Powered by Deep Web Technologies
Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

A coupled model of fluid flow in jointed rock  

SciTech Connect

We present a fully coupled model of fluid flow in jointed rock, where the fluid flow depends on the joint openings and the joint openings depend on the fluid pressure. The joints and rock blocks are modeled discretely using the finite element method. Solutions for the fluid and rock are obtained and iteration is performed until both solutions converge. Example applications include an examination of the effects of back-pressure on flow in a geothermal reservoir and transient fluid injection into a reservoir.

Swenson, Daniel; Martineau, Rick; James, Mark; Brown, Don

1991-01-01T23:59:59.000Z

2

Parameter estimation from flowing fluid temperature logging data in unsaturated fractured rock using multiphase inverse modeling  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media, Soc.fluid and heat flows of multiphase, multicomponent fluid mixtures in porous and fractured media.

Mukhopadhyay, S.

2009-01-01T23:59:59.000Z

3

Fluid Flow Model Development for Representative Geologic Media | Department  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Fluid Flow Model Development for Representative Geologic Media Fluid Flow Model Development for Representative Geologic Media Fluid Flow Model Development for Representative Geologic Media 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 models. Discrete fracture network (DFNs) models are an approach to representing flow in fractured granite that explicitly represents the geometry and flow properties of individual fractures. New DFN generation and computational grid generation methods have been developed and tested. Mesh generation and the generation of flow streamlines within the DFN are also included. Traditional form of Darcy's law is not adequate

4

Can We Accurately Model Fluid Flow in Shale?  

NLE Websites -- All DOE Office Websites (Extended Search)

Can We Accurately Model Fluid Flow 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 trapped in shale, but many shale oil and gas producers still use models of underground fluid flow that date back to the heyday of easy-to-tap gas and liquid crude. 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 Monteiro, Chris Rycroft, and Grigory Isaakovich Barenblatt, with the Computational Research Division and the Advanced Light Source, recently modeled how pressure gradients in the boundary layer between kerogen inclusions and shale matrices affect productivity and can model reservoir longevity.

5

Can We Accurately Model Fluid Flow in Shale?  

NLE Websites -- All DOE Office Websites (Extended Search)

2013 00:00 Over 20 trillion cubic meters of natural gas are trapped in shale, but many shale oil and gas producers still use models of underground fluid flow that date back to...

6

Modeling of fluid and heat flow in fractured geothermal reservoirs  

DOE Green Energy (OSTI)

In most geothermal reservoirs large-scale permeability is dominated by fractures, while most of the heat and fluid reserves are stored in the rock matrix. Early-time fluid production comes mostly from the readily accessible fracture volume, while reservoir behavior at later time depends upon the ease with which fluid and heat can be transferred from the rock matrix to the fractures. Methods for modeling flow in fractured porous media must be able to deal with this matrix-fracture exchange, the so-called interporosity flow. This paper reviews recent work at Lawrence Berkeley Laboratory on numerical modeling of nonisothermal multiphase flow in fractured porous media. We also give a brief summary of simulation applications to problems in geothermal production and reinjection. 29 refs., 1 fig.

Pruess, K.

1988-08-01T23:59:59.000Z

7

Mathematical Modeling And Simulation For Fluid Flow In Porous Media  

E-Print Network (OSTI)

Mathematical models have been widely used to understand, predict, or optimize many complex physical processes. In particular, simulation of environmental effects of air polution is extensive. Here we address the need for using similar models to understand the fate and transport of groundwater contaminants and to design in situ remediation strategies. Three basic problem areas must be addressed in the modeling and simulation of the flow of groundwater contamination. One must first obtain an effective model to describe the complex fluid/fluid and fluid/rock interactions that control the transport of contaminants in groundwater. This includes the problems of determining and modeling the various multiphase or chemically reactive aspects of the problems which govern the flow of fluids, obtaining accurate reservoir descriptions at various length scales, and modeling the effects of this heterogeneity in the reservoir simulators. Next, one must develop accurate discretization techniques that retain the important physical properties of the continuous models without introducing spurious phenomena related to the discretization errors. Finally, one should develop efficient numerical solution algorithms that utilize the potential of the emerging computing architectures. We will discuss recent advances in each of these three areas.

Richard Ewing

2001-01-01T23:59:59.000Z

8

Particle-fluid two-phase flow modeling  

SciTech Connect

This paper describes a numerical scheme and computer program, DISCON, for the calculation of two-phase flows that does not require the use of flow regime maps. This model is intermediate between-thermal instantaneous and the averaged two-fluid model. It solves the Eulerian continuity, momentum, and energy equations for each liquid control volume, and the Lagrangian mass, momentum, energy, and position equations for each bubble. The bubbles are modeled individually using a large representative number of bubbles thus avoiding the numerical diffusion associated with Eulerian models. DISCON has been used to calculate the bubbling of air through a column of water and the subcooled boiling of water in a flow channel. The results of these calculations are presented.

Mortensen, G.A. [EG and G Idaho, Inc., Idaho Falls, ID (United States); Trapp, J.A. [Colorado Univ., Denver, CO (United States)]|[Idaho National Engineering Lab., Idaho Falls, ID (United States)

1992-09-01T23:59:59.000Z

9

Particle-fluid two-phase flow modeling  

Science Conference Proceedings (OSTI)

This paper describes a numerical scheme and computer program, DISCON, for the calculation of two-phase flows that does not require the use of flow regime maps. This model is intermediate between-thermal instantaneous and the averaged two-fluid model. It solves the Eulerian continuity, momentum, and energy equations for each liquid control volume, and the Lagrangian mass, momentum, energy, and position equations for each bubble. The bubbles are modeled individually using a large representative number of bubbles thus avoiding the numerical diffusion associated with Eulerian models. DISCON has been used to calculate the bubbling of air through a column of water and the subcooled boiling of water in a flow channel. The results of these calculations are presented.

Mortensen, G.A. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Trapp, J.A. (Colorado Univ., Denver, CO (United States) Idaho National Engineering Lab., Idaho Falls, ID (United States))

1992-01-01T23:59:59.000Z

10

Computational Fluid Dynamics Modeling of Atmospheric Flow Applied to Wind Energy Research.  

E-Print Network (OSTI)

??High resolution atmospheric flow modeling using computational fluid dynamics (CFD) has many applications in the wind energy industry. A well designed model can accurately calculate… (more)

Russell, Alan

2009-01-01T23:59:59.000Z

11

A Site-Scale Model For Fluid And Heat Flow In The Unsaturated...  

Open Energy Info (EERE)

repository. The modeling approach is based on a mathematical formulation of coupled multiphase, multicomponent fluid and heat flow through porous and fractured rock. Fracture...

12

Direct pore-level modeling of incompressible fluid flow in porous media  

Science Conference Proceedings (OSTI)

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. ... Keywords: Incompressible fluid flow, Micro-CT X-ray imaging, Moving particle semi-implicit, Particle-based methods, Porous media

Saeed Ovaysi; Mohammad Piri

2010-09-01T23:59:59.000Z

13

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

for Modeling Fluid and Heat Flow in Fractured Porous Media,with fluid and heat flow in fractured porous media arefluid and heat flow in porous media, heat pipe, reservoir simulation, fractured

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

14

CFD Modeling of Fluid Flow Behavior and Bath Surface Deformation ...  

Science Conference Proceedings (OSTI)

Direct Numerical Simulation of Inclusion Turbulent Deposition at Liquid ... Flow and Shrinkage Pipe Formation on Macrosegregation of Investment Cast -TiAl Alloys ... Numerical Modeling of the Interaction between a Foreign Particle an ...

15

A Model For The Transient Temperature Effects Of Horizontal Fluid Flow In  

Open Energy Info (EERE)

Transient Temperature Effects Of Horizontal Fluid Flow In Transient Temperature Effects Of Horizontal Fluid Flow In Geothermal Systems Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Model For The Transient Temperature Effects Of Horizontal Fluid Flow In Geothermal Systems Details Activities (1) Areas (1) Regions (0) Abstract: A characteristic temperature versus depth (T-D) profile is observed in various geothermal environments. Particular features of the T-D profile can be explained in terms of a simple time-dependent two-dimensional (x, z) hydrothermal model. In this model a hot fluid is constrained to flow along a thin aquifer buried at a depth l from the surface with conductive heat transfer into the rocks both above and below the aquifer. In many geothermal systems transient changes in the flow

16

A Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca  

Open Energy Info (EERE)

Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca Mountain, Nevada Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca Mountain, Nevada Details Activities (0) Areas (0) Regions (0) Abstract: A three-dimensional unsaturated-zone numerical model has been developed to simulate flow and distribution of moisture, gas and heat at Yucca Mountain, Nevada, a potential repository site for high-level radioactive waste. The model takes into account the simultaneous flow dynamics of liquid water, vapor, air and heat in the highly heterogeneous, fractured porous rock in the unsaturated zone (UZ). This model is intended for use in the prediction of the current and future conditions in the UZ so

17

Pore-scale modeling of immiscible and miscible fluid flows using smoothed particle hydrodynamics  

Science Conference Proceedings (OSTI)

A numerical model based on smoothed particle hydrodynamics (SPH) was developed and used to simulate immiscible and miscible fluid flows in porous media and to study effects of porous scale heterogeneity and anisotropy on such flows. Models for heterogeneous porous media were generated by using randomly located non-intersecting circular grains of different sizes, and pore scale anisotropy was introduced by randomly inserting non-overlapping particles on either side of the gap between two self-affine fractal curves to create a microfracture. . Different fluid wetting behaviors and surface tensions were modeled using pairwise particle-particle interactions. Particles with different masses and viscosities were used to model multiphase flow. In simulations of miscible fluid flow, particles with variable, composition dependent, masses and viscosities were used. Artificial surface tension effects were avoided by basing the SPH equations on the particle number density.

Tartakovsky, Alexandre M.; Meakin, Paul

2006-10-31T23:59:59.000Z

18

Using toughreact to model reactive fluid flow and geochemical transport in hydrothermal systems  

E-Print Network (OSTI)

multiphase flow, solute transport and reactive chemistry in porousmultiphase fluid flow, mass transport and chemical reactions, (2) reactive fluid flow and transport in fractured rocks as well as porous

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

2003-01-01T23:59:59.000Z

19

Density Currents in Shear Flows-A Two-Fluid Model  

Science Conference Proceedings (OSTI)

This paper develops a two-fluid steady-state model of a density current and its front propagating into a uniformly sheared environmental flow. This model is used to examine the kinematic and dynamic factors that control the depth and propagation ...

Qin Xu

1992-03-01T23:59:59.000Z

20

NETL: Releases & Briefs - MFIX: Particle-fluid flow modeling, fast and free  

NLE Websites -- All DOE Office Websites (Extended Search)

MFIX: Particle-fluid Flow Modeling, Fast and Free MFIX: Particle-fluid Flow Modeling, Fast and Free Until recently, full solution of the complex set of equations that describe gas-particle flows was nearly impossible. But an open-source code developed by researchers at the National Energy Technology Laboratory (NETL), and designed to run on inexpensive PC (Beowulf) clusters, makes it relatively simple. Called MFIX (Multi-phase Flow with Interphase eXchange), the code incorporates special numerical techniques that provide an efficient solution to the coupled equations, exceeding the capabilities of commercial software. Originally developed at NETL to model fixed, fluidized and bubbling coal gasification technologies, its power has been used in research ranging from catalytic cracking in oil refineries to volcanology. A free, fully-functional version is available at www.mfix.org

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Modelling two-phase flow in porous media at the pore scale using the volume-of-fluid method  

Science Conference Proceedings (OSTI)

We present a stable numerical scheme for modelling multiphase flow in porous media, where the characteristic size of the flow domain is of the order of microns to millimetres. The numerical method is developed for efficient modelling of multiphase flow ... Keywords: Pore-scale modelling, Porous media, Two-phase flow, Volume of fluid

Ali Q. Raeini; Martin J. Blunt; Branko Bijeljic

2012-07-01T23:59:59.000Z

22

Microwave fluid flow meter  

DOE Patents (OSTI)

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.

Billeter, Thomas R. (Richland, WA); Philipp, Lee D. (Richland, WA); Schemmel, Richard R. (Lynchburg, VA)

1976-01-01T23:59:59.000Z

23

Impact of relative permeability models on fluid flow behavior for gas condensate reservoirs  

E-Print Network (OSTI)

Accurate assessments of reserves and evaluation of productivity trends for gas condensate systems depend on a basic understanding of phase and fluid flow behavior. In gas condensate reservoirs, the gas flow depends on liquid drop out at pressures below the dewpoint pressure. The liquid initially accumulates as a continuous film along the porous media because of the low interfacial tension. Then, as the volume of condensate increases, the interfacial tension increases and capillary forces become more important. Modeling fluid flow in these systems must consider the dependence of relative permeability on both viscous and capillary forces. This research focuses on the evaluation of several recently proposed relative permeability models and on the quantification of their impact on reservoir fluid flow and well performance. We selected three relative permeability models to compare the results obtained in the modeling of relative permeabilities for a published North Sea gas condensate reservoir. The models employ weighting factors to account for the interpolation between miscible and immiscible flow behavior. The Pusch model evaluated using Fevang's weighting factor gave the best estimation of relative permeability when compared to the published data. Using a sector model, we evaluated the effects at the field scale of the selected gas condensate relative permeability models on well performance under different geological heterogeneity and permeability anisotropy scenarios. The Bette and Pusch models as well as the Danesh model, as implemented in a commercial reservoir simulator, were used to quantify the impact of the relative permeability models on fluid-flow and well performance. The results showed that, if the transition between miscible and immiscible behavior is not considered, the condensate saturation could be overestimated and the condensate production could be underestimated. After twenty years of production, the heterogeneous model using the selected relative permeability models predicted between 7.5 - 13% more condensate recovery than was estimated using an immiscible relative permeability model. Using the same relative permeability models, the anisotropic model forecast between 3 - 10% more condensate recovery than predicted using an immiscible relative permeability model. Results using the anisotropic model showed that vertical communication could affect the liquid distribution in the reservoir.

Zapata Arango, Jose? Francisco

2002-01-01T23:59:59.000Z

24

Visualizing multiphase flow and trapped fluid configurations in a model three-dimensional porous medium  

E-Print Network (OSTI)

We report an approach to fully visualize the flow of two immiscible fluids through a model three-dimensional (3D) porous medium at pore-scale resolution. Using confocal microscopy, we directly image the drainage of the medium by the non-wetting oil and subsequent imbibition by the wetting fluid. During imbibition, the wetting fluid pinches off threads of oil in the narrow crevices of the medium, forming disconnected oil ganglia. Some of these ganglia remain trapped within the medium. By resolving the full 3D structure of the trapped ganglia, we show that the typical ganglion size, and the total amount of residual oil, decreases as the capillary number Ca increases; this behavior reflects the competition between the viscous pressure in the wetting fluid and the capillary pressure required to force oil through the pores of the medium. This work thus shows how pore-scale fluid dynamics influence the trapped fluid configurations in multiphase flow through 3D porous media.

Amber T. Krummel; Sujit S. Datta; Stefan Münster; David A. Weitz

2013-01-21T23:59:59.000Z

25

Visualizing multiphase flow and trapped fluid configurations in a model three-dimensional porous medium  

E-Print Network (OSTI)

We report an approach to fully visualize the flow of two immiscible fluids through a model three-dimensional (3D) porous medium at pore-scale resolution. Using confocal microscopy, we directly image the drainage of the medium by the non-wetting oil and subsequent imbibition by the wetting fluid. During imbibition, the wetting fluid pinches off threads of oil in the narrow crevices of the medium, forming disconnected oil ganglia. Some of these ganglia remain trapped within the medium. By resolving the full 3D structure of the trapped ganglia, we show that the typical ganglion size, and the total amount of residual oil, decreases as the capillary number Ca increases; this behavior reflects the competition between the viscous pressure in the wetting fluid and the capillary pressure required to force oil through the pores of the medium. This work thus shows how pore-scale fluid dynamics influence the trapped fluid configurations in multiphase flow through 3D porous media.

Krummel, Amber T; Münster, Stefan; Weitz, David A; 10.1002/aic.14005

2013-01-01T23:59:59.000Z

26

Optimization of a Two-Fluid Hydrodynamic Model of Churn-Turbulent Flow  

DOE Green Energy (OSTI)

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.

Donna Post Guillen

2009-07-01T23:59:59.000Z

27

Modeling and Simulation of Pore Scale Multiphase Fluid Flow and Reactive Transport in Fractured and Porous Media  

Science Conference Proceedings (OSTI)

In the subsurface fluids play a critical role by transporting dissolved minerals, colloids and contaminants (sometimes over long distances), by mediating dissolution and precipitation processes and enabling chemical transformations in solution and at mineral surfaces. Although the complex geometries of fracture apertures, fracture networks and pore spaces may make it difficult to accurately predict fluid flow in saturated (single-phase) subsurface systems, well developed methods are available. The simulation of multiphase fluid flow in the subsurface is much more challenging because of the large density and/or viscosity ratios found in important applications (water/air in the vadose zone, water/oil, water/gas, gas/oil and water/oil/gas in oil reservoirs, water/air/non-aqueous phase liquids (NAPL) in contaminated vadose zone systems and gas/molten rock in volcanic systems, for example). In addition, the complex behavior of fluid-fluid-solid contact lines, and its impact on dynamic contact angles, must also be taken into account, and coupled with the fluid flow. Pore network models and simple statistical physics based models such as the invasion percolation and diffusion-limited aggregation models have been used quite extensively. However, these models for multiphase fluid flow are based on simplified models for pore space geometries and simplified physics. Other methods such a lattice Boltzmann and lattice gas models, molecular dynamics, Monte Carlo methods, and particle methods such as dissipative particle dynamics and smoothed particle hydrodynamics are based more firmly on first principles, and they do not require simplified pore and/or fracture geometries. However, they are less (in some cases very much less) computationally efficient that pore network and statistical physics models. Recently a combination of continuum computation fluid dynamics, fluid-fluid interface tracking or capturing and simple models for the dependence of contact angles on fluid velocity at the contact line has been used to simulate multiphase fluid flow in fracture apertures, fracture networks and pore spaces. Fundamental conservation principles - conservation of momentum, and conservation of mass (or conservation of volume for incompressible fluids) and conservation of energy, as well as symmetries (Galilean invariance and isotropy) are central to the physics of fluids and the models used to simulate them. In molecular and mesoscale models observance of these conservation principles and symmetries at the microscopic level leads to macroscopic fluid dynamics that can be represented by the Navier Stokes equation. The remarkable fact that the flow of all simpe fluids, irrespective of their chemical nature, can be described by the Navier-Stokes equation is a result of these conservation principles and symmetries acting on the molecular level.

Paul Meakin; Alexandre Tartakovsky

2009-07-01T23:59:59.000Z

28

Analysis Of Residence Time Distribution Of Fluid Flow By Axial Dispersion Model  

Science Conference Proceedings (OSTI)

Radioactive tracer {sup 82}Br in the form of KBr-82 with activity {+-} 1 mCi has been injected into steel pipeline to qualify the extent dispersion of water flowing inside it. Internal diameter of the pipe is 3 in. The water source was originated from water tank through which the water flow gravitically into the pipeline. Two collimated sodium iodide detectors were used in this experiment each of which was placed on the top of the pipeline at the distance of 8 and 11 m from injection point respectively. Residence time distribution (RTD) curves obtained from injection of tracer are elaborated numerically to find information of the fluid flow properties. The transit time of tracer calculated from the mean residence time (MRT) of each RTD curves is 14.9 s, therefore the flow velocity of the water is 0.2 m/s. The dispersion number, D/uL, for each RTD curve estimated by using axial dispersion model are 0.055 and 0.06 respectively. These calculations are performed after fitting the simulated axial dispersion model on the experiment curves. These results indicated that the extent of dispersion of water flowing in the pipeline is in the category of intermediate.

Sugiharto [Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132 (Indonesia); Centre for Applications of Isotopes and Radiation Technology-National Nuclear Energy Agency, Jl. Lebak Bulus Raya No. 49, Jakarta 12440 (Indonesia); Su'ud, Zaki; Kurniadi, Rizal; Waris, Abdul [Centre for Applications of Isotopes and Radiation Technology-National Nuclear Energy Agency, Jl. Lebak Bulus Raya No. 49, Jakarta 12440 (Indonesia); Abidin, Zainal [Department of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2010-12-23T23:59:59.000Z

29

Nanoscale Pore Imaging and Pore Scale Fluid Flow Modeling in Chalk  

E-Print Network (OSTI)

NTRODUCTION To model multiphase flow in porous media at porein porous media - pore-network models and multiphase flow”,porous microstructures. ” International Journal of Multiphase

Tomutsa, Liviu; Silin, Dmitriy

2004-01-01T23:59:59.000Z

30

Nanometer-scale imaging and pore-scale fluid flow modeling in chalk  

E-Print Network (OSTI)

pores. To model multiphase flow in porous media at porein porous media - pore-network models and multiphase flow”,porous microstructures. ” International Journal of Multiphase

Tomutsa, Liviu; Silin, Dmitriy; Radmilovich, Velimir

2005-01-01T23:59:59.000Z

31

Enhanced Geothermal Systems Research and Development: Models of Subsurface Chemical Processes Affecting Fluid Flow  

DOE Green Energy (OSTI)

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/or injected fluids is critical to predict important chemical behaviors affecting fluid flow, such as mineral precipitation/dissolution reactions. We successfully achieved the project goal and objectives by demonstrating the ability of our modeling technology to correctly predict the complex pH dependent solution chemistry of the Al3+ cation and its hydrolysis species: Al(OH)2+, Al(OH)2+, Al(OH)30, and Al(OH)4- as well as the solubility of common aluminum hydroxide and aluminosilicate minerals in aqueous brines containing components (Na, K, Cl) commonly dominating hydrothermal fluids. In the sodium chloride system, where experimental data for model parameterization are most plentiful, the model extends to 300°C. Determining the stability fields of aluminum species that control the solubility of aluminum-containing minerals as a function of temperature and composition has been a major objective of research in hydrothermal chemistry.

Moller, Nancy; Weare J. H.

2008-05-29T23:59:59.000Z

32

Models of low-speed flow for near-critical fluids with gravitational and capillary effects  

E-Print Network (OSTI)

We study low-speed flows of a highly compressible, single-phase fluid in the presence of gravity, for example in a regime appropriate for modeling recent space-shuttle experiments on fluids near the liquid-vapor critical point. In the equations of motion, we include forces due to capillary stresses that arise from a contribution made by strong density gradients to the free energy. We derive formally simplified sets of equations in a low-speed limit analogous to the zero Mach number limit in combustion theory. When viscosity is neglected and gravity is weak, the simplified system includes: a hyperbolic equation for velocity, a parabolic equation for temperature, an elliptic equation related to volume expansion, an integro-differential equation for mean pressure, and an algebraic equation (the equation of state). Solutions are determined by initial values for the mean pressure, the temperature field, and the divergence-free part of the velocity field. To model multidimensional flows with strong gravity, we offe...

Denny, D L; Denny, Diane L.; Pego, Robert L.

1998-01-01T23:59:59.000Z

33

Theoretical Studies of Non-Newtonian and Newtonian Fluid Flow through Porous Media  

E-Print Network (OSTI)

for Modeling Fluid and Heat Flow in Fractured Porous Media,"Newtonian fluid flow through porous or fractured media. The

Wu, Y.S.

1990-01-01T23:59:59.000Z

34

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

fluid flow and heat-transfer processes. The physicalcoupled fluid-flow and heat-transfer processes has proven toin which flow and heat transfer processes along drifts are

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

35

Acoustic concentration of particles in fluid flow  

DOE Patents (OSTI)

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.

Ward, Michael D. (Los Alamos, NM); Kaduchak, Gregory (Los Alamos, NM)

2010-11-23T23:59:59.000Z

36

Fluid flow monitoring device  

DOE Patents (OSTI)

This invention consists of 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.

McKay, M.D.; Sweeney, C.E.

1991-03-05T23:59:59.000Z

37

Update and assessment of geothermal economic models, geothermal fluid flow and heat distribution models, and geothermal data bases  

SciTech Connect

Numerical simulation models and data bases that were developed for DOE as part of a number of geothermal programs have been assessed with respect to their overall stage of development and usefulness. This report combines three separate studies that focus attention upon: (1) economic models related to geothermal energy; (2) physical geothermal system models pertaining to thermal energy and the fluid medium; and (3) geothermal energy data bases. Computerized numerical models pertaining to the economics of extracting and utilizing geothermal energy have been summarized and catalogued with respect to their availability, utility and function. The 19 models that are discussed in detail were developed for use by geothermal operators, public utilities, and lending institutions who require a means to estimate the value of a given resource, total project costs, and the sensitivity of these values to specific variables. A number of the models are capable of economically assessing engineering aspects of geothermal projects. Computerized simulations of heat distribution and fluid flow have been assessed and are presented for ten models. Five of the models are identified as wellbore simulators and five are described as reservoir simulators. Each model is described in terms of its operational characteristics, input, output, and other pertinent attributes. Geothermal energy data bases are reviewed with respect to their current usefulness and availability. Summaries of eight data bases are provided in catalogue format, and an overall comparison of the elements of each data base is included.

Kenkeremath, D. (ed.)

1985-05-01T23:59:59.000Z

38

Fluid Metrology Calibration Services - Water Flow  

Science Conference Proceedings (OSTI)

Fluid Metrology Calibration Services - Water Flow. Water Flow Calibrations 18020C. ... NIST provides calibration services for water flow meters. ...

2011-10-03T23:59:59.000Z

39

Proximity functions for modeling fluids and heat flow in reservoirs with stochastic fracture distributions  

DOE Green Energy (OSTI)

Conventional approaches to geothermal reservoir modeling have employed a porous medium approximation, but recently methods have been developed which can take into account the different thermodynamic conditions in rock matrix and fractures. The multiple interacting continua method (MINC) treats the thermal and hydraulic interaction between rock matrix and fractures in terms of a set of geometrical parameters. However, this approach was restricted to idealized fracture distributions with regularly shaped matrix blocks. Fractures in geothermal reservoirs usually occur in nearly parallel sets with a certain scatter in orientation, and a stochastic distribution of spacings and apertures. The MINC-method was extended to realistic fracture systems with stochastic distributions. The interaction between matrix and fractures is parameterized in terms of a proximity function, which represents the volume of matrix rock as a function of distance from the fractures. Monte Carlo techniques were employed to compute proximity functions for a number of two-dimensional systems with regular or stochastic fracture distributions. It is shown how the proximity functions can be used to generate computational grids for modeling fluid and heat flow in fractured reservoirs.

Pruess, K.; Karasaki, K.

1982-10-01T23:59:59.000Z

40

Modeling Fluid Flow and Electrical Resistivity in Fractured Geothermal Reservoir Rocks  

DOE Green Energy (OSTI)

Phase change of pore fluid (boiling/condensing) in rock cores under conditions representative of geothermal reservoirs results in alterations of the electrical resistivity of the samples. In fractured samples, phase change can result in resistivity changes that are more than an order of magnitude greater than those measured in intact samples. These results suggest that electrical resistivity monitoring may provide a useful tool for monitoring the movement of water and steam within fractured geothermal reservoirs. We measured the electrical resistivity of cores of welded tuff containing fractures of various geometries to investigate the resistivity contrast caused by active boiling and to determine the effects of variable fracture dimensions and surface area on water extraction. We then used the Nonisothermal Unsaturated Flow and Transport model (NUFT) (Nitao, 1998) to simulate the propagation of boiling fronts through the samples. The simulated saturation profiles combined with previously reported measurements of resistivity-saturation curves allow us to estimate the evolution of the sample resistivity as the boiling front propagates into the rock matrix. These simulations provide qualitative agreement with experimental measurements suggesting that our modeling approach may be used to estimate resistivity changes induced by boiling in more complex systems.

Detwiler, R L; Roberts, J J; Ralph, W; Bonner, B P

2003-01-14T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Fluid flow modeling of resin transfer molding for composite material wind turbine blade structures.  

SciTech Connect

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.

Cairns, Douglas S. (Montana State University, Bozeman, MT); Rossel, Scott M. (Montana State University, Bozeman, MT)

2004-06-01T23:59:59.000Z

42

Fluid Flow Within Fractured Porous Media  

Science Conference Proceedings (OSTI)

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.

Crandall, D.M.; Ahmadi, G. (Clarkson Univ., Potsdam, NY); Smith, D.H.; Bromhal, G.S.

2006-10-01T23:59:59.000Z

43

Visualization of Fluid Flow  

Science Conference Proceedings (OSTI)

... Goujon and J. Devaney, Large Scale Simulations of Single and Multi- Component Flow in Porous Media in Proceedings of SPIE: The International ...

2010-12-15T23:59:59.000Z

44

Computational fluid dynamics modeling of two-phase flow in a BWR fuel assembly. Final CRADA Report.  

Science Conference Proceedings (OSTI)

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.

Tentner, A.; Nuclear Engineering Division

2009-10-13T23:59:59.000Z

45

Practical method for modeling fluid and heat flow in fractured porous media  

DOE Green Energy (OSTI)

A Multiple Interacting Continua method (MINC) is presented which is applicable for numerical simulation of heat and multi-phase fluid flow in multidimensional, fractured porous media. This method is a generalization of the double-porosity concept. The partitioning of the flow domain into computational volume elements is based on the criterion of approximate thermodynamic equilibrium at all times within each element. The thermodynamic conditions in the rock matrix are assumed to be primarily controlled by the distance from the fractures, which leads to the use of nested grid blocks. The MINC concept is implemented through the Integral Finite Difference (IFD) method. No analytical approximations are made for the coupling between the fracture and matrix continua. Instead, the transient flow of fluid and heat between matrix and fractures is treated by a numerical method. The geometric parameters needed in a simulation are preprocessed from a specification of fracture spacings and apertures, and the geometry of the matrix blocks. The MINC method is verified by comparison with the analytical solution of Warren and Root. Illustrative applications are given for several geothermal reservoir engineering problems.

Pruess, K.; Narasimhan, T.N.

