documented in 23 supporting Analysis/Model Reports (AMRs). Nineteen of these AMRs are for process models, and the remaining 4 describe the abstraction of results for application in TSPA. The process models themselves cluster around four major topics: ''Water Distribution and Removal Model, Physical and Chemical Environment Model, Radionuclide Transport Model, and Multiscale Thermohydrologic Model''. One AMR (Engineered Barrier System-Features, Events, and Processes/Degradation Modes Analysis) summarizes the formal screening analysis used to select the Features, Events, and Processes (FEPs) included in TSPA and those excluded from further consideration. Performance of a potential Yucca Mountain high-level radioactive waste repository depends on both the natural barrier system (NBS) and the engineered barrier system (EBS) and on their interactions. Although the waste packages are generally considered as components of the EBS, the EBS as defined in the EBS PMR includes all engineered components outside the waste packages. The principal function of the EBS is to complement the geologic system in limiting the amount of water contacting nuclear waste. A number of alternatives were considered by the Project for different EBS designs that could provide better performance than the design analyzed for the Viability Assessment. The design concept selected was Enhanced Design Alternative II (EDA II).
Weislogel, Amy
2014-01-31
This report includes description of the Citronelle field study area and the work carried out in the project to characterize the geology and composition of reservoir rock material and to collect an analyze the geochemical composition of produced fluid waters from the Citronelle field. Reservoir rock samples collected from well bore core were made into thin-sections and assessed for textural properties, including pore types and porosity distribution. Compositional framework grain modal data were collected via point-counting, and grain and cement mineralogy was assessed using SEM-EDS. Geochemistry of fluid samples is described and modeled using PHREEQC. Composition of rock and produced fluids were used as inputs for TOUGHREACT reactive transport modeling, which determined the rock-fluid system was in disequilibrium.
Janečka, Adam Průša, Vít
2015-04-28
We discuss the benefits of using the so-called implicit type constitutive relations introduced by K. R. Rajagopal, J. Fluid Mech. 550, 243-249 (2006) and K. R. Rajagopal, Appl. Math. 48, 279-319 (2003) in the description of the behaviour of non-Newtonian fluids. In particular, we focus on the benefits of using the implicit type constitutive relations in the mathematical modelling of fluids in which the shear stress/shear rate dependence is given by an S-shaped curve, and in modelling of fluids that exhibit nonzero normal stress differences. We also discuss a thermodynamical framework that allows one to cope with the implicit type constitutive relations.
Jendrzejczyk, Joseph A.
1982-01-01
An electrical fluid force transducer for measuring the magnitude and direction of fluid forces caused by lateral fluid flow, includes a movable sleeve which is deflectable in response to the movement of fluid, and a rod fixed to the sleeve to translate forces applied to the sleeve to strain gauges attached to the rod, the strain gauges being connected in a bridge circuit arrangement enabling generation of a signal output indicative of the magnitude and direction of the force applied to the sleeve.
Hammond, Glenn E.; Lichtner, Peter C.; Lu, Chuan
2007-07-16
Numerical modeling has become a critical tool to the U.S. Department of Energy for evaluating the environmental impact of alternative energy sources and remediation strategies for legacy waste sites. Unfortunately, the physical and chemical complexity of many sites overwhelms the capabilities of even most state of the art groundwater models. Of particular concern are the representation of highly-heterogeneous stratified rock/soil layers in the subsurface and the biological and geochemical interactions of chemical species within multiple fluid phases. Clearly, there is a need for higher-resolution modeling (i.e. more spatial, temporal, and chemical degrees of freedom) and increasingly mechanistic descriptions of subsurface physicochemical processes. We present SciDAC-funded research being performed in the development of PFLOTRAN, a parallel multiphase flow and multicomponent reactive transport model. Written in Fortran90, PFLOTRAN is founded upon PETSc data structures and solvers. We are employing PFLOTRAN in the simulation of uranium transport at the Hanford 300 Area, a contaminated site of major concern to the Department of Energy, the State of Washington, and other government agencies. By leveraging the billions of degrees of freedom available through high-performance computation using tens of thousands of processors, we can better characterize the release of uranium into groundwater and its subsequent transport to the Columbia River, and thereby better understand and evaluate the effectiveness of various proposed remediation strategies.
Alkasasbeh, Hamzeh Taha Sarif, Norhafizah Md Salleh, Mohd Zuki; Tahar, Razman Mat; Nazar, Roslinda; Pop, Ioan
2015-02-03
In this paper, the effect of radiation on magnetohydrodynamic free convection boundary layer flow on a solid sphere with Newtonian heating in a micropolar fluid, in which the heat transfer from the surface is proportional to the local surface temperature, is considered. The transformed boundary layer equations in the form of nonlinear partial differential equations are solved numerically using an implicit finite difference scheme known as the Keller-box method. Numerical solutions are obtained for the local wall temperature and the local skin friction coefficient, as well as the velocity, angular velocity and temperature profiles. The features of the flow and heat transfer characteristics for various values of the Prandtl number Pr, micropolar parameter K, magnetic parameter M, radiation parameter N{sub R}, the conjugate parameter γ and the coordinate running along the surface of the sphere, x are analyzed and discussed.
AFDM: An advanced fluid-dynamics model. Volume 6: EOS-AFDM interface
Henneges, G.; Kleinheins, S.
1994-01-01
This volume of the Advanced Fluid-Dynamics Model (AFDM) documents the modeling of the equation of state (EOS) in the code. The authors present an overview of the basic concepts underlying the thermodynamics modeling and resulting EOS, which is a set of relations between the thermodynamic properties of materials. The AFDM code allows for multiphase-multimaterial systems, which they explore in three phase models: two-material solid, two-material liquid, and three-material vapor. They describe and compare two ways of specifying the EOS of materials: (1) as simplified analytic expressions, or (2) as tables that precisely describe the properties of materials and their interactions for mechanical equilibrium. Either of the two EOS models implemented in AFDM can be selected by specifying the option when preprocessing the source code for compilation. Last, the authors determine thermophysical properties such as surface tension, thermal conductivities, and viscosities in the model for the intracell exchanges of AFDM. Specific notations, routines, EOS data, plots, test results, and corrections to the code are available in the appendices.
Comparison of two-fluid and gyrokinetic models for kinetic Alfvn waves in solar and space plasmas
Yang, L.; Wu, D. J.; Wang, S. J.; Lee, L. C.
2014-09-01
An analytical comparative study of a two-fluid and a gyrokinetic model of kinetic Alfvn waves (KAWs) is presented for various solar and space plasma environments. Based on the linear KAW dispersion relation for gyrokinetics (Howes et al. 2006), the wave group velocity and electromagnetic polarizations are obtained analytically. Then the gyrokinetic wave properties are compared with those of the two-fluid model. The results show that both models agree well with each other not only in the long wavelength regime (>> the ion gyroradius ? {sub i}) for all cases considered, but also in wavelengths ?? {sub i} and <>1) ion/electron temperature ratio T {sub 0i}/T {sub 0e}, respectively. However, the fluid model calculations deviate strongly from the gyrokinetic model at scales fluid theory, these results may improve our understanding of the applicability of the two-fluid model, and may have important implications for computer simulation studies of KAWs in the solar and space plasma surroundings.
Computational fluid dynamics improves liner cementing operation
Barton, N.A.; Archer, G.L. ); Seymour, D.A. )
1994-09-26
The use of computational fluid dynamics (CFD), an analytical tool for studying fluid mechanics, helped plan the successful cementing of a critical liner in a North Sea extended reach well. The results from CFD analysis increased the confidence in the primary cementing of the liner. CFD modeling was used to quantify the effects of increasing the displacement rate and of rotating the liner on the mud flow distribution in the annulus around the liner.
A Unified Multi-Scale Model for Pore-Scale Flow Simulations in Soils
Yang, Xiaofan; Liu, Chongxuan; Shang, Jianying; Fang, Yilin; Bailey, Vanessa L.
2014-01-30
Pore-scale simulations have received increasing interest in subsurface sciences to provide mechanistic insights into the macroscopic phenomena of water flow and reactive transport processes. The application of the pore scale simulations to soils and sediments is, however, challenged because of the characterization limitation that often only allows partial resolution of pore structure and geometry. A significant proportion of the pore space in soils and sediments is below the spatial resolution, forming a mixed media of pore and porous domains. Here we reported a unified multi-scale model (UMSM) that can be used to simulate water flow and transport in mixed media of pore and porous domains under both saturated and unsaturated conditions. The approach modifies the classic Navier-Stokes equation by adding a Darcy term to describe fluid momentum and uses a generalized mass balance equation for saturated and unsaturated conditions. By properly defining physical parameters, the UMSM can be applied in both pore and porous domains. This paper describes the set of equations for the UMSM, a series of validation cases under saturated or unsaturated conditions, and a real soil case for the application of the approach.
On the modeling of a single-stage, entrained-flow gasifier using Aspen Custom Modeler (ACM)
Kasule, J.; Turton, R.; Bhattacharyya, D.; Zitney, S.
2010-01-01
Coal-fired gasifiers are the centerpiece of integrated gasification combined cycle (IGCC) power plants. The gasifier produces synthesis gas that is subsequently converted into electricity through combustion in a gas turbine. Several mathematical models have been developed to study the physical and chemical processes taking place inside the gasifier. Such models range from simple one-dimensional (1D) steady-state models to sophisticated dynamic 3D computational fluid dynamics (CFD) models that incorporate turbulence effects in the reactor. The practical operation of the gasifier is dynamic in nature but most 1D and some higher-dimensional models are often steady state. On the other hand, many higher order CFD-based models are dynamic in nature, but are too computationally expensive to be used directly in operability and controllability dynamic studies. They are also difficult to incorporate in the framework of process simulation software such as Aspen Plus Dynamics. Thus lower-dimensional dynamic models are still useful in these types of studies. In the current study, a 1D dynamic model for a single-stage, downward-firing, entrained-flow GE-type gasifier is developed using Aspen Custom Modeler{reg_sign} (ACM), which is a commercial equation-based simulator for creating, editing, and re-using models of process units. The gasifier model is based on mass, momentum, and energy balances for the solid and gas phases. The physical and chemical reactions considered in the model are drying, devolatilization/pyrolysis, gasification, combustion, and the homogeneous gas phase reactions. The dynamic gasifier model is being developed for use in a plant-wide dynamic model of an IGCC power plant. For dynamic simulation, the resulting highly nonlinear system of partial differential algebraic equations (PDAE) is solved in ACM using the well-known Method of Lines (MoL) approach. The MoL discretizes the space domain and leaves the time domain continuous, thereby converting the PDAE to
Fluid Dynamics in Sucker Rod Pumps Cutler, R.P.; Mansure, A.J...
Office of Scientific and Technical Information (OSTI)
Fluid Dynamics in Sucker Rod Pumps Cutler, R.P.; Mansure, A.J. 02 PETROLEUM; FLOW MODELS; MATHEMATICAL MODELS; OIL WELLS; PETROLEUM; ROD PUMPS; SANDIA NATIONAL LABORATORIES Sucker...
Dudak, B.; Galbraith, R.; Hansen, L.; Sverjensky, D.; Weres, O.
1982-07-01
The development of a flowthrough sampler capable of obtaining fluid samples from geopressured wells at temperatures up to 400/sup 0/F and pressures up to 20,000 psi is described. The sampler has been designed, fabricated from MP35N alloy, laboratory tested, and used to obtain fluid samples from a geothermal well at The Geysers, California. However, it has not yet been used in a geopressured well. The design features, test results, and operation of this device are described. Alternative sampler designs are also discussed. Another activity was to review the chemistry and geochemistry of geopressured brines and reservoirs, and to evaluate the utility of available computer codes for modeling the chemistry of geopressured brines. The thermodynamic data bases for such codes are usually the limiting factor in their application to geopressured systems, but it was concluded that existing codes can be updated with reasonable effort and can usefully explain and predict the chemical characteristics of geopressured systems, given suitable input data.
Kabadi, V.N.
1992-10-01
The work on this project was initiated on September 1, 1989. The project consisted of three different tasks. 1. A thermodynamic model to predict VLE and calorimetric properties of coal liquids. 2. VLE measurements at high temperature and high pressure for coal model compounds and 3. Chromatographic characterization of coal liquids for distribution of heteroatoms. The thermodynamic model developed is an extension of the previous model developed for VLE of coal derived fluids (DOE Grant no. FG22-86PC90541). The model uses the modified UNIFAC correlation for the liquid phase. Some unavailable UNIFAC interactions parameters have been regressed from experimental VLE and excess enthalpy data. The model is successful in predicting binary VLE and excess enthalpy data. Further refinements of the model are suggested. An apparatus for the high pressure high temperature VLE data measurements has been built and tested. Tetralin-Quinoline is the first binary system selected for data measurements. The equipment was tested by measuring 325{degree}C isotherm for this system and comparing it with literature data. Additional isotherms at 350{degree}C and 370{degree}C have been measured. The framework for a characterization procedure for coal derived liquids has been developed. A coal liquid is defined by a true molecular weight distribution and distribution of heteroatoms as a function of molecular weights. Size exclusions liquid chromatography, elemental analysis and FTIR spectroscopy methods are used to obtain the molecular weight and hetroatom distributions. Further work in this area should include refinements of the characterization procedure, high temperature high pressure VLE data measurements for selective model compound binary systems, and improvement of the thermodynamic model using the new measured data and consistent with the developments in the characterization procedure.
Radvansky, Gabriel A.; D’Mello, Sidney K.; Abbott, Robert G.; Bixler, Robert E.