1982-02-01T23:59:59.000Z

46

This is a 1D model of an active magnetic regenerative refrigerator (AMRR) that was developed in MATLAB. The model uses cycle inputs such as the fluid mass flow and  

E-Print Network (OSTI)

temperature profile of the fluid and regenerator. Using the temperature profiles, the cooling load produced in MATLAB. The model uses cycle inputs such as the fluid mass flow and magnetic field profiles, fluid external hardware. The model starts from an initial temperature profile for the regenerator and fluid

Wisconsin at Madison, University of

47

Modeling fluid flow through single fracture using experimental, stochastic, and simulation approaches  

E-Print Network (OSTI)

This research presents an approach to accurately simulate flow experiments through a fractured core using experimental, stochastic, and simulation techniques. Very often, a fracture is assumed as a set of smooth parallel plates separated by a constant width. However, the flow characteristics of an actual fracture surface are quite different, affected by tortuosity and the impact of surface roughness. Though several researchers have discussed the effect of friction on flow reduction, their efforts lack corroboration from experimental data and have not converged to form a unified methodology for studying flow on a rough fracture surface. In this study, an integrated methodology involving experimental, stochastic, and numerical simulations that incorporate the fracture roughness and the friction factor is shown to describe flow through single fractures more efficiently. Laboratory experiments were performed to support the study in quantifying the flow contributions from the matrix and the fracture. The results were used to modify the cubic law through reservoir simulations. Observations suggest that the fracture apertures need to be distributed to accurately model the experimental results. The methodology successfully modeled fractured core experiments, which were earlier not possible using the parallel plate approach. A gravity drainage experiment using an X-ray CT scan of a fractured core has also validated the methodology.

Alfred, Dicman

2003-12-01T23:59:59.000Z

48

ADVANCED TECHNOLOGY FOR PREDICTING THE FLUID FLOW ATTRIBUTES OF NATURALLY FRACTURED RESERVOIRS FROM QUANTITATIVE GEOLOGIC DATA AND MODELING  

Science Conference Proceedings (OSTI)

This report summarizes the work carried out during the period of September 29, 2000 to January 15, 2004 under DOE Research Contract No. DE-FC26-00BC15308. High temperatures and reactive fluids in sedimentary basins dictate that interplay and feedback between mechanical and geochemical processes significantly influence evolving rock and fracture properties. Not only does diagenetic mineralization fill in once open fractures either partially or completely, it modifies the rock mechanics properties that can control the mechanical aperture of natural fractures. In this study, we have evolved an integrated methodology of fractured reservoir characterization and we have demonstrated how it can be incorporated into fluid flow simulation. The research encompassed a wide range of work from geological characterization methods to rock mechanics analysis to reservoir simulation. With regard to the characterization of mineral infilling of natural fractures, the strong interplay between diagenetic and mechanical processes is documented and shown to be of vital importance to the behavior of many types of fractured reservoirs. Although most recent literature emphasizes Earth stress orientation, cementation in fractures is likely a critically important control on porosity, fluid flow attributes, and even sensitivity to effective stress changes. The diagenetic processes of dissolution and partial cementation are key controls on the creation and distribution of open natural fractures within hydrocarbon reservoirs. The continuity of fracture-porosity is fundamental to how fractures conduct fluids. In this study, we have made a number of important discoveries regarding fundamental properties of fractures, in particular related to the prevalence of kinematically significant structures (crack-seal texture) within otherwise porous, opening-mode fractures, and the presence of an aperture size threshold below which fractures are completely filled and above which porosity is preserved. These observations can be linked to models of quartz cementation. Significant progress has been made as well in theoretical fracture mechanics and geomechanical modeling, allowing prediction of spatial distributions of fractures that mimic patterns observed in nature. Geomechanical modeling shows the spatial arrangement of opening mode fractures (joints and veins) is controlled by the subcritical fracture index of the material. In particular, we have been able to identify mechanisms that control the clustering of fractures in slightly deformed rocks. Fracture mechanics testing of a wide range of clastic rocks shows that the subcritical index is sensitive to diagenetic factors. We show geomechanical simulations of fracture aperture development can be linked to diagenetic models, modifying fracture porosity as fractures grow, and affect the dynamics of fracture propagation. Fluid flow simulation of representative fracture pattern realizations shows how integrated modeling can give new insight into permeability assessment in the subsurface. Using realistic, geomechanically generated fracture patterns, we propose a methodology for permeability estimation in nonpercolating networks.

Jon E. Olson; Larry W. Lake; Steve E. Laubach

2004-11-01T23:59:59.000Z

49

Numerical Modeling of Coupled Variably-Saturated Fluid Flow and Reactive Transport with Fast and Slow Chemical Reactions  

SciTech Connect

The couplings among chemical reaction rates, advective and diffusive transport in fractured media or soils, and changes in hydraulic properties due to precipitation and dissolution within fractures and in rock matrix are important for both nuclear waste disposal and remediation of contaminated sites. This paper describes the development and application of LEHGC2.0, a mechanistically-based numerical model for simulation of coupled fluid flow and reactive chemical transport including both fast and slow reactions invariably saturated media. Theoretical bases and numerical implementations are summarized, and two example problems are demonstrated. The first example deals with the effect of precipitation-dissolution on fluid flow and matrix diffusion in a two-dimensional fractured media. Because of the precipitation and decreased diffusion of solute from the fracture into the matrix, retardation in the fractured medium is not as large as the case wherein interactions between chemical reactions and transport are not considered. The second example focuses on a complicated but realistic advective-dispersive-reactive transport problem. This example exemplifies the need for innovative numerical algorithms to solve problems involving stiff geochemical reactions.

LI, MING-HSU; SIEGEL, MALCOLM D.; YEH, GOUR-TSYH (GEORGE)

1999-09-20T23:59:59.000Z

50

Flow control techniques for real-time media applications in best-effort networks using fluid models  

E-Print Network (OSTI)

Quality of Service (QoS) in real-time media applications is an area of current interest because of the increasing demand for audio/video, and generally multimedia applications, over best effort networks, such as the Internet. Media applications are transported using the User Datagram Protocol (UDP) and tend to use a disproportionate amount of network bandwidth as they do not perform congestion or flow control. Methods for application QoS control are desirable to enable users to perceive a consistent media quality. This can be accomplished by either modifying current protocols at the transport layer or by implementing new control algorithms at the application layer irrespective of the protocol used at the transport layer. The objective of this research is to improve the QoS delivered to end-users in real-time applications transported over best-effort packet-switched networks. This is accomplished using UDP at the transport layer, along with adaptive predictive and reactive control at the application layer. An end-to-end fluid model is used, including the source buffer, the network and the destination buffer. Traditional control techniques, along with more advanced adaptive predictive control methods, are considered in order to provide the desirable QoS and make a best-effort network an attractive channel for interactive multimedia applications. The effectiveness of the control methods, is examined using a Simulink-based fluid-level simulator in combination with trace files extracted from the well-known network simulator ns-2. The results show that improvement in real-time applications transported over best-effort networks using unreliable transport protocols, such as UDP, is feasible. The improvement in QoS is reflected in the reduction of flow loss at the expense of flow dead-time increase or playback disruptions or both.

Konstantinou, Apostolos

2004-08-01T23:59:59.000Z

51

Using toughreact to model reactive fluid flow and geochemical transport in hydrothermal systems  

DOE Green Energy (OSTI)

The interaction between hydrothermal fluids and the rocks through which they migrate alters the earlier formed primary minerals and leads to the formation of secondary minerals, resulting in changes in the physical and chemical properties of the system. We have developed a comprehensive numerical simulator, TOUGHREACT, which considers nonisothermal multi-component chemical transport in both liquid and gas phases. A variety of subsurface thermo-physical-chemical processes is considered under a wide range of conditions of pressure, temperature, water saturation, and ionic strength. The code can be applied to problems in fundamental analysis of the hydrothermal systems and in the exploration of geothermal reservoirs including chemical evolution, mineral alteration, mineral scaling, changes of porosity and permeability, and mineral recovery from geothermal fluids.

Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

2003-07-31T23:59:59.000Z

52

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

grain-specific heat for each model grid layer, are providedand heat flow is simulated using the 3-D TH model grid (

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

53

Groundwater modeling: Application of a multiphase fluid flow model as a decision-making tool for assessing and remediating installation restoration program sites. Master's thesis  

Science Conference Proceedings (OSTI)

This research examined a two-dimensional numerical model, VALOR, which can simulate multiphase fluid flow in soils and groundwater, and evaluated the applicability of the model as a decision-making tool for assessing and remediating IRP sites. Model sensitivity analyses were conducted to study the influence of grid sizes, soil types, and organic release rates on the simulated migration of both light and dense non-aqueous phase liquids (NAPLs). The VALOR model was applied to a case study of a JP-4 release at Wright-Patterson AFB, Ohio. The finer grid sizes provide the most accurate definition of NAPL distribution. The soil type and release rate sensitivity analyses demonstrate that NAPL migrates quicker through coarse sands than fine sand and clay. The light NAPL ponds at the water table and spreads laterally. The dense NAPL migrates through the subsurface and ponds at the aquifer bottom. The fast organic release simulations predict wider vertical pathways of migration. The slow organic release simulations predict higher light NAPL saturation at the water table. The case study indicates that within limits, VALOR may be useful for assessing NAPL distribution, estimating contaminated soil volumes, and evaluating remediation alternatives.... Groundwater modeling, Non-aqueous Phase Liquids: NAPL, Multiphase fluid flow model, Installation Restoration Program, IRP.

Scott, D.J.

1993-09-01T23:59:59.000Z

54

ADVANCED TECHNOLOGY FOR PREDICTING THE FLUID FLOW ATTRIBUTES OF NATURALLY FRACTURED RESERVOIRS FROM QUANTITATIVE GEOLOGIC DATA AND MODELING  

Science Conference Proceedings (OSTI)

This report summarizes the work carried out during the period of September 29, 2000 to September 28, 2001 under DOE Research Contract No. DE-FC26-00BC15308. Our goal is to establish an integrated methodology of fractured reservoir characterization and show how that can be incorporated into fluid flow simulation. We have made progress in the characterization of mineral infilling of natural fractures. The main advancement in this regard was to recognize the strong interplay between diagenetic and mechanical processes. We accomplished several firsts in documenting and quantifying these processes, including documenting the range of emergent threshold in several formations and quantifying the internal structures of crack-seal bridges in fractures. These results will be the basis for an appreciation of fracture opening and filling rates that go well beyond our original goals. Looking at geochemical modeling of fracture infilling, our theoretical analysis addressed the problem of calcite precipitation in a fracture. We have built a model for the deposition of calcite within a fracture. The diagenetic processes of dissolution and partial cementation are key controls on the creation and distribution of natural fractures within hydrocarbon reservoirs. Even with extensive data collection, fracture permeability still creates uncertainty in reservoir description and the prediction of well performance. Data on the timing and stages of diagenetic events can provide explanation as to why, when and where natural fractures will be open and permeable. We have been pursuing the fracture mechanics testing of a wide range of rocks, particularly sandstone using a key rock property test that has hitherto not been widely applied to sedimentary rocks. A major accomplishment in this first year has been to identify sample suites available in the core repository at the University of Texas that represent a wide range of diagenetic alteration and to begin to test these samples. The basis for the fluid flow simulations to be carried out in this part of the project is the adequate spatial characterization of fracture networks. Our initial focus has been on the tendency of fracture sets to cluster into highly fracture zones that are often widely separated. Our preliminary modeling work shows the extent of this clustering to be controlled by the subcritical fracture index of the material. With continued progress, we move toward an integrated fracture characterization methodology that will ultimately be applied through detailed reservoir simulation.

Jon E. Olson; Larry W. Lake; Steve E. Laubach

2003-04-01T23:59:59.000Z

55

Preferential mode of gas invasion in sediments : grain-scale model of coupled multiphase fluid flow and sediment mechanics  

E-Print Network (OSTI)

We present a discrete element model for simulating, at the grain scale, gas migration in brine-saturated deformable media. We rigorously account for the presence of two fluids in the pore space by incorporating forces on ...

Jain, Antone Kumar

2009-01-01T23:59:59.000Z

56

Detailed Simulations of Atmospheric Flow and Dispersion in Downtown Manhattan: An Application of Five Computational Fluid Dynamics Models  

Science Conference Proceedings (OSTI)

Computational fluid dynamics (CFD) model simulations of urban boundary layers have improved in speed and accuracy so that they are useful in assisting in planning emergency response activities related to releases of chemical or biological agents ...

Steven R. Hanna; Michael J. Brown; Fernando E. Camelli; Stevens T. Chan; William J. Coirier; Sura Kim; Olav R. Hansen; Alan H. Huber; R. Michael Reynolds

2006-12-01T23:59:59.000Z

57

Practical Use of Fluid Flow and Solidification Modeling in the Shape ...  

Science Conference Proceedings (OSTI)

Solidification modeling is a very potent tool for the prediction of internal shrinkage ... Frequency Modulation Effect on the Solidification of Alloy 718 Fusion Zone.

58

A high order kinetic flux-vector splitting method for the reduced five-equation model of compressible two-fluid flows  

Science Conference Proceedings (OSTI)

We present a high order kinetic flux-vector splitting (KFVS) scheme for the numerical solution of a conservative interface-capturing five-equation model of compressible two-fluid flows. This model was initially introduced by Wackers and Koren (2004) ... Keywords: 35L45, 35L65, 35L67, 65M99, 65Y99, 76T99, Central schemes, Conservation laws, Five-equation model, Hyperbolic systems, Kinetic flux-vector splitting schemes, Shock solutions

Shamsul Qamar; Munshoor Ahmed

2009-12-01T23:59:59.000Z

59

Valve for controlling flow of cryogenic fluid  

DOE Patents (OSTI)

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.

Knapp, P.A.

1995-12-31T23:59:59.000Z

60

Overview of heat transfer and fluid flow problem areas encountered in stirling engine modeling  

SciTech Connect

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.

Tew, R.C. Jr.

1988-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Improved Fluid Flow Measurements: Feedwater Flow  

Science Conference Proceedings (OSTI)

This report describes the combined results of a utility survey and site visits concerning feedwater flow measurement in fossil-fueled power plants. In addition, a summary is provided of the technologies available to measure the volumetric feedwater flow rate in plants. This volumetric flow rate can be converted to a mass flow rate by knowing the pressure and temperature of the flow media. Velocity meters, differential pressure meters, and other closed-conduit flowmeters are discussed along with ...

2012-11-28T23:59:59.000Z

62

Standardization of Thermo-Fluid Modeling in Modelica.Fluid  

E-Print Network (OSTI)

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.

Rüdiger Franke; et al.

2009-01-01T23:59:59.000Z

63

Computational Fluid Dynamics Modeling of The Dalles Project: Effects of Spill Flow Distribution Between the Washington Shore and the Tailrace Spillwall  

DOE Green Energy (OSTI)

The U.S. Army Corps of Engineers-Portland District (CENWP) has ongoing work to improve the survival of juvenile salmonids (smolt) migrating past The Dalles Dam. As part of that effort, a spillwall was constructed to improve juvenile egress through the tailrace downstream of the stilling basin. The spillwall was designed to improve smolt survival by decreasing smolt retention time in the spillway tailrace and the exposure to predators on the spillway shelf. The spillwall guides spillway flows, and hence smolt, more quickly into the thalweg. In this study, an existing computational fluid dynamics (CFD) model was modified and used to characterize tailrace hydraulics between the new spillwall and the Washington shore for six different total river flows. The effect of spillway flow distribution was simulated for three spill patterns at the lowest total river flow. The commercial CFD solver, STAR-CD version 4.1, was used to solve the unsteady Reynolds-averaged Navier-Stokes equations together with the k-epsilon turbulence model. Free surface motion was simulated using the volume-of-fluid (VOF) technique. The model results were used in two ways. First, results graphics were provided to CENWP and regional fisheries agency representatives for use and comparison to the same flow conditions at a reduced-scale physical model. The CFD results were very similar in flow pattern to that produced by the reduced-scale physical model but these graphics provided a quantitative view of velocity distribution. During the physical model work, an additional spill pattern was tested. Subsequently, that spill pattern was also simulated in the numerical model. The CFD streamlines showed that the hydraulic conditions were likely to be beneficial to fish egress at the higher total river flows (120 kcfs and greater, uniform flow distribution). At the lowest flow case, 90 kcfs, it was necessary to use a non-uniform distribution. Of the three distributions tested, splitting the flow evenly between Bay 7 and Bay 8 had hydraulics deemed most beneficial for egress by CENWP fisheries biologists and regional fishery agency representatives. The numerical and physical model results were very similar, building confidence in both hydraulic tools.

Rakowski, Cynthia L.; Serkowski, John A.; Richmond, Marshall C.

2010-12-01T23:59:59.000Z

64

Directed flow fluid rinse trough  

SciTech Connect

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.

Kempka, Steven N. (9504 Lona La., Albuquerque, NM 87111); Walters, Robert N. (11872 LaGrange St., Boise, ID 83709)

1996-01-01T23:59:59.000Z

65

Ultrasonic fluid flow measurement method and apparatus  

DOE Patents (OSTI)

This invention is comprised of 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.

Kronberg, J.W.

1992-12-31T23:59:59.000Z

66

Fluid flow analysis in a rough fracture (type II) using complex networks and lattice Boltzmann method  

E-Print Network (OSTI)

Complexity of fluid flow in a rough fracture is induced by the complex configurations of opening areas between the fracture planes. In this study, we model fluid flow in an evolvable real rock joint structure, which under certain normal load is sheared. In an experimental study, information regarding about apertures of the rock joint during consecutive 20 mm displacements and fluid flow (permeability) in different pressure heads have been recorded by a scanner laser. Our aim in this study is to simulate the fluid flow in the mentioned complex geometries using the lattice Boltzmann method (LBM), while the characteristics of the aperture field will be compared with the modeled fluid flow permeability To characterize the aperture, we use a new concept in the graph theory, namely: complex networks and motif analysis of the corresponding networks. In this approach, the similar aperture profile along the fluid flow direction is mapped in to a network space. The modeled permeability using the LBM shows good correlat...

Ghaffari, H; Sharifzadeh, M; Young, R P

2011-01-01T23:59:59.000Z

67

Fluid Flow in Fractured Rock: Theory and Application  

E-Print Network (OSTI)

Porous Media, Pullman, WA, July 9-18,1989, and to be published in the Proceedings Fluid Flow in Fractured

Long, J.C.S.

2012-01-01T23:59:59.000Z

68

Heuristic optimality criterion algorithm for shape design of fluid flow  

Science Conference Proceedings (OSTI)

This paper presents a heuristic optimality criterion algorithm for shape design of fluid flow. In this algorithm, the lattice Boltzmann method (LBM) is utilized to calculate the flow field of a fluid domain which is divided into elemental cells. A heuristic ... Keywords: Fluid flow, Heuristic optimality criterion, Lattice Boltzmann method, Pressure drop, Shape design

Limin Wang; Yilin Fan; Lingai Luo

2010-10-01T23:59:59.000Z

69

Thermal-fluid and electrochemical modeling and performance study of a planar solid oxide electrolysis cell : analysis on SOEC resistances, size, and inlet flow conditions.  

DOE Green Energy (OSTI)

Argonne National Laboratory and Idaho National Laboratory researchers are analyzing the electrochemical and thermal-fluid behavior of solid oxide electrolysis cells (SOECs) for high temperature steam electrolysis using computational fluid dynamics (CFD) techniques. The major challenges facing commercialization of steam electrolysis technology are related to efficiency, cost, and durability of the SOECs. The goal of this effort is to guide the design and optimization of performance for high temperature electrolysis (HTE) systems. An SOEC module developed by FLUENT Inc. as part of their general CFD code was used for the SOEC analysis by INL. ANL has developed an independent SOEC model that combines the governing electrochemical mechanisms based on first principals to the heat transfer and fluid dynamics in the operation of SOECs. The ANL model was embedded into the commercial STAR-CD CFD software, and is being used for the analysis of SOECs by ANL. The FY06 analysis performed by ANL and reported here covered the influence of electrochemical properties, SOEC component resistances and their contributing factors, SOEC size and inlet flow conditions, and SOEC flow configurations on the efficiency and expected durability of these systems. Some of the important findings from the ANL analysis are: (1) Increasing the inlet mass flux while going to larger cells can be a compromise to overcome increasing thermal and current density gradients while increasing the cell size. This approach could be beneficial for the economics of the SOECs; (2) The presence of excess hydrogen at the SOEC inlet to avoid Ni degradation can result in a sizeable decrease in the process efficiency; (3) A parallel-flow geometry for SOEC operation (if such a thing be achieved without sealing problems) yields smaller temperature gradients and current density gradients across the cell, which is favorable for the durability of the cells; (4) Contact resistances can significantly influence the total cell resistance and cell temperatures over a large range of operating potentials. Thus it is important to identify and avoid SOEC stack conditions leading to such high resistances due to poor contacts.

Yildiz, B.; Smith, J.; Sofu, T.; Nuclear Engineering Division

2008-06-25T23:59:59.000Z

70

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

heat flow in porous media, heat pipe, reservoir simulation,and vapor often leads to “heat-pipe” conditions, the steadytwo-phase zone, is the heat-pipe (i.e. , a zone of constant

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

71

Markov Random Field Models for High-Dimensional Parameters in Simulations of Fluid Flow in Porous Media  

E-Print Network (OSTI)

is injected along with the water at the input wells and its concentration is recorded over time at the uptake on the solution to the forward problem, i.e. determining the flow of water when the physical characteristics. It is this inverse problem that we address in this paper. A review of the inverse problem can be found in Yeh (1986

West, Mike

72

Markov Random Field Models for HighDimensional Parameters in Simulations of Fluid Flow in Porous Media  

E-Print Network (OSTI)

is injected along with the water at the input wells and its concentration is recorded over time at the uptake on the solution to the forward problem, i.e. determining the flow of water when the physical characteristics. It is this inverse problem that we address in this paper. A review of the inverse problem can be found in Yeh (1986

West, Mike

73

Handbook of thermodynamics, heat transfer and fluid flow  

E-Print Network (OSTI)

9 Nov 2010 ... Handbook of thermodynamics, heat transfer and fluid flow | JUNE 1992 | 3 Volume | U.S. Department of Energy FSC-6910 Washington, D.C. ...

74

Stress and Fluid-Flow Interaction for the Coso Geothermal Field Derived  

Open Energy Info (EERE)

Stress and Fluid-Flow Interaction for the Coso Geothermal Field Derived Stress and Fluid-Flow Interaction for the Coso Geothermal Field Derived from 3D Numerical Models Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Stress and Fluid-Flow Interaction for the Coso Geothermal Field Derived from 3D Numerical Models Details Activities (1) Areas (1) Regions (0) Abstract: The efficiency of geothermal energy production at the Coso Geothermal Field in eastern California is reliant on the knowledge of fluid flow directions associated with fracture networks. We use finite element analysis to establish the 3D state of stress within the tectonic setting of the Coso Range. The mean and differential stress distributions are used to infer fluid flow vectors and second order fracture likelihood and orientation. The results show that the Coso Range and adjacent areas are

75

Standardization of Thermo-Fluid Modeling in Modelica.Fluid  

E-Print Network (OSTI)

tion driven heat transfer for distributed pipe flows: Thepipe wall, is described by a lumped approach based on a heatpipe flow model still needs to add the source terms Qb_flow and Wb_flow for heat and

Franke, Rudiger

2010-01-01T23:59:59.000Z

76

HYDROGEN ELECTROLYZER FLOW DISTRIBUTOR MODEL  

DOE Green Energy (OSTI)

The hybrid sulfur process (HyS) hydrogen electrolyzer consists of a proton exchange membrane (PEM) sandwiched between two porous graphite layers. An aqueous solution of sulfuric acid with dissolved SO{sub 2} gas flows parallel to the PEM through the porous graphite layer on the anode side of the electrolyzer. A flow distributor, consisting of a number of parallel channels acting as headers, promotes uniform flow of the anolyte fluid through the porous graphite layer. A numerical model of the hydraulic behavior of the flow distributor is herein described. This model was developed to be a tool to aid the design of flow distributors. The primary design objective is to minimize spatial variations in the flow through the porous graphite layer. The hydraulic data from electrolyzer tests consists of overall flowrate and pressure drop. Internal pressure and flow distributions are not measured, but these details are provided by the model. The model has been benchmarked against data from tests of the current electrolyzer. The model reasonably predicts the viscosity effect of changing the fluid from water to an aqueous solution of 30 % sulfuric acid. The permeability of the graphite layer was the independent variable used to fit the model to the test data, and the required permeability for a good fit is within the range literature values for carbon paper. The model predicts that reducing the number of parallel channels by 50 % will substantially improve the uniformity of the flow in the porous graphite layer, while maintaining an acceptable pressure drop across the electrolyzer. When the size of the electrolyzer is doubled from 2.75 inches square to 5.5 inches square, the same number of channels as in the current design will be adequate, but it is advisable to increase the channel cross-sectional flow area. This is due to the increased length of the channels.

Shadday, M

2006-09-28T23:59:59.000Z

77

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

Studies Using the Yucca Mountain Unsaturated Zone Model,Unsaturated Zone at Yucca Mountain, Nevada, to Thermal LoadUnsaturated Zone, Yucca Mountain, Nevada, Water-Resources

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

78

Nonlinear dynamics of three dimensional fluid flow separation  

E-Print Network (OSTI)

Flow separation (the detachment of fluid from a no-slip boundary) is a major cause of performance loss in engineering devices, including diffusers, airfoils and jet engines. The systematic study of flow separation dates ...

Surana, Amit

2007-01-01T23:59:59.000Z

79

Dissipative Particle Dynamics Simulation of Pore-Scale Multiphase Fluid Flow  

Science Conference Proceedings (OSTI)

Multiphase fluid flow through porous media involves complex fluid dynamics, and it is difficult to model such complex behavior, on the pore scale, using grid-based continuum models. In this paper, the application of dissipative particle dynamics (DPD), a relatively new mesoscale method, to the simulation of pore-scale multiphase fluid flows under a variety of flow conditions is described. We demonstrate that the conventional DPD method using purely repulsive conservative (nondissipative) particle-particle interactions is capable of modeling single-phase flow fields in saturated porous media. In order to simulate unsaturated multiphase flow through porous media, we applied a modified model for the conservative particle-particle interactions that combines short-range repulsive and long-range attractive interactions. This form for the conservative particle-particle interactions allows the behavior of multiphase systems consisting of gases, liquids, and solids to be simulated. We also demonstrated that the flow of both wetting and nonwetting fluids through porous media can be simulated by controlling the ratios between the fluid-fluid and fluid-solid (fluid-wall) interparticle interaction strengths.

Paul Meakin; Hai Huang; Moubin Liu

2007-04-01T23:59:59.000Z

80

Limits of the Turbine Efficiency for Free Fluid Flow  

E-Print Network (OSTI)

l propeller, at least in water applications. Moreover, well-documented tests have shown that the helical turbine has an efficiency of 35 percent, making it preferable for use in free water currents. @DOI: 10.1115/1.1414137# 1 Modeling Turbines for Free Flow 1.1 The Betz Model for Rectilinear Flow. The efficiency limit of 59.3 percent was obtained by Betz back in the 1920s for propeller-type turbines in free flow. It became common practice to use this limit for estimating the maximum efficiency of such turbines, when designing wind farms. The derivation of the Betz limit can be found in many textbooks and other publications on fluid mechanics. Betz considered a one-dimensional model for a plane turbine positioned in an incompressible fluid with rectilinear streams of constant velocity across any section of the current ~Fig. 1~a!!. The turbine was assumed to be under uniformly distributed pressure. The efficiency of the turbine was defined as the ratio of the turbine power to the pow

Alexander N. Gorban; Krasnoyarsk Russia; Assoc Mem Asme; Alexander M. Gorlov; Mem Asme; Valentin M. Silantyev

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Engineering Fundamentals - Heat Transfer & Fluid Flow, Version 6.0  

Science Conference Proceedings (OSTI)

The Heat Transfer and Fluid Flow module covers basic terms and concepts of heat transfer and fluid flow and discusses their applications in nuclear power plants. This course will help new engineers understand how their work might impact and/or be ...

2013-01-17T23:59:59.000Z

82

Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations  

Science Conference Proceedings (OSTI)

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^3^D geomechanical ... Keywords: FLAC3D, Fluid flow, Geomechanics, Modeling, TOUGH

Jonny Rutqvist

2011-06-01T23:59:59.000Z

83

Method and apparatus for chemically altering fluids in continuous flow  

DOE Patents (OSTI)

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.

Heath, W.O.; Virden, J.W. Jr.; Richardson, R.L.; Bergsman, T.M.

1993-10-19T23:59:59.000Z

84

Method and apparatus for chemically altering fluids in continuous flow  

DOE Patents (OSTI)

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.

Heath, William O. (Richland, WA); Virden, Jr., Judson W. (Richland, WA); Richardson, R. L. (West Richland, WA); Bergsman, Theresa M. (Richland, WA)

1993-01-01T23:59:59.000Z

85

Modeling subsidence due to geothermal fluid production  

DOE Green Energy (OSTI)

Currently, liquid dominated geothermal systems hold the maximum promise for exploiting geothermal energy in the United States. The principal characteristic of such systems is that most of the heat is transferred by flowing water, which also controls subsurface fluid pressures and stress changes. The reduction in pore pressures brought about by geothermal fluid extraction is potentially capable of causing appreciable deformation of the reservoir rocks leading to displacements at the land surface. In order to foresee the pattern and magnitude of potential ground displacements in and around producing liquid dominated geothermal fields, a numerical model has been developed. Conceptually, the simulator combines conductive and convective heat transfer in a general three dimensional heterogeneous porous medium with a one-dimensional deformation of the reservoir rocks. The capabilities of the model and its potential applicability to field cases are illustrated with examples considering the effects of temperature and pressure dependent properties, material heterogeneities and previous stress history.

Lippmann, M.J.; Narasimhan, T.N.; Witherspoon, P.A.

1977-10-01T23:59:59.000Z

86

A CFD Model for Simulating Urban Flow and Dispersion  

Science Conference Proceedings (OSTI)

A three-dimensional computational fluid dynamics (CFD) model is developed to simulate urban flow and dispersion, to understand fluid dynamical processes therein, and to provide practical solutions to some emerging problems of urban air pollution. ...

Jong-Jin Baik; Jae-Jin Kim; Harindra J. S. Fernando

2003-11-01T23:59:59.000Z

87

Fluid mechanics experiments in oscillatory flow. Volume 1  

DOE Green Energy (OSTI)

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).

Seume, J.; Friedman, G.; Simon, T.W. [Univ. of Minnesota, Minneapolis, MN (United States)

1992-03-01T23:59:59.000Z

88

Unsteady flows of in homogeneous in compressible fluids  

SciTech Connect

In this paper, we study the unsteady motion of in homogeneous in compressible viscous fluids. We present the results corresponding to Stokes second problem and for the flow between two parallel plates where one is oscillating.

Massoudi, Mehrdad; Vaidya, Ashwin

2011-01-01T23:59:59.000Z

89

Controls on Fault-Hosted Fluid Flow: Preliminary Results from the Coso  

Open Energy Info (EERE)

Controls on Fault-Hosted Fluid Flow: Preliminary Results from the Coso Controls on Fault-Hosted Fluid Flow: Preliminary Results from the Coso Geothermal Field, CA Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Controls on Fault-Hosted Fluid Flow: Preliminary Results from the Coso Geothermal Field, CA Details Activities (1) Areas (1) Regions (0) Abstract: cap rock, permeability, fault, fracture, clay, Coso Author(s): Davatzes, N.C.; Hickman, S.H. Published: Geothermal Resource Council Transactions 2005, 1/1/2005 Document Number: Unavailable DOI: Unavailable Conceptual Model At Coso Geothermal Area (2005-2007) Coso Geothermal Area Retrieved from "http://en.openei.org/w/index.php?title=Controls_on_Fault-Hosted_Fluid_Flow:_Preliminary_Results_from_the_Coso_Geothermal_Field,_CA&oldid=473359"

90

Direct Numerical Simulation Of Solidification Microstructures Affected By Fluid Flow  

E-Print Network (OSTI)

The effects of fluid flow on the solidification morphology of pure materials and solute microsegregation patterns of binary alloys are studied using a computational methodology based on a front tracking/finite difference method. A general single-field formulation is presented for the full coupling of phase change, fluid flow, heat and solute transport. This formulation accounts for interfacial rejection/absorption of latent heat and solute, interfacial anisotropies, discontinuities in material properties between the liquid and solid phases, shrinkage/expansion upon solidification and motion and deformation of the solid. Numerical results are presented for the two-dimensional dendritic solidification of pure succinonitrile and the solidification of globulitic grains of a Plutonium-Gallium alloy. For both problems, comparisons are made between solidification without fluid flow and solidification within a shear flow. Introduction Nearly all materials of engineering interest have, at som...

Damir Juric

1998-01-01T23:59:59.000Z

91

Using x-ray microtomography and pore-scale modeling to quantify sediment mixing and fluid flow in a developing streambed  

SciTech Connect

X-ray micro-tomography (XMT), image processing, and lattice Boltzmann (LB) methods were combined to observe sediment mixing, subsurface structure, and patterns of hydrogeological properties associated with bed sediment transport. Transport and mixing of sand and spherical glass beads were observed in a laboratory flume, beginning from a well-defined layered initial condition. Cores were obtained from the streambed at four different times, and each core was scanned by XMT in order to assess the evolution of spatial patterns within the bed. Image analysis clearly revealed the propagation of a sediment mixing front that began at the bed surface. The image data were used as boundary conditions in 3D LB simulation of pore fluid flow, showing that sediment sorting produced strong vertical gradients in permeability near the streambed surface. This new methodological approach offers potential for greatly improved characterization of mixing and transport of fine sediments in a wide variety of aquatic systems.

Chen, Cheng; Packman, Aaron I.; Gaillard, Jean-Francois; (NWU)

2010-01-22T23:59:59.000Z

92

Computational Fluid Dynamics Based Investigation of Sensitivity of Furnace Operational Conditions to Burner Flow Controls  

Science Conference Proceedings (OSTI)

As aggressive reductions in boiler emissions are mandated, the electric utility industry has been moving toward installation of improved methods of burner flow measurement and control to optimize combustion for reduced emissions. Development of cost effective controls requires an understanding of how variations in air and coal flows relate to emission rates. This project used computational fluid dynamic (CFD) modeling to quantify the impacts of variations of burner air and fuel flows on furnace operating...

2005-12-12T23:59:59.000Z

93

Multiphase Flow Modeling Research  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Science Chris Guenther, Director Computational Science Division RUA Spring Meeting, Morgantown, WV March 2013 2 NETL's Multiphase Flow Science Team * The Multiphase Flow Science Team develops physics-based simulation models to conduct applied scientific research. - Development of new theory - Extensive on-site and collaborative V&V efforts and testing - Engages in technology transfer - Applies the models to industrial scale problems. 3 Why is Multiphase Flow Science Needed? * Industry is increasingly relying on multiphase technologies to produce clean and affordable energy with carbon capture. * Unfortunately, the presence of a solid phase reduces the operating capacity of a typical energy device from its original design on average by 40% [1].

94

Characterizing two-phase flow relative permeabilities in chemical flooding using a pore-scale network model  

E-Print Network (OSTI)

simultaneous flow of multiphase fluids in a porous medium byin porous media-pore network models and multiphase flow,simulating multiphase flow and transport processes in porous

Liu, Qingjie; Shen, Pingping; Wu, Yu-Shu

2008-01-01T23:59:59.000Z

95

Optical techniques for fluid flow and heat transfer  

Science Conference Proceedings (OSTI)

A review is presented of optical measuring techniques employed in momentum heat and mass transfer studies. A classification is given of those techniques that are nowadays widely employed in studies to advance the understanding of transport phenomena in fluids. Techniques that employ effects caused by fluid molecules are briefly treated, and examples of measurements are given to demonstrate the kind of information that can be obtained by these techniques. Optical techniques using tracers to obtain transport information are summarized, and laser-Doppler anemometry and its application to fluid flow studies are emphasized. Applications of this technique in single-phase and two-phase flows are given that demonstrate its potential in experimental fluid mechanics and convective heat transfer studies. 63 refs.

Durst, F. (Erlangen-Nuernberg Universitaet, Erlangen (Germany, F.R.))

1990-01-01T23:59:59.000Z

96

Porosity, Permeability, And Fluid Flow In The Yellowstone Geothermal  

Open Energy Info (EERE)

Porosity, Permeability, And Fluid Flow In The Yellowstone Geothermal Porosity, Permeability, And Fluid Flow In The Yellowstone Geothermal System, Wyoming Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Porosity, Permeability, And Fluid Flow In The Yellowstone Geothermal System, Wyoming Details Activities (1) Areas (1) Regions (0) Abstract: Cores from two of 13 U.S. Geological Survey research holes at Yellowstone National Park (Y-5 and Y-8) were evaluated to characterize lithology, texture, alteration, and the degree and nature of fracturing and veining. Porosity and matrix permeability measurements and petrographic examination of the cores were used to evaluate the effects of lithology and hydrothermal alteration on porosity and permeability. The intervals studied in these two core holes span the conductive zone and the upper portion of

97

Pollutant dispersion in a large indoor space: Part 2 -Computational Fluid Dynamics (CFD) predictions and comparison with ascale model experiment for isothermal flow  

SciTech Connect

This paper reports on an investigation of the adequacy of Computational fluid dynamics (CFD), using a standard Reynolds Averaged Navier Stokes (RANS) model, for predicting dispersion of neutrally buoyant gas in a large indoor space. We used CFD to predict pollutant (dye) concentration profiles in a water filled scale model of an atrium with a continuous pollutant source. Predictions from the RANS formulation are comparable to an ensemble average of independent identical experiments. Model results were compared to pollutant concentration data in a horizontal plane from experiments in a scale model atrium. Predictions were made for steady-state (fully developed) and transient (developing) pollutant concentrations. Agreement between CFD predictions and ensemble averaged experimental measurements is quantified using the ratios of CFD-predicted and experimentally measured dye concentration at a large number of points in the measurement plane. Agreement is considered good if these ratios fall between 0.5 and 2.0 at all points in the plane. The standard k-epsilon two equation turbulence model obtains this level of agreement and predicts pollutant arrival time to the measurement plane within a few seconds. These results suggest that this modeling approach is adequate for predicting isothermal pollutant transport in a large room with simple geometry.

Finlayson, Elizabeth U.; Gadgil, Ashok J.; Thatcher, Tracy L.; Sextro, Richard G.

2002-10-01T23:59:59.000Z

98

MODELING SUBSIDENCE DUE TO GEOTHERMAL FLUID PRODUCTION  

E-Print Network (OSTI)

compaction, computers, geothermal energy, pore-waternot MODELING SUBSIDENCE DUE T GEOTHERMAL FLUID PRODUCTION Opromise f o r developing geothermal energy i n the United

Lippmann, M.J.

2011-01-01T23:59:59.000Z

99

Theory and Modeling of Fluids Group Homepage  

Science Conference Proceedings (OSTI)

... Modeling of Fluids Group is working in consort with the University of Colorado and the Division's Cryogenics Group on a DARPA funded project to ...

2013-07-23T23:59:59.000Z

100

Fluid-structure interaction for a pressure driven flow  

Science Conference Proceedings (OSTI)

In this article we discuss the application of a Lagrange multiplier based fictitious domain method for the simulation of the motion of two rigid flaps in an unsteady flow generated by pressure gradients. The distributed Lagrange multiplier technique ... Keywords: Distributed Lagrange multiplier method, Fluid-structure interaction, Marchuk-Yanenko splitting scheme, Pulse pressure

Arati Nanda Pati

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Fully Coupled Well Models for Fluid Injection and Production  

SciTech Connect

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 these equations varies from zero coupling to full coupling. In this paper we describe a fully coupled solution approach for well model that allows for a flexible well trajectory and screened interval within a structured hexahedral computational grid. In this scheme the nonlinear well equations have been fully integrated into the Jacobian matrix for the reservoir conservation equations, minimizing the matrix bandwidth.

White, Mark D.; Bacon, Diana H.; White, Signe K.; Zhang, Z. F.

2013-08-05T23:59:59.000Z

102

Cancellation of vorticity in steady-state non-isentropic flows of complex fluids  

E-Print Network (OSTI)

In steady-state non-isentropic flows of perfect fluids there is always thermodynamic generation of vorticity when the difference between the product of the temperature with the gradient of the entropy and the gradient of total enthalpy is different from zero. We note that this property does not hold in general for complex fluids for which the prominent influence of the material substructure on the gross motion may cancel the thermodynamic vorticity. We indicate the explicit condition for this cancellation (topological transition from vortex sheet to shear flow) for general complex fluids described by coarse-grained order parameters and extended forms of Ginzburg-Landau energies. As a prominent sample case we treat first Korteweg's fluid, used commonly as a model of capillary motion or phase transitions characterized by diffused interfaces. Then we discuss general complex fluids. We show also that, when the entropy and the total enthalpy are constant throughout the flow, vorticity may be generated by the inhomogeneous character of the distribution of material substructures, and indicate the explicit condition for such a generation. We discuss also some aspects of unsteady motion and show that in two-dimensional flows of incompressible perfect complex fluids the vorticity is in general not conserved, due to a mechanism of transfer of energy between different levels.

Paolo Maria Mariano

2003-07-11T23:59:59.000Z

103

DYNAMIC MODELING STRATEGY FOR FLOW REGIME TRANSITION IN GAS-LIQUID TWO-PHASE FLOWS  

SciTech Connect

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 which flow regime transition occurs.

X. Wang; X. Sun; H. Zhao

2011-09-01T23:59:59.000Z

104

CHARACTERIZATION OF HETEROGENEITIES AT THE RESERVOIR SCALE: SPATIAL DISTRIBUTION AND INFLUENCE ON FLUID FLOW  

DOE Green Energy (OSTI)

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.

Michael R. Gross; Kajari Ghosh; Alex K. Manda; Sumanjit Aich

2006-05-08T23:59:59.000Z

105

Device and method for measuring multi-phase fluid flow in a conduit using an elbow flow meter  

DOE Patents (OSTI)

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.

Ortiz, M.G.; Boucher, T.J.

1997-06-24T23:59:59.000Z

106

Self-potential modeling from primary flows  

DOE Green Energy (OSTI)

A new method for the calculation of self potentials (SP) based on induced current sources is presented. The induced current sources are due to divergences of the convective current which is driven, in turn, by a primary flow, either heat or fluid. Numerical modeling utilizing this method has been implemented using a two-dimensional transmission surface algorithm. When the primary flow is driven by the gradient of a potential, joint modeling of the primary flow and the resultant SP is possible with this algorithm. Examples of simple geometrical models in the presence of point sources for the primary flow are presented and discussed. Lastly, a field example of the joint modeling of temperature and SP data is illustrated with data from Red Hill Hot Spring, Utah.

Sill, W.R.

1981-03-01T23:59:59.000Z

107

TOUGH+CO2: A multiphase fluid-flow simulator for CO2 geologic sequestration in saline aquifers  

Science Conference Proceedings (OSTI)

TOUGH+CO"2 is a new simulator for modeling of CO"2 geologic sequestration in saline aquifers. It is a member of TOUGH+, the successor to the TOUGH2 family of codes for multicomponent, multiphase fluid and heat flow simulation. The code accounts for heat ... Keywords: CO2 geologic sequestration, Modeling, Multiphase flow, Parallel computing, Saline aquifer, TOUGH+, TOUGH2

Keni Zhang; George Moridis; Karsten Pruess

2011-06-01T23:59:59.000Z

108

HYDROLYZED WOOD SLURRY FLOW MODELING  

E-Print Network (OSTI)

LBL-10090 UC-61 HYDROLYZED WOOD SLURRY FLOW MODELING JimLBL-10090 HYDROLYZED WOOD SLURRY FLOW MODELING Jim Wrathallconversion of hydrolyzed wood slurry to fuel oil, Based on

Wrathall, Jim

2012-01-01T23:59:59.000Z

109

Thermodynamic Model for Fluid-Fluid Interfacial Areas in Porous Media for Arbitrary Drainage-Imbibition Sequences  

SciTech Connect

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 medium’s 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 TBM’s 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.

Schroth, Martin H.; Oostrom, Mart; Dobson, Richard; Zeyer, Josef

2008-08-01T23:59:59.000Z

110

Modeling Turbulent Flow  

National Nuclear Security Administration (NNSA)

Turbulent Turbulent Flow with Implicit LES L.G. Margolin 1 Proceedings of the Joint Russian-American Five Laboratory Conference on Computational Mathematics/Physics 19-23 June, 2005 Vienna, Austria 1 Applied Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545, len@lanl.gov 1 Abstract Implicit large eddy simulation (ILES) is a methodology for modeling high Reynolds' num- ber flows that combines computational efficiency and ease of implementation with predictive calculations and flexible application. Although ILES has been used for more than fifteen years, it is only recently that significant effort has gone into providing a physical rationale that speaks to its capabilities and its limitations. In this talk, we will present new theoret- ical results aimed toward building a justification and discuss some remaining gaps in our understanding and our practical

111

Multiphase Flow Modeling Research  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Chris Guenther, Director Computational Science Division RUA Spring Meeting, Morgantown, WV March 2013 2 NETL's Multiphase Flow Science Team * The Multiphase Flow Science...

112

Variational formulations for resting irreversible fluids with heat flow  

Science Conference Proceedings (OSTI)

Nonequilibrium statistical mechanics helps to estimate corrections to the entropy and energy of the fluid with heat flux in terms of the nonequilibrium distribution function, f. This leads to the coefficients of wave model of heat: relaxation ... Keywords: conservation laws, entropy, grad solution, variational calculus, wave equations

Stanislaw Sieniutycz; Piotr Kuran

2008-09-01T23:59:59.000Z

113

Improved modeling techniques for turbomachinery flow fields  

DOE Green Energy (OSTI)

This program has the objective of developing an improved methodology for modeling turbomachinery flow fields, including the prediction of losses and efficiency. Specifically, the program addresses the treatment of the mixing stress tensor terms attributed to deterministic flow field mechanisms required in steady-state Computational Fluid Dynamic (CFD) models for turbomachinery flow fields. These mixing stress tensors arise due to spatial and temporal fluctuations (in an absolute frame of reference) caused by rotor-stator interaction due to various blade rows and by blade-to-blade variation of flow properties. This will be accomplished in a cooperative program by Penn State University and the Allison Engine Company. These tasks include the acquisition of previously unavailable experimental data in a high-speed turbomachinery environment, the use of advanced techniques to analyze the data, and the development of a methodology to treat the deterministic component of the mixing stress tenor.

Lakshminarayana, B.; Fagan, J.R. Jr.

1995-12-31T23:59:59.000Z

114

UZ Flow Models and Submodels  

SciTech Connect

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.

Y. Wu

2004-11-01T23:59:59.000Z

115

Multiphase fluid flow and subsequent geochemical transport in variably saturated fractured rocks: 1. Approaches  

E-Print Network (OSTI)

multiphase flow, solute transport and reactive chemistry in porousmultiphase flow, solute transport and reactive chemistry in porousmultiphase fluid flow, mass transport and chemical reactions, (2) we consider not only porous

Xu, Tianfu; Pruess, Karsten

2000-01-01T23:59:59.000Z

116

COMPUTATIONAL FLUID DYNAMICS MODELING ANALYSIS OF COMBUSTORS  

DOE Green Energy (OSTI)

In the current fiscal year FY01, several CFD simulations were conducted to investigate the effects of moisture in biomass/coal, particle injection locations, and flow parameters on carbon burnout and NO{sub x} inside a 150 MW GEEZER industrial boiler. Various simulations were designed to predict the suitability of biomass cofiring in coal combustors, and to explore the possibility of using biomass as a reburning fuel to reduce NO{sub x}. Some additional CFD simulations were also conducted on CERF combustor to examine the combustion characteristics of pulverized coal in enriched O{sub 2}/CO{sub 2} environments. Most of the CFD models available in the literature treat particles to be point masses with uniform temperature inside the particles. This isothermal condition may not be suitable for larger biomass particles. To this end, a stand alone program was developed from the first principles to account for heat conduction from the surface of the particle to its center. It is envisaged that the recently developed non-isothermal stand alone module will be integrated with the Fluent solver during next fiscal year to accurately predict the carbon burnout from larger biomass particles. Anisotropy in heat transfer in radial and axial will be explored using different conductivities in radial and axial directions. The above models will be validated/tested on various fullscale industrial boilers. The current NO{sub x} modules will be modified to account for local CH, CH{sub 2}, and CH{sub 3} radicals chemistry, currently it is based on global chemistry. It may also be worth exploring the effect of enriched O{sub 2}/CO{sub 2} environment on carbon burnout and NO{sub x} concentration. The research objective of this study is to develop a 3-Dimensional Combustor Model for Biomass Co-firing and reburning applications using the Fluent Computational Fluid Dynamics Code.

Mathur, M.P.; Freeman, Mark (U.S. DOE National Energy Technology Laboratory); Gera, Dinesh (Fluent, Inc.)

2001-11-06T23:59:59.000Z

117

Production of Natural Gas and Fluid Flow in Tight Sand Reservoirs  

Science Conference Proceedings (OSTI)

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.

Maria Cecilia Bravo

2006-06-30T23:59:59.000Z

118

Vlasov fluid model with electron pressure  

SciTech Connect

The Vlasov-ion, fluid-electron model of Freidberg for studying the linear stability of hot-ion pinch configurations is here extended to include electron pressure. Within the framework of an adiabatic electron-gas picture, it is shown that this model is still amenable to the numerical methods described by Lewis and Freidberg. (auth)

Gerwin, R.

1975-11-01T23:59:59.000Z

119

Hydrostatic bearings for a turbine fluid flow metering device  

DOE Patents (OSTI)

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.

Fincke, J.R.

1982-05-04T23:59:59.000Z

120

Hydrostatic bearings for a turbine fluid flow metering device  

DOE Patents (OSTI)

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.

Fincke, James R. (Rigby, ID)

1982-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

A course in flow visualization: The art and physics of fluid flow  

E-Print Network (OSTI)

In Spring 2003, a new experimental course on flow visualization was offered to a mixed class of Fine Arts Photography and Engineering students. Course content included fluid flow physics, history of photography with respect to the relationship of science and art, as well as flow visualization and photography techniques. Issues such as “What makes an image art? What makes an image scientific? ” were addressed. The class focused on studio/laboratory experiences for mixed teams of students. A range of fluids apparatus were made available, and students also created novel flows. Writeups were required for each image (to the art students ’ shock). Student work was evaluated for both artistic and scientific merit. This course represents a radical departure from normal engineering curricula; typically all fine arts studio courses are specifically excluded. However, the course proved to be very successful in attracting both graduate and undergraduate students, engineering women in particular. One outcome of the course is the recognition by students of the beauty of fluid physics that surrounds us each day, leading to motivation for life-long learning.

Jean Hertzberg; Alex Sweetman

2004-01-01T23:59:59.000Z

122

TOUGH Simulations of the Updegraff's Set of Fluid and Heat Flow Problems  

Science Conference Proceedings (OSTI)

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.

Moridis, G.J.; Pruess (editor), K.

1992-11-01T23:59:59.000Z

123

Hydrostatic bearings for a turbine fluid flow metering device  

DOE Patents (OSTI)

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.

Fincke, J.R.

1980-05-02T23:59:59.000Z

124

Complexity analysis of the turbulent environmental fluid flow time series  

E-Print Network (OSTI)

We have used the Kolmogorov complexities, sample and permutation entropies to quantify the randomness degree in river flow time series of two mountain rivers in Bosnia and Herzegovina, representing the turbulent environmental fluid, for the period 1926-1990. In particular, we have examined the monthly river flow time series from two rivers (Miljacka and Bosnia) in mountain part of their flow and then calculated the Kolmogorov Complexity (KL) based on the Lempel-Ziv Algorithm (LZA) (Lower - KLL and Upper - KLU), Sample Entropy (SE) and Permutation Entropy (PE) values for each time series. The results indicate that the KLL, KLU, SE and PE values in two rivers are close to each other regardless of the amplitude differences in their monthly flow rates. We have illustrated the changes in mountain river flow complexity by experiments using (i) the data set for the Bosnia River and (ii) anticipated human activities and projected climate changes. We have explored the sensitivity of considered measures in dependence on the length of time series. In addition, we have divided the period 1926-1990 into three sub-intervals: (a) 1926-1945, (b)1946-1965 and (c)1966-1990, and calculated the KLL, KLU, SE and PE values for the various time series in these sub-intervals. It is found that during the period 1946-1965, there is a decrease in their complexities, and corresponding changes in the SE and PE, in comparison to the period 1926-1990. This complexity loss may be primarily attributed to (i) human interventions, after Second World War, on these rivers because of their use for water consumption and (ii) climate change in recent time.

Dragutin T. Mihailovic; Emilija Nikolic-Djoric; Nusret Dreskovic; Gordan Mimic

2013-01-10T23:59:59.000Z

125

A Finite-Difference Numerical Method for Onsager's Pancake Approximation for Fluid Flow in a Gas Centrifuge  

SciTech Connect

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.

de Stadler, M; Chand, K

2007-11-12T23:59:59.000Z

126

Scaled Experimental Modeling of VHTR Plenum Flows  

DOE Green Energy (OSTI)

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.

ICONE 15

2007-04-01T23:59:59.000Z

127

Effects of Port Geometries on Fluid Flow Patterns in Slab Moulds  

Science Conference Proceedings (OSTI)

Analysis of Residence Time Distribution (RTD) of Fluid Flows in a Four Strand Delta-shaped Tundish Operating Under Isothermal and Non-isothermal ...

128

Study on Fluid Flow in a Twelve-strand Tundish under the Operation ...  

Science Conference Proceedings (OSTI)

Analysis of Residence Time Distribution (RTD) of Fluid Flows in a Four Strand Delta-shaped Tundish Operating Under Isothermal and Non-isothermal ...

129

Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations  

E-Print Network (OSTI)

multiphase fluid flow, heat transfer, and deformation in fractured porousmultiphase fluid flow, heat transfer and deformation in porousmultiphase flow of brine and gas through saline media. Transport in Porous

Rutqvist, J.

2011-01-01T23:59:59.000Z

130

On fluid flow in a heterogeneous medium under nonisothermal conditions  

SciTech Connect

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.

D.W., Vasco

2010-11-01T23:59:59.000Z

131

The Illinois basin as a flow path for ore fluids  

SciTech Connect

Three major Mississippi Valley-type Pb-Zn{plus minus}F districts may be the result of fluid migration through the Illinois basin. To establish aquifers and flow vectors possibly associated with mineralizing fluids, the authors measured trace element and F abundances on acid insoluble residues in samples from 63 drill holes in the southern part of the basin and S and Pb isotopes for a subset of these samples. Anomalously high amounts of F associated with barite and sphalerite are common in Ordovician and Mississippian strata of the basin, as well as in an area to the southwest of the basin in Ste. Genevieve and Perry counties, Missouri. Fluorine anomalies also extend north of the Illinois-Kentucky fluorspar district into Galatin County, Illinois. Previous studies report elevated Zn (>200 ppm) and Pb (>100 ppm) contents at several stratigraphic intervals, with elevated Pb contents predominant in Cambrian rocks and Zn relatively more abundant upsection. A prominent Pb enrichment in the deepest part of the basin resides largely in FeS{sub 2}. Similar Pb isotope data for these Pb-rich pyrites and for galena from the overlying fluorspar district suggests possible vertical transport of ore-forming fluids. This Pb is isotopically distinct from and was not involved in the formation of the southeast Missouri Pb belts. Sulfur isotope data suggest that isotopically heavy H{sub 2}S ({delta}{sup 34}S > 10{per thousand}), characteristic of thermochemical sulfate reduction has sulfidized parts of the Mt. Simon formation and lighter H{sub 2}S, having small positive or negative {delta}{sup 34}S values, has sulfidized the overlying carbonate strata. They have not recognized a signature coincident with the upper Mississippi Valley ores at the north end of the basin.

Goldhaber, M.B.; Mosier, E.; Church, S.; Whitney, H.; Gacetta, G. (Geological Survey, Denver, CO (USA)); Eidel, J.; Hackley, K. (Illinois State Geological Survey, Champaign (USA))

1990-05-01T23:59:59.000Z

132

On enhanced non-linear free surface flow simulations with a hybrid LBM-VOF model  

Science Conference Proceedings (OSTI)

In this paper, we present extensions, extensive validations and applications of our previously published hybrid volume-of-fluid-based (VOF) model for the simulation of free-surface flow problems. For the solution of the flow field, the lattice Boltzmann ... Keywords: Free surface, Lattice Boltzmann method, PLIC, Plunging breaker, Potential flow, Volume of fluid

Christian F. JaníEn; Stephan T. Grilli; Manfred Krafczyk

2013-01-01T23:59:59.000Z

133

Two-phase flow modeling with discrete particles  

SciTech Connect

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.

Mortensen, G.A. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Trapp, J.A. (Colorado Univ., Denver, CO (United States) EG and G Idaho, Inc., Idaho Falls, ID (United States))

1992-03-23T23:59:59.000Z

134

Imaging Fluid Flow in Geothermal Wells Using Distributed Thermal Perturbation Sensing  

SciTech Connect

The objective of Task 2 is to develop a numerical method for the efficient and accurate analysis of distributed thermal perturbation sensing (DTPS) data for (1) imaging flow profiles and (2) in situ determination of thermal conductivities and heat fluxes. Numerical forward and inverse modeling is employed to: (1) Examine heat and fluid flow processes near a geothermal well under heating and cooling conditions; (2) Demonstrate ability to interpret DTPS thermal profiles with acceptable estimation uncertainty using inverse modeling of synthetic temperature data; and (3) Develop template model and analysis procedure for the inversion of temperature data collected during a thermal perturbation test using fiber-optic distributed temperature sensors. This status report summarizes initial model developments and analyses.

Freifeld, B.; Finsterle, S.

2010-12-10T23:59:59.000Z

135

Computational fluid dynamic modeling of fluidized-bed polymerization reactors  

SciTech Connect

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.

Rokkam, Ram [Ames Laboratory

2012-11-02T23:59:59.000Z

136

Ten iterative steps for model development and evaluation applied to Computational Fluid Dynamics for Environmental Fluid Mechanics  

Science Conference Proceedings (OSTI)

Computational Fluid Dynamics (CFD) is increasingly used to study a wide variety of complex Environmental Fluid Mechanics (EFM) processes, such as water flow and turbulent mixing of contaminants in rivers and estuaries and wind flow and air pollution ... Keywords: Air and water quality, Building aerodynamics, Environmental Fluid Mechanics, River hydraulics, Transverse mixing, Wind flow

B. Blocken; C. Gualtieri

2012-07-01T23:59:59.000Z

137

Dynamic van der Waals Theory of Two-Phase Fluids in Heat Flow Akira Onuki  

E-Print Network (OSTI)

Dynamic van der Waals Theory of Two-Phase Fluids in Heat Flow Akira Onuki Department of Physics as a functional of the order parameter and the energy density. Let us consider one-component fluids, where-component fluids the effect is drastically altered due to latent heat generation or absorption at the interface [12

138

DOE Fundamentals Handbook: Thermodynamics, Heat Transfer, and Fluid Flow, Volume 1  

Science Conference Proceedings (OSTI)

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.

Not Available

1992-06-01T23:59:59.000Z

139

DOE Fundamentals Handbook: Thermodynamics, Heat Transfer, and Fluid Flow, Volume 2  

Science Conference Proceedings (OSTI)

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.

Not Available

1992-06-01T23:59:59.000Z

140

DOE Fundamentals Handbook: Thermodynamics, Heat Transfer, and Fluid Flow, Volume 3  

SciTech Connect

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.

Not Available

1992-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Multiscale modeling in granular flow  

E-Print Network (OSTI)

Granular materials are common in everyday experience, but have long-resisted a complete theoretical description. Here, we consider the regime of slow, dense granular flow, for which there is no general model, representing ...

Rycroft, Christopher Harley

2007-01-01T23:59:59.000Z

142

A model for the ATW target region fluid dynamics  

SciTech Connect

In the Los Alamos National Laboratory's concept for the accelerator transmutation of waste (ATW), a lead-bismuth eutectic has been chosen as a spallation target for the proton beam. Because of the high local heat fluxes anticipated, the target is in liquid form to facilitate heat removal. The upper boundary of the target region is a hard vacuum. The primary purpose of the analysis is to determine the location of the flow boundary based on the target design parameters. This method of analysis should prove to be useful for performing preliminary scoping and design of the ATW target region's fluid dynamics. Eventually, this model should be tested against experimental data.