2016-01-27
The Fluid Events Model is aimed at predicting changes in the actions people take on a moment-by-moment basis. In contrast with other research on action selection, this work does not investigate why some course of action was selected, but rather the likelihood of discontinuing the current course of action and selecting another in the near future. This is done using both task-based and experience-based factors. Prior work evaluated this model in the context of trial-by-trial, independent, interactive events, such as choosing how to copy a figure of a line drawing. In this paper, we extend this model to more covertmore » event experiences, such as reading narratives, as well as to continuous interactive events, such as playing a video game. To this end, the model was applied to existing data sets of reading time and event segmentation for written and picture stories. It was also applied to existing data sets of performance in a strategy board game, an aerial combat game, and a first person shooter game in which a participant’s current state was dependent on prior events. The results revealed that the model predicted behavior changes well, taking into account both the theoretically defined structure of the described events, as well as a person’s prior experience. Hence, theories of event cognition can benefit from efforts that take into account not only how events in the world are structured, but also how people experience those events.« less
Development of a three-phase reacting flow computer model for analysis of petroleum cracking
Chang, S.L.; Lottes, S.A.; Petrick, M.
1995-07-01
A general computational fluid dynamics computer code (ICRKFLO) has been developed for the simulation of the multi-phase reacting flow in a petroleum fluid catalytic cracker riser. ICRKFLO has several unique features. A new integral reaction submodel couples calculations of hydrodynamics and cracking kinetics by making the calculations more efficient in achieving stable convergence while still preserving the major physical effects of reaction processes. A new coke transport submodel handles the process of coke formation in gas phase reactions and the subsequent deposition on the surface of adjacent particles. The code was validated by comparing with experimental results of a pilot scale fluid cracker unit. The code can predict the flow characteristics of gas, liquid, and particulate solid phases, vaporization of the oil droplets, and subsequent cracking of the oil in a riser reactor, which may lead to a better understanding of the internal processes of the riser and the impact of riser geometry and operating parameters on the riser performance.
Modeling the Air Flow in the 3410 Building Filtered Exhaust Stack System
Recknagle, Kurtis P.; Barnett, J. M.; Suffield, Sarah R.
2013-01-23
Additional ventilation capacity has been designed for the 3410 Building filtered exhaust stack system. The updated system will increase the number of fans from two to three and will include ductwork to incorporate the new fan into the existing stack. Stack operations will involve running various two-fan combinations at any given time. The air monitoring system of the existing two-fan stack was previously found to be in compliance with the ANSI/HPS N13.1-1999 standard, however it is not known if the modified (three-fan) system will comply. Subsequently, a full-scale three-dimensional (3-D) computational fluid dynamics (CFD) model of the modified stack system has been created to examine the sampling location for compliance with the standard. The CFD modeling results show good agreement with testing data collected from the existing 3410 Building stack and suggest that velocity uniformity and flow angles will remain well within acceptance criteria when the third fan and associated ductwork is installed. This includes two-fan flow rates up to 31,840 cfm for any of the two-fan combinations. For simulation cases in which tracer gas and particles are introduced in the main duct, the model predicts that both particle and tracer gas coefficients of variance (COVs) may be larger than the acceptable 20 percent criterion of the ANSI/HPS N13.1-1999 standard for each of the two-fan, 31,840 cfm combinations. Simulations in which the tracers are introduced near the fans result in improved, though marginally acceptable, COV values for the tracers. Due to the remaining uncertainty that the stack will qualify with the addition of the third fan and high flow rates, a stationary air blender from Blender Products, Inc. is considered for inclusion in the stack system. A model of the air blender has been developed and incorporated into the CFD model. Simulation results from the CFD model that includes the air blender show striking improvements in tracer gas mixing and tracer particle
Modeling flow in a pressure-sensitive, heterogeneous medium
Vasco, Donald W.; Minkoff, Susan E.
2009-06-01
Using an asymptotic methodology, including an expansion in inverse powers of {radical}{omega}, where {omega} is the frequency, we derive a solution for flow in a medium with pressure dependent properties. The solution is valid for a heterogeneous medium with smoothly varying properties. That is, the scale length of the heterogeneity must be significantly larger then the scale length over which the pressure increases from it initial value to its peak value. The resulting asymptotic expression is similar in form to the solution for pressure in a medium in which the flow properties are not functions of pressure. Both the expression for pseudo-phase, which is related to the 'travel time' of the transient pressure disturbance, and the expression for pressure amplitude contain modifications due to the pressure dependence of the medium. We apply the method to synthetic and observed pressure variations in a deforming medium. In the synthetic test we model one-dimensional propagation in a pressure-dependent medium. Comparisons with both an analytic self-similar solution and the results of a numerical simulation indicate general agreement. Furthermore, we are able to match pressure variations observed during a pulse test at the Coaraze Laboratory site in France.
1998-09-01
The title describes the two tasks summarized in this report. The remainder of the report contains information on meetings held or to be held on the subjects. The US National Committee for Rock Mechanics (USNC/RM) provides for US participation in international activities in rock mechanics, principally through adherence to the International Society for Rock Mechanics (ISRM). It also keeps the US rock mechanics community informed about new programs directed toward major areas of national concern in which rock mechanics problems represent critical or limiting factors, such as energy resources, excavation, underground storage and waste disposal, and reactor siting. The committee also guides or produces advisory studies and reports on problem areas in rock mechanics. A new panel under the auspices of the US National Committee for Rock Mechanics has been appointed to conduct a study on Conceptual Models of Fluid Infiltration in Fractured Media. The study has health and environmental applications related to the underground flow of pollutants through fractured rock in and around mines and waste repositories. Support of the study has been received from the US Nuclear Regulatory Commission and the Department of Energy`s Yucca Mountain Project Office. The new study builds on the success of a recent USNC/RM report entitled Rock Fractures and Fluid Flow: Contemporary Understanding and Applications (National Academy Press, 1996, 551 pp.). A summary of the new study is provided.
Loth, E.; Tryggvason, G.; Tsuji, Y.; Elghobashi, S. E.; Crowe, Clayton T.; Berlemont, A.; Reeks, M.; Simonin, O.; Frank, Th; Onishi, Yasuo; Van Wachem, B.
2005-09-01
Slurry flows occur in many circumstances, including chemical manufacturing processes, pipeline transfer of coal, sand, and minerals; mud flows; and disposal of dredged materials. In this section we discuss slurry flow applications related to radioactive waste management. The Hanford tank waste solids and interstitial liquids will be mixed to form a slurry so it can be pumped out for retrieval and treatment. The waste is very complex chemically and physically. The ARIEL code is used to model the chemical interactions and fluid dynamics of the waste.
Robinson, Mark R.; Ward, Kenneth J.; Eaton, Robert P.; Haaland, David M.
1990-01-01
The characteristics of a biological fluid sample having an analyte are determined from a model constructed from plural known biological fluid samples. The model is a function of the concentration of materials in the known fluid samples as a function of absorption of wideband infrared energy. The wideband infrared energy is coupled to the analyte containing sample so there is differential absorption of the infrared energy as a function of the wavelength of the wideband infrared energy incident on the analyte containing sample. The differential absorption causes intensity variations of the infrared energy incident on the analyte containing sample as a function of sample wavelength of the energy, and concentration of the unknown analyte is determined from the thus-derived intensity variations of the infrared energy as a function of wavelength from the model absorption versus wavelength function.
Usmanov, Arcadi V.; Matthaeus, William H.; Goldstein, Melvyn L.
2014-06-10
We have developed a three-fluid, three-dimensional magnetohydrodynamic solar wind model that incorporates turbulence transport, eddy viscosity, turbulent resistivity, and turbulent heating. The solar wind plasma is described as a system of co-moving solar wind protons, electrons, and interstellar pickup protons, with separate energy equations for each species. Numerical steady-state solutions of Reynolds-averaged solar wind equations coupled with turbulence transport equations for turbulence energy, cross helicity, and correlation length are obtained by the time relaxation method in the corotating with the Sun frame of reference in the region from 0.3 to 100 AU (but still inside the termination shock). The model equations include the effects of electron heat conduction, Coulomb collisions, photoionization of interstellar hydrogen atoms and their charge exchange with the solar wind protons, turbulence energy generation by pickup protons, and turbulent heating of solar wind protons and electrons. The turbulence transport model is based on the Reynolds decomposition and turbulence phenomenologies that describe the conversion of fluctuation energy into heat due to a turbulent cascade. In addition to using separate energy equations for the solar wind protons and electrons, a significant improvement over our previous work is that the turbulence model now uses an eddy viscosity approximation for the Reynolds stress tensor and the mean turbulent electric field. The approximation allows the turbulence model to account for driving of turbulence by large-scale velocity gradients. Using either a dipole approximation for the solar magnetic field or synoptic solar magnetograms from the Wilcox Solar Observatory for assigning boundary conditions at the coronal base, we apply the model to study the global structure of the solar wind and its three-dimensional properties, including embedded turbulence, heating, and acceleration throughout the heliosphere. The model results are
MSET modeling of Crystal River-3 venturi flow meters.
Bockhorst, F. K.; Gross, K. C.; Herzog, J. P.; Wegerich, S. W.
1998-01-05
The analysis of archived Crystal River-3 feedwater flow data reveals a slow and steady degradation of the flow meter measurements during the 1992/1993 operating cycle. MSET can reliably estimate the true flow rate and quantify the degree of departure between the indicated signal and the true flow rate with high accuracy. The MSET computed flow rate could, in principle, be used to provide an improved estimate of the reactor power and hence avoid the revenue loss associated with derating the reactor based on a faulty feedwater flow rate indication.
Li, Zhihui; Ma, Qiang; Wu, Junlin; Jiang, Xinyu; Zhang, Hanxin
2014-12-09
Based on the Gas-Kinetic Unified Algorithm (GKUA) directly solving the Boltzmann model equation, the effect of rotational non-equilibrium is investigated recurring to the kinetic Rykov model with relaxation property of rotational degrees of freedom. The spin movement of diatomic molecule is described by moment of inertia, and the conservation of total angle momentum is taken as a new Boltzmann collision invariant. The molecular velocity distribution function is integrated by the weight factor on the internal energy, and the closed system of two kinetic controlling equations is obtained with inelastic and elastic collisions. The optimization selection technique of discrete velocity ordinate points and numerical quadrature rules for macroscopic flow variables with dynamic updating evolvement are developed to simulate hypersonic flows, and the gas-kinetic numerical scheme is constructed to capture the time evolution of the discretized velocity distribution functions. The gas-kinetic boundary conditions in thermodynamic non-equilibrium and numerical procedures are studied and implemented by directly acting on the velocity distribution function, and then the unified algorithm of Boltzmann model equation involving non-equilibrium effect is presented for the whole range of flow regimes. The hypersonic flows involving non-equilibrium effect are numerically simulated including the inner flows of shock wave structures in nitrogen with different Mach numbers of 1.5-Ma-25, the planar ramp flow with the whole range of Knudsen numbers of 0.0009-Kn-10 and the three-dimensional re-entering flows around tine double-cone body.
Joan B. Blainey; Claudia C. Faunt, and Mary C. Hill
2006-05-16
This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.
Modelling on dynamics properties of a stationary argon cascaded arc plasma flows
Wei, G. D.; Qi, X.; Yang, L.
2014-03-15
The gas dynamics properties of a stationary arc plasma flows are studied through the numerical simulations. A two dimensional axis-symmetric turbulent magneto-hydrodynamic plasma model is developed with the commercial code ANSYS FLUENT. The reliable ?-? model is used to account for turbulence. In this paper, the plasma is assumed to be a fluid following NavierStokes equations, respecting local thermodynamic equilibrium, and described by only one temperature. Distributions of the pressure, velocity, temperature, density, and electric potential inside of thus cascaded arc are obtained for an arc current density of 10{sup 6}?A/m{sup 2}. The pressure inside the arc varies from 10{sup 5}?Pa to 100?Pa. The temperature at the arc axis can reach as high as 13?600?K. The electric potential drops uniformly along the axis with a magnitude of 160?V. In addition, distributions of the sonic velocity and Mach number are shown to describe supersonic behavior of thus cascaded arc, which have a good agreement with the analytical formula.
Anh Bui; Nam Dinh; Brian Williams
2013-09-01
In addition to validation data plan, development of advanced techniques for calibration and validation of complex multiscale, multiphysics nuclear reactor simulation codes are a main objective of the CASL VUQ plan. Advanced modeling of LWR systems normally involves a range of physico-chemical models describing multiple interacting phenomena, such as thermal hydraulics, reactor physics, coolant chemistry, etc., which occur over a wide range of spatial and temporal scales. To a large extent, the accuracy of (and uncertainty in) overall model predictions is determined by the correctness of various sub-models, which are not conservation-laws based, but empirically derived from measurement data. Such sub-models normally require extensive calibration before the models can be applied to analysis of real reactor problems. This work demonstrates a case study of calibration of a common model of subcooled flow boiling, which is an important multiscale, multiphysics phenomenon in LWR thermal hydraulics. The calibration process is based on a new strategy of model-data integration, in which, all sub-models are simultaneously analyzed and calibrated using multiple sets of data of different types. Specifically, both data on large-scale distributions of void fraction and fluid temperature and data on small-scale physics of wall evaporation were simultaneously used in this works calibration. In a departure from traditional (or common-sense) practice of tuning/calibrating complex models, a modern calibration technique based on statistical modeling and Bayesian inference was employed, which allowed simultaneous calibration of multiple sub-models (and related parameters) using different datasets. Quality of data (relevancy, scalability, and uncertainty) could be taken into consideration in the calibration process. This work presents a step forward in the development and realization of the CIPS Validation Data Plan at the Consortium for Advanced Simulation of LWRs to enable
Statistical modeling support for calibration of a multiphysics model of subcooled boiling flows
Bui, A. V.; Dinh, N. T.; Nourgaliev, R. R.; Williams, B. J.
2013-07-01
Nuclear reactor system analyses rely on multiple complex models which describe the physics of reactor neutronics, thermal hydraulics, structural mechanics, coolant physico-chemistry, etc. Such coupled multiphysics models require extensive calibration and validation before they can be used in practical system safety study and/or design/technology optimization. This paper presents an application of statistical modeling and Bayesian inference in calibrating an example multiphysics model of subcooled boiling flows which is widely used in reactor thermal hydraulic analysis. The presence of complex coupling of physics in such a model together with the large number of model inputs, parameters and multidimensional outputs poses significant challenge to the model calibration method. However, the method proposed in this work is shown to be able to overcome these difficulties while allowing data (observation) uncertainty and model inadequacy to be taken into consideration. (authors)
A simple model of gas flow in a porous powder compact
Shugard, Andrew D.; Robinson, David B.