Rider, W.J.; Cappiello, M.W. (Los Alamos National Lab., NM (United States))

1991-01-01T23:59:59.000Z

143

Synthetic aperture imaging for three dimensional resolution of fluid flows  

E-Print Network (OSTI)

Fluid mechanics and instrumentation have a long history together, as experimental fluids studies play an important role in describing a more complete physical picture in a variety of problems. Presently. state-of-the-art ...

Belden, Jesse (Jesse Levi)

2011-01-01T23:59:59.000Z

144

A nonlocal model for fluid-structure interaction with applications in hydraulic fracturing  

E-Print Network (OSTI)

Modeling important engineering problems related to flow-induced damage (in the context of hydraulic fracturing among others) depends critically on characterizing the interaction of porous media and interstitial fluid flow. This work presents a new formulation for incorporating the effects of pore pressure in a nonlocal representation of solid mechanics. The result is a framework for modeling fluid-structure interaction problems with the discontinuity capturing advantages of an integral based formulation. A number of numerical examples are used to show that the proposed formulation can be applied to measure the effect of leak-off during hydraulic fracturing as well as modeling consolidation of fluid saturated rock and surface subsidence caused by fluid extraction from a geologic reservoir. The formulation incorporates the effect of pore pressure in the constitutive description of the porous material in a way that is appropriate for nonlinear materials, easily implemented in existing codes, straightforward in i...

Turner, Daniel Z

2012-01-01T23:59:59.000Z

145

Proceedings of the Second International Symposium on Dynamics of Fluids in Fractured Rock  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media. Soc.Modelling Fluid and Heat Flow in Fractured Porous Media. SPEmodeling fluid and heat flow in fractured porous media. Soc

Faybishenko, Boris; Witherspoon, Paul A.

2004-01-01T23:59:59.000Z

146

A simplified sizing and mass model for axial flow turbines  

SciTech Connect

An axial flow turbine mass model has been developed and used to study axial flow turbines for space power systems. Hydrogen, helium-xenon, hydrogen-water vapor, air, and potassium vapor working fluids have been investigated to date. The impact of construction material, inlet temperature, rotational speed, pressure ratio, and power level on turbine mass and volume has been analyzed. This paper presents the turbine model description and results of parametric studies showing general design trends characteristic of any axial flow machine. Also, a comparison of axial flow turbine designs using helium-xenon mixtures and potassium vapor working fluids, which are used in Brayton and Rankine space power systems, respectively, is presented. 9 refs., 4 figs., 2 tabs.

Hudson, S.L.

1989-01-01T23:59:59.000Z

147

Relaxation and curvature-induced molecular flows within fluid membranes  

E-Print Network (OSTI)

The quantitative understanding of bilayer membranes is still rooted in work performed in the 1970s by Helfrich and others. Retaining the spirit of the original work, this article draws analogy with nematic liquid-crystals, but instead of a static description, we present a dynamical (out-of-equilibrium) description. The approach combines nemato-hydrodynamics in the linear regime and a proper use of (differential-) geometry. The main result is to demonstrate that one can obtain equations describing a cross-diffusion effect (similar to the Soret and Dufour effects) between curvature and the flow of amphiphilic molecules. Surprisingly, the shape of a membrane relaxes according to a simple heat equation in the mean curvature: a process that is accompanied by a simultaneous boost to the diffusion of amphiphiles away from regions of high curvature. The model also predicts the inverse process, by which the forced bending of a membrane induces molecular flows towards areas of high curvature. In principle, numerical values for the relevant diffusion coefficients should be verifiable by experiment.

Richard G. Morris

2013-10-09T23:59:59.000Z

148

A Darcy law for the drift velocity in a two-phase flow model  

Science Conference Proceedings (OSTI)

This work deals with the design and numerical approximation of an Eulerian mixture model for the simulation of two-phase dispersed flows. In contrast to the more classical two-fluid or Drift-flux models, the influence of the velocity disequilibrium is ... Keywords: Bubbly flows, Chapman-Enskog expansion, Darcy law, Drift-flux, Riemann solver, Two-phase flows

H. Guillard; F. Duval

2007-05-01T23:59:59.000Z

149

In situ stress, fracture, and fluid flow analysis in Well 38C-9: an  

Open Energy Info (EERE)

In situ stress, fracture, and fluid flow analysis in Well 38C-9: an In situ stress, 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 Conference Paper: In situ stress, fracture, and fluid flow analysis in Well 38C-9: an enhanced geothermal system in the Coso geothermal field Abstract Geoscientists from the Coso Operating Company, EGI-Utah, GeoMechanics International, and the U.S. Geological Survey are cooperating in a multi-year study to develop an Enhanced Geothermal System (EGS) in the Coso Geothermal Field. Key to the creation of an EGS is an understanding of the relationship among natural fracture distribution, fluid flow, and the ambient tectonic stresses that exist within the resource in order to design

150

IN SITU STRESS, FRACTURE, AND FLUID FLOW ANALYSIS IN WELL 38C-9:AN ENHANCED  

Open Energy Info (EERE)

FRACTURE, AND FLUID FLOW ANALYSIS IN WELL 38C-9:AN ENHANCED FRACTURE, AND FLUID FLOW ANALYSIS IN WELL 38C-9:AN ENHANCED GEOTHERMAL SYSTEM IN THE COSO GEOTHERMAL FIELD Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: IN SITU STRESS, FRACTURE, AND FLUID FLOW ANALYSIS IN WELL 38C-9:AN ENHANCED GEOTHERMAL SYSTEM IN THE COSO GEOTHERMAL FIELD Details Activities (2) Areas (1) Regions (0) Abstract: Geoscientists from the Coso Operating Company, EGI-Utah, GeoMechanics International, and the U.S. Geological Survey are cooperating in a multi-year study to develop an Enhanced Geothermal System (EGS) in the Coso Geothermal Field. Key to the creation of an EGS is an understanding of the relationship among natural fracture distribution, fluid flow, and the ambient tectonic stresses that exist within the resource in order to design

151

Fluid Models of Many-server Queues with Abandonment  

E-Print Network (OSTI)

We study many-server queues with abandonment in which customers have general service and patience time distributions. The dynamics of the system are modeled using measure- valued processes, to keep track of the residual service and patience times of each customer. Deterministic fluid models are established to provide first-order approximation for this model. The fluid model solution, which is proved to uniquely exists, serves as the fluid limit of the many-server queue, as the number of servers becomes large. Based on the fluid model solution, first-order approximations for various performance quantities are proposed.

Zhang, Jiheng

2009-01-01T23:59:59.000Z

152

Inhomogeneity of fluid flow in Stirling engine regenerators  

SciTech Connect

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

Jones, J.D. (School of Engineering Science, Simon Fraser Univ. Burnaby, British Columbia (CA))

1989-10-01T23:59:59.000Z

153

Permeability of illite-bearing shale: 2. Influence of fluid chemistry on flow and functionally  

E-Print Network (OSTI)

Permeability of illite-bearing shale: 2. Influence of fluid chemistry on flow and functionally; accepted 14 July 2004; published 14 October 2004. [1] Bedding-parallel permeability of illite-rich shale Geochemistry: Low-temperature geochemistry; KEYWORDS: permeability, shale, fluid chemistry Citation: Kwon, O

Herbert, Bruce

154

Lisburne Formation fracture characterization and flow modeling  

E-Print Network (OSTI)

Evaluation of fractured reservoirs for fluid flow and optimal well placement is often very complicated. In general, fractures enhance permeability and increase access to matrix surface, but their random aspects create difficulties for analysis and performance prediction. Each reservoir has unique aspects which require individual assessment. This study examined fracture properties in a part of the Carboniferous Lisburne Formation. Field study of outcrops yielded information on two sets of large-scale fractures (NNW and ENE orientations) from the lower Wahoo Limestone in the eastern Sadlerochit Mountains. Several statistical methods were used on these data to find appropriate models describing the megafracture properties. For NNW fracture height and ENE fracture spacing, the gamma model appears to adequately describe the distribution. NNW fracture spacing and ENE fracture height are lognormally distributed. Results of the statistical analyses were used as input for fracture set generation and modeling using "FracMan". Modeling different borehole orientations in the fractured domain revealed that horizontal wells with 60? azimuth have an optimal trajectory, resulting in the maximum number and area of fracture connections. The orientation maximizing the number of fracture connections did not necessarily give the maximum area. Conductivity analysis showed that the fracture network is weakly anisotropic and above the percolation threshold. The fracture conductance is strongly dependent on the NNW fracture set; larger fractures influence fluid flow more than smaller fractures. Fracture strike and dip variability increased the system interconnectivity, but did not affect the optimal wellbore orientation. Incorporating ENE fracture termination against the NNW fractures decreased the system conductance and shifted the optimal wellbore trajectory towards the direction perpendicular to the NNW set. Reservoir engineering implications of this study include: guidelines for optimal wellbore orientations, the relative placement of injectors and producers along the bisectors between the two fracture sets, and the importance of including fracture terminations. Further work should investigate the influence of variations in fracture aperture and transmissivities, and drainage area, and extend the analysis to additional units of the Lisburne Group.

Karpov, Alexandre Valerievich

2001-01-01T23:59:59.000Z

155

Fluid Flow Transport Phenomena in Steel Continuous Casting FC ...  

Science Conference Proceedings (OSTI)

Ab Initio Local Energy and Local Stress Calculations: Applications to Materials ... Computational Fluid Dynamics and Experimental Results for the Horizontal .... Films and Applications to a New Generation of Multifunctional Devices/Systems.

156

An overview of instability and fingering during immiscible fluid flow in porous and fractured media  

SciTech Connect

Wetting front instability is an important phenomenon affecting fluid flow and contaminant transport in unsaturated soils and rocks. It causes the development of fingers which travel faster than would a uniform front and thus bypass much of the medium. Water saturation and solute concentration in such fingers tend to be higher than in the surrounding medium. During infiltration, fingering may cause unexpectedly rapid arrival of water and solute at the water-table. This notwithstanding, most models of subsurface flow and transport ignore instability and fingering. In this report, we survey the literature to assess the extent to which this may or may not be justified. Our overview covers experiments, theoretical studies, and computer simulations of instability and fingering during immiscible two-phase flow and transport, with emphasis on infiltration into soils and fractured rocks. Our description of instability in an ideal fracture (Hele-Shaw cell) includes an extension of existing theory to fractures and interfaces having arbitrary orientations in space. Our discussion of instability in porous media includes a slight but important correction of existing theory for the case of an inclined interface. We conclude by outlining some potential directions for future research. Among these, we single out the effect of soil and rock heterogeneities on instability and preferential flow as meriting special attention in the context of nuclear waste storage in unsaturated media.

Chen, G.; Neuman, S.P. [Univ. of Arizona, Tucson, AZ (United States). Dept. of Hydrology and Water Resources; Taniguchi, M. [Nara Univ. of Education (Japan). Dept. of Earth Sciences

1995-04-01T23:59:59.000Z

157

Numerical study on coupled fluid flow and heat transfer process in parabolic trough solar collector tube  

SciTech Connect

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)

Tao, Y.B.; He, Y.L. [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China)

2010-10-15T23:59:59.000Z

158

Fluid and heat flow in gas-rich geothermal reservoirs  

DOE Green Energy (OSTI)

Numerical-simulation techniques are used to study the effects of noncondensible gases (CO/sub 2/) on geothermal reservoir behavior in the natural state and during exploitation. It is shown that the presence of CO/sub 2/ has large effects on the thermodynamic conditions of a reservoir in the natural state, especially on temperature distributions and phase compositions. The gas will expand two-phase zones and increase gas saturations to enable flow of CO/sub 2/ through the system. During exploitation, the early pressure drop is primarily due to degassing of the system. This process can cause a very rapid initial pressure drop, on the order of tens of bars, depending upon the initial partial pressure of CO/sub 2/. The following gas content from wells can provide information on in-place gas saturations and relative permeability curves that apply at a given geothermal resource. Site-specific studies are made for the gas-rich two-phase reservoir at the Ohaki geothermal field in New Zealand. A simple lumped-parameter model and a vertical column model are applied to the field data. The results obtained agree well with the natural thermodynamic state of the Ohaki field (pressure and temperature profiles) and a partial pressure of 15 to 25 bars is calculated in the primary reservoirs. The models also agree reasonably well with field data obtained during exploitation of the field. The treatment of thermophysical properties of H/sub 2/O-CO/sub 2/ mixtures for different phase compositions is summarized.

O'Sullivan, M.J.; Bodvarsson, G.S.; Pruess, K.; Blakeley, M.R.

1983-07-01T23:59:59.000Z

159

Fluid flow through a vertical to horizontal 90 elbow bend III three phase flow  

SciTech Connect

Three phase water/oil/air flow was studied around a vertical upward to horizontal 90 elbow bend of R/d = 0.654. The results were more complex than corresponding two phase data. The pressure drop recorded for the two tangent legs sometimes showed significant variations to the straight pipe data. In most cases this variation was caused by differences in the flow regimes between the two systems. The elbow bend tended to constrict the flow presented by the vertical inlet tangent leg while sometimes acting as a wave and droplet generator for the horizontal outlet tangent leg. It could be argued that the inclusion of the elbow bend altered the flow regime map transitional boundaries but it also is possible that insufficient settling length was provided in the apparatus design. The elbow bend pressure drop was best presented as l{sub e}/d the equivalent length to diameter ratio using the actual total pressure drop in the vertical inlet tangent leg. Generally l{sub e}/d values rose with gas rate, but exhibited an increasingly complex relation with f{sub o} the oil to liquid volumetric ratio as liquid rate was increased. A significant maximum in l{sub e}/d was in evidence around the inversion from water dominated to oil dominated flows. Several models are presented to predict the data. (author)

Spedding, P.L.; Benard, E.; Crawford, N.M. [School of Mechanical and Aerospace Engineering, Queen's University Belfast, Ashby Building, Belfast BT9 5AH (United Kingdom)

2008-01-15T23:59:59.000Z

160

AIR INGRESS ANALYSIS: PART 2 – COMPUTATIONAL FLUID DYNAMIC MODELS  

Science Conference Proceedings (OSTI)

The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature reactors (VHTRs). Phenomena Identification and Ranking Studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the High Temperature Gas Cooled Reactor through the break, possibly causing oxidation of the in-the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of the lower plenum graphite can lead to a loss of structural support. Excessive oxidation of core graphite can also lead to the release of fission products into the confinement, which could be detrimental to a reactor safety. Computational fluid dynamic model developed in this study will improve our understanding of this phenomenon. This paper presents two-dimensional and three-dimensional CFD results for the quantitative assessment of the air ingress phenomena. A portion of results of the density-driven stratified flow in the inlet pipe will be compared with results of the experimental results.

Chang H. Oh; Eung S. Kim; Richard Schultz; Hans Gougar; David Petti; Hyung S. Kang

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Flow Of Mantle Fluids Through The Ductile Lower Crust- Helium Isotope  

Open Energy Info (EERE)

Of Mantle Fluids Through The Ductile Lower Crust- Helium Isotope Of Mantle Fluids Through The Ductile Lower Crust- Helium Isotope Trends Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Flow Of Mantle Fluids Through The Ductile Lower Crust- Helium Isotope Trends Details Activities (5) Areas (5) Regions (0) Abstract: Heat and mass are injected into the shallow crust when mantle fluids are able to flow through the ductile lower crust. Minimum He-3/He-4 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

162

Fluid Flow In The Resurgent Dome Of Long Valley Caldera- Implications From  

Open Energy Info (EERE)

Fluid Flow In The Resurgent Dome Of Long Valley Caldera- Implications From Fluid Flow In The Resurgent Dome Of Long Valley Caldera- Implications From Thermal Data And Deep Electrical Sounding Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Fluid Flow In The Resurgent Dome Of Long Valley Caldera- Implications From Thermal Data And Deep Electrical Sounding Details Activities (5) Areas (1) Regions (0) Abstract: Temperatures of 100°C are measured at 3 km depth in a well located on the resurgent dome in the center of Long Valley Caldera, California, despite an assumed >800°C magma chamber at 6-8 km depth. Local downflow of cold meteoric water as a process for cooling the resurgent dome is ruled out by a Peclet-number analysis of temperature logs. These analyses reveal zones with fluid circulation at the upper and lower

163

IN SITU STRESS, FRACTURE AND FLUID FLOW ANALYSIS-EAST FLANK OF THE COSO  

Open Energy Info (EERE)

IN SITU STRESS, FRACTURE AND FLUID FLOW ANALYSIS-EAST FLANK OF THE COSO IN SITU STRESS, FRACTURE AND FLUID FLOW ANALYSIS-EAST FLANK OF THE COSO GEOTHERMAL FIELD Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: IN SITU STRESS, FRACTURE AND FLUID FLOW ANALYSIS-EAST FLANK OF THE COSO GEOTHERMAL FIELD Details Activities (1) Areas (1) Regions (0) Abstract: High rock temperatures, a high degree of fracturing, high tectonic stresses, and low permeability are the combination of qualities that define an ideal candidate-Enhanced Geothermal System (EGS) reservoir. The Coso Geothermal Field is an area where fluid temperatures exceeding 300°C have been measured at depths less than 10,000 feet and the reservoir is both highly fractured and tectonically stressed. Some of the wells within this portion of the reservoir are relatively impermeable,

164

Multiscale modeling for fluid transport in nanosystems.  

SciTech Connect

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.

Lee, Jonathan W.; Jones, Reese E.; Mandadapu, Kranthi Kiran; Templeton, Jeremy Alan; Zimmerman, Jonathan A.

2013-09-01T23:59:59.000Z

165

A model for multiphase flows through poroelastic media  

Science Conference Proceedings (OSTI)

A continuum model for multiphase fluid mixture flows through poroelastic media is presented. The basic conservation laws developed via a volume averaging technique are considered. Effects of phasic equilibrated forces are included in the model. Based on the thermodynamics of the multiphase mixture flows, appropriate constitutive equations are formulated. The entropy inequality is exploited, and the method of Lagrangian multiplier is used along with the phasic conservation laws to derive the constitutive equations for the phasic stress tensors, equilibrated stress vectors, and the interactions terms. The special cases of wave propagation in poroelastic media saturated with multiphase fluids, and multiphase flows through porous media, are studied. It is shown that the present theory leads to the extended Darcy’s law and contains, as a special case, Biot’s theory of saturated poroelastic media.

Ahmadi, Goodarz; Mazaheri, Ali Reza; Smith, D.H

2003-01-01T23:59:59.000Z

166

An efficient S-DDM iterative approach for compressible contamination fluid flows in porous media  

Science Conference Proceedings (OSTI)

In this paper, we develop an efficient splitting domain decomposition method (S-DDM) for compressible contamination fluid flows in porous media over multiple block-divided sub-domains by combining the non-overlapping domain decomposition, splitting, ... Keywords: Compressible contamination flow, Domain decomposition, Extrapolation, Non-overlapping, Porous media, Splitting

Chuanbin Du; Dong Liang

2010-06-01T23:59:59.000Z

167

A ghost fluid method for compressible reacting flows with phase change  

Science Conference Proceedings (OSTI)

A modified interfacial Riemann problem accounting for phase change and surface tension was developed to couple a reacting gas to a vaporizing compressible liquid. Results from the proposed numerical method compare well with empirically measured separation ... Keywords: Chemically reacting flow, Compressible multiphase flow, Ghost fluid method, Level set method, Navier-Stokes equations, Vaporization

Ryan W. Houim; Kenneth K. Kuo

2013-02-01T23:59:59.000Z

168

A quadrature-based moment method for dilute fluid-particle flows  

Science Conference Proceedings (OSTI)

Gas-particle and other dispersed-phase flows can be described by a kinetic equation containing terms for spatial transport, acceleration, and particle processes (such as evaporation or collisions). In principle, the kinetic description is valid from ... Keywords: Fluid-particle flows, Kinetic equation, Multiphase systems, Number density function, Quadrature method of moments

O. Desjardins; R. O. Fox; P. Villedieu

2008-02-01T23:59:59.000Z

169

Fluid Dynamical Prediction of Changed v1-flow at LHC  

E-Print Network (OSTI)

Substantial collective flow is observed in collisions between Lead nuclei at LHC as evidenced by the azimuthal correlations in the transverse momentum distributions of the produced particles. Our calculations indicate that the Global v1-flow, which at RHIC peaked at negative rapidities (named as 3rd flow component or anti-flow), now at LHC is going to turn toward forward rapidities (to the same side and direction as the projectile residue). Potentially this can provide a sensitive barometer to estimate the pressure and transport properties of the Quark-Gluon Plasma. Our calculations also take into account the initial state Center of Mass rapidity fluctuations, and demonstrate that these are crucial for v1 simulations. In order to better study the transverse momentum flow dependence we suggest a new "symmetrized" v1S flow component; and we also propose a new method to disentangle Global v1 flow from the contribution generated by the random fluctuations in the initial state. This will enhance the possibilities of studying the collective Global v1 flow both at the STAR Beam Energy Scan program and at LHC.

L. P. Csernai; V. K. Magas; H. Stöcker; D. D. Strottman

2011-01-18T23:59:59.000Z

170

A fracture network model for water flow and solute transport  

DOE Green Energy (OSTI)

This paper summarizes code development work and sample calculations for FRACNET, a two-dimensional steady state simulator of fluid flow and solute transport in fractured porous media. The model analyzes flow and transport by generating a fracture network based on statistical characteristics of fractures obtained from well logs and other data. After a network is generated, flow and tracer transport are computed for appropriate boundary conditions and wellbore source/sink terms. In addition, for a given realization, the code can be used to indicate whether the medium can be treated as an equivalent porous medium. 18 refs., 7 figs.

Robinson, B.A.

1989-01-01T23:59:59.000Z

171

Fluid Temperature and Power Estimation of Geothermal Power Plants by a Simplified Numerical Model  

Science Conference Proceedings (OSTI)

This paper presents an estimation of power generated in a given geothermal heat pipe system. Such power generation is basically controlled by the ultimate temperature of fluid flowing through the u-shape pipes and could also be affected by power consumption ... Keywords: energy, geothermal power plant, numerical model, heat conduction, optimum design

Ge Ou; Itai Einav

2010-08-01T23:59:59.000Z

172

A Simple Family of Models for Eccentric Keplerian Fluid Disks  

E-Print Network (OSTI)

In order to be in a long-lived configuration, the density in a fluid disk should be constant along streamlines to prevent compressional (PdV) work from being done cyclically around every orbit. In a pure Kepler potential, flow along aligned, elliptical streamlines of constant eccentricity will satisfy this condition. For most density profiles, differential precession driven by the pressure gradient will destroy the alignment; however, in the razor-thin approximation there is a family of simple equilibria in which the precession frequency is the same at all radii. These disks may therefore be long-lived at significant eccentricities. The density can be made axisymmetric as r goes to 0, while maintaining the precession rate, by relaxing the requirement of constancy along streamlines in an arbitrarily small transition region near the center. In the limit of small eccentricity, the models can be seen as acoustically perturbed axisymmetric disks, and the precession rate is shown to agree with linear theory. The perturbation is a traveling wave similar to an ocean wave, with the fluid rising and falling epicyclically in the gravitational field of the central mass. The expected emission line profiles from the eccentric disks are shown to be strongly asymmetric in general, and, in extreme cases, prone to misinterpretation as single narrow lines with significant velocity offsets.

T. S. Statler

2001-08-06T23:59:59.000Z

173

PC-based fluid and heat transfer analyzer for two-phase flow in pipes.  

E-Print Network (OSTI)

??Modeling the simultaneous flow of gas and liquid or two-phase gas-liquid flow in pipes is a key aspect in petroleum production. These models can enhance… (more)

Afonja, Gbolahan.

2006-01-01T23:59:59.000Z

174

Production of Natural Gas and Fluid Flow in Tight Sand Reservoirs  

Science Conference Proceedings (OSTI)

This document reports progress of this research effort in identifying possible relationships and defining dependencies between macroscopic reservoir parameters strongly affected by microscopic flow dynamics and production well performance in tight gas sand reservoirs. Based on a critical review of the available literature, a better understanding of the main weaknesses of the current state of the art of modeling and simulation for tight sand reservoirs has been reached. Progress has been made in the development and implementation of a simple reservoir simulator that is still able to overcome some of the deficiencies detected. The simulator will be used to quantify the impact of microscopic phenomena in the macroscopic behavior of tight sand gas reservoirs. Phenomena such as, Knudsen diffusion, electro-kinetic effects, ordinary diffusion mechanisms and water vaporization are being considered as part of this study. To date, the adequate modeling of gas slippage in porous media has been determined to be of great relevance in order to explain unexpected fluid flow behavior in tight sand reservoirs.

Maria Cecilia Bravo; Mariano Gurfinkel

2005-06-30T23:59:59.000Z

175

Computational Methods for Analyzing Fluid Flow Dynamics from Digital Imagery  

SciTech Connect

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.

Luttman, A.

2012-03-30T23:59:59.000Z

176

A Baroclinic Model of turbulent dusty flows  

SciTech Connect

The problem considered here is the numerical simulation of the turbulent dusty flow induced by explosions over soil surfaces. Some of the unresolved issues are: (1) how much dust is scoured from such surfaces; (2) where does the dust go in the boundary layer; (3) what is the dusty boundary layer height versus time; (4) what are the dusty boundary layer profiles; (5) how much of the dust mass becomes entrained into the dust stem; and (6) where does the dust go in the buoyant cloud? The author proposes a Baroclinic Model for flows with large density variations that actually calculates the turbulent mixing and transport of dust on an adaptive grid. The model is based on the following idealizations: (1) a loose dust bed; (2) an instantaneous shock fluidization of the dust layer; (3) the dust and air are in local equilibrium (so air viscosity enforces the no-slip condition); (4) the dust-air mixture is treated as a continuum dense fluid with zero viscosity; and (5) the turbulent mixing is dominated by baroclinically-generated vorticity. These assumptions lead to an inviscid set of conservation laws for the mixture, which are solved by means of a high-order Godunov algorithm for gasdynamics. Adaptive Mesh Refinement (AMR) is used to capture the turbulent mixing processes on the grid. One of the unique characteristics of these flows is that mixing occurs because vorticity is produced by an inviscid, baroclinic mechanism. A number of examples are presented to illustrate these baroclinic effects including shock interactions with dense-gas layers and dust beds, and dusty wall jets of airblast precursors. The conclusion of these studies is that dusty boundary layers grow because of mass entrainment from the fluidized bed (and not because of viscous wall drag) as proven by the Mass Integral Equation.

Kuhl, A.L.

1992-04-01T23:59:59.000Z

177

GMINC - A MESH GENERATOR FOR FLOW SIMULATIONS IN FRACTURED RESERVOIRS  

E-Print Network (OSTI)

Simulation of Fluid Flow in Fractured Porous Media, Watergovern fluid flow in fractured porous media. These are (i)for Modeling Fluid and Heat Flow in fractured Porous Media,

Pruess, K.

2010-01-01T23:59:59.000Z

178

Magnetohydrodynamic pump with a system for promoting flow of fluid in one direction  

DOE Patents (OSTI)

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.

Lemoff, Asuncion V. (Union City, CA); Lee, Abraham P. (Irvine, CA)

2010-07-13T23:59:59.000Z

179

Evaluation of uncertainties due to hydrogeological modeling and groundwater flow analysis: Steady flow, transient flow, and thermal studies  

SciTech Connect

Starting with regional geographic, geologic, surface and subsurface hydrologic, and geophysical data for the Tono area in Gifu, Japan, we develop an effective continuum model to simulate subsurface flow and transport in a 4 km by 6 km by 3 km thick fractured granite rock mass overlain by sedimentary layers. Individual fractures are not modeled explicitly. Rather, continuum permeability and porosity distributions are assigned stochastically, based on well-test data and fracture density measurements. Lithologic layering and one major fault, the Tsukiyoshi Fault, are assigned deterministically. We conduct three different studies: (1) the so-called base case, in which the model simulates the steady-state groundwater flow through the site, and then stream trace analysis is used to calculate travel times to the model boundary from specified release points; (2) simulations of transient flow during long term pump tests (LTPT) using the base-case model; and (3) thermal studies in which coupled heat flow and fluid flow are modeled, to examine the effects of the geothermal gradient on groundwater flow. The base-case study indicates that the choice of open or closed lateral boundaries has a strong influence on the regional groundwater flow patterns produced by the models, but no field data exist that can be used to determine which boundary conditions are more realistic. The LTPT study cannot be used to distinguish between the alternative boundary conditions, because the pumping rate is too small to produce an analyzable pressure response at the model boundaries. In contrast, the thermal study shows that the temperature distributions produced by the open and closed models differ greatly. Comparison with borehole temperature data may be used to eliminate the closed model from further consideration.

Doughty, Christine; Karasaki, Kenzi

2002-12-11T23:59:59.000Z

180

Energy of eigen-modes in magnetohydrodynamic flows of ideal fluids  

E-Print Network (OSTI)

Analytical expression for energy of eigen-modes in magnetohydrodynamic flows of ideal fluids is obtained. It is shown that the energy of unstable modes is zero, while the energy of stable oscillatory modes (waves) can assume both positive and negative values. Negative energy waves always correspond to non-symmetric eigen-modes -- modes that have a component of wave-vector along the equilibrium velocity. These results suggest that all non-symmetric instabilities in ideal MHD systems with flows are associated with coupling of positive and negative energy waves. As an example the energy of eigen-modes is calculated for incompressible conducting fluid rotating in axial magnetic field.

I. V. Khalzov; A. I. Smolyakov; V. I. Ilgisonis

2007-12-11T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

A heuristic method to minimise the chattering problem in dynamic mathematical two-phase flow models  

Science Conference Proceedings (OSTI)

This paper introduces the chattering problem in dynamic mathematical two-phase flow models. The real system object of study is also introduced, the DISS test facility, a parabolic-trough solar power plant using as heat transfer fluid the steam-water ... Keywords: Chattering, Heuristic methods, Modelling and simulation, Parabolic-trough solar power plant, Two-phase flow, Zeno phenomenon

J. Bonilla; L. J. Yebra; S. Dormido

2011-09-01T23:59:59.000Z

182

Laminar Flow Forced Convection Heat Transfer Behavior of Phase Change Material Fluid in Straight and Staggered Pin Microchannels  

E-Print Network (OSTI)

Microchannels have been studied extensively for electronic cooling applications ever since they were found to be effective in removing high heat flux from small areas. The rate of heat removed using microchannels depends on many factors including the geometry shape, solid and fluid materials used, and surface roughness, among others. Many configurations of microchannels have been studied with various materials and compared for their effectiveness in heat removal. However, there is little research done so far in using Phase Change Material (PCM) fluids and pin fins in microchannels to enhance the heat transfer. PCM fluids exhibit greater heat transfer when the phase change material undergoes liquid-to-solid transformation. Staggered pins in microchannels have also shown higher heat removal characteristics because of the continuous breaking and formation of the thermal and hydrodynamic boundary layer; they also exhibit higher pressure drop because pins act as flow obstructers. This paper presents numerical results of circular, square, straight rectangular microchannels with various aspect ratios (1:2, 1:4 and 1:8), and rectangular microchannels with two characteristic staggered pins (square and circular, fixed height with no variation in aspect ratio). The heat transfer performance of a single phase fluid and PCM fluid in all of these microchannels and the corresponding pressure drop characteristics are also presented. An effective specific heat capacity model was used to account for the phase change process of PCM fluid. Comparison of heat transfer characteristics of single phase fluid and PCM fluid are presented for all the geometries considered. Among the straight microchannels, 1:8 geometry was found to have the highest Nusselt number. The use of PCM fluid in straight microchannels increased the Nusselt number by 3-7 percent compared to the single phase fluids. Among the staggered pin microchannels, circular pins were found to be more effective in terms of heat transfer by exhibiting higher Nusselt number. Circular pin microchannels were also found to have lower pressure drop compared to the square pin microchannels. Overall, for all the geometries considered, it was found that the PCM fluid enhances the heat transfer compared to the SPF fluid.

Kondle, Satyanarayana

2010-08-01T23:59:59.000Z

183

Eulerian multi-fluid models for the simulation of dynamics and coalescence of particles in solid propellant combustion  

Science Conference Proceedings (OSTI)

The accurate simulation of polydisperse sprays undergoing coalescence in unsteady gaseous flows is a crucial issue. In solid rocket motors, the internal flow depends strongly on the alumina droplet size distribution, which spreads up with coalescence. ... Keywords: Adaptive quadrature for coalescence integrals, Aluminum oxide droplets, CEDRE code, High order Eulerian multi-fluid model, Polydisperse spray, Solid propellant combustion

F. Doisneau; F. Laurent; A. Murrone; J. Dupays; M. Massot

2013-02-01T23:59:59.000Z

184

Simulation of Tailrace Hydrodynamics Using Computational Fluid Dynamics Models  

DOE Green Energy (OSTI)

This report investigates the feasibility of using computational fluid dynamics (CFD) tools to investigate hydrodynamic flow fields surrounding the tailrace zone below large hydraulic structures. Previous and ongoing studies using CFD tools to simulate gradually varied flow with multiple constituents and forebay/intake hydrodynamics have shown that CFD tools can provide valuable information for hydraulic and biological evaluation of fish passage near hydraulic structures. These studies however are incapable of simulating the rapidly varying flow fields that involving breakup of the free-surface, such as those through and below high flow outfalls and spillways. Although the use of CFD tools for these types of flow are still an active area of research, initial applications discussed in this report show that these tools are capable of simulating the primary features of these highly transient flow fields.

Cook, Chris B; Richmond, Marshall C

2001-05-01T23:59:59.000Z

185

Wind flow modeling and simulation over the Giza Plateau cultural heritage site in Egypt  

Science Conference Proceedings (OSTI)

In this article, the wind flow over one of the most important Egyptian historical heritage sites, the Giza Plateau, was investigated using the Computational Fluid Dynamics (CFD) state-of-the-art techniques. The present study addresses the influences ... Keywords: Cultural heritage, Giza Plateau, Great Sphinx, computational fluid dynamics, wind modeling and simulation, wind over heritage sites

Ashraf S. Hussein; Hisham El-Shishiny

2009-11-01T23:59:59.000Z

186

Application of x-ray microtomography to environmental fluid flow D. Wildenschild*a,c  

E-Print Network (OSTI)

pores and therefore facilitates previously unattainable measurements. We report on experiments performed-scale measurements make it possible to test existing and new theory, as well as emerging numerical modeling schemes for Advanced Radiation Sources #12;For instance, fluid-fluid interfaces significantly impact the rate at which

Wildenschild, Dorthe

187

Advanced Model and Methodology Development [Heat Transfer and Fluid  

NLE Websites -- All DOE Office Websites (Extended Search)

Advanced Model and Advanced Model and Methodology Development Capabilities Engineering Computation and Design Engineering and Structural Mechanics Systems/Component Design, Engineering and Drafting Heat Transfer and Fluid Mechanics Overview Thermal Hydraulic Optimization of Nuclear Systems Underhood Thermal Management Combustion Simulations Advanced Model and Methodology Development Multi-physics Reactor Performance and Safety Simulations Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Heat Transfer and Fluid Mechanics Bookmark and Share Advanced Model and Methodology Development Electrorefiner Model for Treatment of Spent Nuclear Fuel Electrorefiner Model for Treatment of Spent Nuclear Fuel. Click on image to

188

Fluid Flow, Solidification and Inclusion Entrapment during Steel ...  

Science Conference Proceedings (OSTI)

... to add the entrapment condition of inclusions at the solidifying shell and export the ... A Coupled CFD-Thermodynamic-Kinetic Model to Simulate a Gas Stirred ...

189

Computational Fluid Dynamics Based Investigation of Sensitivity of Furnace Operational Conditions to Burner Flow Controls  

SciTech Connect

This is the first 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. A project kickoff meeting was held in conjunction with NETL's 2002 Sensors and Control Program Portfolio Review and Roadmapping Workshop, in Pittsburgh, PA during October 15-16, 2002. Dr. Marc Cremer, REI, and Dr. Paul Wolff, EPRI I&C, both attended and met with the project COR, Susan Maley. Following the review of REI's database of wall-fired coal units, the project team selected a front wall fired 150 MW unit with a Riley Low NOx firing system including overfire air for evaluation. In addition, a test matrix outlining approximately 25 simulations involving variations in burner secondary air flows, and coal and primary air flows was constructed. During the reporting period, twenty-two simulations have been completed, summarized, and tabulated for sensitivity analysis. Based on these results, the team is developing a suitable approach for quantifying the sensitivity coefficients associated with the parametric tests. Some of the results of the CFD simulations of the single wall fired unit were presented in a technical paper entitled, ''CFD Investigation of the Sensitivity of Furnace Operational Conditions to Burner Flow Controls,'' presented at the 28th International Technical Conference on Coal Utilization and Fuel Systems in Clearwater, FL March 9-14, 2003. In addition to the work completed on the single wall fired unit, the project team made the selection of a 580 MW opposed wall fired unit to be the subject of evaluation in this program. Work is in progress to update the baseline model of this unit so that the parametric simulations can be initiated.

Marc Cremer; Kirsi St. Marie; Dave Wang

2003-04-30T23:59:59.000Z

190

A new method for determining fluid flow paths during hydraulic fracturing  

DOE Green Energy (OSTI)

Although hydraulic fracturing is a popular method for increasing the productivity of oil and gas wells, there is no direct way other than drilling additional boreholes to determine where the injected fluid has gone and thus what direction a fracture has propagated. Information about fluid flow paths is important for designing subsequent fracturing operations for nearby wells. Determining the locations and orientations of permeable fractures is also important in studies of potential toxic waste repositories where it is critical to understand fluid flow paths. We have developed a method for determining the orientations and locations of fractures along which fluid flows during hydraulic fracturing. The method is based on accurate determination of the locations of microseismic events, or microearthquakes, that accompany the hydraulic injection. By applying a pattern recognition technique to the locations of events from one hydraulic fracturing operation we find planes in the data along which we presume that the fluid has traveled. The planes determined using our method intersect the injection borehole and a second, nearby borehole, in regions where other data indicate that fractures are present.

Fehler, M.

1987-01-01T23:59:59.000Z

191

Two fluid model using kinetic theory for modeling of one-step hydrogen production gasifier  

SciTech Connect

A Two Fluid Model (TFM) using kinetic theory of granular flow has been developed to describe an innovative process of hydrogen production in a single step. An extended Multi-species of Solid Phase (MSP) method is proposed to simulate the gas-solid heterogeneous reactions in an entrained flow gasifier, as opposed to Single-species of Solid Phase (SSP) in previous studies. The intrinsic equations of methane steam reforming and water-gas shift reactions are used for a good understanding of the reaction mechanism for high concentration of hydrogen production under higher pressure. On the basis of the results of computing, the main feature of core-annular reaction zone is predicted in the fully developed flow region. And the similar flame-like structure for velocity and temperature is observed to emerge from the feed injection zone at the bottom of gasifier. The model well illustrates the effects of CaO on enhancing the concentration of hydrogen and sequestering CO{sub 2} in the process of coal gasification. The advantages of pressure gasification are also shown that coal conversion increases with increasing pressure while H{sub 2}S concentration and tar content decreases. Moreover, there is a steep increase in H{sub 2}S and tar species initiated from the entrance of gasifier and then a decrease at the next section. The model shows good agreement with the measurements of flow field and gas products concentration in laboratory-scale plants.

Yu, L.; Lu, J.; Zhang, X.P.; Zhang, S.J.; Wang, X.L. [Chinese Academy of Sciences, Beijing (China)

2008-11-15T23:59:59.000Z

192

Fluid-Structure Interaction for Coolant Flow in Research-type Nuclear Reactors  

Science Conference Proceedings (OSTI)

The High Flux Isotope Reactor (HFIR), located at the Oak Ridge National Laboratory (ORNL), is scheduled to undergo a conversion of the fuel used and this proposed change requires an extensive analysis of the flow through the reactor core. The core consists of 540 very thin and long fuel plates through which the coolant (water) flows at a very high rate. Therefore, the design and the flow conditions make the plates prone to dynamic and static deflections, which may result in flow blockage and structural failure which in turn may cause core damage. To investigate the coolant flow between fuel plates and associated structural deflections, the Fluid-Structure Interaction (FSI) module in COMSOL will be used. Flow induced flutter and static deflections will be examined. To verify the FSI module, a test case of a cylinder in crossflow, with vortex induced vibrations was performed and validated.

Curtis, Franklin G [ORNL; Ekici, Kivanc [ORNL; Freels, James D [ORNL

2011-01-01T23:59:59.000Z

193

Classical analogous of quantum cosmological perfect fluid models  

E-Print Network (OSTI)

Quantization in the mini-superspace of a gravity system coupled to a perfect fluid, leads to a solvable model which implies singularity free solutions through the construction of a superposition of the wavefunctions. We show that such models are equivalent to a classical system where, besides the perfect fluid, a repulsive fluid with an equation of state $p_Q = \\rho_Q$ is present. This leads to speculate on the true nature of this quantization procedure. A perturbative analysis of the classical system reveals the condition for the stability of the classical system in terms of the existence of an anti-gravity phase.

A. B. Batista; J. C. Fabris; S. V. B. Goncalves; J. Tossa

2000-11-28T23:59:59.000Z

194

Numerical simulation of fluid flow and heat transfer in a water heater  

Science Conference Proceedings (OSTI)

Energy consumption represents a major concern, considering the limited resources and latest targets for lower emissions of carbon dioxide. Therefore design of electric heating elements for household and industry are more and more subject to optimization, ... Keywords: electric heating, finite elements, fluid flow, heat transfer

Mircea Nicoar?; Aurel R?du??; Lauren?iu Roland Cucuruz; Cosmin Locovei

2010-04-01T23:59:59.000Z

195

A parallel FE-FV scheme to solve fluid flow in complex geologic media  

Science Conference Proceedings (OSTI)

Field data-based simulations of geologic systems require much computational time because of their mathematical complexity and the often desired large scales in space and time. To conduct accurate simulations in an acceptable time period, methods to reduce ... Keywords: CSMP, Computational geoscience, MPI, Multi-phase fluid flow, Parallel computing, Porous media

Dim Coumou; Stephan Matthäi; Sebastian Geiger; Thomas Driesner

2008-12-01T23:59:59.000Z

196

Hybrid atomistic-continuum method for the simulation of dense fluid flows  

Science Conference Proceedings (OSTI)

We present a hybrid atomistic-continuum method for multiscale simulations of dense fluids. In this method, the atomistic part is described using a molecular dynamics description, while the continuum flow is described by a finite volume discretization ... Keywords: Hybrid algorithms, Molecular dynamics, Multiscale simulation, Nanofluidics

Thomas Werder; Jens H. Walther; Petros Koumoutsakos

2005-05-01T23:59:59.000Z

197

Volumetric 3-component velocimetry measurements of the flow around a Rushton turbine: A fluid dynamics video  

E-Print Network (OSTI)

This article describes a video uploaded to the APS DFD Annual Meeting 2009 Gallery of Fluid Motion. The video contains both animations and still images from a three-dimensional volumetric velocimetry measurement set acquired in the flow around a Rushton turbine.

Sharp, K V; Troolin, D; Walters, G; Lai, W

2009-01-01T23:59:59.000Z

198

Development and evaluation of a meter for measuring return line fluid flow rates during drilling  

DOE Green Energy (OSTI)

The most costly problem routinely encountered in geothermal drilling is lost circulation, which occurs when drilling fluid is lost to the formation rather than circulating back to the surface. The successful and economical treatment of lost circulation requires the accurate measurement of drilling fluid flow rate both into and out of the well. This report documents the development of a meter for measuring drilling fluid outflow rates in the return line of a drilling rig. The meter employs a rolling counterbalanced float that rides on the surface of the fluid in the return line. The angle of the float pivot arm is sensed with a pendulum potentiometer, and the height of the float is calculated from this measurement. The float height is closely related to the fluid height and, therefore, the flow rate in the line. The prototype rolling float meter was extensively tested under laboratory conditions in the Wellbore Hydraulics Flow Facility; results from these tests were used in the design of the field prototype rolling float meter. The field prototype meter was tested under actual drilling conditions in August and September 1991 at the Long Valley Exploratory Well near Mammoth Lakes, Ca. In addition, the performance of several other commercially available inflow and outflow meters was evaluated in the field. The tested inflow meters included conventional pump stroke counters, rotary pump speed counters, magnetic flowmeters, and an ultrasonic Doppler flowmeter. On the return flow line, a standard paddlemeter, an acoustic level meter, and the prototype rolling float meter were evaluated for measuring drilling fluid outflow rates.

Loeppke, G.E.; Schafer, D.M.; Glowka, D.A.; Scott, D.D.; Wernig, M.D. (Sandia National Labs., Albuquerque, NM (United States)); Wright, E.K. (Ktech Corp., Albuquerque, NM (United States))

1992-06-01T23:59:59.000Z

199

Flow of mantle fluids through the ductile lower crust: Heliumisotope trends  

DOE Green Energy (OSTI)

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.

Kennedy, B. Mack; van Soest, Matthijs C.

2007-10-07T23:59:59.000Z

200

Device and method for measuring multi-phase fluid flow in a conduit having an abrupt gradual bend  

DOE Patents (OSTI)

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.

Ortiz, M.G.

1998-02-10T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

A turnstile mechanism for fronts propagating in fluid flows  

E-Print Network (OSTI)

We consider the propagation of fronts in a periodically driven flowing medium. It is shown that the progress of fronts in these systems may be mediated by a turnstile mechanism akin to that found in chaotic advection. We first define the modified ("active") turnstile lobes according to the evolution of point sources across a transport boundary. We then show that the lobe boundaries may be constructed from stable and unstable \\emph{burning invariant manifolds}---one-way barriers to front propagation analogous to traditional invariant manifolds for passive advection. Because the burning invariant manifolds (BIMs) are one-dimensional curves in a three-dimensional ($xy\\theta$) phase space, their projection into $xy$-space exhibits several key differences from their advective counterparts: (lobe) areas are not preserved, BIMs may self-intersect, and an intersection between stable and unstable BIMs does not map to another such intersection. These differences must be accommodated in the correct construction of the new turnstile. As an application, we consider a lobe-based treatment protocol for protecting an ocean bay from an invading algae bloom.

John R. Mahoney; Kevin A. Mitchell

2013-05-22T23:59:59.000Z

202

Elastic encapsulation in bicomponent stratified flow of viscoelastic fluids  

E-Print Network (OSTI)

, Midland, Michigan 48667 James J. Fenga) Department of Chemical and Biological Engineering and Department. The simulations are based on a phase-field theoretical model and use finite elements with adaptive meshing the transport of highly viscous heavy crude oil in pipelines, where the addition of a small amount of water

Feng, James J.

203

Flow of power-law fluids in self-affine fracture channels  

E-Print Network (OSTI)

The two-dimensional pressure driven flow of non-Newtonian power-law fluids in self-affine fracture channels at finite Reynolds number is calculated. The channels have constant mean aperture and two values $\\zeta$=0.5 and 0.8 of the Hurst exponent are considered. The calculation is based on the lattice-Boltzmann method, using a novel method to obtain a power-law variation in viscosity, and the behavior of shear-thinning, Newtonian and shear-thickening liquids is compared. Local aspects of the flow fields, such as maximum velocity and pressure fluctuations, were studied, and the non-Newtonian fluids were compared to the (previously-studied) Newtonian case. The permeability results may be collapsed into a master curve of friction factor vs. Reynolds number using a scaling similar to that employed for porous media flow, and exhibits a transition from a linear regime to a more rapid variation at Re increases.

Yiguang Yan; Joel Koplik

2007-11-29T23:59:59.000Z

204

Passenger Flow Model for Airline Networks  

Science Conference Proceedings (OSTI)

We present a model that rapidly finds an approximation of the expected passenger flow on an airline network, given forecast data concerning (1) the distribution of the demand for each itinerary, seen as a random variable; (2) the time distribution of ... Keywords: airline transportation, equilibrium model, passenger flow, recapture, spill

Jonathan Dumas; François Soumis

2008-05-01T23:59:59.000Z

205

Application of direct-fitting, mass-integral, and multi-rate methods to analysis of flowing fluid electric conductivity logs from Horonobe, Japan  

E-Print Network (OSTI)

traces of drilling mud) and formation fluid flowing into theof drilling mud in the wellbore may impact fluid logging twodrilling mud itself is presumably significantly denser than formation fluid,

Doughty, C.; Tsang, C.-F.; Hatanaka, K.; Yabuuchi, S.; Kurikami, H.

2008-01-01T23:59:59.000Z

206

A Robust Four-Fluid Transient Flow Simulator as an Analysis and Decision Making Tool for Dynamic Kill Operation  

E-Print Network (OSTI)

The worst scenario of drilling operation is blowout which is uncontrolled flow of formation fluid into the wellbore. Blowouts result in environmental damage with potential risk of injuries and fatalities. Although not all blowouts result in disaster, outcomes of blowouts are unknown and should be studied before starting an operation. Plans should be available to prevent blowouts or provide safe and secure ways of controlling the well before the drilling operation starts. The plan should include procedures in case of any blowout incident as a proactive measure. A few commercial softwares are available in the industry for dynamic kill and transient modeling. All models are proprietary and very complex which reduces the flexibility of the program for specific cases. The purpose of this study is to develop a pseudo transient hydraulic simulator for dynamic kill operations. The idea and concept is to consider the flow of each phase as a single phase flow. The summation of hydrostatic and frictional pressure of each phase determines the bottomhole pressure during the dynamic kill operation. The simulator should be versatile and capable of handling special cases that may encounter during blowouts. Some of the main features of the proposed dynamic kill simulator include; quick and robust simulation, fluid properties are corrected for pressure and temperature, sensitivity analysis can be performed through slide bars, and capable of handling variety of wellbore trajectories. The results from the proposed simulator were compared to the result of commercial software, OLGA ABC. The results were in agreement with each other. It is recommended to apply the simulator for operations with required kill fluid volumes of one to two wellbore volumes.

Haghshenas, Arash

2013-05-01T23:59:59.000Z

207

Three fluid cosmological model using Lie and Noether symmetries  

E-Print Network (OSTI)

We employ a three fluid model in order to construct a cosmological model in the Friedmann Robertson Walker flat spacetime, which contains three types of matter dark energy, dark matter and a perfect fluid with a linear equation of state. Dark matter is described by dust and dark energy with a scalar field with potential V({\\phi}). In order to fix the scalar field potential we demand Lie symmetry invariance of the field equations, which is a model-independent assumption. The requirement of an extra Lie symmetry selects the exponential scalar field potential. The further requirement that the analytic solution is invariant under the point transformation generated by the Lie symmetry eliminates dark matter and leads to a quintessence and a phantom cosmological model containing a perfect fluid and a scalar field. Next we assume that the Lagrangian of the system admits an extra Noether symmetry. This new assumption selects the scalar field potential to be exponential and forces the perfect fluid to be stiff. Furthermore the existence of the Noether integral allows for the integration of the dynamical equations. We find new analytic solutions to quintessence and phantom cosmologies which contain all three fluids. Using these solutions one is able to compute analytically all main cosmological functions, such as the scale factor, the scalar field, the Hubble expansion rate, the deceleration parameter etc.

Michael Tsamparlis; Andronikos Paliathanasis

2011-11-23T23:59:59.000Z

208

Proceedings of the Workshop on Numerical Modeling of Thermohydrological Flow in Fractured Rock Masses, Feb. 19-20, 1980, Berkeley, CA  

E-Print Network (OSTI)

governing fluid flow through fractured porous media consistSIMULATION OF FLUID FLOW IN FRACTURED POROUS MEDIA T . N .ABSTRACT Fluid flow in fractured porous media can be

Witherspoon, P.A.

2010-01-01T23:59:59.000Z

209

ON THE TRANSFER OF HEAT TO FLUIDS FLOWING THROUGH PIPES, ANNULI, AND PARALLEL PLATES  

SciTech Connect

Nusselt numbers were calculated for heat transfer to fluids flowing through annuli under conditions of uniform heat flux and fully established velocity and temperature profiles. The following cases were considered: (a) laminar flow, (b) slug flow, (c) turbulent flow with molecular conduction only, and (d) turbulent flow with both molecular and eddy conduction. These Nusselt numbers were determined for two conditions: heat transfer from the inner wall only and heat transfer from the outer wall only. The results were correlated by semi-empirical equations. The final results obtained on cases (a), (b), amd (c) are applicable to any fluid, whereas those obtained on (d) are for liquid metals only. Wall- and bulk-temperature relationships for the above four cases were also determined. These relationships were treated as dimensionless temperature ratios. Both the Nusselt numbers ad temperature ratios were evaluated over the r/ sub 1//r/sub 2/ range, zero to unity; the former being the case of the circular pipe, and the later, the case of infinite parallel plates. (auth)

Dwyer, O.E.

1963-01-01T23:59:59.000Z

210

Computational analysis of fluid flow and zonal deposition in ferrocyanide single-shell tanks. Ferrocyanide Safety Program  

SciTech Connect

Safety of single-shell tanks containing ferrocyanide wastes is of concern. Ferrocyanide in the presence of an oxidizer such as NaNO{sub 3} or NaNO{sub 2} is explosively combustible when concentrated and heated. Evaluating the processes that could affect the fuel content of waste and distribution of the tank heat load is important. Highly alkaline liquid wastes were transferred in and out of the tanks over several years. Since Na{sub 2}NiFe(CN){sub 6} is much more soluble in alkaline media, the ferrocyanide could be dispersed from the tank more easily. If Cs{sub 2}NiFe(CN){sub 6} or CsNaNiFe(CN){sub 6} are also soluble in alkaline media, solubilization and transport of {sup 137}Cs could also occur. Transporting this heat generating radionuclide to a localized area in the tanks is a potential mechanism for generating a ``hot spot.`` Fluid convection could potentially speed the transport process considerably over aqueous diffusion alone. A stability analysis was performed for a dense fluid layer overlying a porous medium saturated by a less dense fluid with the finding that the configuration is unconditionally unstable and independent of the properties of the porous medium or the magnitude of the fluid density difference. A parametric modeling study of the buoyancy-driven flow due to a thermal gradient was combusted to establish the relationship between the waste physical and thermal properties and natural convection heat transfer. The effects of diffusion and fluid convection on the redistribution of the {sup 137}Cs were evaluated with a 2-D coupled heat and mass transport model. The maximum predicted temperature rise associated with the formation of zones was only 5{degrees}C and thus is of no concern in terms of generating a localized ``hot spot.``

McGrail, B.P.; Trent, D.S.; Terrones, G.; Hudson, J.D.; Michener, T.E.

1993-10-01T23:59:59.000Z

211

Fluid flow release regulating device, ERIP {number_sign}624: Final report  

DOE Green Energy (OSTI)

DOE/ERIP project {number_sign}624 ``Fluid Flow Release Regulating Device`` designed, constructed, tested, and installed a rubber crest gate for regulating water levels at an impoundment such as a hydroelectric dam. A 92 foot long by 27 inch high rubber panel was installed in January 1997. Initial results were good until fabric degradation internal to the rubber caused loss of stiffness. Substitutes for the failed fabric are being tested. The project will continue after DOE participation terminates.

NONE

1997-12-01T23:59:59.000Z

212

Nonlinear evolution of the magnetized Kelvin-Helmholtz instability: from fluid to kinetic modeling  

E-Print Network (OSTI)

The nonlinear evolution of collisionless plasmas is typically a multi-scale process where the energy is injected at large, fluid scales and dissipated at small, kinetic scales. Accurately modelling the global evolution requires to take into account the main micro-scale physical processes of interest. This is why comparison of different plasma models is today an imperative task aiming at understanding cross-scale processes in plasmas. We report here the first comparative study of the evolution of a magnetized shear flow, through a variety of different plasma models by using magnetohydrodynamic, Hall-MHD, two-fluid, hybrid kinetic and full kinetic codes. Kinetic relaxation effects are discussed to emphasize the need for kinetic equilibriums to study the dynamics of collisionless plasmas in non trivial configurations. Discrepancies between models are studied both in the linear and in the nonlinear regime of the magnetized Kelvin-Helmholtz instability, to highlight the effects of small scale processes on the nonl...

Henri, P; Califano, F; Pegoraro, F; Rossi, C; Faganello, M; Šebek, O; Trávní?ek, P M; Hellinger, P; Frederiksen, J T; Nordlund, Ĺ; Markidis, S; Keppens, R; Lapenta, G

2013-01-01T23:59:59.000Z

213

Efficient Production Optimization Using Flow Network Models  

E-Print Network (OSTI)

Reservoir simulation is an important tool for decision making and field development management. It enables reservoir engineers to predict reservoir production performance, update an existing model to reproduce monitoring data, assess alternative field development scenarios and design robust production optimization strategies by taking into account the existing uncertainties. A big obstacle in automating model calibration and production optimization approaches is the massive computation required to predict the response of real reservoirs under proposed changes in the model inputs. To speed up reservoir response predictions without compromising accuracy, fast surrogate models have been proposed. These models are either derived by preserving the physics of the involved processes (e.g. mass balance equations) to provide reliable long-range predictions or are developed based solely on statistical relations, in which case they can only provide short-range predictions due to the absence of the physical processes that govern the long-term behavior of the reservoir. We present an alternative solution that combines the advantages of both statistics-based and physics-based methods by deriving the flow predictions in complex two-dimensional models from one-dimensional flow network models. The existing injection/production wells in the original model form the nodes or vertices of the flow network. Each pair of wells (nodes) in the flow network is connected using a one-dimensional numerical simulation model; hence, the entire reservoir is reduced to a connected network of one-dimensional simulation models where the coupling between the individual one-dimensional models is enforced at the nodes where network edges intersect. The proposed flow network model provides a useful and fast tool for characterizing inter-well connectivity, estimating drainage volume between each pair of wells, and predicting reservoir production over an extended period of time for optimization purposes. We estimate the parameters of the flow network model using a robust training approach to ensure that the flow network model reproduces the response of the original full model under a wide range of development strategies. This step helps preserve the flow network model's predictive power during the production optimization when development strategies can change at different iterations. The robust networks training and the subsequent production optimization iterations are computationally efficient as they are performed with the faster flow network model. We demonstrate the effectiveness and applicability of our proposed flow network modeling approach to rapid production optimization using two-phase waterflooding simulations in synthetic and benchmark models.

Lerlertpakdee, Pongsathorn

2012-08-01T23:59:59.000Z

214

MODELING SUBSIDENCE DUE TO GEOTHERMAL FLUID PRODUCTION  

E-Print Network (OSTI)

pore-water pressures , subsidence. DISCLAIMER NeiIher ( h ehere," do not MODELING SUBSIDENCE DUE T GEOTHERMAL FLUIDSecond Syhposium on Land Subsidence 1976 a t Anaheim, I n t

Lippmann, M.J.

2011-01-01T23:59:59.000Z

215

Thermally driven escape from Pluto's atmosphere: A combined fluid/kinetic model  

E-Print Network (OSTI)

A combined fluid/kinetic model is developed to calculate thermally driven escape of N2 from Pluto's atmosphere for two solar heating conditions: no heating above 1450 km and solar minimum heating conditions. In the combined model, one-dimensional fluid equations are applied for the dense part of the atmosphere, while the exobase region is described by a kinetic model and calculated by the direct simulation Monte Carlo method. Fluid and kinetic parts of the model are iteratively solved in order to maintain constant total mass and energy fluxes through the simulation region. Although the atmosphere was found to be highly extended, with an exobase altitude at ~6000 km at solar minimum, the outflow remained subsonic and the escape rate was within a factor of two of the Jeans rate for the exobase temperatures determined. This picture is drastically different from recent predictions obtained solely using a fluid model which, in itself, requires assumptions about atmospheric density, flow velocity and energy flux ca...

Tucker, O J; Deighan, J I; Volkov, A N; Johnson, R E

2011-01-01T23:59:59.000Z

216

Energy Flow Models for the Steel Industry  

E-Print Network (OSTI)

Energy patterns in the U. S. steel industry are examined using several models. First is an end-use model based on data in the 1994 Manufacturing Energy Consumption Survey (MECS). Then a seven-step process model is presented and material flow through each step is calibrated against Commerce Dept. data. Third, a detailed energy flow model is presented for coke ovens and blast furnaces, two very energy-intensive steps in our seven step model of steelmaking. This process-step model is calibrated against both our energy end use and material flow models. These models can serve as the base case for simulating changes in energy utilization and waste streams for steelmaking spurred by economic or regulatory conditions or technology innovations.