2014-04-01
This report describes a simple model for ideal gas flow from a vessel through a bed of porous material into another vessel. It assumes constant temperature and uniform porosity. Transport is treated as a combination of viscous and molecular flow, with no inertial contribution (low Reynolds number). This model can be used to fit data to obtain permeability values, determine flow rates, understand the relative contributions of viscous and molecular flow, and verify volume calibrations. It draws upon the Dusty Gas Model and other detailed studies of gas flow through porous media.
Zhang, Le; Luo, Feng; Xu, Ruina; Jiang, Peixue; Liu, Huihai
2014-12-31
The heat transfer and fluid transport of supercritical CO2 in enhanced geothermal system (EGS) is studied numerically with local thermal non-equilibrium model, which accounts for the temperature difference between solid matrix and fluid components in porous media and uses two energy equations to describe heat transfer in the solid matrix and in the fluid, respectively. As compared with the previous results of our research group, the effect of local thermal non-equilibrium mainly depends on the volumetric heat transfer coefficient ah, which has a significant effect on the production temperature at reservoir outlet and thermal breakthrough time. The uniformity of volumetricmore » heat transfer coefficient ah has little influence on the thermal breakthrough time, but the temperature difference become more obvious with time after thermal breakthrough with this simulation model. The thermal breakthrough time reduces and the effect of local thermal non-equilibrium becomes significant with decreasing ah.« less
OPF incorporating load models maximizing net revenue. [Optimal Power Flow
Dias, L.G.; El-Hawary, M.E. . Dept. of Electrical Engineering)
1993-02-01
Studies of effects of load modeling in optimal power flow studies using minimum cost and minimum loss objective reveal that a main disadvantage of cost minimization is the reduction of the objective via a reduction in the power demand. This inevitably results in lowering the total revenue and in most cases, reducing net revenue as well. An alternative approach for incorporating load models in security-constrained OPF (SCOPF) studies apparently avoids reducing the total power demand for the intact system, but reduces the voltages. A study of the behavior of conventional OPF solutions in the presence of loads not controlled by ULTC's shows that this result in a reducing the total power demand for the intact system. In this paper, the authors propose an objective that avoids the tendency to lower the total power demand, total revenue and net revenue, for OPF neglecting contingencies (normal OPF), as well as for security-constrained OPF. The minimum cost objective is modified by subtracting the total power demand from the total fuel cost. This is equivalent to maximizing the net revenue.
A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus
Raustad, Richard A.
2013-01-01
This paper provides an overview of the variable refrigerant flow heat pump computer model included with the Department of Energy's EnergyPlusTM whole-building energy simulation software. The mathematical model for a variable refrigerant flow heat pump operating in cooling or heating mode, and a detailed model for the variable refrigerant flow direct-expansion (DX) cooling coil are described in detail.
Analytical model for transient gas flow in nuclear fuel rods. [PWR; BWR
Rowe, D.S.; Oehlberg, R.N.
1981-08-01
An analytical model for calculating gas flow and pressure inside a nuclear fuel rod is presented. Such a model is required to calculate the pressure loading of cladding during ballooning that could occur for postulated reactor accidents. The mathematical model uses a porous media (permeability) concept to define the resistance to gas flow along the fuel rod. 7 refs.
Ultrasonic fluid quality sensor system
Gomm, Tyler J.; Kraft, Nancy C.; Phelps, Larry D.; Taylor, Steven C.
2002-10-08
A system for determining the composition of a multiple-component fluid and for determining linear flow comprising at least one sing-around circuit that determines the velocity of a signal in the multiple-component fluid and that is correlatable to a database for the multiple-component fluid. A system for determining flow uses two of the inventive circuits, one of which is set at an angle that is not perpendicular to the direction of flow.
Ultrasonic Fluid Quality Sensor System
Gomm, Tyler J.; Kraft, Nancy C.; Phelps, Larry D.; Taylor, Steven C.
2003-10-21
A system for determining the composition of a multiple-component fluid and for determining linear flow comprising at least one sing-around circuit that determines the velocity of a signal in the multiple-component fluid and that is correlatable to a database for the multiple-component fluid. A system for determining flow uses two of the inventive circuits, one of which is set at an angle that is not perpendicular to the direction of flow.
Image-based Stokes flow modeling in bulk proppant packs and propped...
Office of Scientific and Technical Information (OSTI)
Image-based Stokes flow modeling in bulk proppant packs and propped fractures under high loading stresses Citation Details In-Document Search This content will become publicly ...
A self-consistent two-fluid model of a magnetized plasma-wall transition
Gyergyek, T.; Kovačič, J.
2015-09-15
A self-consistent one-dimensional two-fluid model of the magnetized plasma-wall transition is presented. The model includes magnetic field, elastic collisions between ions and electrons, and creation/annihilation of charged particles. Two systems of differential equations are derived. The first system describes the whole magnetized plasma-wall transition region, which consists of the pre-sheath, the magnetized pre-sheath (Chodura layer), and the sheath, which is not neutral, but contains a positive space charge. The second system of equations describes only the neutral part of the plasma-wall transition region—this means only the pre-sheath and the Chodura layer, but not also the sheath. Both systems are solved numerically. The first system of equations has two singularities. The first occurs when ion velocity in the direction perpendicularly to the wall drops below the ion thermal velocity. The second occurs when the electron velocity in the direction perpendicularly to the wall exceeds the electron thermal velocity. The second system of differential equations only has one singularity, which has also been derived analytically. For finite electron to ion mass ratio, the integration of the second system always breaks down before the Bohm criterion is fulfilled. Some properties of the first system of equations are examined. It is shown that the increased collision frequency demagnetizes the plasma. On the other hand, if the magnetic field is so strong that the ion Larmor radius and the Debye length are comparable, the electron velocity in the direction perpendicularly to the wall reaches the electron thermal velocity before the ion velocity in the direction perpendicularly to the wall reaches the ion sound velocity. In this case, the integration of the model equations breaks down before the Bohm criterion is fulfilled and the sheath is formed.
COUNTERCURRENT FLOW LIMITATION EXPERIMENTS AND MODELING FOR IMPROVED REACTOR SAFETY
Vierow, Karen
2008-09-26
This project is investigating countercurrent flow and “flooding” phenomena in light water reactor systems to improve reactor safety of current and future reactors. To better understand the occurrence of flooding in the surge line geometry of a PWR, two experimental programs were performed. In the first, a test facility with an acrylic test section provided visual data on flooding for air-water systems in large diameter tubes. This test section also allowed for development of techniques to form an annular liquid film along the inner surface of the “surge line” and other techniques which would be difficult to verify in an opaque test section. Based on experiences in the air-water testing and the improved understanding of flooding phenomena, two series of tests were conducted in a large-diameter, stainless steel test section. Air-water test results and steam-water test results were directly compared to note the effect of condensation. Results indicate that, as for smaller diameter tubes, the flooding phenomena is predominantly driven by the hydrodynamics. Tests with the test sections inclined were attempted but the annular film was easily disrupted. A theoretical model for steam venting from inclined tubes is proposed herein and validated against air-water data. Empirical correlations were proposed for air-water and steam-water data. Methods for developing analytical models of the air-water and steam-water systems are discussed, as is the applicability of the current data to the surge line conditions. This report documents the project results from July 1, 2005 through June 30, 2008.
Zuo, Wangda; Chen, Qingyan
2011-06-01
To design a healthy indoor environment, it is important to study airborne particle distribution indoors. As an intermediate model between multizone models and computational fluid dynamics (CFD), a fast fluid dynamics (FFD) model can be used to provide temporal and spatial information of particle dispersion in real time. This study evaluated the accuracy of the FFD for predicting transportation of particles with low Stokes number in a duct and in a room with mixed convection. The evaluation was to compare the numerical results calculated by the FFD with the corresponding experimental data and the results obtained by the CFD. The comparison showed that the FFD could capture major pattern of particle dispersion, which is missed in models with well-mixed assumptions. Although the FFD was less accurate than the CFD partially due to its simplification in numeric schemes, it was 53 times faster than the CFD.
Morozov, Victor
2011-01-18
A flow chamber having a vacuum chamber and a specimen chamber. The specimen chamber may have an opening through which a fluid may be introduced and an opening through which the fluid may exit. The vacuum chamber may have an opening through which contents of the vacuum chamber may be evacuated. A portion of the flow chamber may be flexible, and a vacuum may be used to hold the components of the flow chamber together.
Modeling, Analysis and Simulation of Multiscale Preferential Flow - 8/05-8/10 - Final Report
Ralph Showalter; Malgorzata Peszynska
2012-07-03
The research agenda of this project are: (1) Modeling of preferential transport from mesoscale to macroscale; (2) Modeling of fast flow in narrow fractures in porous media; (3) Pseudo-parabolic Models of Dynamic Capillary Pressure; (4) Adaptive computational upscaling of flow with inertia from porescale to mesoscale; (5) Adaptive modeling of nonlinear coupled systems; and (6) Adaptive modeling and a-posteriori estimators for coupled systems with heterogeneous data.
Integrated Nozzle Flow, Spray, Combustion, & Emission Modeling using KH-ACT
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Primary Breakup Model & Detailed Chemistry | Department of Energy Nozzle Flow, Spray, Combustion, & Emission Modeling using KH-ACT Primary Breakup Model & Detailed Chemistry Integrated Nozzle Flow, Spray, Combustion, & Emission Modeling using KH-ACT Primary Breakup Model & Detailed Chemistry Poster presented at the 16th Directions in Engine-Efficiency and Emissions Research (DEER) Conference in Detroit, MI, September 27-30, 2010. p-13_som.pdf (285.53 KB) More Documents
Thermal Storage and Advanced Heat Transfer Fluids (Fact Sheet)
Not Available
2010-08-01
Fact sheet describing NREL CSP Program capabilities in the area of thermal storage and advanced heat transfer fluids: measuring thermophysical properties, measuring fluid flow and heat transfer, and simulating flow of thermal energy and fluid.
Transient One-dimensional Pipe Flow Analyzer
Energy Science and Technology Software Center (OSTI)
1986-04-08
TOPAZ-SNLL, the Transient One- dimensional Pipe flow AnalyZer code, is a user-friendly computer program for modeling the heat transfer, fluid mechanics, and thermodynamics of multi-species gas transfer in arbitrary arrangements of pipes, valves, vessels, and flow branches. Although the flow conservation equations are assumed to be one-dimensional and transient, multidimensional features of internal fluid flow and heat transfer may be accounted for using the available quasi-steady flow correlations (e.g., Moody friction factor correlation and variousmore » form loss and heat transfer correlations). Users may also model the effects of moving system boundaries such as pistons, diaphragms, and bladders. The features of fully compressible flow are modeled, including the propagation of shocks and rarefaction waves, as well as the establishment of multiple choke points along the flow path.« less
Fluid cooled electrical assembly
Rinehart, Lawrence E.; Romero, Guillermo L.
2007-02-06
A heat producing, fluid cooled assembly that includes a housing made of liquid-impermeable material, which defines a fluid inlet and a fluid outlet and an opening. Also included is an electrical package having a set of semiconductor electrical devices supported on a substrate and the second major surface is a heat sink adapted to express heat generated from the electrical apparatus and wherein the second major surface defines a rim that is fit to the opening. Further, the housing is constructed so that as fluid travels from the fluid inlet to the fluid outlet it is constrained to flow past the opening thereby placing the fluid in contact with the heat sink.
MODELING STRATEGIES FOR UNSTEADY TURBULENT FLOWS IN THE LOWER PLENUM OF THE VHTR
Richard W. Johnson
2006-09-01
Validation simulations are presented for turbulent flow in a staggered tube bank, geometry similar to that in the lower plenum of a block very high temperature reactor. Steady 2D RANS predictions are compared to unsteady 2D RANS results and experiment. The unsteady calculations account for the fact that nonturbulent fluctuations (due to vortex-shedding) are present in the flow. The unsteady computations are shown to predict the mean variables and the total shear stress quite well. Previous workers have presented results that indicated that 3D simulations were necessary to obtain reasonable results. Best practices are based on requirements for the ASME Journal of Fluids Engineering.
Selective evaporation of focusing fluid in two-fluid hydrodynamic print head.
Keicher, David M.; Cook, Adam W.
2014-09-01
The work performed in this project has demonstrated the feasibility to use hydrodynamic focusing of two fluid steams to create a novel micro printing technology for electronics and other high performance applications. Initial efforts focused solely on selective evaporation of the sheath fluid from print stream provided insight in developing a unique print head geometry allowing excess sheath fluid to be separated from the print flow stream for recycling/reuse. Fluid flow models suggest that more than 81 percent of the sheath fluid can be removed without affecting the print stream. Further development and optimization is required to demonstrate this capability in operation. Print results using two-fluid hydrodynamic focusing yielded a 30 micrometers wide by 0.5 micrometers tall line that suggests that the cross-section of the printed feature from the print head was approximately 2 micrometers in diameter. Printing results also demonstrated that complete removal of the sheath fluid is not necessary for all material systems. The two-fluid printing technology could enable printing of insulated conductors and clad optical interconnects. Further development of this concept should be pursued.