Hyman, B.; Andersen, J. P.

1998-04-01T23:59:59.000Z

217

Discrete-element modeling of particulate aerosol flows  

Science Conference Proceedings (OSTI)

A multiple-time step computational approach is presented for efficient discrete-element modeling of aerosol flows containing adhesive solid particles. Adhesive aerosol particulates are found in numerous dust and smoke contamination problems, including smoke particle transport in the lungs, particle clogging of heat exchangers in construction vehicles, industrial nanoparticle transport and filtration systems, and dust fouling of electronic systems and MEMS components. Dust fouling of equipment is of particular concern for potential human occupation on dusty planets, such as Mars. The discrete-element method presented in this paper can be used for prediction of aggregate structure and breakup, for prediction of the effect of aggregate formation on the bulk fluid flow, and for prediction of the effects of small-scale flow features (e.g., due to surface roughness or MEMS patterning) on the aggregate formation. After presentation of the overall computational structure, the forces and torques acting on the particles resulting from fluid motion, particle-particle collision, and adhesion under van der Waals forces are reviewed. The effect of various parameters of normal collision and adhesion of two particles are examined in detail. The method is then used to examine aggregate formation and particle clogging in pipe and channel flow.

Marshall, J.S. [School of Engineering, University of Vermont, 33 Colchecter Avenue, Burlington, Vermont 05405 (United States)], E-mail: jeffm@cems.uvm.edu

2009-03-20T23:59:59.000Z

218

Computational Fluid Dynamics Based Investigation of Sensitivity of Furnace Operational Conditions to Burner Flow Controls  

SciTech Connect

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 defined in order to accommodate sensitivity analyses of the results. The sensitivity analyses provide a strategy for quantifying the rate of change of NOx or unburned carbon in the fly ash to a rate of change in secondary air or fuel or stoichiometric ratio for individual burners or groups of burners in order to assess the value associated with individual burner flow control. In addition, the sensitivity coefficients that were produced provide a basis for quantifying the differences in sensitivities for the different boiler types. In a ranking of the sensitivity of NOx emissions to variations in secondary air flow between the burners at a fixed lower furnace stoichiometric ratio in order of least sensitive to most sensitive, the results were: (1) 600 MW T-Fired Unit; (2) 500 MW Opposed Wall-Fired Unit; (3) 150 MW Wall-Fired Unit; (4) 100 MW T-Fired Unit; and (5) 330 MW Cyclone-Fired Unit.

Marc Cremer; Dave Wang; Connie Senior; Andrew Chiodo; Steven Hardy; Paul Wolff

2005-07-01T23:59:59.000Z

219

A compressible flow model with capillary effects  

Science Conference Proceedings (OSTI)

A quasi-conservative formulation for compressible flows with interfaces including both capillary and viscous effects is developed. The model involves: (i) acoustic and convective transport; (ii) surface tension effects introduced as an extension of the ... Keywords: break-up, coalescence, compressibility, conservative formulation, interface capturing, mixture thermodynamics, surface tension, two-phase flows, viscosity

Guillaume Perigaud; Richard Saurel

2005-10-01T23:59:59.000Z

220

Large Matched-Index-of-Refraction (MIR) Flow Systems for International Collaboration In Fluid Mechanics  

SciTech Connect

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.

Donald M. McEligot; Stefan Becker; Hugh M. McIlroy, Jr.

2010-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

A Numerical Algorithm for Fluid Flow in 3D Naturally Fractured Porous Media  

E-Print Network (OSTI)

Fluid flow in three-dimensional (3D) fractured porous media is considered. The governing system of partial differential equations consists of two subsystems -- one describing the flow in the fractures, and the other describing the flow in the matrix blocks. In this paper, wedevelop an efficient algorithm for the numerical solution of the problem. An operator splitting technique is employed, as a part of the time-stepping procedure, to decouple the system into easy subsystems. The fracture concentration equation is discretized by the modified method of characteristics (MMOC) in time due to high velocityin the fractures and bytheRaviart-Thomas-Nedelec mixed method of index zero (RTN0) in space. The matrix concentration equation is discretized byabackward Euler scheme and the linear finite element method. The pressure equation is approximated byRTN0 and the linear Galerkin method for the fractures and the matrix blocks, respectively. For the fracture system, a domain decomposition (DD) it...

Seongjai Kim

2000-01-01T23:59:59.000Z

222

Numerical simulation of single-phase and multiphase non-Darcy flow in porous and fractured reservoirs  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media, Soc.flow of single-phase and multi-phase fluids in porous and fractured media.

Wu, Yu-Shu

2000-01-01T23:59:59.000Z

223

Mathematical Modeling of Fluid Dynamics and Vessel Vibration in ...  

Science Conference Proceedings (OSTI)

Direct Numerical Simulation of Inclusion Turbulent Deposition at Liquid ... Flow and Shrinkage Pipe Formation on Macrosegregation of Investment Cast -TiAl Alloys ... Numerical Modeling of the Interaction between a Foreign Particle an ...

224

A new method for determining dominant fluid flow paths during hydraulic fracturing  

DOE Green Energy (OSTI)

Although hydraulic fracturing is a method that has been applied for many years to increase fracture permeability of reservoirs, there is no direct way other than drilling additional boreholes to determine where the injected fluid has gone and thus what direction fractures have propagated. Information about fluid flow paths is important for designing subsequent fracturing operations for nearby wells or for choosing a trajectory for a second well to drill through the fracture system, and thus create a hot dry rock geothermal energy reservoir. A method has been developed for determining the orientations and locations of fractures along which fluid flows during hydraulic fracturing. The method is based on accurate determination of the locations of microseismic events, or microearthquakes, that accompany the hydraulic injection. The method has been applied to data collected during a massive hydraulic fracturing experiment carried out as part of the hot dry rock project. Planes with five different orientations were found in the data. The planes determined using the method intersect the injection borehole and a second, nearby borehole, in regions where other data indicate that fractures are present.

Fehler, M.

1987-01-01T23:59:59.000Z

225

Use of vertical slip flow and flooding models in LOCA analysis  

SciTech Connect

Vertical slip flow and flooding models, which have been incorporated in a version of the RELAP4 computer code by Aerojet Nuclear Company have led to significant improvements in modeling nuclear reactor coolant system phenomena during postulated large and small break loss-of-coolant accidents. The vertical slip flow model computes the separated fluid component velocities and directions at vertical flow junctions. Use of the slip model allows the energy transfer between volumes to be based on individual liquid and vapor component flows rather than on the net junction flow. Continuity and momentum equations are unaffected by the addition of slip. The vertical flow slip model logic is based on the assumption that gravity forces dominate causing slip between phases. 7 references (auth)

Fischer, S.R.

1975-01-01T23:59:59.000Z

226

Application of the pseudolinear flow model to the pressure transient analysis of fractured wells  

SciTech Connect

The theoretical basis for the pseudolinear flow model is established. It is demonstrated by using an analytical model that the linear flow graph (p vs ..sqrt..t) can be extended to the analysis of pressure data of fractured wells intersected by an intermediate or a high conductivity fracture ((k /SUB f/ b /SUB f/ greater than or equal to 15). It appears that the fracture conductivity effect during the pseudolinear flow period can be handled as a pseudo skin pressure drop which is additive to the pressure drop caused by fluid loss damage. The combination of the pseudolinear flow analysis with other interpretation techniques is illustrated through examples of field cases.

Cinco-Ley, H.; Rodriguez, F.; Samaniego, F.

1984-09-01T23:59:59.000Z

227

On the Fundamental Unsteady Fluid Dynamics of Shock-Induced Flows through Ducts  

E-Print Network (OSTI)

Unsteady shock wave propagation through ducts has many applications, ranging from blast wave shelter design to advanced high-speed propulsion systems. The research objective of this study was improved fundamental understanding of the transient flow structures during unsteady shock wave propagation through rectangular ducts with varying cross-sectional area. This research focused on the fluid dynamics of the unsteady shock-induced flow fields, with an emphasis placed on understanding and characterizing the mechanisms behind flow compression (wave structures), flow induction (via shock waves), and enhanced mixing (via shock-induced viscous shear layers). A theoretical and numerical (CFD) parametric study was performed, in which the effects of these parameters on the unsteady flow fields were examined: incident shock strength, area ratio, and viscous mode (inviscid, laminar, and turbulent). Two geometries were considered: the backward-facing step (BFS) geometry, which provided a benchmark and conceptual framework, and the splitter plate (SP) geometry, which was a canonical representation of the engine flow path. The theoretical analysis was inviscid, quasi-1D and quasi-steady; and the computational analysis was fully 2D, time-accurate, and viscous. The theory provided the wave patterns and primary wave strengths for the BFS geometry, and the simulations verified the wave patterns and quantified the effects of geometry and viscosity. It was shown that the theoretical wave patterns on the BFS geometry can be used to systematically analyze the transient, 2D, viscous flows on the SP geometry. This work also highlighted the importance and the role of oscillating shock and expansion waves in the development of these unsteady flows. The potential for both upstream and downstream flow induction was addressed. Positive upstream flow induction was not found in this study due to the persistent formation of an upstream-moving shock wave. Enhanced mixing was addressed by examining the evolution of the unsteady shear layer, its instability, and their effects on the flow field. The instability always appeared after the reflected shock interaction, and was exacerbated in the laminar cases and damped out in the turbulent cases. This research provided new understanding of the long-term evolution of these confined flows. Lastly, the turbulent work is one of the few turbulent studies on these flows.

Mendoza, Nicole Renee

2013-05-01T23:59:59.000Z

228

Status of the TOUGH-FLAC simulator and recent applications related to coupled fluid flow and crustal deformations  

SciTech Connect

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.

Rutqvist, J.

2010-06-01T23:59:59.000Z

229

State-of-the-art review of computational fluid dynamics modeling for fluid-solids systems  

DOE Green Energy (OSTI)

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.

Lyczkowski, R.W.; Bouillard, J.X.; Ding, J.; Chang, S.L. [Argonne National Lab., IL (United States); Burge, S.W. [Babcock and Wilcox, Alliance, OH (United States). Alliance Research Center

1994-05-12T23:59:59.000Z

230

TOUGH2: A general-purpose numerical simulator for multiphase fluid and heat flow  

DOE Green Energy (OSTI)

TOUGH2 is a numerical simulation program for nonisothermal flows of multicomponent, multiphase fluids in porous and fractured media. The chief applications for which TOUGH2 is designed are in geothermal reservoir engineering, nuclear waste disposal, and unsaturated zone hydrology. A successor to the TOUGH program, TOUGH2 offers added capabilities and user features, including the flexibility to handle different fluid mixtures, facilities for processing of geometric data (computational grids), and an internal version control system to ensure referenceability of code applications. This report includes a detailed description of governing equations, program architecture, and user features. Enhancements in data inputs relative to TOUGH are described, and a number of sample problems are given to illustrate code applications. 46 refs., 29 figs., 12 tabs.

Pruess, K.

1991-05-01T23:59:59.000Z

231

ESS 2012 Peer Review - Flow Battery Modeling - Soowhan Kim, PNNL  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Pacific Northwest National Laboratory, vilayanur.viswanathan@pnnl.gov Flow Battery Modeling (a) (b) Developed shunt and flow models were used to successfully develop a...

232

Hybrid fluid/kinetic modeling of Pluto's escaping atmosphere  

E-Print Network (OSTI)

Predicting the rate of escape and thermal structure of Pluto's upper atmosphere in preparation for the New Horizons Spacecraft encounter in 2015 is important for planning and interpreting the expected measurements. Having a moderate Jeans parameter Pluto's atmosphere does not fit the classic definition of Jeans escape for light species escaping from the terrestrial planets, nor does it fit the hydrodynamic outflow from comets and certain exoplanets. It has been proposed for some time that Pluto lies in the region of slow-hydrodynamic escape. Using a hybrid fluid/molecular-kinetic model, we previously demonstrated the typical implementation of this model fails to correctly describe the appropriate temperature structure for the upper atmosphere for solar minimum conditions. Here we used a time-dependent solver to allow us to extend those simulations to higher heating rates and we examined fluid models in which Jeans-like escape expressions are used for the upper boundary conditions. We compare these to our hybr...

Erwin, Justin T; Johnson, Robert E

2012-01-01T23:59:59.000Z

233

Viscous potential free-surface flows in a fluid layer of finite depth  

E-Print Network (OSTI)

It is shown how to model weakly dissipative free-surface flows using the classical potential flow approach. The Helmholtz-Leray decomposition is applied to the linearized 3D Navier-Stokes equations. The governing equations are treated using Fourier--Laplace transforms. We show how to express the vortical component of the velocity only in terms of the potential and free-surface elevation. A new predominant nonlocal viscous term is derived in the bottom kinematic boundary condition. The resulting formulation is simple and does not involve any correction procedure as in previous viscous potential flow theories [Joseph2004]. Corresponding long wave model equations are derived.

Denys Dutykh; Frederic Dias

2007-05-09T23:59:59.000Z

234

Theoretical Studies of Non-Newtonian and Newtonian Fluid Flow through Porous Media  

E-Print Network (OSTI)

to Shear Rate in Drilling Fluids and Cement Slurries," Soc.1989). Drilling and hydraulic fracturing fluids used in theNewtonian drilling muds or hydraulic fluids will infiltrate

Wu, Y.S.

1990-01-01T23:59:59.000Z

235

Review and selection of unsaturated flow models  

SciTech Connect

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.

Reeves, M.; Baker, N.A.; Duguid, J.O. [INTERA, Inc., Las Vegas, NV (United States)

1994-04-04T23:59:59.000Z

236

The Properties of Confined Water and Fluid Flow at the Nanoscale  

DOE Green Energy (OSTI)

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.

Schwegler, E; Reed, J; Lau, E; Prendergast, D; Galli, G; Grossman, J C; Cicero, G

2009-03-09T23:59:59.000Z

237

DOE Hydrogen Analysis Repository: FLOW Model  

NLE Websites -- All DOE Office Websites (Extended Search)

FLOW Model FLOW Model Project Summary Full Title: Chemical Engineering Process Simulation Platform - FLOW Project ID: 131 Principal Investigator: Juan Ferrada Brief Description: FLOW is a steady-state chemical process simulator. Modules have been developed for supply chain calculations, micro-economic calculations, and other calculations. Purpose Simulate steady-state chemical processes to support hydrogen infrastructure and transition analysis. Performer Principal Investigator: Juan Ferrada Organization: Oak Ridge National Laboratory (ORNL) Address: Bethel Valley 1, Bldg 5700, N217 Oak Ridge, TN 37831-6166 Telephone: 865-574-4998 Email: ferradajj@ornl.gov Sponsor(s) Name: Fred Joseck Organization: DOE Hydrogen Program Telephone: 202-586-7932 Email: Fred.Joseck@ee.doe.gov

238

A ghost fluid, level set methodology for simulating multiphase electrohydrodynamic flows with application to liquid fuel injection  

Science Conference Proceedings (OSTI)

In this paper, we present the development of a sharp numerical scheme for multiphase electrohydrodynamic (EHD) flows for a high electric Reynolds number regime. The electric potential Poisson equation contains EHD interface boundary conditions, which ... Keywords: Conservative level set, DNS, Electrohydrodynamics, Ghost fluid method, Multiphase flow, Primary atomization

B. P. Van Poppel; O. Desjardins; J. W. Daily

2010-10-01T23:59:59.000Z

239

Statistical mechanical theory for steady-state systems. III. Heat flow in a Lennard-Jones fluid  

E-Print Network (OSTI)

flow is developed based upon the second entropy for dynamical transitions between energy moment a molecular-dynamics trajectory was generated, and various time-dependent properties were accumulatedStatistical mechanical theory for steady-state systems. III. Heat flow in a Lennard-Jones fluid

Attard, Phil

240

Three-Dimensional Computational Fluid Dynamics Modeling of Solid Oxide Electrolysis Cells and Stacks  

DOE Green Energy (OSTI)

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created for detailed analysis of a high-temperature electrolysis stack (solid oxide fuel cells operated as electrolyzers). Inlet and outlet plenum flow distributions are discussed. Maldistribution of plena flow show deviations in per-cell operating conditions due to non-uniformity of species concentrations. Models have also been created to simulate experimental conditions and for code validation. Comparisons between model predictions and experimental results are discussed. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the electrolysis mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation over-potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Variations in flow distribution, and species concentration are discussed. End effects of flow and per-cell voltage are also considered. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Contour plots of local electrolyte temperature, current density, and Nernst potential indicate the effects of heat transfer, reaction cooling/heating, and change in local gas composition.

Grant Hawkes; James O'Brien; Carl Stoots; Stephen Herring

2008-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Symmetries of Discontinuous Flows and the Dual Rankine-Hugoniot Conditions in Fluid Dynamics  

E-Print Network (OSTI)

It has recently been shown that the maximal kinematical invariance group of polytropic fluids, for smooth subsonic flows, is the semidirect product of SL(2,R) and the static Galilei group G. This result purports to offer a theoretical explanation for an intriguing similarity, that was recently observed, between a supernova explosion and a plasma implosion. In this paper we extend this result to discuss the symmetries of discontinuous flows, which further validates the explanation by taking into account shock waves, which are the driving force behind both the explosion and implosion. This is accomplished by constructing a new set of Rankine-Hugoniot conditions, which follow from Noether's conservation laws. The new set is dual to the standard Rankine-Hugoniot conditions and is related to them through the SL(2,R) transformations. The entropy condition, that the shock needs to satisfy for physical reasons, is also seen to remain invariant under the transformations.

Oliver Jahn; V. V. Sreedhar; Amitabh Virmani

2004-07-26T23:59:59.000Z

242

Mathematical Model for Efficient Water Flow Curic Vladimir  

E-Print Network (OSTI)

Industry, Mathematical and Computer Modelling, 39, pp. 1353- 1374, 2004 [6] Jeppson R. Analysis of flow

Krejiæ, Nata�a

243

Computational fluid dynamics simulation of the air/suppressant flow in an uncluttered F18 engine nacelle  

DOE Green Energy (OSTI)

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.

Lopez, A.R.; Gritzo, L.A.; Hassan, B.

1997-06-01T23:59:59.000Z

244

Wind Turbine Modeling for Computational Fluid Dynamics: December 2010 - December 2012  

DOE Green Energy (OSTI)

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.

Tossas, L. A. M.; Leonardi, S.

2013-07-01T23:59:59.000Z

245

A STOCHASTIC METHOD FOR MODELING FLUID DISPLACEMENT IN PETROLEUM RESERVOIRS  

E-Print Network (OSTI)

FLUID DISPLACEMENT IN PETROLEUM RESERVOIRS C. Anderson andFLUID DISPLACEMENT IN PETROLEUM RESERVOIRS C. Anderson andachieve optimal recovery of petroleum from a reservoir, it

Anderson, C.

2011-01-01T23:59:59.000Z

246

DOE-HDBK-1012/2-92; DOE Fundamentals Handbook Thermodynamics, Heat Transfer, and Fluid Flow Volume 2 of 3  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

2-92 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. Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161. Order No. DE92019790 THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Rev. 0 HT ABSTRACT The Thermodynamics, Heat Transfer, and Fluid Flow Fundamentals Handbook was

247

DOE-HDBK-1012/1-92; DOE Fundamentals Handbook Thermodynamics, Heat Transfer, and Fluid Flow Volume 1 of 3  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

1-92 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 Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161. Order No. DE92019789 THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Rev. 0 HT ABSTRACT The Thermodynamics, Heat Transfer, and Fluid Flow Fundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance

248

DOE-HDBK-1012/3-92; DOE Fundamentals Handbook Thermodynamics, Heat Transfer, and Fluid Flow Volume 3 of 3  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

3-92 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. Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161. Order No. DE92019791 THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Rev. 0 HT ABSTRACT The Thermodynamics, Heat Transfer, and Fluid Flow Fundamentals Handbook was

249

A triple-continuum approach for modeling flow and transport processes in fractured rock  

E-Print Network (OSTI)

Multiphase Tracer Transport in Heterogeneous Fractured Porousmultiphase, nonisothermal flow and solute transport in fractured porousmultiphase fluid flow, heat transfer, and chemical migration in a fractured porous

Wu, Yu-Shu; Liu, H.H.; Bodvarsson, G.S; Zellmer, K .E.

2001-01-01T23:59:59.000Z

250

CFD modeling of entrained-flow coal gasifiers with improved physical and chemical sub-models  

Science Conference Proceedings (OSTI)

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.

Ma, J.; Zitney, S.

2012-01-01T23:59:59.000Z

251

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  

SciTech Connect

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

Spane, Frank A.

2013-04-29T23:59:59.000Z

252

Shear-slip analysis in multiphase fluid-flow reservoir engineeringap plications using TOUGH-FLAC  

DOE Green Energy (OSTI)

This paper describes and demonstrates the use of the coupledTOUGH-FLAC simulator for geomechanical shear-slip (failure) analysis inmultiphase fluid-flow reservoir-engineering applications. Two approachesfor analyzing shear-slip are described, one using continuum stress-strainanalysis and another using discrete fault analysis. The use of shear-slipanalysis in TOUGH-FLAC is demonstrated on application examples related toCO2 sequestration and geothermal energy extraction. In the case of CO2sequestration, the shear-slip analysis is used to evaluate maximumsustainable CO2-injection pressure under increasing reservoir pressure,whereas in the case of geothermal energy extraction, the shear-slipanalysis is used to study induced seismicity during steam productionunder decreasing reservoir pressure and temperature.

Rutqvist, Jonny; Birkholzer, Jens; Cappa, Frederic; Oldenburg,Curt; Tsang, Chin-Fu

2006-01-15T23:59:59.000Z

253

Influence of asperities on fluid and thermal flow in a fracture: a coupled Lattice Boltzmann study  

E-Print Network (OSTI)

The characteristics of the hydro-thermal flow which occurs when a cold fluid is injected into a hot fractured bedrock depend on the morphology of the fracture. We consider a sharp triangular asperity, invariant in one direction, perturbing an otherwise flat fracture. We investigate its influence on the macroscopic hydraulic transmissivity and heat transfer efficiency, at fixed low Reynolds number. In this study, numerical simulations are done with a coupled lattice Boltzmann method that solves both the complete Navier-Stokes and advection-diffusion equations in three dimensions. The results are compared with those obtained under lubrication approximations which rely on many hypotheses and neglect the three-dimensional (3D) effects. The lubrication results are obtained by analytically solving the Stokes equation and a two-dimensional (integrated over the thickness) advection-diffusion equation. We use a lattice Boltzmann method with a double distribution (for mass and energy transport) on hypercubic and cubic ...

Neuville, Amélie; Toussaint, Renaud

2013-01-01T23:59:59.000Z

254

Continuum modeling of two-phase flows  

SciTech Connect

Continuum modeling of two-phase flows can essentially be achieved in two ways. The first approach, the so-called continuum theory of mixtures, ignores the details of the flow occurring on the microscopic level, while the second one is the result of some averaging procedure. Although they both lead, as expected, to the same set of basic equations, they differ strongly in their spirit when closure equations have to be found. In the present report, we have attempted to give a brief critical review of both approaches, to compare them and to discuss some of the major difficulties which arise. It is shown that the application of the continuum theory of mixtures is, in most cases, questionable and that the only appropriate way of finding closure equations, besides correlating experimental results, consists in a useful investigation of the microscopic flow pattern associated with an adequate averaging technique.

Bataille, J.; Kestin, J.

1981-12-01T23:59:59.000Z

255

Modeling Turbulent Flow in an Urban Central Business District  

Science Conference Proceedings (OSTI)

The Realistic Urban Spread and Transport of Intrusive Contaminants (RUSTIC) model has been developed as a simplified computational fluid dynamics model with a k–? turbulence model to be used to provide moderately fast simulations of turbulent ...

Donald A. Burrows; Eric A. Hendricks; Steve R. Diehl; Robert Keith

2007-12-01T23:59:59.000Z

256

Lagrangian simulations of unstable gravity-driven flow of fluids with ...  

Science Conference Proceedings (OSTI)

Jun 24, 2010 ... Heavier fluid under influence of gravity will displace a less dense fluid, a process known as the Rayleigh–Taylor instability (Taylor 1950).

257

The Dynamics of Fluid Flow and Associated Chemical Fluxes at Active Continental Margins  

E-Print Network (OSTI)

mixture of fluids introduced during drilling and in situdrilling and geologic setting……………………..13 1.4.2 The three fluidof drilling indicators (IR imagery and pore fluid chemical

Solomon, Evan A

2007-01-01T23:59:59.000Z

258

The Dynamics of fluid flow and associated chemical fluxes at active continental margins  

E-Print Network (OSTI)

mixture of fluids introduced during drilling and in situdrilling and geologic setting……………………..13 1.4.2 The three fluidof drilling indicators (IR imagery and pore fluid chemical

Solomon, Evan Alan

2007-01-01T23:59:59.000Z

259

Reduced-order, trajectory piecewise-linear models for nonlinear computational fluid dynamics  

E-Print Network (OSTI)

Computational fluid dynamics (CFD) is now widely used throughout the fluid dynamics community and yields accurate models for problems of interest. However, due to its high computational cost, CFD is limited for some ...

Gratton, David, 1979-

2004-01-01T23:59:59.000Z

260

Evaluation of fluid-modeling techniques in the seismic analysis of LMFBR reactors  

Science Conference Proceedings (OSTI)

Fluid modeling is of great importance in the seismic analysis of the LMFBR primary system. If the fluid model used in the analysis is too simplified, the results could be very uncertain. On the other hand, if the model is too detailed, considerable difficulty might be encountered in the analysis. The objectives of this study are to examine the validity of the two commonly used fluid modeling techniques. i.e. simplified added mass method and lumped mass method and to provide some useful information on the treatment of fluid in seismic analysis. The validity of these two methods of analysis is examined by comparing the calculated seismic responses of a fluid-structure system based on these two methods with that calculated from a coupled fluid-structure interaction analysis in which the fluid is treated by continuum fluid elements.

Ma, D.C.; Gvildys, J.; Chang, Y.W.

1983-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Lattice Boltzmann modeling of microchannel flow in slip flow regime  

Science Conference Proceedings (OSTI)

We present the lattice Boltzmann equation (LBE) with multiple relaxation times (MRT) to simulate pressure-driven gaseous flow in a long microchannel. We obtain analytic solutions of the MRT-LBE with various boundary conditions for the incompressible ... Keywords: Gas flow through microchannel, Lattice Boltzmann equation with multiple relaxation times, Slip flow

Frederik Verhaeghe; Li-Shi Luo; Bart Blanpain

2009-01-01T23:59:59.000Z

262

Unit physics performance of a mix model in Eulerian fluid computations  

SciTech Connect

In this report, we evaluate the performance of a K-L drag-buoyancy mix model, described in a reference study by Dimonte-Tipton [1] hereafter denoted as [D-T]. The model was implemented in an Eulerian multi-material AMR code, and the results are discussed here for a series of unit physics tests. The tests were chosen to calibrate the model coefficients against empirical data, principally from RT (Rayleigh-Taylor) and RM (Richtmyer-Meshkov) experiments, and the present results are compared to experiments and to results reported in [D-T]. Results show the Eulerian implementation of the mix model agrees well with expectations for test problems in which there is no convective flow of the mass averaged fluid, i.e., in RT mix or in the decay of homogeneous isotropic turbulence (HIT). In RM shock-driven mix, the mix layer moves through the Eulerian computational grid, and there are differences with the previous results computed in a Lagrange frame [D-T]. The differences are attributed to the mass averaged fluid motion and examined in detail. Shock and re-shock mix are not well matched simultaneously. Results are also presented and discussed regarding model sensitivity to coefficient values and to initial conditions (IC), grid convergence, and the generation of atomically mixed volume fractions.

Vold, Erik [Los Alamos National Laboratory; Douglass, Rod [Los Alamos National Laboratory

2011-01-25T23:59:59.000Z

263

Massively parallel computing simulation of fluid flow in the unsaturated zone of Yucca Mountain, Nevada  

E-Print Network (OSTI)

flows of multiphase, multicomponents in porous and fracturedmultiphase flow and multicomponent transport in porous and

Zhang, Keni; Wu, Yu-Shu; Bodvarsson, G.S.

2001-01-01T23:59:59.000Z

264

Analyzing flow patterns in unsaturated fractured rock of YuccaMountain using an integrated modeling approach  

SciTech Connect

This paper presents a series of modeling investigations to characterize percolation patterns in the unsaturated zone of Yucca Mountain, Nevada, a proposed underground repository site for storing high-level radioactive waste. The investigations are conducted using a modeling approach that integrates a wide variety of moisture, pneumatic, thermal, and isotopic geochemical field data into a comprehensive three-dimensional numerical model through model calibration. This integrated modeling approach, based on a dual-continuum formulation, takes into account the coupled processes of fluid and heat flow and chemical isotopic transport in Yucca Mountain's highly heterogeneous, unsaturated fractured tuffs. In particular, the model results are examined against different types of field-measured data and used to evaluate different hydrogeological conceptual models and their effects on flow patterns in the unsaturated zone. The objective of this work to provide understanding of percolation patterns and flow behavior through the unsaturated zone, which is a crucial issue in assessing repository performance.

Wu, Yu-Shu; Lu, Guoping; Zhang, Keni; Pan, Lehua; Bodvarsson,Gudmundur S.

2003-11-03T23:59:59.000Z

265

Review and selection of unsaturated flow models  

SciTech Connect

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 ground-water flow models; to conduct performance assessments; and to develop performance assessment models, where necessary. In the area of scientific modeling, the M&O CRWMS has the following responsibilities: To provide overall management and integration of modeling activities. To provide a framework for focusing modeling and model development. To identify areas that require increased or decreased emphasis. To ensure that the tools necessary to conduct performance assessment are available. These responsibilities are being initiated through a three-step process. It consists of a thorough review of existing models, testing of models which best fit the established requirements, and making recommendations for future development that should be conducted. Future model enhancement will then focus on the models selected during this activity. Furthermore, in order to manage future model development, particularly in those areas requiring substantial enhancement, the three-step process will be updated and reported periodically in the future.