Multi-fluid transport code modeling of time-dependent recycling in ELMy H-mode
Pigarov, A. Yu.; Krasheninnikov, S. I.; Rognlien, T. D.; Hollmann, E. M.; Lasnier, C. J.; Unterberg, Ezekial A
2014-01-01
Simulations of a high-confinement-mode (H-mode) tokamak discharge with infrequent giant type-I ELMs are performed by the multi-fluid, multi-species, two-dimensional transport code UEDGE-MB, which incorporates the Macro-Blob approach for intermittent non-diffusive transport due to filamentary coherent structures observed during the Edge Localized Modes (ELMs) and simple time-dependent multi-parametric models for cross-field plasma transport coefficients and working gas inventory in material surfaces. Temporal evolutions of pedestal plasma profiles, divertor recycling, and wall inventory in a sequence of ELMs are studied and compared to the experimental time-dependent data. Short- and long-time-scale variations of the pedestal and divertor plasmas where the ELM is described as a sequence of macro-blobs are discussed. It is shown that the ELM recovery includes the phase of relatively dense and cold post-ELM divertor plasma evolving on a several ms scale, which is set by the transport properties of H-mode barrier. The global gas balance in the discharge is also analyzed. The calculated rates of working gas deposition during each ELM and wall outgassing between ELMs are compared to the ELM particle losses from the pedestal and neutral-beam-injection fueling rate, correspondingly. A sensitivity study of the pedestal and divertor plasmas to model assumptions for gas deposition and release on material surfaces is presented. The performed simulations show that the dynamics of pedestal particle inventory is dominated by the transient intense gas deposition into the wall during each ELM followed by continuous gas release between ELMs at roughly a constant rate.
Multi-fluid transport code modeling of time-dependent recycling in ELMy H-mode
Pigarov, A. Yu.; Krasheninnikov, S. I.; Hollmann, E. M.; Rognlien, T. D.; Lasnier, C. J.; Unterberg, E.
2014-06-15
Simulations of a high-confinement-mode (H-mode) tokamak discharge with infrequent giant type-I ELMs are performed by the multi-fluid, multi-species, two-dimensional transport code UEDGE-MB, which incorporates the Macro-Blob approach for intermittent non-diffusive transport due to filamentary coherent structures observed during the Edge Localized Modes (ELMs) and simple time-dependent multi-parametric models for cross-field plasma transport coefficients and working gas inventory in material surfaces. Temporal evolutions of pedestal plasma profiles, divertor recycling, and wall inventory in a sequence of ELMs are studied and compared to the experimental time-dependent data. Short- and long-time-scale variations of the pedestal and divertor plasmas where the ELM is described as a sequence of macro-blobs are discussed. It is shown that the ELM recovery includes the phase of relatively dense and cold post-ELM divertor plasma evolving on a several ms scale, which is set by the transport properties of H-mode barrier. The global gas balance in the discharge is also analyzed. The calculated rates of working gas deposition during each ELM and wall outgassing between ELMs are compared to the ELM particle losses from the pedestal and neutral-beam-injection fueling rate, correspondingly. A sensitivity study of the pedestal and divertor plasmas to model assumptions for gas deposition and release on material surfaces is presented. The performed simulations show that the dynamics of pedestal particle inventory is dominated by the transient intense gas deposition into the wall during each ELM followed by continuous gas release between ELMs at roughly a constant rate.
A coke/soot formation model for multiphase reacting flow simulation
Chang, S.L.; Lottes, S.A.; Petrick, M.; Zhou, C.Q. |
1997-03-01
Coke is a by-product in petroleum fluid catalytic cracking (FCC) processes. The concentration of coke in an FCC riser reactor is a critical parameter used to evaluate the riser performance. A coke formation and transport model was developed. It was incorporated into a computational fluid dynamic (CFD) computer code, ICRKFLO, to simulate the coke formation processes in an FCC riser reactor. Based on a similar process, a soot formation model can be derived from the coke formation model and used for diesel combustion processes, where soot is emitted as one of the primary pollutants.
Flow field computation of the NREL S809 airfoil using various turbulence models
Chang, Y.L.; Yang, S.L.; Arici, O. [Michigan Technological Univ., Houghton, MI (United States). Mechanical Engineering-Engineering Mechanics Dept.
1996-10-01
Performance comparison of three popular turbulence models, namely Baldwin-Lomas algebraic model, Chien`s Low-Reynolds-Number {kappa}-{epsilon} model, and Wilcox`s Low-Reynolds-Number {kappa}-{omega} model, is given. These models were applied to calculate the flow field around the National Renewable Energy Laboratory S809 airfoil using Total Variational Diminishing scheme. Numerical results of C{sub P}, C{sub L}, and C{sub D} are presented along with the Delft experimental data. It is shown that all three models perform well for attached flow, i.e., no flow separation at low angles of attack. However, at high angles of attack with flow separation, convergence characteristics show Wilcox`s model outperforms the other models. Results of this study will be used to guide the authors in their dynamic stall research.
Computational flow modeling of a simplified integrated tractor...
Office of Scientific and Technical Information (OSTI)
The objective of this work is to demonstrate the feasibility of using the steady Reynolds-Averaged Navier-Stokes (RANS) approach to predict the flow field around heavy vehicles, ...
Multiphase fluid characterization system
Sinha, Dipen N.
2014-09-02
A measurement system and method for permitting multiple independent measurements of several physical parameters of multiphase fluids flowing through pipes are described. Multiple acoustic transducers are placed in acoustic communication with or attached to the outside surface of a section of existing spool (metal pipe), typically less than 3 feet in length, for noninvasive measurements. Sound speed, sound attenuation, fluid density, fluid flow, container wall resonance characteristics, and Doppler measurements for gas volume fraction may be measured simultaneously by the system. Temperature measurements are made using a temperature sensor for oil-cut correction.
Saenz, Juan A.; Chen, Qingshan; Ringler, Todd
2015-05-19
Recent work has shown that taking the thickness-weighted average (TWA) of the Boussinesq equations in buoyancy coordinates results in exact equations governing the prognostic residual mean flow where eddy–mean flow interactions appear in the horizontal momentum equations as the divergence of the Eliassen–Palm flux tensor (EPFT). It has been proposed that, given the mathematical tractability of the TWA equations, the physical interpretation of the EPFT, and its relation to potential vorticity fluxes, the TWA is an appropriate framework for modeling ocean circulation with parameterized eddies. The authors test the feasibility of this proposition and investigate the connections between the TWAmore » framework and the conventional framework used in models, where Eulerian mean flow prognostic variables are solved for. Using the TWA framework as a starting point, this study explores the well-known connections between vertical transfer of horizontal momentum by eddy form drag and eddy overturning by the bolus velocity, used by Greatbatch and Lamb and Gent and McWilliams to parameterize eddies. After implementing the TWA framework in an ocean general circulation model, we verify our analysis by comparing the flows in an idealized Southern Ocean configuration simulated using the TWA and conventional frameworks with the same mesoscale eddy parameterization.« less
Saenz, Juan A.; Chen, Qingshan; Ringler, Todd
2015-05-19
Recent work has shown that taking the thickness-weighted average (TWA) of the Boussinesq equations in buoyancy coordinates results in exact equations governing the prognostic residual mean flow where eddy–mean flow interactions appear in the horizontal momentum equations as the divergence of the Eliassen–Palm flux tensor (EPFT). It has been proposed that, given the mathematical tractability of the TWA equations, the physical interpretation of the EPFT, and its relation to potential vorticity fluxes, the TWA is an appropriate framework for modeling ocean circulation with parameterized eddies. The authors test the feasibility of this proposition and investigate the connections between the TWA framework and the conventional framework used in models, where Eulerian mean flow prognostic variables are solved for. Using the TWA framework as a starting point, this study explores the well-known connections between vertical transfer of horizontal momentum by eddy form drag and eddy overturning by the bolus velocity, used by Greatbatch and Lamb and Gent and McWilliams to parameterize eddies. After implementing the TWA framework in an ocean general circulation model, we verify our analysis by comparing the flows in an idealized Southern Ocean configuration simulated using the TWA and conventional frameworks with the same mesoscale eddy parameterization.
Electrorheological fluids and methods
Green, Peter F.; McIntyre, Ernest C.
2015-06-02
Electrorheological fluids and methods include changes in liquid-like materials that can flow like milk and subsequently form solid-like structures under applied electric fields; e.g., about 1 kV/mm. Such fluids can be used in various ways as smart suspensions, including uses in automotive, defense, and civil engineering applications. Electrorheological fluids and methods include one or more polar molecule substituted polyhedral silsesquioxanes (e.g., sulfonated polyhedral silsesquioxanes) and one or more oils (e.g., silicone oil), where the fluid can be subjected to an electric field.
Aminmansoor, F.; Abbasi, H.
2015-08-15
The present paper is devoted to simulation of nonlinear disintegration of a localized perturbation into ion-acoustic solitons train in a plasma with hot electrons and cold ions. A Gaussian initial perturbation is used to model the localized perturbation. For this purpose, first, we reduce fluid system of equations to a Korteweg de-Vries equation by the following well-known assumptions. (i) On the ion-acoustic evolution time-scale, the electron velocity distribution function (EVDF) is assumed to be stationary. (ii) The calculation is restricted to small amplitude cases. Next, in order to generalize the model to finite amplitudes cases, the evolution of EVDF is included. To this end, a hybrid code is designed to simulate the case, in which electrons dynamics is governed by Vlasov equation, while cold ions dynamics is, like before, studied by the fluid equations. A comparison between the two models shows that although the fluid model is capable of demonstrating the general features of the process, to have a better insight into the relevant physics resulting from the evolution of EVDF, the use of kinetic treatment is of great importance.
Modeling of stagnation-line nonequilibrium flows by means of quantum based collisional models
Munafò, A. Magin, T. E.
2014-09-15
The stagnation-line flow over re-entry bodies is analyzed by means of a quantum based collisional model which accounts for dissociation and energy transfer in N{sub 2}-N interactions. The physical model is based on a kinetic database developed at NASA Ames Research Center. The reduction of the kinetic mechanism is achieved by lumping the rovibrational energy levels of the N{sub 2} molecule in energy bins. The energy bins are treated as separate species, thus allowing for non-Boltzmann distributions of their populations. The governing equations are discretized in space by means of the Finite Volume method. A fully implicit time-integration is used to obtain steady-state solutions. The results show that the population of the energy bins strongly deviate from a Boltzmann distribution close to the shock wave and across the boundary layer. The sensitivity analysis to the number of energy bins reveals that accurate estimation of flow quantities (such as chemical composition and wall heat flux) can be obtained by using only 10 energy bins. A comparison with the predictions obtained by means of conventional multi-temperature models indicates that the former can lead to an overestimation of the wall heat flux, due to an inaccurate modeling of recombination in the boundary layer.
Dual FIB-SEM 3D imaging and lattice boltzmann modeling of porosimetry and multiphase flow in chalk.
Rinehart, Alex; Petrusak, Robin (Advanced Resources International, Inc., Arlington, VA); Heath, Jason E.; Dewers, Thomas A.; Yoon, Hongkyu
2010-12-01
Mercury intrusion porosimetry (MIP) is an often-applied technique for determining pore throat distributions and seal analysis of fine-grained rocks. Due to closure effects, potential pore collapse, and complex pore network topologies, MIP data interpretation can be ambiguous, and often biased toward smaller pores in the distribution. We apply 3D imaging techniques and lattice-Boltzmann modeling in interpreting MIP data for samples of the Cretaceous Selma Group Chalk. In the Mississippi Interior Salt Basin, the Selma Chalk is the apparent seal for oil and gas fields in the underlying Eutaw Fm., and, where unfractured, the Selma Chalk is one of the regional-scale seals identified by the Southeast Regional Carbon Sequestration Partnership for CO2 injection sites. Dual focused ion - scanning electron beam and laser scanning confocal microscopy methods are used for 3D imaging of nanometer-to-micron scale microcrack and pore distributions in the Selma Chalk. A combination of image analysis software is used to obtain geometric pore body and throat distributions and other topological properties, which are compared to MIP results. 3D data sets of pore-microfracture networks are used in Lattice Boltzmann simulations of drainage (wetting fluid displaced by non-wetting fluid via the Shan-Chen algorithm), which in turn are used to model MIP procedures. Results are used in interpreting MIP results, understanding microfracture-matrix interaction during multiphase flow, and seal analysis for underground CO2 storage.
R. A. Berry; R. Saurel; F. Petitpas; E. Daniel; O. Le Metayer; S. Gavrilyuk; N. Dovetta
2008-10-01
In nuclear reactor safety and optimization there are key issues that rely on in-depth understanding of basic two-phase flow phenomena with heat and mass transfer. Within the context of multiphase flows, two bubble-dynamic phenomena boiling (heterogeneous) and flashing or cavitation (homogeneous boiling), with bubble collapse, are technologically very important to nuclear reactor systems. The main difference between boiling and flashing is that bubble growth (and collapse) in boiling is inhibited by limitations on the heat transfer at the interface, whereas bubble growth (and collapse) in flashing is limited primarily by inertial effects in the surrounding liquid. The flashing process tends to be far more explosive (and implosive), and is more violent and damaging (at least in the near term) than the bubble dynamics of boiling. However, other problematic phenomena, such as crud deposition, appear to be intimately connecting with the boiling process. In reality, these two processes share many details.
A saturated zone site-scale flow model for Yucca mountain
Eddebbarh, Al Aziz
2008-01-01
A saturated zone site-scale flow model (YMSZFM) was developed for licensing requirements for the Yucca Mountain nuclear waste repository to incorporate recent data and analyses including recent stratigraphic and water-level data from Nye County wells, single-and multiple-well hydraulic testing data, and recent hydrochemistry data. Analyses include use of data from the 2004 transient Death Valley Regional (ground-water) Flow System (DVRFS) model, the 2003 unsaturated zone flow model, and the latest hydrogeologic framework model (HFM). This model includes: (1) the latest understanding of SZ flow, (2) enhanced model validation and uncertainty analyses, (3) improved locations and definitions of fault zones, (4) refined grid resolution (500-to 250-m grid spacing), and (5) use of new data. The flow model was completed using the three-dimensional, Finite-Element Heat and Mass Transfer computer code (FEHM). The SZ site-scale flow model was calibrated with the commercial parameter estimation code, PEST to achieve a minimum difference between observed water levels and predicted water levels, and also between volumetric/mass flow rates along specific boundary segments as supplied by the DVRFS. A total of 161 water level and head measurements with varied weights were used for calibration. A comparison between measured water-level data and the potentiometric surface yielded an RMSE of 20.7 m (weighted RMSE of 8.8 m). The calibrated model was used to generate flow paths and specific discharge predictions. Model confidence was built by comparing: (l) calculated to observed hydraulic heads, and (2) calibrated to measured permeabilities (and therefore specific discharge). In addition, flowpaths emanating from below the repository footprint are consistent with those inferred both from gradients of measured head and from independent water-chemistry data. Uncertainties in the SZ site-scale flow model were quantified because all uncertainty contributes to inaccuracy in system
Imaging, Characterizing, and Modeling of Fracture Networks and...
Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)
Imaging, Characterizing, and Modeling of Fracture Networks and Fluid Flow in EGS ... 97 through 2004. lianjieimagingmodelingpeer2013.pdf (428.85 KB) More Documents ...
Angel, S. Michael
1989-01-01
Particular gases or liquids are detected with a fiber optic element (11, 11a to 11j) having a cladding or coating of a material (23, 23a to 23j) which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector (24, 24a to 24j) may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses.
Angel, S.M.
1987-02-27
Particular gases or liquids are detected with a fiber optic element having a cladding or coating of a material which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses. 10 figs.
Solids mass flow determination
Macko, Joseph E.
1981-01-01
Method and apparatus for determining the mass flow rate of solids mixed with a transport fluid to form a flowing mixture. A temperature differential is established between the solids and fluid. The temperature of the transport fluid prior to mixing, the temperature of the solids prior to mixing, and the equilibrium temperature of the mixture are monitored and correlated in a heat balance with the heat capacities of the solids and fluid to determine the solids mass flow rate.
Fu, P; Johnson, S M; Hao, Y; Carrigan, C R
2011-01-18
The primary objective of our current research is to develop a computational test bed for evaluating borehole techniques to enhance fluid flow and heat transfer in enhanced geothermal systems (EGS). Simulating processes resulting in hydraulic fracturing and/or the remobilization of existing fractures, especially the interaction between propagating fractures and existing fractures, represents a critical goal of our project. To this end, we are continuing to develop a hydraulic fracturing simulation capability within the Livermore Distinct Element Code (LDEC), a combined FEM/DEM analysis code with explicit solid-fluid mechanics coupling. LDEC simulations start from an initial fracture distribution which can be stochastically generated or upscaled from the statistics of an actual fracture distribution. During the hydraulic stimulation process, LDEC tracks the propagation of fractures and other modifications to the fracture system. The output is transferred to the Non-isothermal Unsaturated Flow and Transport (NUFT) code to capture heat transfer and flow at the reservoir scale. This approach is intended to offer flexibility in the types of analyses we can perform, including evaluating the effects of different system heterogeneities on the heat extraction rate as well as seismicity associated with geothermal operations. This paper details the basic methodology of our approach. Two numerical examples showing the capability and effectiveness of our simulator are also presented.
Boiler using combustible fluid
Baumgartner, H.; Meier, J.G.
1974-07-03
A fluid fuel boiler is described comprising a combustion chamber, a cover on the combustion chamber having an opening for introducing a combustion-supporting gaseous fluid through said openings, means to impart rotation to the gaseous fluid about an axis of the combustion chamber, a burner for introducing a fluid fuel into the chamber mixed with the gaseous fluid for combustion thereof, the cover having a generally frustro-conical configuration diverging from the opening toward the interior of the chamber at an angle of between 15/sup 0/ and 55/sup 0/; means defining said combustion chamber having means defining a plurality of axial hot gas flow paths from a downstream portion of the combustion chamber to flow hot gases into an upstream portion of the combustion chamber, and means for diverting some of the hot gas flow along paths in a direction circumferentially of the combustion chamber, with the latter paths being immersed in the water flow path thereby to improve heat transfer and terminating in a gas outlet, the combustion chamber comprising at least one modular element, joined axially to the frustro-conical cover and coaxial therewith. The modular element comprises an inner ring and means of defining the circumferential, radial, and spiral flow paths of the hot gases.
Symmetry Methods for a Geophysical Mass Flow Model
Torrisi, Mariano; Tracina, Rita
2011-09-14
In the framework of symmetry analysis, the class of 2 x 2 PDE systems to whom belong the Savage and Hutter model and the Iverson model is considered. New classes of exact solutions are found.
A fluid pressure and deformation analysis for geological sequestration of carbon dioxide
Xu, Zhijie; Fang, Yilin; Scheibe, Timothy D.; Bonneville, Alain
2012-06-07
We present a hydro-mechanical model and deformation analysis for geological sequestration of carbon dioxide. The model considers the poroelastic effects by taking into account the two-way coupling between the geomechanical response and the fluid flow process in greater detail. In order for analytical solutions, the simplified hydro-mechanical model includes the geomechanical part that relies on the theory of linear elasticity, while the fluid flow is based on the Darcys law. The model was derived through coupling the two parts using the standard linear poroelasticity theory. Analytical solutions for fluid pressure field were obtained for a typical geological sequestration scenario and the solutions for ground deformation were obtained using the method of Greens function. Solutions predict the temporal and spatial variation of fluid pressure, the effect of permeability and elastic modulus on the fluid pressure, the ground surface uplift, and the radial deformation during the entire injection period.
Ultrasonic flow metering system
Gomm, Tyler J.; Kraft, Nancy C.; Mauseth, Jason A.; Phelps, Larry D.; Taylor, Steven C.
2002-01-01
A system for determining the density, flow velocity, and mass flow of a fluid comprising at least one sing-around circuit that determines the velocity of a signal in the fluid and that is correlatable to a database for the fluid. A system for determining flow velocity uses two of the inventive circuits with directional transmitters and receivers, one of which is set at an angle to the direction of flow that is different from the others.
Lawson, M. J.; Li, Y.; Sale, D. C.
2011-10-01
This paper describes the development of a computational fluid dynamics (CFD) methodology to simulate the hydrodynamics of horizontal-axis tidal current turbines. Qualitative measures of the CFD solutions were independent of the grid resolution. Conversely, quantitative comparisons of the results indicated that the use of coarse computational grids results in an under prediction of the hydrodynamic forces on the turbine blade in comparison to the forces predicted using more resolved grids. For the turbine operating conditions considered in this study, the effect of the computational timestep on the CFD solution was found to be minimal, and the results from steady and transient simulations were in good agreement. Additionally, the CFD results were compared to corresponding blade element momentum method calculations and reasonable agreement was shown. Nevertheless, we expect that for other turbine operating conditions, where the flow over the blade is separated, transient simulations will be required.
COMIS -- an international multizone air-flow and contaminant transport model
Feustel, H.E.
1998-08-01
A number of interzonal models have been developed to calculate air flows and pollutant transport mechanisms in both single and multizone buildings. A recent development in multizone air-flow modeling, the COMIS model, has a number of capabilities that go beyond previous models, much as COMIS can be used as either a stand-alone air-flow model with input and output features or as an infiltration module for thermal building simulation programs. COMIS was designed during a 12 month workshop at Lawrence Berkeley National Laboratory (LBNL) in 1988-89. In 1990, the Executive Committee of the International Energy Agency`s Energy Conservation in Buildings and Community Systems program created a working group on multizone air-flow modeling, which continued work on COMIS. The group`s objectives were to study physical phenomena causing air flow and pollutant (e.g., moisture) transport in multizone buildings, develop numerical modules to be integrated in the previously designed multizone air flow modeling system, and evaluate the computer code. The working group supported by nine nations, officially finished in late 1997 with the release of IISiBat/COMIS 3.0, which contains the documented simulation program COMIS, the user interface IISiBat, and reports describing the evaluation exercise.
Celik, I.; Chattree, M.
1988-07-01
An assessment of the theoretical and numerical aspects of the computer code, PCGC-2, is made; and the results of the application of this code to the Morgantown Energy Technology Center (METC) advanced gasification facility entrained-flow reactor, ''the gasifier,'' are presented. PCGC-2 is a code suitable for simulating pulverized coal combustion or gasification under axisymmetric (two-dimensional) flow conditions. The governing equations for the gas and particulate phase have been reviewed. The numerical procedure and the related programming difficulties have been elucidated. A single-particle model similar to the one used in PCGC-2 has been developed, programmed, and applied to some simple situations in order to gain insight to the physics of coal particle heat-up, devolatilization, and char oxidation processes. PCGC-2 was applied to the METC entrained-flow gasifier to study numerically the flash pyrolysis of coal, and gasification of coal with steam or carbon dioxide. The results from the simulations are compared with measurements. The gas and particle residence times, particle temperature, and mass component history were also calculated and the results were analyzed. The results provide useful information for understanding the fundamentals of coal gasification and for assessment of experimental results performed using the reactor considered. 69 refs., 35 figs., 23 tabs.
Experimentally Determined Interfacial Area Between Immiscible Fluids in Porous Media
Crandall, Dustin; Niessner, J; Hassanizadeh, S.M; Smith, Duane
2008-01-01
When multiple fluids flow through a porous medium, the interaction between the fluid interfaces can be of great importance. While this is widely recognized in practical applications, numerical models often disregard interactios between discrete fluid phases due to the computational complexity. And rightly so, for this level of detail is well beyond most extended Darcy Law relationships. A new model of two-phase flow including the interfacial area has been proposed by Hassarizadeh and Gray based upon thermodynamic principles. A version of this general equation set has been implemented by Nessner and Hassarizadeh. Many of the interfacial parameters required by this equation set have never been determined from experiments. The work presented here is a description of how the interfacial area, capillary pressure, interfacial velocity and interfacial permeability from two-phase flow experiments in porous media experiments can be used to determine the required parameters. This work, while on-going, has shown the possibility of digitizing images within translucent porous media and identifying the location and behavior of interfaces under dynamic conditions. Using the described methods experimentally derived interfacial functions to be used in larger scale simulations are currently being developed. In summary, the following conclusions can be drawn: (1) by mapping a pore-throat geometry onto an image of immiscible fluid flow, the saturation of fluids and the individual interfaces between the fluids can be identified; (2) the resulting saturation profiles of the low velocity drainage flows used in this study are well described by an invasion percolation fractal scaling; (3) the interfacial area between fluids has been observed to increase in a linear fashion during the initial invasion of the non-wetting fluid; and (4) the average capillary pressure within the entire cell and representative elemental volumes were observed to plateau after a small portion of the volume was
Koenig, W.M.; Hennecke, D.K.; Fottner, L.
1996-01-01
New blading concepts as used in modern transonic axial-flow compressors require improved loss and deviation angle correlations. The new model presented in this paper incorporates several elements and treats blade-row flows having subsonic and supersonic inlet conditions separately. The second part of the present report focuses on the extension of a well-known correlation for cascade losses at supersonic inlet flows. It was originally established for DCA bladings and is now modified to reflect the flow situation in blade rows having low-cambered, arbitrarily designed blades including precompression blades. Finally, the steady loss increase from subsonic to supersonic inlet-flow velocities demonstrates the matched performance of the different correlations of the new model.
Soria, José; Gauthier, Daniel; Flamant, Gilles; Rodriguez, Rosa; Mazza, Germán
2015-09-15
Highlights: • A CFD two-scale model is formulated to simulate heavy metal vaporization from waste incineration in fluidized beds. • MSW particle is modelled with the macroscopic particle model. • Influence of bed dynamics on HM vaporization is included. • CFD predicted results agree well with experimental data reported in literature. • This approach may be helpful for fluidized bed reactor modelling purposes. - Abstract: Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with the flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073 K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator.
Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model
P. Tucci
2001-12-20
This Analysis/Model Report (AMR) documents an updated analysis of water-level data performed to provide the saturated-zone, site-scale flow and transport model (CRWMS M&O 2000) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for model calibration. The previous analysis was presented in ANL-NBS-HS-000034, Rev 00 ICN 01, Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model (USGS 2001). This analysis is designed to use updated water-level data as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain. The objectives of this revision are to develop computer files containing (1) water-level data within the model area (DTN: GS010908312332.002), (2) a table of known vertical head differences (DTN: GS0109083 12332.003), and (3) a potentiometric-surface map (DTN: GS010608312332.001) using an alternate concept from that presented in ANL-NBS-HS-000034, Rev 00 ICN 01 for the area north of Yucca Mountain. The updated water-level data include data obtained from the Nye County Early Warning Drilling Program (EWDP) and data from borehole USW WT-24. In addition to being utilized by the SZ site-scale flow and transport model, the water-level data and potentiometric-surface map contained within this report will be available to other government agencies and water users for ground-water management purposes. The potentiometric surface defines an upper boundary of the site-scale flow model, as well as provides information useful to estimation of the magnitude and direction of lateral ground-water flow within the flow system. Therefore, the analysis documented in this revision is important to SZ flow and transport calculations in support of total system performance assessment.
Oborny, Michael C.; Paul, Phillip H.; Hencken, Kenneth R.; Frye-Mason, Gregory C.; Manginell, Ronald P.
2001-01-01
A valve for controlling fluid flows. This valve, which includes both an actuation device and a valve body provides: the ability to incorporate both the actuation device and valve into a unitary structure that can be placed onto a microchip, the ability to generate higher actuation pressures and thus control higher fluid pressures than conventional microvalves, and a device that draws only microwatts of power. An electrokinetic pump that converts electric potential to hydraulic force is used to operate, or actuate, the valve.