NONE

1993-09-10T23:59:59.000Z

266

A physically based numerical approach for modeling fracture-matrix interaction in fractured reservoirs  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media, Soc.flow through unsaturated fractured porous media, Proceedings of the Second International Symposium on Dynamics of Fluids

Wu, Yu-Shu; Pruess, Karsten

2004-01-01T23:59:59.000Z

267

A Physically Based Approach for Modeling Multiphase Fracture-Matrix Interaction in Fractured Porous Media  

E-Print Network (OSTI)

modeling fluid and heat flow in fractured porous media, Soc.flow through unsaturated fractured porous media, Proceedings of the Second International Symposium on Dynamics of Fluids

Wu, Yu-Shu; Pan, Lehua; Pruess, Karsten

2004-01-01T23:59:59.000Z

268

Inverse modeling and forecasting for the exploitation of the Pauzhetsky geothermal field, Kamchatka, Russia  

E-Print Network (OSTI)

for modeling fluid and heat flow in fractured porous media.phase fluid and heat flow in porous and fractured media. The

Kiryukhin, A.V.

2008-01-01T23:59:59.000Z

269

TOUGH +: Modeling Fluid and Heat Flow in Porous and Fractured ...  

geologic carbon sequestration sites; saline and freshwater aquifers (including the vadose zone) sites contaminated by radionuclides or volatile organic compounds;

270

MODELING COUPLED FLUID FLOW AND GEOMECHANICAL AND GEOPHYSICAL PHENOMENA WITHIN  

E-Print Network (OSTI)

. Specifically, the Mandel-Cryer effect (initially higher pore pressures resulting from a drained boundary condition) and the Noordbergum effect (initially higher pore pressures resulting from layered heterogeneity investigations, including sample-scale loading experiments, wellbore pressure-transient testing, and reservoir

271

Modelling Information Flows in Financial Markets  

E-Print Network (OSTI)

This paper presents an overview of information-based asset pricing. In this approach, an asset is defined by its cash-flow structure. The market is assumed to have access to "partial" information about future cash flows. Each cash flow is determined by a collection of independent market factors called X-factors. The market filtration is generated by a set of information processes, each of which carries information about one of the X-factors, and eventually reveals the X-factor. Each information process has two terms, one of which contains a "signal" about the associated X-factor, and the other of which represents "market noise". The price of an asset is given by the expectation of the discounted cash flows in the risk-neutral measure, conditional on the information provided by the market. When the market noise is modelled by a Brownian bridge one is able to construct explicit formulae for asset prices, as well as semi-analytic expressions for the prices and greeks of options and derivatives. In particular, op...

Brody, Dorje C; Macrina, Andrea

2010-01-01T23:59:59.000Z

272

Heat Transfer and Fluid Flow of Benard-Cell Convection in Rectangular Container with Free Surface Sensed by Infrared Thermography  

Science Conference Proceedings (OSTI)

The natural convection flow phenomena that occur inside an enclosed space are very interesting examples of complex fluid systems that may yield to analytical, empirical and numerical solutions, and many reports have looked into this basic problem. In ... Keywords: Gas-liquid Interface, Heat Transfer, Infrared Thermography, Natural Convection, Thermal Visualization, Turbulence

T. Inagaki; M. Hatori; T. Suzuki; Y. Shiina

2006-04-01T23:59:59.000Z

273

Nitrogen geochemistry as a tracer of fluid flow in a hydrothermal vent complex in the Karoo Basin, South Africa  

E-Print Network (OSTI)

Nitrogen geochemistry as a tracer of fluid flow in a hydrothermal vent complex in the Karoo Basin and hydrothermal vent complexes (HVC) in the Karoo Basin in South Africa. The HVC formed during phreatic eruptions from the lower stratigraphic units of the Karoo Basin shows that the vitrinite reflectance and d15 N

Svensen, Henrik

274

Shock Scattering in Multiphase Flow Model  

Science Conference Proceedings (OSTI)

Multiphase flow models have been proposed for use in situations which have combined Rayleigh-Taylor (RTI) and Richtmyer-Meshkov (RMI) instabilities. Such an approach works poorly for the case of a heavy to light shock incidence on a developed interface. The physical original of this difficulty is traced to an inadequate model of the interfacial pressure term as it appears in the momentum and turbulence kinetic energy equations. Constraints on the form of a better model from a variety of sources are considered. In this context it is observed that a new constraint on closures arises. This occurs because of the discontinuity within the shock responsible for the RMI. The proposed model (Shock Scattering) is shown to give useful results.

Klem, D

2003-10-16T23:59:59.000Z

275

Shock Scattering in a Multiphase Flow Model  

Science Conference Proceedings (OSTI)

Multiphase flow models have been proposed for use in situations which have combined Rayleigh-Taylor (RTI) and Richtmyer-Meshkov (RMI) instabilities. Such an approach work poorly for the case of a heavy to light shock incidence on a developed interface. The physical original of this difficulty is traced to an inadequate model of the interfacial pressure term as it appears in the momentum and turbulence kinetic energy equations. Constraints on the form of a better model from a variety of sources are considered. In this context it is observed that a new constraint on closures arises. This occurs because of the discontinuity within the shock responsible for the RMI. The proposed model (Shock Scattering) is shown to give useful results.

Klem, D

2003-04-08T23:59:59.000Z

276

Secondary Flow and Upstream Dynamics in Double Bifurcation Model  

E-Print Network (OSTI)

Flow behavior in bifurcation models is of great importance to health risk assessments and pulmonary drug delivery. This is particularly true of secondary flow behavior in multi-bifurcation models. Previously, both numerical ...

Leong, Fong Yew

277

A Geostrophic Adjustment Model of Two Buoyant Fluids  

Science Conference Proceedings (OSTI)

A combination of analytical calculations and laboratory experiments has been used to investigate the geostrophic adjustment of two buoyant fluids having different densities in a third denser ambient fluid. The frontal position, the depth profile, ...

Claudia Cenedese; James A. Lerczak; Giuseppe Bartone

2012-11-01T23:59:59.000Z

278

Numerical simulation of the air flow field in a laboratory fume hood using the CFD-ACE(TM) computational fluid dynamics code  

E-Print Network (OSTI)

The purpose of this research was the numerical simulation of the air flow field within a standard laboratory fume hood using the k-6 turbulence model. The study investigated the flow field at different sash openings. The results of the computation realized information on the hood entry losses and other design parameters that are of interest to the users, designers and owners of fume hoods. After the specification of the problem and generation of the mesh, the modeled hood was simulated using CFD-ACE TM , a commercial computational fluid dynamics software package. The code is based on the finite volume method. In defining the grid, due care was exercised in maintaining the cell aspect ratio and grid orthogonality within the recommended limits. The air flow patterns at full open sash compared favorably with experimental results. The results at lowered sash revealed air flow characteristics and slot volume flows that were not reported in previously published literature on fume hoods. These results along with smaller hood entry losses confirmed the better performance of fume hoods at sash openings that are less than half open. Further, comparison between the computed volume flow rates and published design data was favorable.

D'Sousa, Cedric Benedict

1997-01-01T23:59:59.000Z

279

Acoustically Induced Streaming Flows near a Model Cod Otolith and their Potential Implications for Fish Hearing  

SciTech Connect

The ears of fishes are remarkable sensors for the small acoustic disturbances associated with underwater sound. For example, each ear of the Atlantic cod (Gadus morhua) has three dense bony bodies (otoliths) surrounded by fluid and tissue, and detects sounds at frequencies from 30 to 500 Hz. Atlantic cod have also been shown to localize sounds. However, how their ears perform these functions is not fully understood. Steady streaming, or time-independent, flows near a 350% scale model Atlantic cod otolith immersed in a viscous fluid were studied to determine if these fluid flows contain acoustically relevant information that could be detected by the ear s sensory hair cells. The otolith was oscillated sinusoidally at various orientations at frequencies of 8 24 Hz, corresponding to an actual frequency range of 280 830 Hz. Phaselocked particle pathline visualizations of the resulting flows give velocity, vorticity, and rate of strain fields over a single plane of this mainly two-dimensional flow. Although the streaming flows contain acoustically relevant information, the displacements due to these flows are likely too small to explain Atlantic cod hearing abilities near threshold. The results, however, may suggest a possible mechanism for detection of ultrasound in some fish species.

Kotas, Charlotte W [ORNL; Rogers, Peter [Georgia Institute of Technology; Yoda, Minami [Georgia Institute of Technology

2011-01-01T23:59:59.000Z

280

Improving the accuracy of flow units prediction through two committee machine models: An example from the South Pars Gas Field, Persian Gulf Basin, Iran  

Science Conference Proceedings (OSTI)

Intelligent reservoir characterization is a prerequisite study for development of oil and gas fields. Hydraulic flow units are mappable portions of hydrocarbon-bearing rocks that control fluid flow, and their modeling allows an accurate understanding ... Keywords: Committee machine, Flow units, Fuzzy logic, Genetic algorithm, Iran, Neural network, Neuro-fuzzy, South Pars Gas Field

Javad Ghiasi-Freez; Ali Kadkhodaie-Ilkhchi; Mansur Ziaii

2012-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Force interaction of high pressure glow discharge with fluid flow for active separation control  

SciTech Connect

Radio frequency based discharges at atmospheric pressures are the focus of increased interest in aerodynamics because of the wide range of potential applications including, specifically, actuation in flows at moderate speeds. Recent literature describing promising experimental observations, especially on separation control, has spurred efforts in the development of parallel theoretical modeling to lift limitations in the current understanding of the actuation mechanism. The present effort demonstrates higher fidelity first-principle models in a multidimensional finite-element framework to predict surface discharge-induced momentum exchange. The complete problem of a dielectric barrier discharge at high pressure with axially displaced electrodes is simulated in a self-consistent manner. Model predictions for charge densities, the electric field, and gas velocity distributions are shown to mimic trends reported in the experimental literature. Results show that a residual of electrons remains deposited on the dielectric surface downstream of the exposed powered electrode for the entire duration of the cycle and causes a net electric force in the direction from the electrode to the downstream surface. For the first time, results document the mitigation process of a separation bubble formed due to flow past a flat plate inclined at 12 degree sign angle of attack. This effort sets the basis for extending the formulation further to include polyphase power input in multidimensional settings, and to apply the simulation method to flows past common aerodynamic configurations.

Roy, Subrata; Gaitonde, Datta V. [Computational Plasma Dynamics Laboratory, Mechanical Engineering, Kettering University, Flint, Michigan 48504 (United States); Computational Sciences Branch, Air Vehicles Directorate, Air Force Research Laboratory, Wright Patterson AFB, Ohio 45433 (United States)

2006-02-15T23:59:59.000Z

282

Observing and modeling Earths energy flows  

SciTech Connect

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 contribute importantly to this adjustment and thus contribute both to uncertainty in estimates of radiative forcing and to uncertainty in the response. Models are indispensable to calculation of the adjustment of the system to a compositional change but are known to be flawed in their representation of clouds. Advances in tracking Earth's energy flows and compositional changes on daily through decadal timescales are shown to provide both a critical and constructive framework for advancing model development and evaluation.

Stevens B.; Schwartz S.

2012-05-11T23:59:59.000Z

283

Numerical modeling of the elution peak profiles of retained solutes in supercritical fluid chromatography  

Science Conference Proceedings (OSTI)

In supercritical fluid chromatography (SFC), the significant expansion of the mobile phase along the column causes the formation of axial and radial gradients of temperature. Due to these gradients, the mobile phase density, its viscosity, its velocity, its diffusion coefficients, etc. are not constant throughout the column. This results in a nonuniform flow velocity distribution, itself causing a loss of column efficiency in certain cases, even at low flow rates, as they do in HPLC. At high flow rates, an important deformation of the elution profiles of the sample components may occur. The model previously used to account satisfactorily for the retention of an unsorbed solute in SFC is applied to the modeling of the elution peak profiles of retained compounds. The numerical solution of the combined heat and mass balance equations provides the temperature and the pressure profiles inside the column and values of the retention time and the band profiles of retained compounds that are in excellent agreement with independent experimental data for large value of mobile phase reduced density. At low reduced densities, the band profiles can strongly depend on the column axial distribution of porosity.

Kaczmarski, Krzysztof [University of Tennessee and Rzeszow University of Technology, Poland; Guiochon, Georges A [ORNL

2011-01-01T23:59:59.000Z

284

DEVELOPMENT AND VALIDATION OF A MULTIFIELD MODEL OF CHURN-TURBULENT GAS/LIQUID FLOWS  

DOE Green Energy (OSTI)

The accuracy of numerical predictions for gas/liquid two-phase flows using Computational Multiphase Fluid Dynamics (CMFD) methods strongly depends on the formulation of models governing the interaction between the continuous liquid field and bubbles of different sizes. The purpose of this paper is to develop, test and validate a multifield model of adiabatic gas/liquid flows at intermediate gas concentrations (e.g., churn-turbulent flow regime), in which multiple-size bubbles are divided into a specified number of groups, each representing a prescribed range of sizes. The proposed modeling concept uses transport equations for the continuous liquid field and for each bubble field. The overall model has been implemented in the NPHASE-CMFD computer code. The results of NPHASE-CMFD simulations have been validated against the experimental data from the TOPFLOW test facility. Also, a parametric analysis on the effect of various modeling assumptions has been performed.

Elena A. Tselishcheva; Steven P. Antal; Michael Z. Podowski; Donna Post Guillen

2009-07-01T23:59:59.000Z

285

Investigation of combustive flows and dynamic meshing in computational fluid dynamics  

E-Print Network (OSTI)

Computational Fluid Dynamics (CFD) is a ?eld that is constantly advancing. Its advances in terms of capabilities are a result of new theories, faster computers, and new numerical methods. In this thesis, advances in the computational ?uid dynamic modeling of moving bodies and combustive ?ows are investigated. Thus, the basic theory behind CFD is being extended to solve a new class of problems that are generally more complex. The ?rst chapter that investigates some of the results, chapter IV, discusses a technique developed to model unsteady aerodynamics with moving boundaries such as ?apping winged ?ight. This will include mesh deformation and ?uid dynamics theory needed to solve such a complex system. Chapter V will examine the numerical modeling of a combustive ?ow. A three dimensional single vane burner combustion chamber is numerically modeled. Species balance equations along with rates of reactions are introduced when modeling combustive ?ows and these expressions are discussed. A reaction mechanism is validated for use with in situ reheat simulations. Chapter VI compares numerical results with a laminar methane ?ame experiment to further investigate the capabilities of CFD to simulate a combustive ?ow. A new method of examining a combustive ?ow is introduced by looking at the solutions ability to satisfy the second law of thermodynamics. All laminar ?ame simulations are found to be in violation of the entropy inequality.

Chambers, Steven B.

2004-12-01T23:59:59.000Z

286

A Dense Current Flowing down a Sloping Bottom in a Rotating Fluid  

Science Conference Proceedings (OSTI)

A density-driven current was generated in the laboratory by releasing dense fluid over a sloping bottom in a rotating freshwater system. The behavior of the dense fluid descending the slope has been investigated by systematically varying four ...

C. Cenedese; J. A. Whitehead; T. A. Ascarelli; M. Ohiwa

2004-01-01T23:59:59.000Z

287

Partitioned solution to fluid-structure interaction problem in application to free-surface flows  

E-Print Network (OSTI)

distribution). Fluid material properties are the dynamic viscosity µ and the density . To write a unique Computational fluid Dynamic programs solve the fluid equations on a fixed (Eulerian) grid. The classical and structure sub-problems. Contrary to explicit algorithms which generate spurious energy at the in- terface

Paris-Sud XI, Université de

288

Analyzing Unsatirated Flow Patterns in Fractured Rock Using an Integrated Modeling Approach  

Science Conference Proceedings (OSTI)

Characterizing percolation patterns in unsaturated fractured rock has posed a greater challenge to modeling investigations than comparable saturated zone studies, because of the heterogeneous nature of unsaturated media and the great number of variables impacting unsaturated flow. This paper presents an integrated modeling methodology for quantitatively characterizing percolation patterns in the unsaturated zone of Yucca Mountain, Nevada, a proposed underground repository site for storing high-level radioactive waste. The modeling approach integrates a wide variety of moisture, pneumatic, thermal, and isotopic geochemical field data into a comprehensive three-dimensional numerical model for modeling analyses. It takes into account the coupled processes of fluid and heat flow and chemical isotopic transport in Yucca Mountain's highly heterogeneous, unsaturated fractured tuffs. Modeling results are examined against different types of field-measured data and then used to evaluate different hydrogeological conceptualizations and their results of flow patterns in the unsaturated zone. In particular, this model provides a much clearer understanding of percolation patterns and flow behavior through the unsaturated zone, both crucial issues in assessing repository performance. The integrated approach for quantifying Yucca Mountain's flow system is demonstrated to provide a practical modeling tool for characterizing flow and transport processes in complex subsurface systems.

Y.S. Wu; G. Lu; K. Zhang; L. Pan; G.S. Bodvarsson

2006-08-03T23:59:59.000Z

289

Fluid Queue Models of Renewable Energy Storage Gareth L. Jones and Peter G. Harrison  

E-Print Network (OSTI)

Fluid Queue Models of Renewable Energy Storage Gareth L. Jones and Peter G. Harrison Department 30 Source 3 0 30 Source 4 25 25 45 Node 1 Node 2 Node 3 Renewable energy sources are modeled of networks of fluid queues. Such models can be used to describe the generation and storage of renewable

Imperial College, London

290

Physical Model Development and Benchmarking for MHD Flows in Blanket Design  

SciTech Connect

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.

Ramakanth Munipalli; P.-Y.Huang; C.Chandler; C.Rowell; M.-J.Ni; N.Morley; S.Smolentsev; M.Abdou

2008-06-05T23:59:59.000Z

291

Network flow model for multi-energy systems  

Science Conference Proceedings (OSTI)

This paper describes a novel approach to model networks with multiple energy carrier. The proposed nodal matrix establishes a link between an optimization of enclosed areas and their interconnections via networks. In the envisioned network flow model ... Keywords: energy conversion, energy hubs, grids, line losses, network flow, optimal power flow

Matthias Schulze; Goran Gašparovi?

2010-02-01T23:59:59.000Z

292

A macroscopic collisional model for debris-flows simulation  

Science Conference Proceedings (OSTI)

SCIDDICA S"4"c is the latest hexagonal release of a family of Cellular Automata models for the simulation of flow-type landslides. It is able to simulate the erosion of the regolith along the flow path, besides branching and re-joining events of the ... Keywords: Calibration, Cellular automata, Debris flows, Genetic algorithms, Modelling, Parallel processing, Sarno, Sensitivity analysis, Simulation

Donato D'Ambrosio; Giulio Iovine; William Spataro; Hideaki Miyamoto

2007-10-01T23:59:59.000Z

293

Application of the pseudolinear-flow model to the pressure-transient analysis of fractured wells  

SciTech Connect

The theoretical basis for the pseudolinear-flow model is established. In this paper it is demonstrated by use of an analytical model that the linear-flow graph (rho vs. {Lambda}tau) can be extended to the analysis of pressure data of fractured wells intersected by an intermediate- or high-conductivity fracture (C/sub fD/ > 5{pi}). It appears that the fracture-conductivity effect during the pseudolinear-flow period can be handled as pseudoskin pressure drop that adds to the pressure drop caused by fluid-loss damage. The combination of the pseudolinear-flow analysis with other interpretation techniques is illustrated through examples of field cases.

Cinco-Ley, H.; Samanlego, V.F. (Univ. of Mexico/Pemex (MX)); Rodriguez, F. (Univ. of Mexico/IMP (MX))

1989-09-01T23:59:59.000Z

294

Elliptic Flow from a Hybrid CGC, Full 3D Hydro and Hadronic Cascade Model  

E-Print Network (OSTI)

We investigate the robustness of the discovery of the perfect fluid through comparison of hydrodynamic calculations with the elliptic flow coefficient v_2 at midrapidity in Au+Au collisions at sqrt{s_{NN}}=200 GeV. Employing the Glauber model for initial entropy density distributions, the centrality dependence of v_2 is reasonably reproduced by using an ideal fluid description of the early QGP stage followed by a hadronic cascade in the late hadronic stage. On the other hand, initial conditions based on the Colour Glass Condensate model are found to generate larger elliptic flow due to larger initial eccentricity epsilon. We further predict v_2/epsilon at a fixed impact parameter as a function of collision energy sqrt{s_{NN}} up to the LHC energy.

Tetsufumi Hirano; Ulrich W. Heinz; Dmitri Kharzeev; Roy Lacey; Yasushi Nara

2007-01-25T23:59:59.000Z

295

Resummed Green-Kubo relations for a fluctuating fluid-particle model  

E-Print Network (OSTI)

A recently introduced stochastic model for fluid flow can be made Galilean invariant by introducing a random shift of the computational grid before collisions. This grid shifting procedure accelerates momentum transfer between cells and leads to a collisional contribution to transport coefficients. By resumming the Green-Kubo relations derived in a previous paper, it is shown that this collisional contribution to the transport coefficients can be determined exactly. The resummed Green-Kubo relations also show that there are no mixed kinetic-collisional contributions to the transport coefficients. The leading correlation corrections to the transport coefficients are discussed, and explicit expressions for the transport coefficients are presented and compared with simulation data.

Thomas Ihle; Erkan Tuzel; Daniel M. Kroll

2004-04-13T23:59:59.000Z

296

Coupled urban wind flow and indoor natural ventilation modelling on a high-resolution grid: A case study for the Amsterdam ArenA stadium  

Science Conference Proceedings (OSTI)

Wind flow in urban environments is an important factor governing the dispersion of heat and pollutants from streets, squares and buildings. This paper presents a coupled CFD modelling approach for urban wind flow and indoor natural ventilation. A specific ... Keywords: Air exchange rate, Air quality, Computational Fluid Dynamics (CFD), Cross-ventilation, Full-scale measurements, Grid generation technique, Integrated model, Model validation and solution verification, Numerical simulation, Outdoor and indoor air flow, Sports stadium

T. van Hooff; B. Blocken

2010-01-01T23:59:59.000Z

297

MAX Fluid Dynamics facility  

NLE Websites -- All DOE Office Websites (Extended Search)

MAX Fluid Dynamics facility MAX Fluid Dynamics facility Capabilities Engineering Experimentation Reactor Safety Testing and Analysis Overview Nuclear Reactor Severe Accident Experiments MAX NSTF SNAKE Aerosol Experiments System Components Laser Applications Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr MAX Fluid Dynamics facility Providing high resolution data for development of computational tools that model fluid flow and heat transfer within complex systems such as the core of a nuclear reactor. 1 2 3 4 5 Hot and cold air jets are mixed within a glass tank while laser-based anemometers and a high-speed infrared camera characterize fluid flow and heat transfer behavior. Click on image to view larger size image.

298

A Study of Barotropic Model Flows: Intermittency, Waves and Predictability  

Science Conference Proceedings (OSTI)

The régime flows corresponding to the barotropic nondivergent equation with forcing, drag and subgrid-scale dissipation are studied using spectral model on the plane and on the sphere. The flow régimes obtained exhibit clear evidence of the ...

C. Basdevant; B. Legras; R. Sadourny; M. Béland

1981-11-01T23:59:59.000Z

299

Modeling of Hydraulically Controlled Exchange Flow in the Bosphorus Strait  

Science Conference Proceedings (OSTI)

Recent hydrographic observations obtained in the Bosphorus Strait illustrate several features of the flow that may be related with the internal hydraulics. A two-layer numerical model indicates that the two-way exchange flow may indeed be subject ...

Temel Oguz; Emin Özsoy; Mohammed A. Latif; Halil I. Sur; Ümit Ünlüata

1990-07-01T23:59:59.000Z

300

Experimental and Computational Studies of Fluid Flow Phenomena in Carbon Dioxide Sequestration in Brine and Oil Fields  

NLE Websites -- All DOE Office Websites (Extended Search)

EXPERIMENTAL AND COMPUTATIONAL STUDIES OF FLUID EXPERIMENTAL AND COMPUTATIONAL STUDIES OF FLUID FLOW PHENOMENA IN CARBON DIOXIDE SEQUESTRATION IN BRINE AND OIL FIELDS Chuang Ji ( chuang.ji@netl.doe.gov ) National Energy Technology Laboratory Department of Energy, Morgantown, WV 26507-0880 BOX 5725 Clarkson University Potsdam, NY 13699 Goodarz Ahmadi ( ahmadi@clarkson.edu ) BOX 5725 Clarkson University Potsdam, NY 13699 Duane H. Smith ( duane.smith@netl.doe.gov ) National Energy Technology Laboratory Department of Energy, Morgantown, WV 26507-0880 2 INTRODUCTION Sequestration of CO 2 by injection into deep geological formations is a method to reduce CO 2 emissions into the atmosphere. However, when CO 2 is injected underground, it forms fingers extending into the rock pores saturated with brine or petroleum. This flow

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

JOM-e 0612: Transient Fluid-Flow Phenomena in the Continuous ...  

Science Conference Proceedings (OSTI)

Animations of some of these transient flow phenomena are presented from ... Animations of the transient flow pattern were presented previously.8 The current  ...

302

THERMO-HYDRO-MECHANICAL MODELING OF WORKING FLUID INJECTION AND THERMAL ENERGY EXTRACTION IN EGS FRACTURES AND ROCK MATRIX  

DOE Green Energy (OSTI)

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 evolution.

Robert Podgorney; Chuan Lu; Hai Huang

2012-01-01T23:59:59.000Z

303

Cold flow modeling of pulverized coal combustors for magnetohydrodynamic channel applications  

DOE Green Energy (OSTI)

This report describes an experimental program and techniques for studying the internal aerodynamics of pulverized coal combustors of the type used in magnetohydrodynamic test trains at The University of Tennessee Space Institute. The combustors are modeled with small scale, cold flow models that permit both flow visualization and velocity field surveys to be performed. Water was selected as the working fluid so that the model flow fields had the same Reynolds number as the actual reactive combustors, and also to facilitate flow visualization. The systems used for flow visualization and velocity field surveying are described in detail. The velocity field survey equipment is based on a vector-velocity, laser doppler velocimeter coupled to a controllable field scanning device and a microprocessor for on-line data reduction. Results are presented that were obtained from a laser velocimeter study of recirculating flows in a combustor model. The results show that, even for exceedingly simple geometrical arrangements of oxidant injector configurations, complex three dimensional highly turbulent flow fields exist in the combustor. A brief discussion of the impact of the results on fuel injector positioning is presented.

Schulz, R.J.; Giel, T.V.; Ghosh, A.; Morris, R.D.

1984-03-01T23:59:59.000Z

304

Computational fluid dynamics modelling of sewage sludge mixing in an anaerobic digester  

Science Conference Proceedings (OSTI)

In this paper, the development of a computational fluid dynamics (CFD) model to simulate the mechanical mixing of sewage sludge at laboratory scale is reported. The paper recommends a strategy for modelling mechanically mixed sewage sludge at laboratory ... Keywords: Biogas, CFD, Digestion, Energy, Non-Newtonian fluid, Sewage sludge, Turbulence

J. Bridgeman

2012-02-01T23:59:59.000Z

305

Multidimensional Data Model Research for Data Mart Based Analysis System of Drilling Fluid  

Science Conference Proceedings (OSTI)

For the sake of complex analysis requirements of drilling fluid analysis system, this paper proposes a multidimensional data model and implement the solution of data mart due to the analyzing weaknesses of conventional information system. Since the database ... Keywords: drilling fluid, Data Mart, Multidimensional Data Model, Multi-Analysis, Fact Tables, Dimension Tables

Li Jian; Wang Bing; Xu Bihua; Liang Dachun

2010-12-01T23:59:59.000Z

306

A new coupled fluid-structure modeling methodology for running ductile fracture  

Science Conference Proceedings (OSTI)

A coupled fluid-structure modeling methodology for running ductile fracture in pressurized pipelines has been developed. The pipe material and fracture propagation have been modeled using the finite-element method with a ductile fracture criterion. The ... Keywords: CFD, FEM, Fluid-structure, Fracture, Leak, Pipeline

H. O. Nordhagen; S. Kragset; T. Berstad; A. Morin; C. Dřrum; S. T. Munkejord

2012-03-01T23:59:59.000Z

307

U-Sr isotopic speedometer: Fluid flow and chemical weathering rates inaquifers  

E-Print Network (OSTI)

zone sediment from the Hanford Reservation—RCRA boreholecontamination at the Hanford Site in Washington using high-vadose zone pore fluids at Hanford, Washington: implications

Maher, Kate; DePaolo, Donald J.; Christensen, John N.

2005-01-01T23:59:59.000Z

308

Modeling Flows Around Merging Black Hole Binaries  

E-Print Network (OSTI)

Coalescing massive black hole binaries are produced by the mergers of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne LISA. In cases where the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a step towards solving this problem by mapping the flow of pressureless matter in the dynamic, 3-D general relativistic spacetime around the merging black holes. We find qualitative differences in collision and outflow speeds, including a signature of the merger when the net angular momentum of the matter is low, between the results from single and binary black holes, and between nonrotating and rotating holes in binaries. If future magnetohydrodynamic results confirm ...

van Meter, James R; Miller, M Coleman; Reynolds, Christopher S; Centrella, Joan M; Baker, John G; Boggs, William D; Kelly, Bernard J; McWilliams, Sean T

2009-01-01T23:59:59.000Z

309

Center for Energy Efficiency and Renewable Energy at University of Massachusetts 3D Model of Heat Transfer and Fluid3D Model of Heat Transfer and Fluid  

E-Print Network (OSTI)

Center for Energy Efficiency and Renewable Energy at University of Massachusetts 3D Model of Heat for Energy Efficiency and Renewable Energy at University of Massachusetts 3D Model of Heat Transfer and Fluid WindowModeling a 3D Window Future WorkFuture Work #12;Center for Energy Efficiency and Renewable Energy

Massachusetts at Amherst, University of

310

Modeling high gradient magnetic separation from biological fluids.  

SciTech Connect

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.

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

2006-01-01T23:59:59.000Z

311

Binary fish passage models for uniform and nonuniform flows  

Science Conference Proceedings (OSTI)

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 prediction of the percentage 43 of fish passing would be particularly useful near flow speed thresholds where binary 44 passage models are clearly limited.

Neary, Vincent S [ORNL

2011-01-01T23:59:59.000Z

312

Swirling structure for mixing two concentric fluid flows at nozzle outlet  

DOE Patents (OSTI)

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.