Donna Post Guillen; Tami Grimmett; Anastasia M. Gribik; Steven P. Antal
2010-09-01
The Hybrid Energy Systems Testing (HYTEST) Laboratory is being established at the Idaho National Laboratory to develop and test hybrid energy systems with the principal objective to safeguard U.S. Energy Security by reducing dependence on foreign petroleum. A central component of the HYTEST is the slurry bubble column reactor (SBCR) in which the gas-to-liquid reactions will be performed to synthesize transportation fuels using the Fischer Tropsch (FT) process. SBCRs are cylindrical vessels in which gaseous reactants (for example, synthesis gas or syngas) is sparged into a slurry of liquid reaction products and finely dispersed catalyst particles. The catalyst particles are suspended in the slurry by the rising gas bubbles and serve to promote the chemical reaction that converts syngas to a spectrum of longer chain hydrocarbon products, which can be upgraded to gasoline, diesel or jet fuel. These SBCRs operate in the churn-turbulent flow regime which is characterized by complex hydrodynamics, coupled with reacting flow chemistry and heat transfer, that effect reactor performance. The purpose of this work is to develop a computational multiphase fluid dynamic (CMFD) model to aid in understanding the physico-chemical processes occurring in the SBCR. Our team is developing a robust methodology to couple reaction kinetics and mass transfer into a four-field model (consisting of the bulk liquid, small bubbles, large bubbles and solid catalyst particles) that includes twelve species: (1) CO reactant, (2) H2 reactant, (3) hydrocarbon product, and (4) H2O product in small bubbles, large bubbles, and the bulk fluid. Properties of the hydrocarbon product were specified by vapor liquid equilibrium calculations. The absorption and kinetic models, specifically changes in species concentrations, have been incorporated into the mass continuity equation. The reaction rate is determined based on the macrokinetic model for a cobalt catalyst developed by Yates and Satterfield [1]. The
A Two-Dimensional Compressible Gas Flow Code
Energy Science and Technology Software Center (OSTI)
1995-03-17
F2D is a general purpose, two dimensional, fully compressible thermal-fluids code that models most of the phenomena found in situations of coupled fluid flow and heat transfer. The code solves momentum, continuity, gas-energy, and structure-energy equations using a predictor-correction solution algorithm. The corrector step includes a Poisson pressure equation. The finite difference form of the equation is presented along with a description of input and output. Several example problems are included that demonstrate the applicabilitymore » of the code in problems ranging from free fluid flow, shock tubes and flow in heated porous media.« less
Hugh M. McIlroy Jr.; Donald M. McEligot; Robert J. Pink
2008-09-01
The experimental program that is being conducted at the Matched Index-of-Refraction (MIR) Flow Facility at Idaho National Laboratory (INL) to obtain benchmark data on measurements of flow phenomena in a scaled model of a prismatic gas-cooled reactor lower plenum using 3-D Particle Image Velocimetry (PIV) is presented. A description of the scaling analysis, experimental facility, 3-D PIV system, measurement uncertainties and analysis, experimental procedures and samples of the data sets that have been obtained are included. Samples of the data set that will be presented include mean-velocity-field and turbulence data in an approximately 1:7 scale model of a region of the lower plenum of a typical prismatic gas-cooled reactor (GCR) similar to a General Atomics Gas-Turbine-Modular Helium Reactor (GTMHR) design. This experiment has been selected as the first Standard Problem endorsed by the Generation IV International Forum. The flow in the lower plenum consists of multiple jets injected into a confined cross flow - with obstructions. The model consists of a row of full circular posts along its centerline with half-posts on the two parallel walls to approximate flow scaled to that expected from the staggered parallel rows of posts in the reactor design. The model is fabricated from clear, fused quartz to match the refractive-index of the mineral oil working fluid. The benefit of the MIR technique is that it permits high-quality measurements to be obtained without locating intrusive transducers that disturb the flow field and without distortion of the optical paths. An advantage of the INL MIR system is its large size which allows improved spatial and temporal resolution compared to similar facilities at smaller scales. Results concentrate on the region of the lower plenum near its far reflector wall (away from the outlet duct). Inlet jet Reynolds numbers (based on the jet diameter and the time-mean average flow rate) are approximately 4,300 and 12,400. The measurements
Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model
K. Rehfeldt
2004-10-08
This report is an updated analysis of water-level data performed to provide the ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]) (referred to as the saturated zone (SZ) site-scale flow model or site-scale SZ flow model in this report) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for calibration of groundwater flow models. This report also contains an expanded discussion of uncertainty in the potentiometric-surface map. The analysis of the potentiometric data presented in Revision 00 of this report (USGS 2001 [DIRS 154625]) provides the configuration of the potentiometric surface, target heads, and hydraulic gradients for the calibration of the SZ site-scale flow model (BSC 2004 [DIRS 170037]). Revision 01 of this report (USGS 2004 [DIRS 168473]) used updated water-level data for selected wells through the year 2000 as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain based on an alternative interpretation of perched water conditions. That revision developed computer files containing: Water-level data within the model area (DTN: GS010908312332.002); A table of known vertical head differences (DTN: GS010908312332.003); and A potentiometric-surface map (DTN: GS010608312332.001) using an alternative concept from that presented by USGS (2001 [DIRS 154625]) for the area north of Yucca Mountain. The updated water-level data presented in USGS (2004 [DIRS 168473]) include data obtained from the Nye County Early Warning Drilling Program (EWDP) Phases I and II and data from Borehole USW WT-24. This document is based on Revision 01 (USGS 2004 [DIRS 168473]) and expands the discussion of uncertainty in the potentiometric-surface map. This uncertainty assessment includes an analysis of the impact of more recent water-level data and the impact of adding data from the EWDP Phases III and IV wells. In addition to being utilized
Pohlmann Karl,Ye Ming
2012-03-01
Models of groundwater flow for the Yucca Flat area of the Nevada National Security Site (NNSS) are under development by the U.S. Department of Energy (DOE) for corrective action investigations of the Yucca Flat-Climax Mine Corrective Action Unit (CAU). One important aspect of these models is the quantity of inter-basin groundwater flow from regional systems to the north. This component of flow, together with its uncertainty, must be properly accounted for in the CAU flow models to provide a defensible regional framework for calculations of radionuclide transport that will support determinations of the Yucca Flat-Climax Mine contaminant boundary. Because characterizing flow boundary conditions in northern Yucca Flat requires evaluation to a higher level of detail than the scale of the Yucca Flat-Climax Mine CAU model can efficiently provide, a study more focused on this aspect of the model was required.
Lawson, Mi. J.; Li, Y.; Sale, D. C.
2011-01-01
This paper describes the development of a computational fluid dynamics (CFD) methodology to simulate the hydrodynamics of horizontal-axis tidal current turbines (HATTs). First, an HATT blade was designed using the blade element momentum method in conjunction with a genetic optimization algorithm. Several unstructured computational grids were generated using this blade geometry and steady CFD simulations were used to perform a grid resolution study. Transient simulations were then performed to determine the effect of time-dependent flow phenomena and the size of the computational timestep on the numerical solution. Qualitative measures of the CFD solutions were independent of the grid resolution. Conversely, quantitative comparisons of the results indicated that the use of coarse computational grids results in an under prediction of the hydrodynamic forces on the turbine blade in comparison to the forces predicted using more resolved grids. For the turbine operating conditions considered in this study, the effect of the computational timestep on the CFD solution was found to be minimal, and the results from steady and transient simulations were in good agreement. Additionally, the CFD results were compared to corresponding blade element momentum method calculations and reasonable agreement was shown. Nevertheless, we expect that for other turbine operating conditions, where the flow over the blade is separated, transient simulations will be required.
Leishear, Robert A.; Lee, Si Y.; Poirier, Michael R.; Steeper, Timothy J.; Ervin, Robert C.; Giddings, Billy J.; Stefanko, David B.; Harp, Keith D.; Fowley, Mark D.; Van Pelt, William B.
2012-10-07
Computational fluid dynamics (CFD) is recognized as a powerful engineering tool. That is, CFD has advanced over the years to the point where it can now give us deep insight into the analysis of very complex processes. There is a danger, though, that an engineer can place too much confidence in a simulation. If a user is not careful, it is easy to believe that if you plug in the numbers, the answer comes out, and you are done. This assumption can lead to significant errors. As we discovered in the course of a study on behalf of the Department of Energy's Savannah River Site in South Carolina, CFD models fail to capture some of the large variations inherent in complex processes. These variations, or scatter, in experimental data emerge from physical tests and are inadequately captured or expressed by calculated mean values for a process. This anomaly between experiment and theory can lead to serious errors in engineering analysis and design unless a correction factor, or safety factor, is experimentally validated. For this study, blending times for the mixing of salt solutions in large storage tanks were the process of concern under investigation. This study focused on the blending processes needed to mix salt solutions to ensure homogeneity within waste tanks, where homogeneity is required to control radioactivity levels during subsequent processing. Two of the requirements for this task were to determine the minimum number of submerged, centrifugal pumps required to blend the salt mixtures in a full-scale tank in half a day or less, and to recommend reasonable blending times to achieve nearly homogeneous salt mixtures. A full-scale, low-flow pump with a total discharge flow rate of 500 to 800 gpm was recommended with two opposing 2.27-inch diameter nozzles. To make this recommendation, both experimental and CFD modeling were performed. Lab researchers found that, although CFD provided good estimates of an average blending time, experimental blending times varied
Diomede, P.; Michau, A.; Redolfi, M.; Hassouni, K.; Morscheidt, W.; Longo, S.; Capitelli, M.
2008-10-15
A comparative study of two models, a kinetic and a fluid one, for the numerical simulation of H{sub 2} plasmas in parallel plate capacitively coupled rf discharges in one space dimension is presented. Both models adopt a multicomponent plasma description including several ionic species, take into account the self-consistent electric field by solving the Poisson equation and include a self-consistent coupling with the vibrational kinetics of the electronic ground state of H{sub 2} molecules. The peculiarities of this particular test case for model comparison with respect to previous studies are highlighted. The merits and the limitations of both approaches are discussed and the results are compared, in particular the steady-state density of charged species, the space-time variation of the electron energy, the vibrational distribution, and the atomic density.
Isotopic Constraints on the Chemical Evolution of Geothermal Fluids, Long Valley, CA
Brown, Shaun; Kennedy, Burton; DePaolo, Donald; Evans, William
2008-08-01
A spatial survey of the chemical and isotopic composition of fluids from the Long Valley hydrothermal system was conducted. Starting at the presumed hydrothermal upwelling zone in the west moat of the caldera, samples were collected from the Casa Diablo geothermal field and a series of monitoring wells defining a nearly linear, ~;;14 km long, west-to-east trend along the proposed fluid flow path (Sorey et al., 1991). Samples were analyzed for the isotopes of water, Sr, Ca, and noble gases, the concentrations of major cations and anions and total CO2. Our data confirm earlier models in which the variations in water isotopes along the flow path reflect mixing of a single hydrothermal fluid with local groundwater. Variations in Sr data are poorly constrained and reflect fluid mixing, multiple fluid-pathways or water-rock exchange along the flow path as suggested by Goff et al. (1991). Correlated variations among total CO2, noble gases and the concentration and isotopic composition of Ca suggest progressive fluid degassing (loss of CO2, noble gases) driving calcite precipitation as the fluid flows west-to-east across the caldera. This is the first evidence that Ca isotopes may trace and provide definitive evidence of calcite precipitation along fluid flow paths in geothermal systems.
Meixler, Lewis D.
1993-01-01
The low flow monitor provides a means for determining if a fluid flow meets a minimum threshold level of flow. The low flow monitor operates with a minimum of intrusion by the flow detection device into the flow. The electrical portion of the monitor is externally located with respect to the fluid stream which allows for repairs to the monitor without disrupting the flow. The electronics provide for the adjustment of the threshold level to meet the required conditions. The apparatus can be modified to provide an upper limit to the flow monitor by providing for a parallel electronic circuit which provides for a bracketing of the desired flow rate.
A hybrid stochastic-deconvolution model for large-eddy simulation of particle-laden flow
Michałek, W. R.; Kuerten, J. G. M.; Faculty EEMCS, University of Twente, 7500 AE Enschede ; Zeegers, J. C. H.; Liew, R.; Pozorski, J.; Geurts, B. J.; Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven
2013-12-15
We develop a hybrid model for large-eddy simulation of particle-laden turbulent flow, which is a combination of the approximate deconvolution model for the resolved scales and a stochastic model for the sub-grid scales. The stochastic model incorporates a priori results of direct numerical simulation of turbulent channel flow, which showed that the parameters in the stochastic model are quite independent of Reynolds and Stokes number. In order to correctly predict the flux of particles towards the walls an extra term should be included in the stochastic model, which corresponds to the term related to the well-mixed condition in Langevin models for particle dispersion in inhomogeneous turbulent flow. The model predictions are compared with results of direct numerical simulation of channel flow at a frictional Reynolds number of 950. The inclusion of the stochastic forcing is shown to yield a significant improvement over the approximate deconvolution model for the particles alone when combined with a Stokes dependent weight-factor for the well-mixed term.
Shi, Xing; Lin, Guang
2014-11-01
To model the sedimentation of the red blood cell (RBC) in a square duct and a circular pipe, the recently developed technique derived from the lattice Boltzmann method and the distributed Lagrange multiplier/fictitious domain method (LBM-DLM/FD) is extended to employ the mesoscopic network model for simulations of the sedimentation of the RBC in flow. The flow is simulated by the lattice Boltzmann method with a strong magnetic body force, while the network model is used for modeling RBC deformation. The fluid-RBC interactions are enforced by the Lagrange multiplier. The sedimentation of the RBC in a square duct and a circular pipe is simulated, revealing the capacity of the current method for modeling the sedimentation of RBC in various flows. Numerical results illustrate that that the terminal setting velocity increases with the increment of the exerted body force. The deformation of the RBC has significant effect on the terminal setting velocity due to the change of the frontal area. The larger the exerted force is, the smaller the frontal area and the larger deformation of the RBC are.
NEW MODEL AND MEASUREMENT PRINCIPLE OF FLOWING AND HEAT TRANSFER CHARACTERISTICS OF REGENERATOR
Chen, Y. Y.; Luo, E. C.; Dai, W.
2008-03-16
Regenerators play key role in oscillating-flow cryocoolers or thermoacoustic heat engine systems. However, their flowing and heat transfer mechanism is still not well understood. The complexities of the oscillating flow regenerator make traditional method of heat transfer research become difficult or helpless. In this paper, a model for porous media regenerator was given based on the linear thermoacoustic theory. Then the correlations for characteristic parameters were obtained by deducing universal expressions for thermoacoustic viscous function F{sub v} and thermal function F{sub T}. A simple acoustical method and experimental system to get F{sub v} and F{sub T} via measurements of isothermal regenerators were presented. Some measurements of packed stainless screen regenerators were performed, and preliminary experimental results for flow and convective coefficients were derived, which showing flowing friction factor is approximately within 132/Re to 173/Re.
Koenig, W.M.; Hennecke, D.K.; Fottner, L.
1996-01-01
New blading concepts as used in modern transonic axial-flow compressors require improved loss and deviation angle correlations. The new model presented in this paper incorporates several elements and treats blade-row flows having subsonic and supersonic inlet conditions separately. In the first part of this paper two proved and well-established profile loss correlations for subsonic flows are extended to quasi-two-dimensional conditions and to custom-tailored blade designs. Instead of a deviation angle correlation, a simple method based on singularities is utilized. The comparison between the new model and a recently published model demonstrates the improved accuracy in prediction of cascade performance achieved by the new model.
Variable flexure-based fluid filter
Brown, Steve B.; Colston, Jr., Billy W.; Marshall, Graham; Wolcott, Duane
2007-03-13
An apparatus and method for filtering particles from a fluid comprises a fluid inlet, a fluid outlet, a variable size passage between the fluid inlet and the fluid outlet, and means for adjusting the size of the variable size passage for filtering the particles from the fluid. An inlet fluid flow stream is introduced to a fixture with a variable size passage. The size of the variable size passage is set so that the fluid passes through the variable size passage but the particles do not pass through the variable size passage.
He, W.; Anderson, R.N.
1998-08-25
A method is disclosed for inverting 3-D seismic reflection data obtained from seismic surveys to derive impedance models for a subsurface region, and for inversion of multiple 3-D seismic surveys (i.e., 4-D seismic surveys) of the same subsurface volume, separated in time to allow for dynamic fluid migration, such that small scale structure and regions of fluid and dynamic fluid flow within the subsurface volume being studied can be identified. The method allows for the mapping and quantification of available hydrocarbons within a reservoir and is thus useful for hydrocarbon prospecting and reservoir management. An iterative seismic inversion scheme constrained by actual well log data which uses a time/depth dependent seismic source function is employed to derive impedance models from 3-D and 4-D seismic datasets. The impedance values can be region grown to better isolate the low impedance hydrocarbon bearing regions. Impedance data derived from multiple 3-D seismic surveys of the same volume can be compared to identify regions of dynamic evolution and bypassed pay. Effective Oil Saturation or net oil thickness can also be derived from the impedance data and used for quantitative assessment of prospective drilling targets and reservoir management. 20 figs.
He, Wei; Anderson, Roger N.
1998-01-01
A method is disclosed for inverting 3-D seismic reflection data obtained from seismic surveys to derive impedance models for a subsurface region, and for inversion of multiple 3-D seismic surveys (i.e., 4-D seismic surveys) of the same subsurface volume, separated in time to allow for dynamic fluid migration, such that small scale structure and regions of fluid and dynamic fluid flow within the subsurface volume being studied can be identified. The method allows for the mapping and quantification of available hydrocarbons within a reservoir and is thus useful for hydrocarbon prospecting and reservoir management. An iterative seismic inversion scheme constrained by actual well log data which uses a time/depth dependent seismic source function is employed to derive impedance models from 3-D and 4-D seismic datasets. The impedance values can be region grown to better isolate the low impedance hydrocarbon bearing regions. Impedance data derived from multiple 3-D seismic surveys of the same volume can be compared to identify regions of dynamic evolution and bypassed pay. Effective Oil Saturation or net oil thickness can also be derived from the impedance data and used for quantitative assessment of prospective drilling targets and reservoir management.
Chen, Zhaoquan; Yin, Zhixiang Chen, Minggong; Hong, Lingli; Hu, Yelin; Huang, Yourui; Xia, Guangqing; Liu, Minghai; Kudryavtsev, A. A.
2014-10-21
In present study, a pulsed lower-power microwave-driven atmospheric-pressure argon plasma jet has been introduced with the type of coaxial transmission line resonator. The plasma jet plume is with room air temperature, even can be directly touched by human body without any hot harm. In order to study ionization process of the proposed plasma jet, a self-consistent hybrid fluid model is constructed in which Maxwell's equations are solved numerically by finite-difference time-domain method and a fluid model is used to study the characteristics of argon plasma evolution. With a Guass type input power function, the spatio-temporal distributions of the electron density, the electron temperature, the electric field, and the absorbed power density have been simulated, respectively. The simulation results suggest that the peak values of the electron temperature and the electric field are synchronous with the input pulsed microwave power but the maximum quantities of the electron density and the absorbed power density are lagged to the microwave power excitation. In addition, the pulsed plasma jet excited by the local enhanced electric field of surface plasmon polaritons should be the discharge mechanism of the proposed plasma jet.
Caughey, David
2010-10-08
A Symposium on Turbulence and Combustion was held at Cornell University on August 3-4, 2009. The overall goal of the Symposium was to promote future advances in the study of turbulence and combustion, through an unique forum intended to foster interactions between leading members of these two research communities. The Symposium program consisted of twelve invited lectures given by world-class experts in these fields, two poster sessions consisting of nearly 50 presentations, an open forum, and other informal activities designed to foster discussion. Topics covered in the lectures included turbulent dispersion, wall-bounded flows, mixing, finite-rate chemistry, and others, using experiment, modeling, and computations, and included perspectives from an international community of leading researchers from academia, national laboratories, and industry.
Mesoscale Simulations of Particulate Flows with Parallel Distributed
Office of Scientific and Technical Information (OSTI)
Lagrange Multiplier Technique (Conference) | SciTech Connect Mesoscale Simulations of Particulate Flows with Parallel Distributed Lagrange Multiplier Technique Citation Details In-Document Search Title: Mesoscale Simulations of Particulate Flows with Parallel Distributed Lagrange Multiplier Technique Fluid particulate flows are common phenomena in nature and industry. Modeling of such flows at micro and macro levels as well establishing relationships between these approaches are needed to
Molecular dynamics simulations of microscale fluid transport
Wong, C.C.; Lopez, A.R.; Stevens, M.J.; Plimpton, S.J.
1998-02-01
Recent advances in micro-science and technology, like Micro-Electro-Mechanical Systems (MEMS), have generated a group of unique liquid flow problems that involve characteristic length scales of a Micron. Also, in manufacturing processes such as coatings, current continuum models are unable to predict microscale physical phenomena that appear in these non-equilibrium systems. It is suspected that in these systems, molecular-level processes can control the interfacial energy and viscoelastic properties at the liquid/solid boundary. A massively parallel molecular dynamics (MD) code has been developed to better understand microscale transport mechanisms, fluid-structure interactions, and scale effects in micro-domains. Specifically, this MD code has been used to analyze liquid channel flow problems for a variety of channel widths, e.g. 0.005-0.05 microns. This report presents results from MD simulations of Poiseuille flow and Couette flow problems and addresses both scaling and modeling issues. For Poiseuille flow, the numerical predictions are compared with existing data to investigate the variation of the friction factor with channel width. For Couette flow, the numerical predictions are used to determine the degree of slip at the liquid/solid boundary. Finally, the results also indicate that shear direction with respect to the wall lattice orientation can be very important. Simulation results of microscale Couette flow and microscale Poiseuille flow for two different surface structures and two different shear directions will be presented.
Heat Transfer in Complex Fluids
Mehrdad Massoudi
2012-01-01
Amongst the most important constitutive relations in Mechanics, when characterizing the behavior of complex materials, one can identify the stress tensor T, the heat flux vector q (related to heat conduction) and the radiant heating (related to the radiation term in the energy equation). Of course, the expression 'complex materials' is not new. In fact, at least since the publication of the paper by Rivlin & Ericksen (1955), who discussed fluids of complexity (Truesdell & Noll, 1992), to the recently published books (Deshpande et al., 2010), the term complex fluids refers in general to fluid-like materials whose response, namely the stress tensor, is 'non-linear' in some fashion. This non-linearity can manifest itself in variety of forms such as memory effects, yield stress, creep or relaxation, normal-stress differences, etc. The emphasis in this chapter, while focusing on the constitutive modeling of complex fluids, is on granular materials (such as coal) and non-linear fluids (such as coal-slurries). One of the main areas of interest in energy related processes, such as power plants, atomization, alternative fuels, etc., is the use of slurries, specifically coal-water or coal-oil slurries, as the primary fuel. Some studies indicate that the viscosity of coal-water mixtures depends not only on the volume fraction of solids, and the mean size and the size distribution of the coal, but also on the shear rate, since the slurry behaves as shear-rate dependent fluid. There are also studies which indicate that preheating the fuel results in better performance, and as a result of such heating, the viscosity changes. Constitutive modeling of these non-linear fluids, commonly referred to as non-Newtonian fluids, has received much attention. Most of the naturally occurring and synthetic fluids are non-linear fluids, for example, polymer melts, suspensions, blood, coal-water slurries, drilling fluids, mud, etc. It should be noted that sometimes these fluids show Newtonian
Multiphase Flow Modeling - Validation and Application CRADA MC94-019, Final Report
Madhava Syamlal; Philip A. Nicoletti
1995-08-31
For the development and validation of multiphase flow modeling capability, a cooperative research and development agreement (CRADA) is in effect between Morgantown Energy Technology Center (METC) and Fluent Inc. To validate the Fluent multiphase model, several simulations were conducted at METC and the results were compared with the results of MFIX, a multiphase flow code developed at METC, and with experimental data. The results of these validation studies will be presented. In addition, the application of multiphase flow modeling will be illustrated by presenting the results of simulations of a filter back- flushing and a fluidized bed coal gasifier. These simulations were conducted only with MFIX, since certain features needed in these simulations will be available only in the next release of Fluent.
Freeze, G.A.; Larson, K.W.; Davies, P.B.
1995-10-01
Eight alternative methods for approximating salt creep and disposal room closure in a multiphase flow model of the Waste Isolation Pilot Plant (WIPP) were implemented and evaluated: Three fixed-room geometries three porosity functions and two fluid-phase-salt methods. The pressure-time-porosity line interpolation method is the method used in current WIPP Performance Assessment calculations. The room closure approximation methods were calibrated against a series of room closure simulations performed using a creep closure code, SANCHO. The fixed-room geometries did not incorporate a direct coupling between room void volume and room pressure. The two porosity function methods that utilized moles of gas as an independent parameter for closure coupling. The capillary backstress method was unable to accurately simulate conditions of re-closure of the room. Two methods were found to be accurate enough to approximate the effects of room closure; the boundary backstress method and pressure-time-porosity line interpolation. The boundary backstress method is a more reliable indicator of system behavior due to a theoretical basis for modeling salt deformation as a viscous process. It is a complex method and a detailed calibration process is required. The pressure lines method is thought to be less reliable because the results were skewed towards SANCHO results in simulations where the sequence of gas generation was significantly different from the SANCHO gas-generation rate histories used for closure calibration. This limitation in the pressure lines method is most pronounced at higher gas-generation rates and is relatively insignificant at lower gas-generation rates. Due to its relative simplicity, the pressure lines method is easier to implement in multiphase flow codes and simulations have a shorter execution time.
Analytical solution for two-phase flow in a wellbore using the drift-flux model
Pan, L.; Webb, S.W.; Oldenburg, C.M.
2011-11-01
This paper presents analytical solutions for steady-state, compressible two-phase flow through a wellbore under isothermal conditions using the drift flux conceptual model. Although only applicable to highly idealized systems, the analytical solutions are useful for verifying numerical simulation capabilities that can handle much more complicated systems, and can be used in their own right for gaining insight about two-phase flow processes in wells. The analytical solutions are obtained by solving the mixture momentum equation of steady-state, two-phase flow with an assumption that the two phases are immiscible. These analytical solutions describe the steady-state behavior of two-phase flow in the wellbore, including profiles of phase saturation, phase velocities, and pressure gradients, as affected by the total mass flow rate, phase mass fraction, and drift velocity (i.e., the slip between two phases). Close matching between the analytical solutions and numerical solutions for a hypothetical CO{sub 2} leakage problem as well as to field data from a CO{sub 2} production well indicates that the analytical solution is capable of capturing the major features of steady-state two-phase flow through an open wellbore, and that the related assumptions and simplifications are justified for many actual systems. In addition, we demonstrate the utility of the analytical solution to evaluate how the bottomhole pressure in a well in which CO{sub 2} is leaking upward responds to the mass flow rate of CO{sub 2}-water mixture.
Semans, Joseph P.; Johnson, Peter G.; LeBoeuf, Jr., Robert F.; Kromka, Joseph A.; Goron, Ronald H.; Hay, George D.
1993-01-01
A trainer, mounted and housed within a mobile console, is used to teach and reinforce fluid principles to students. The system trainer has two centrifugal pumps, each driven by a corresponding two-speed electric motor. The motors are controlled by motor controllers for operating the pumps to circulate the fluid stored within a supply tank through a closed system. The pumps may be connected in series or in parallel. A number of valves are also included within the system to effect different flow paths for the fluid. In addition, temperature and pressure sensing instruments are installed throughout the closed system for measuring the characteristics of the fluid, as it passes through the different valves and pumps. These measurements are indicated on a front panel mounted to the console, as a teaching aid, to allow the students to observe the characteristics of the system.
CURRENT - A Computer Code for Modeling Two-Dimensional, Chemically Reaccting, Low Mach Number Flows
Winters, W.S.; Evans, G.H.; Moen, C.D.
1996-10-01
This report documents CURRENT, a computer code for modeling two- dimensional, chemically reacting, low Mach number flows including the effects of surface chemistry. CURRENT is a finite volume code based on the SIMPLER algorithm. Additional convergence acceleration for low Peclet number flows is provided using improved boundary condition coupling and preconditioned gradient methods. Gas-phase and surface chemistry is modeled using the CHEMKIN software libraries. The CURRENT user-interface has been designed to be compatible with the Sandia-developed mesh generator and post processor ANTIPASTO and the post processor TECPLOT. This report describes the theory behind the code and also serves as a user`s manual.
Grid Generator for Two, Three-dimensional Finite Element Subsurface Flow Models
Energy Science and Technology Software Center (OSTI)
1993-04-28
GRIDMAKER serves as a preprocessor for finite element models in solving two- and three-dimensional subsurface flow and pollutant transport problems. It is designed to generate three-point triangular or four-point quadrilateral elements for two-dimensional domains and eight-point hexahedron elements for three-dimensional domains. A two-dimensional domain of an aquifer with a variable depth layer is treated as a special case for depth-integrated two-dimensional, finite element subsurface flow models. The program accommodates the need for aquifers with heterogeneousmore » systems by identifying the type of material in each element.« less
Cardiovascular Flow Simulations at Extreme Scale | Argonne Leadership
U.S. Department of Energy (DOE) all webpages (Extended Search)
Computing Facility Cardiovascular Flow Simulations at Extreme Scale Authors: Zhou, M., Sahni, O., Kim, H.J., Figueroa, C.A., Taylor, C.A., Shephard, M.S., Jansen, K.E. As cardiovascular models grow more sophisticated in terms of the geometry considered, and more physiologically realistic boundary conditions are applied, and fluid flow is coupled to structural models, the computational complexity grows. Massively parallel adaptivity and flow solvers with extreme scalability enable
Fraser, D.W.H.; Abdelmessih, A.H.
1995-09-01
A general unified model is developed to predict one-component critical two-phase pipe flow. Modelling of the two-phase flow is accomplished by describing the evolution of the flow between the location of flashing inception and the exit (critical) plane. The model approximates the nonequilibrium phase change process via thermodynamic equilibrium paths. Included are the relative effects of varying the location of flashing inception, pipe geometry, fluid properties and length to diameter ratio. The model predicts that a range of critical mass fluxes exist and is bound by a maximum and minimum value for a given thermodynamic state. This range is more pronounced at lower subcooled stagnation states and can be attributed to the variation in the location of flashing inception. The model is based on the results of an experimental study of the critical two-phase flow of saturated and subcooled water through long tubes. In that study, the location of flashing inception was accurately controlled and adjusted through the use of a new device. The data obtained revealed that for fixed stagnation conditions, the maximum critical mass flux occurred with flashing inception located near the pipe exit; while minimum critical mass fluxes occurred with the flashing front located further upstream. Available data since 1970 for both short and long tubes over a wide range of conditions are compared with the model predictions. This includes test section L/D ratios from 25 to 300 and covers a temperature and pressure range of 110 to 280{degrees}C and 0.16 to 6.9 MPa. respectively. The predicted maximum and minimum critical mass fluxes show an excellent agreement with the range observed in the experimental data.
Joseph, Ilon
2014-05-27
Jacobian-free Newton-Krylov (JFNK) algorithms are a potentially powerful class of methods for solving the problem of coupling codes that address dfferent physics models. As communication capability between individual submodules varies, different choices of coupling algorithms are required. The more communication that is available, the more possible it becomes to exploit the simple spa sity pattern of the Jacobian, albeit of a large system. The less communication that is available, the more dense the Jacobian matrices become and new types of preconditioners must be sought to efficiently take large time steps. In general, methods that use constrained or reduced subsystems can offer a compromise in complexity. The specific problem of coupling a fluid plasma code to a kinetic neutrals code is discussed as an example.
From many body wee partons dynamics to perfect fluid: a standard model for heavy ion collisions
Venugopalan, R.
2010-07-22
We discuss a standard model of heavy ion collisions that has emerged both from experimental results of the RHIC program and associated theoretical developments. We comment briefly on the impact of early results of the LHC program on this picture. We consider how this standard model of heavy ion collisions could be solidified or falsified in future experiments at RHIC, the LHC and a future Electro-Ion Collider.
Comparative analysis for various redox flow batteries chemistries using a cost performance model
Crawford, Aladsair J.; Viswanathan, Vilayanur V.; Stephenson, David E.; Wang, Wei; Thomsen, Edwin C.; Reed, David M.; Li, Bin; Balducci, Patrick J.; Kintner-Meyer, Michael CW; Sprenkle, Vincent L.
2015-10-20
A robust performance-based cost model is developed for all-vanadium, iron-vanadium and iron chromium redox flow batteries. Systems aspects such as shunt current losses, pumping losses and thermal management are accounted for. The objective function, set to minimize system cost, allows determination of stack design and operating parameters such as current density, flow rate and depth of discharge (DOD). Component costs obtained from vendors are used to calculate system costs for various time frames. A 2 kW stack data was used to estimate unit energy costs and compared with model estimates for the same size electrodes. The tool has been shared with the redox flow battery community to both validate their stack data and guide future direction.
Coupled Fluid Energy Solute Transport
Energy Science and Technology Software Center (OSTI)
1992-02-13
CFEST is a Coupled Fluid, Energy, and Solute Transport code for the study of a multilayered, nonisothermal ground-water system. It can model discontinuous as well as continuous layers, time-dependent and constant source/sinks, and transient as well as steady-state flow. The finite element method is used for analyzing isothermal and nonisothermal events in a confined aquifer system. Only single-phase Darcian flow is considered. In the Cartesian coordinate system, flow in a horizontal plane, in a verticalmore » plane, or in a fully three-dimensional region can be simulated. An option also exists for the axisymmetric analysis of a vertical cross section. The code employs bilinear quadrilateral elements in all two dimensional analyses and trilinear quadrilateral solid elements in three dimensional simulations. The CFEST finite element formulation can approximate discontinuities, major breaks in slope or thickness, and fault zones in individual hydrogeologic units. The code accounts for heterogeneity in aquifer permeability and porosity and accommodates anisotropy (collinear with the Cartesian coordinates). The variation in the hydraulic properties is described on a layer-by-layer basis for the different hydrogeologic units. Initial conditions can be prescribed hydraulic head or pressure, temperature, or concentration. CFEST can be used to support site, repository, and waste package subsystem assessments. Some specific applications are regional hydrologic characterization; simulation of coupled transport of fluid, heat, and salinity in the repository region; consequence assessment due to natural disruption or human intrusion scenarios in the repository region; flow paths and travel-time estimates for transport of radionuclides; and interpretation of well and tracer tests.« less
Self-sustaining turbulence in a restricted nonlinear model of plane Couette flow
Thomas, Vaughan L.; Gayme, Dennice F.; Lieu, Binh K.; Jovanović, Mihailo R.; Farrell, Brian F.; Ioannou, Petros J.
2014-10-15
This paper demonstrates the maintenance of self-sustaining turbulence in a restricted nonlinear (RNL) model of plane Couette flow. The RNL system is derived directly from the Navier-Stokes equations and permits higher resolution studies of the dynamical system associated with the stochastic structural stability theory (S3T) model, which is a second order approximation of the statistical state dynamics of the flow. The RNL model shares the dynamical restrictions of the S3T model but can be easily implemented by reducing a DNS code so that it retains only the RNL dynamics. Comparisons of turbulence arising from DNS and RNL simulations demonstrate that the RNL system supports self-sustaining turbulence with a mean flow as well as structural and dynamical features that are consistent with DNS. These results demonstrate that the simplified RNL system captures fundamental aspects of fully developed turbulence in wall-bounded shear flows and motivate use of the RNL/S3T framework for further study of wall-turbulence.
Uncertainty Analysis Framework - Hanford Site-Wide Groundwater Flow and Transport Model
Cole, Charles R.; Bergeron, Marcel P.; Murray, Christopher J.; Thorne, Paul D.; Wurstner, Signe K.; Rogers, Phillip M.
2001-11-09
Pacific Northwest National Laboratory (PNNL) embarked on a new initiative to strengthen the technical defensibility of the predictions being made with a site-wide groundwater flow and transport model at the U.S. Department of Energy Hanford Site in southeastern Washington State. In FY 2000, the focus of the initiative was on the characterization of major uncertainties in the current conceptual model that would affect model predictions. The long-term goals of the initiative are the development and implementation of an uncertainty estimation methodology in future assessments and analyses using the site-wide model. This report focuses on the development and implementation of an uncertainty analysis framework.
Chaplin, Vernon H.; Bellan, Paul M.
2015-12-28
A time-dependent two-fluid model has been developed to understand axial variations in the plasma parameters in a very high density (peak n_{e~} > 5x10^{19} m^{–3}) argon inductively coupled discharge in a long 1.1 cm radius tube. The model equations are written in 1D, with radial losses to the tube walls accounted for by the inclusion of effective particle and energy sink terms. The ambipolar diffusion equation and electron energy equation are solved to find the electron density n_{e}(z,t) and temperature T_{e}(z,t), and the populations of the neutral argon 4s metastable, 4s resonant, and 4p excited state manifolds are calculated in order to determine the stepwise ionization rate and calculate radiative energy losses. The model has been validated through comparisons with Langmuir probe ion saturation current measurements; close agreement between the simulated and measured axial plasma density profiles and the initial density rise rate at each location was obtained at p_{Ar} = 30-60 mTorr. Lastly, we present detailed results from calculations at 60 mTorr, including the time-dependent electron temperature, excited state populations, and energy budget within and downstream of the radiofrequency (RF) antenna.
Chaplin, Vernon H.; Bellan, Paul M.
2015-12-28
A time-dependent two-fluid model has been developed to understand axial variations in the plasma parameters in a very high density (peak ne~ > 5x1019 m–3) argon inductively coupled discharge in a long 1.1 cm radius tube. The model equations are written in 1D, with radial losses to the tube walls accounted for by the inclusion of effective particle and energy sink terms. The ambipolar diffusion equation and electron energy equation are solved to find the electron density ne(z,t) and temperature Te(z,t), and the populations of the neutral argon 4s metastable, 4s resonant, and 4p excited state manifolds are calculated inmore » order to determine the stepwise ionization rate and calculate radiative energy losses. The model has been validated through comparisons with Langmuir probe ion saturation current measurements; close agreement between the simulated and measured axial plasma density profiles and the initial density rise rate at each location was obtained at pAr = 30-60 mTorr. Lastly, we present detailed results from calculations at 60 mTorr, including the time-dependent electron temperature, excited state populations, and energy budget within and downstream of the radiofrequency (RF) antenna.« less
Multi-fluid model of a sun-grazing comet in the rapidly ionizing, magnetized low corona
Jia, Y.-D.; Russell, C. T.; Liu, W.; Shou, Y. S.
2014-11-20
Two Sun-grazing comets were recently imaged in the low solar corona by space telescopes in unprecedented detail, revealing a wide range of new phenomena. This sparked growing interest in the interaction of comets with the coronal plasma and magnetic field and their diagnostic potential as solar probes. However, interpretation of such rich observational data requires profound understanding of relevant physical processes in an unexplored regime. Here advanced numerical modeling can provide critical clues. To this end, we present a prototype, multi-fluid, magnetohydrodynamic model of a steady-state comet in the low solar corona. These simulation results are compared with previously modeled comets in the solar wind environment. By inspecting their projection and column densities, we find a dominance of O{sup 6+} ions in the cometary tail, which can explain the observed extreme ultraviolet emission. The tail is found to be comparable to recent EUV images of these comets. In addition, the comet tail appears wider when the observer's line of sight is perpendicular rather than parallel to the local magnetic field. This is opposite to the trend in the interplanetary space permeated in the solar wind, because the ratio between dynamic pressure and magnetic pressure is an order of magnitude smaller than at 1 AU. On the other hand, we find that iron ions in the comet head build up to a density comparable to that of oxygen ions, but are unlikely to form a visible tail because of the shorter mean free paths of the neutrals.
A two-dimensional multispecies fluid model of the plasma in an ac plasma display panel
Campbell, R.B.; Veerasingam, R.; McGrath, R.T.
1995-08-01
A time dependent, two-dimensional mode for simulating the plasma evolution in an AC plasma display panel (AC-PDP) is described. Reaction-convection (mobility)-diffusion equations for charged particles and excited heavy neutral species are solved along with Poisson`s equation, a radiation transport equation, a surface charge buildup equation, and an external L-R-C circuit equation using a fully implicit numerical method. Electron-driven rate coefficients are computed with a 0-D Boltzmann solver in the local field approximation. For studying the particle dynamics in pure helium, they consider a reduced model in which radiation transport is ignored and the excited species manifold is collapsed to composite metastable and excited states. The model predictions of breakdown voltage are quite sensitive to the value of the secondary electron emission coefficient assumed and the uncertainties in the electron-driven reaction rates. An initial comparison between the model predictions and I-V measurements from a specially constructed helium-filled panel is made with qualitatively similar behavior. The lack of quantitative agreement can be explained by a combination of uncertainties in the model input data and uncertainty in the initial surface charge state in the experiments.
Phase-Contrast MRI and CFD Modeling of Apparent 3He Gas Flow in Rat Pulmonary Airways
Minard, Kevin R.; Kuprat, Andrew P.; Kabilan, Senthil; Jacob, Rick E.; Einstein, Daniel R.; Carson, James P.; Corley, Richard A.
2012-08-01
Phase-contrast (PC) magnetic resonance imaging (MRI) with hyperpolarized 3He is potentially useful for developing and testing patient-specific models of pulmonary airflow. One challenge, however, is that PC-MRI provides apparent values of local 3He velocity that not only depend on actual airflow but also on gas diffusion. This not only blurs laminar flow patterns in narrow airways but also introduces anomalous airflow structure that reflects gas-wall interactions. Here, both effects are predicted in a live rat using computational fluid dynamics (CFD), and for the first time, simulated patterns of apparent 3He gas velocity are compared with in-vivo PC-MRI. Results show (1) that correlations (R2) between measured and simulated airflow patterns increase from 0.23 to 0.79 simply by accounting for apparent 3He transport, and that (2) remaining differences are mainly due to uncertain airway segmentation and partial volume effects stemming from relatively coarse MRI resolution. Higher-fidelity testing of pulmonary airflow predictions should therefore be possible with future imaging improvements.