Mensink, Daniel L. (3578 Gregory La., Lynchburg, VA 24503)

1993-01-01T23:59:59.000Z

313

Physics and modeling of thermal flow and soil mechanics in unconsolidated porous media  

SciTech Connect

This paper describes a new formulation of nonlinear soil mechanics and multiphase thermal flow. The nonlinearites of the soil behavior and their interactions with fluid flow causing shear failure of the soil are the dominant features of the process. The numerical formulation of the coupled flow/stress solution model includes nonlinear compressibility and flow properties as functions of pressure, stress, and temperature; nonlinear, incremental, thermal poroelastic stress analysis; and shear or tensile failure and its effects on transport properties, porosity, and stress. An efficient sequential numerical scheme was developed. It is mass conservative and applicable to external coupling of existing simulators. The 1D examples show some startling new features of reservoir mechanics in unconsolidated media.

Settari, A. (Simtech Consulting Services Ltd. (US))

1992-02-01T23:59:59.000Z

314

A Quasi-Three-Dimensional Variably Saturated Groundwater Flow Model for Climate Modeling  

Science Conference Proceedings (OSTI)

In this study, a quasi-three-dimensional, variably saturated groundwater flow model was developed by approximately dividing the three-dimensional soil water and groundwater flow into an unsaturated vertical soil water flow and a horizontal ...

Zhenghui Xie; Zhenhua Di; Zhendong Luo; Qian Ma

2012-02-01T23:59:59.000Z

315

Flow in geothermal wells: Part III. Calculation model for self-flowing well  

DOE Green Energy (OSTI)

The theoretical model described predicts the temperature, pressure, dynamic dryness fraction, and void fraction along the vertical channel of two-phase flow. The existing data from operating wells indicate good agreement with the model. (MHR)

Bilicki, Z.; Kestin, J.; Michaelides, E.E.

1981-06-01T23:59:59.000Z

316

Double-diffusive convection for a non-Newtonian fluid flow past a permeable surface embedded in a porous medium with uniform heat and mass fluxes  

Science Conference Proceedings (OSTI)

The problem of steady, laminar, double-diffusive mixed convective flow of a non-Newtonian power-law fluid past a vertical semi-infinite permeable surface embedded in a porous medium with uniform heat and mass fluxes. A mixed convection parameter for ... Keywords: heat and mass transfer, mixed convection, non-Newtonian fluid, numerical solution, porous media, suction or injection

Ali J. Chamkha

2008-03-01T23:59:59.000Z

317

Fracture Modeling and Flow Behavior in Shale Gas Reservoirs Using Discrete Fracture Networks  

E-Print Network (OSTI)

Fluid flow process in fractured reservoirs is controlled primarily by the connectivity of fractures. The presence of fractures in these reservoirs significantly affects the mechanism of fluid flow. They have led to problems in the reservoir which results in early water breakthroughs, reduced tertiary recovery efficiency due to channeling of injected gas or fluids, dynamic calculations of recoverable hydrocarbons that are much less than static mass balance ones due to reservoir compartmentalization, and dramatic production changes due to changes in reservoir pressure as fractures close down as conduits. These often lead to reduced ultimate recoveries or higher production costs. Generally, modeling flow behavior and mass transport in fractured porous media is done using the dual-continuum concept in which fracture and matrix are modeled as two separate kinds of continua occupying the same control volume (element) in space. This type of numerical model cannot reproduce many commonly observed types of fractured reservoir behavior since they do not explicitly model the geometry of discrete fractures, solution features, and bedding that control flow pathway geometry. This inaccurate model of discrete feature connectivity results in inaccurate flow predictions in areas of the reservoir where there is not good well control. Discrete Fracture Networks (DFN) model has been developed to aid is solving some of these problems experienced by using the dual continuum models. The Discrete Fracture Networks (DFN) approach involves analysis and modeling which explicitly incorporates the geometry and properties of discrete features as a central component controlling flow and transport. DFN are stochastic models of fracture architecture that incorporate statistical scaling rules derived from analysis of fracture length, height, spacing, orientation, and aperture. This study is focused on developing a methodology for application of DFN to a shale gas reservoir and the practical application of DFN simulator (FracGen and NFflow) for fracture modeling of a shale gas reservoir and also studies the interaction of the different fracture properties on reservoir response. The most important results of the study are that a uniform fracture network distribution and fracture aperture produces the highest cumulative gas production for the different fracture networks and fracture/well properties considered.

Ogbechie, Joachim Nwabunwanne

2011-12-01T23:59:59.000Z

318

Liquefied Natural Gas (LNG) Vapor Dispersion Modeling with Computational Fluid Dynamics Codes  

E-Print Network (OSTI)

Federal regulation 49 CFR 193 and standard NFPA 59A require the use of validated consequence models to determine the vapor cloud dispersion exclusion zones for accidental liquefied natural gas (LNG) releases. For modeling purposes, the physical process of dispersion of LNG release can be simply divided into two stages: source term and atmospheric dispersion. The former stage occurs immediately following the release where the behavior of fluids (LNG and its vapor) is mainly controlled by release conditions. After this initial stage, the atmosphere would increasingly dominate the vapor dispersion behavior until it completely dissipates. In this work, these two stages are modeled separately by a source term model and a dispersion model due to the different parameters used to describe the physical process at each stage. The principal focus of the source term study was on LNG underwater release, since there has been far less research conducted in developing and testing models for the source of LNG release underwater compared to that for LNG release onto land or water. An underwater LNG release test was carried out to understand the phenomena that occur when LNG is released underwater and to determine the characteristics of pool formation and the vapor cloud generated by the vaporization of LNG underwater. A mathematical model was used and validated against test data to calculate the temperature of the vapor emanating from the water surface. This work used the ANSYS CFX, a general-purpose computational fluid dynamics (CFD) package, to model LNG vapor dispersion in the atmosphere. The main advantages of CFD codes are that they have the capability of defining flow physics and allowing for the representation of complex geometry and its effects on vapor dispersion. Discussed are important parameters that are essential inputs to the ANSYS CFX simulations, including the mesh size and shape, atmospheric conditions, turbulence from the source term, ground surface roughness height, and effects of obstacles. A sensitivity analysis was conducted to illustrate the impact of key parameters on the accuracy of simulation results. In addition, a series of medium-scale LNG spill tests have been performed at the Brayton Fire Training Field (BFTF), College Station, TX. The objectives of these tests were to study key parameters of modeling the physical process of LNG vapor dispersion and collect data for validating the ANSYS CFX prediction results. A comparison of test data with simulation results demonstrated that CFX described the physical behavior of LNG vapor dispersion well, and its prediction results of distances to the half lower flammable limit were in good agreement with the test data.

Qi, Ruifeng

2011-08-01T23:59:59.000Z

319

Fast and informative flow simulation in a building by using fast...  

NLE Websites -- All DOE Office Websites (Extended Search)

and informative flow simulation in a building by using fast fluid dynamics model on graphics processing unit Title Fast and informative flow simulation in a building by using...

320

A Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei  

Open Energy Info (EERE)

Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Caldera Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Caldera Details Activities (0) Areas (0) Regions (0) Abstract: We present here a consistent model, which explains the mechanisms of unrest phenomena at Campi Flegrei (Italy), both at short-term (years) and at secular scales. The model consists basically of two effects: the first one is related to the elastic response of the shallow crust to increasing pressure within a shallow magma chamber; the second involves the fluid-dynamics of shallow aquifers in response to increasing pressure and/or temperature at depth. The most important roles in the proposed model

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Interfacial exchange relations for two-fluid vapor-liquid flow : a simplified regime map approach  

E-Print Network (OSTI)

A simplified approach is described for selection of the constitutive relations for the inter-phase exchange terms in the two-fluid code, THERMIT. The approach used distinguishes between pre-CHF and post-CHF conditions. ...

Kelly, J. E.

1981-01-01T23:59:59.000Z

322

Modeling Flows Around Merging Black Hole Binaries  

E-Print Network (OSTI)

Coalescing massive black hole binaries are produced by the mergers of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne LISA. In cases where the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a step towards solving this problem by mapping the flow of pressureless matter in the dynamic, 3-D general relativistic spacetime around the merging black holes. We find qualitative differences in collision and outflow speeds, including a signature of the merger when the net angular momentum of the matter is low, between the results from single and binary black holes, and between nonrotating and rotating holes in binaries. If future magnetohydrodynamic results confirm these differences, it may allow assessment of the properties of the binaries as well as yielding an identifiable electromagnetic counterpart to the attendant gravitational wave signal.

James R. van Meter; John H. Wise; M. Coleman Miller; Christopher S. Reynolds; Joan M. Centrella; John G. Baker; William D. Boggs; Bernard J. Kelly; Sean T. McWilliams

2009-07-31T23:59:59.000Z

323

Review: Application of computational fluid dynamics for modeling and designing photobioreactors for microalgae production: A review  

Science Conference Proceedings (OSTI)

The past decade has seen a rapid increase of numerical simulation studies on photobioreactors (PBRs). Developments in computational fluid dynamics (CFD) and the availability of more powerful computers have paved the way for the modeling and designing ... Keywords: Computational fluid dynamics (CFD), Computer simulation, Microalgae, Photobioreactors

J. P. Bitog; I. -B. Lee; C. -G. Lee; K. -S. Kim; H. -S. Hwang; S. -W. Hong; I. -H. Seo; K. -S. Kwon; E. Mostafa

2011-05-01T23:59:59.000Z

324

Importance of considering intraborehole flow in solute transport modeling under highly dynamic flow conditions  

SciTech Connect

Correct interpretation of tracer test data is critical for understanding transport processes in the subsurface. This task can be greatly complicated by the presence of intraborehole flows in a highly dynamic flow environment. At a new tracer test site (Hanford IFRC) a dynamic flow field created by changes in the stage of the adjacent Columbia River, coupled with a heterogeneous hydraulic conductivity distribution, leads to considerable variations in vertical hydraulic gradients. These variations, in turn, create intraborehole flows in fully-screened (6.5 m) observation wells with frequently alternating upward and downward movement. This phenomenon, in conjunction with a highly permeable aquifer formation and small horizontal hydraulic gradients, makes modeling analysis and model calibration a formidable challenge. Groundwater head data alone were insufficient to define the flow model boundary conditions, and the movement of the tracer was highly sensitive to the dynamics of the flow field. This study shows that model calibration can be significantly improved by explicitly considering (a) dynamic flow model boundary conditions and (b) intraborehole flow. The findings from this study underscore the difficulties in interpreting tracer tests and understanding solute transport under highly dynamic flow conditions.

Ma, Rui; Zheng, Chunmiao; Tonkin, Matthew J.; Zachara, John M.

2011-04-01T23:59:59.000Z

325

A mountain-scale model for characterizing unsaturated flow and transport in fractured tuffs of Yucca Mountain  

E-Print Network (OSTI)

development and analysis of radionuclide transport in theinvestigate fluid flow and radionuclide transport processeson moisture flow and radionuclide transport within or near

Wu, Yu-Shu; Lu, Guoping; Zhang, Keni; Bodvarsson, G.S.

2003-01-01T23:59:59.000Z

326

Electrochemical Model of the Fe/V Redox Flow Battery  

Science Conference Proceedings (OSTI)

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.

Stephenson, David E.; Kim, Soowhan; Chen, Feng; Thomsen, Edwin C.; Viswanathan, Vilayanur V.; Wang, Wei; Sprenkle, Vincent L.

2012-11-05T23:59:59.000Z

327

Raindrop Oscillations: Evaluation of a Potential Flow Model with Gravity  

Science Conference Proceedings (OSTI)

Potential flow oscillations about an equilibrium raindrop distortion were modeled for ellipsoidal variations driven by changes in surface and gravitational potential energy with linear dissipation of kinetic energy. The model was found to be ...

Kenneth V. Beard

1984-05-01T23:59:59.000Z

328

Synthetic benchmark for modeling flow in 3D fractured media  

Science Conference Proceedings (OSTI)

Intensity and localization of flows in fractured media have promoted the development of a large range of different modeling approaches including Discrete Fracture Networks, pipe networks and equivalent continuous media. While benchmarked usually within ... Keywords: Benchmark, Fractured media, Single-phase flow, Stochastic model

Jean-Raynald De Dreuzy; GéRaldine Pichot; Baptiste Poirriez; Jocelyne Erhel

2013-01-01T23:59:59.000Z

329

Measurement of Flow Phenomena in a Lower Plenum Model of a Prismatic Gas-Cooled Reactor  

Science Conference Proceedings (OSTI)

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 12,400. Uncertainty analysis and a discussion of the standard problem are included. The measurements reveal undeveloped, non-uniform, turbulent flow in the inlet jets and complicated flow patterns in the model lower plenum. Data include three-dimensional vector plots, data displays along the coordinate planes (slices) and presentations that describe the component flows at specific regions in the model. Information on inlet conditions are also presented.

Hugh M. McIlroy, Jr.; Donald M. McEligot; Robert J. Pink

2008-05-01T23:59:59.000Z

330

Diffusion driven object propulsion in density stratified fluids  

E-Print Network (OSTI)

An experimental study was conducted in order to verify the appropriateness of a two dimensional model of the flow creating diffusion driven object propulsion in density stratified fluids. Initial flow field experiments ...

Lenahan, Conor (Conor P.)

2009-01-01T23:59:59.000Z

331

Transient Heat and Material Flow Modeling of Friction Stir Processing of Magnesium Alloy using Threaded Tool  

SciTech Connect

A three-dimensional transient computational fluid dynamics (CFD) model was developed to investigate the material flow and heat transfer during friction stir processing (FSP) in an AZ31B magnesium alloy. The material was assumed to be a non-Newtonian viscoplastic fluid, and the Zener-Hollomon parameter was used to describe the dependence of material viscosity on temperature and strain rate. The material constants used in the constitutive equation were determined experimentally from compression tests of the AZ31B Mg alloy under a wide range of strain rates and temperatures. A dynamic mesh method, combining both Lagrangian and Eulerian formulations, was used to capture the material flow induced by the movement of the threaded tool pin. Massless inert particles were embedded in the simulation domain to track the detailed history of material flow. The actual FSP was also carried out on a wrought Mg plate where temperature profiles were recorded by embedding thermocouples. The predicted transient temperature history was found to be consistent with that measured during FSP. Finally, the influence of the thread on the simulated results of thermal history and material flow was studied by comparing two models: one with threaded pin and the other with smooth pin surface.

Yu, Zhenzhen [ORNL; Zhang, Wei [ORNL; Choo, Hahn [ORNL; Feng, Zhili [ORNL

2012-01-01T23:59:59.000Z

332

Numerical and experimental investigations on vibration of simulated CANDU fuel bundles subjected to turbulent fluid flow.  

E-Print Network (OSTI)

??Vibration of simulated CANDU fuel bundles induced by coolant flow is investigated in this thesis through experiments and numerical simulations. Two simulated bundles and a… (more)

Zhang, Xuan

2011-01-01T23:59:59.000Z

333

A unified numerical framework model for simulating flow, transport, and heat transfer in porous and fractured media  

E-Print Network (OSTI)

fluid flow, multicomponent transport, and heat transfer in porous and fractured media,fluid flow, solute transport, and heat transfer occur in porous and fractured media.fluid flow, mass transport, and heat-transfer processes through porous and fractured media.

Wu, Yu-Shu

2004-01-01T23:59:59.000Z

334

Magnetohydrodynamic Model Coupling Multiphase Flow in ...  

Science Conference Proceedings (OSTI)

Compact Filter Design for Gas Treatment Centers ... Gas-Solid Flow Applications for Powder Handling in Aluminum Smelters Processes ... Replacement of Damaged Electrical Insulators on Live Cross-Over Busbars inside a Tunnel: A ...

335

Spacelike Ricci Inheritance Vectors in a Model of String Cloud and String Fluid Stress Tensor  

E-Print Network (OSTI)

We study the consequences of the existence of spacelike Ricci inheritance vectors (SpRIVs) parallel to $x^a$ for model of string cloud and string fluid stress tensor in the context of general relativity. Necessary and sufficient conditions are derived for a spacetime with a model of string cloud and string fluid stress tensor to admit a SpRIV and a SpRIV which is also a spacelike conformal Killing vector (SpCKV). Also, some results are obtained.

H. Baysal; I. Yilmaz

2005-05-02T23:59:59.000Z

336

MIT-CTP-3519 Symmetries of Discontinuous Flows and the Dual Rankine-Hugoniot Conditions in Fluid Dynamics  

E-Print Network (OSTI)

It has recently been shown that the maximal kinematical invariance group of polytropic fluids, for smooth subsonic flows, is the semidirect product of SL(2, R) and the static Galilei group G. This result purports to offer a theoretical explanation for an intriguing similarity, that was recently observed, between a supernova explosion and a plasma implosion. In this paper we extend this result to discuss the symmetries of discontinuous flows, which further validates the explanation by taking into account shock waves, which are the driving force behind both the explosion and implosion. This is accomplished by constructing a new set of Rankine-Hugoniot conditions, which follow from Noether’s conservation laws. The new set is dual to the standard Rankine-Hugoniot conditions and is related to them through the SL(2, R) transformations. The entropy condition, that the shock needs to satisfy for physical reasons, is also seen to remain invariant under the transformations.

Oliver Jahn; V. V. Sreedhar; Amitabh Virmani

2004-01-01T23:59:59.000Z

337

A Model For The Transient Temperature Effects Of Horizontal Fluid...  

Open Energy Info (EERE)

to flow along a thin aquifer buried at a depth l from the surface with conductive heat transfer into the rocks both above and below the aquifer. In many geothermal systems...

338

Global Stability Analysis of Fluid Flows using Sum-of-Squares  

E-Print Network (OSTI)

flow is globally stable, if the flow does remain globally stable for Reynolds numbers at least ... ?v1,v2 · ?v3? = ??v3,v2 · ?v1?,. (2) ... Note that the nonlinear term u·?u in (4a) does not feature in the energy equation ...... Transactions on Automatic Control, 54(5):1007–1011, May 2009. ... Handbook of semidefinite program-.

339

Experimental Modeling of VHTR Plenum Flows during Normal Operation and Pressurized Conduction Cooldown  

DOE Green Energy (OSTI)

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.

Glenn E McCreery; Keith G Condie

2006-09-01T23:59:59.000Z

340

Formulation, Implementation and Validation of a Two-Fluid model in a Fuel Cell CFD Code  

SciTech Connect

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 more complications. A general approach would be to form a mixture continuity equation by linearly combining the phasic continuity equations using appropriate weighting factors. Analogous to mixture equation for pressure correction, a difference equation is used for the volume/phase fraction by taking the difference between the phasic continuity equations. The relative advantages of the above mentioned algorithmic variants for computing pressure correction and volume fractions are discussed and quantitatively assessed. Preliminary model validation is done for each component of the fuel cell. The two-phase transport in the channel is validated using empirical correlations. Transport in the GDL is validated against results obtained from LBM and VOF simulation techniques. The Channel-GDL interface transport will be validated against experiment and empirical correlation of droplet detachment at the interface. References [1] Y. Wang S. Basu and C.Y. Wang. Modeling two-phase flow in pem fuel cell channels. J. Power Sources, 179:603{617, 2008. [2] P. K. Sinha and C. Y. Wang. Liquid water transport in a mixed-wet gas diffusion layer of a polymer electrolyte fuel cell. Chem. Eng. Sci., 63:1081-1091, 2008. [3] Guangyu Lin and Trung Van Nguyen. A two-dimensional two-phase model of a pem fuel cell. J. Electrochem. Soc., 153(2):A372{A382, 2006. [4] T. Berning and N. Djilali. A 3d, multiphase, multicomponent model of the cathode and anode of a pem fuel cell. J. Electrochem. Soc., 150(12):A1589{A1598, 2003.

Kunal Jain, Vernon Cole, Sanjiv Kumar and N. Vaidya

2008-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Analysis of fluid flow and heat transfer in a rib grit roughened surface solar air heater using CFD  

SciTech Connect

This paper presents the study of fluid flow and heat transfer in a solar air heater by using Computational Fluid Dynamics (CFD) which reduces time and cost. Lower side of collector plate is made rough with metal ribs of circular, square and triangular cross-section, having 60 inclinations to the air flow. The grit rib elements are fixed on the surface in staggered manner to form defined grid. The system and operating parameters studied are: e/D{sub h} = 0.044, p/e = 17.5 and l/s = 1.72, for the Reynolds number range 3600-17,000. To validate CFD results, experimental investigations were carried out in the laboratory. It is found that experimental and CFD analysis results give the good agreement. The optimization of rib geometry and its angle of attack is also done. The square cross-section ribs with 58 angle of attack give maximum heat transfer. The percentage enhancement in the heat transfer for square plate over smooth surface is 30%. (author)

Karmare, S.V. [Department of Mechanical Engineering, Government College Engineering, Karad 415 124, Maharashtra (India); Shivaji University, Kolhapur, Maharashtra (India); Tikekar, A.N. [Department of Mechanical Engineering, Walchand College of Engineering, Sangli (India); Shivaji University, Kolhapur, Maharashtra (India)

2010-03-15T23:59:59.000Z

342

ICPIG, July 15-20, 2007, Prague, Czech Republi Negative streamer fronts: comparison of particle and fluid models and  

E-Print Network (OSTI)

. This front region is also important for the generation of high energy electrons in streamer and leader. Fluid model The fluid model approximates the average dynamics of the local electrons as local densitiesV is the ionization energy. Panel (d) zooms into panel (c), both in space and in densities. Both fluid and particle

Ebert, Ute

343

Combined seismic and hydraulic method of modeling flow in fractured low permeability rocks  

DOE Green Energy (OSTI)

Modeling flow of ground water in hard rocks where a network of fractures provides the dominant flow paths is a major problem. This paper summarizes a program of investigations currently underway in this laboratory to characterize the geometry of fractured rocks and develop methods of handling flow in such systems. Numerical models have been developed to investigate flow behavior in two- and three-dimensional fracture networks. The results demonstrate the insights that can be gained from modeling studies of fractured rocks. A key problem is gathering the necessary data on fracture geometry. Investigations have been started to determine how vertical seismic profiling (VSP) might be improved and applied to this problem. A VSP experiment in The Geysers geothermal field in northern California, where fracture orientation is known, produced shear wave splitting and velocity anisotropy in agreement with theory. The results suggest the potential application of 3-component, multi-source VSP data in determining fracture orientation and average spacing. We believe a combination of seismic and hydraulic methods can greatly enhance an understanding of fluid flow and transport in low permeability rock systems where fractures provide the dominant paths. 40 refs, 16 figs., 4 tabs.

Witherspoon, P.A.; Long, J.C.S.; Majer, E.L.; Myer, L.R.

1987-06-01T23:59:59.000Z

344

DENSE MULTIPHASE FLOW SIMULATION: CONTINUUM MODEL FOR POLY-DISPERSED SYSTEMS USING KINETIC THEORY  

SciTech Connect

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.

Moses Bogere

2011-08-31T23:59:59.000Z

345

COMPUTATIONAL FLUID DYNAMICS MODELING OF SCALED HANFORD DOUBLE SHELL TANK MIXING - CFD MODELING SENSITIVITY STUDY RESULTS  

SciTech Connect

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.

JACKSON VL

2011-08-31T23:59:59.000Z

346

Development of a model to predict flow oscillations in low-flow sodium boiling. [Loss-of-Piping Integrity accidents  

Science Conference Proceedings (OSTI)

Tests performed in a small scale water loop showed that voiding oscillations, similar to those observed in sodium, were present in water, as well. An analytical model, appropriate for either sodium or water, was developed and used to describe the water flow behavior. The experimental results indicate that water can be successfully employed as a sodium simulant, and further, that the condensation heat transfer coefficient varies significantly during the growth and collapse of vapor slugs during oscillations. It is this variation, combined with the temperature profile of the unheated zone above the heat source, which determines the oscillatory behavior of the system. The analytical program has produced a model which qualitatively does a good job in predicting the flow behavior in the wake experiment. The amplitude discrepancies are attributable to experimental uncertainties and model inadequacies. Several parameters (heat transfer coefficient, unheated zone temperature profile, mixing between hot and cold fluids during oscillations) are set by the user. Criteria for the comparison of water and sodium experiments have been developed.

Levin, A.E.; Griffith, P.

1980-04-01T23:59:59.000Z

347

Theoretical Studies of Non-Newtonian and Newtonian Fluid Flow through Porous Media  

E-Print Network (OSTI)

of Multicomponent, Multiphase Displacement in Porous Media,"C. M. (1981) : Multiphase Flow in Porous Media, Technip,porous media can always be considered as a special case of the multiphase

Wu, Y.S.

1990-01-01T23:59:59.000Z

348

TOUGH Simulations of the Updegraff's Set of Fluid and Heat Flow Problems  

E-Print Network (OSTI)

in Porous Media," SAND84-2057, Sandia National Laboratories,and Field Comparison of the Sandia . Waste-Isolation FlowNUREG/CR-3316, SAND83- 1154, Sandia National Laboratories,

Moridis, G.J.

2010-01-01T23:59:59.000Z

349

Stratified Flow over Two-Dimensional Topography in Fluid of Infinite Depth: A Laboratory Simulation  

Science Conference Proceedings (OSTI)

This paper describes some laboratory experiments with two-dimensional stratified flow over isolated topography, in which a novel configuration simulating a radiating upper boundary condition is employed. Several experimental tests show that the ...

Peter G. Baines; Klaus P. Hoinka

1985-08-01T23:59:59.000Z

350

Solyndra Facts vs. Fiction: Cash Flow Modeling | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

You are here You are here Home » Solyndra Facts vs. Fiction: Cash Flow Modeling Solyndra Facts vs. Fiction: Cash Flow Modeling September 23, 2011 - 5:25pm Addthis 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." The cash flow models never said that Solyndra (the parent company) would run short of cash in September 2011. The email noted that the subsidiary was projected to have relatively low levels of cash in one particular month, and that the parent company would need to make up any potential shortfall.

351

ESS 2012 Peer Review - Flow Battery Modeling - Mario Martinez, SNL  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Photos placed in horizontal position with even amount of white space between photos and header Photos placed in horizontal position with even amount of white space between photos and header Flow Battery Modeling Energy Storage Systems Peer Review September 26-28, 2012 MJ Martinez (PI), J Clausen, SM Davison, HK Moffat Flow Battery Modeling Schematic of a Flow Battery PURPOSE: The flow battery modeling task seeks to improve fundamental understanding and enable high-performing, low-cost designs of flow batteries through

352

Measurement of Flow Phenomena in a Lower Plenum Model of a Prismatic Gas-Cooled Reactor  

Science Conference Proceedings (OSTI)

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. 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 geometry 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 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 bulk velocity) are approximately 4,300 and 12,400. Uncertainty analyses and a discussion of the standard problem are included. The measurements reveal developing, non-uniform, turbulent flow in the inlet jets and complicated flow patterns in the model lower plenum. Data include three-dimensional vector plots, data displays along the coordinate planes (slices) and presentations that describe the component flows at specific regions in the model. Information on inlet conditions is also presented.

Hugh M. McIlroy, Jr.; Doanld M. McEligot; Robert J. Pink

2010-02-01T23:59:59.000Z

353

Capillary instability in models for three-phase flow  

Science Conference Proceedings (OSTI)

Standard models for immiscible three-phase flow in porous media exhibit unusual behavior associated with loss of strict hyperbolicity. Anomalies were at one time thought to be confined to the region of nonhyperbolicity, where the purely convective form ... Keywords: capillary pressure instability, flow in porous media, nonunique Riemann solution

A. V. Azevedo; D. Marchesin; B. Plohr; K. Zumbrun

2002-09-01T23:59:59.000Z

354

Discrete-element modeling of particulate aerosol flows  

Science Conference Proceedings (OSTI)

A multiple-time step computational approach is presented for efficient discrete-element modeling of aerosol flows containing adhesive solid particles. Adhesive aerosol particulates are found in numerous dust and smoke contamination problems, including ... Keywords: Aerosols, Aggregation, Particle adhesion, Particulate flow

J. S. Marshall

2009-03-01T23:59:59.000Z

355

The Entropy Solutions for the Lighthill-Whitham-Richards Traffic Flow Model with a Discontinuous Flow-Density Relationship  

Science Conference Proceedings (OSTI)

In this paper we explicitly construct the entropy solutions for the Lighthill-Whitham-Richards (LWR) traffic flow model with a flow-density relationship which is piecewise quadratic, concave, but not continuous at the junction points where two quadratic ... Keywords: LWR model, WENO scheme, discontinuous flow-density relationship, entropy solution, traffic flow

Yadong Lu; S. C. Wong; Mengping Zhang; Chi-Wang Shu

2009-11-01T23:59:59.000Z

356

Two-dimensional fluid model simulation of bell jar top inductively coupled plasma  

SciTech Connect

In the present paper, argon (Ar) plasmas in a bell jar inductively coupled plasma (ICP) source are systematically studied over pressures from 5 to 20 mtorr and power inputs from 0.2 to 0.5 kW. In this study, both a two-dimensional (2-D) fluid model simulation and global model calculation are compared. The 2-D fluid model simulation with a self-consistent power deposition is developed to describe the Ar plasma behavior as well as predict the plasma parameter distributions. Finally, a quantitative comparison between the global model and the fluid model is made to test their validity. Low-pressure ICP has been employed for etching processing for the last few years.

Wu, H.M.; Yu, B.W. [CFD Research Corp., Huntsville, AL (United States); Li, M. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering; Yang, Y. [Chinese Academy of Sciences, Beijing (China). Inst. of Mechanics

1997-02-01T23:59:59.000Z

357

Analysis and macroscopic limit of a one-dimensional model for aging fluids  

E-Print Network (OSTI)

We study a one-dimensional equation arising in the multiscale modeling of some non-Newtonian fluids. At a given shear rate, the equation provides the instantaneous mesoscopic response of the fluid, allowing to compute the corresponding stress. In a simple setting, we study the well-posedness of the equation and next the long-time behavior of its solution. In the limit of a response of the fluid much faster than the time variations of the ambient shear rate, we derive some equivalent macroscopic differential equations that relate the shear rate and the stress. Our analytical conclusions are confronted to some numerical experiments. The latter quantitatively confirm our derivations.

David Benoit; Claude Le Bris; Tony Leličvre

2013-10-15T23:59:59.000Z

358

Fluid turbine  

SciTech Connect

A fluid turbine designed for increased power output includes an annular housing provided with a semi-spherical dome for directing incoming fluid flow to impinge on a plurality of rotor blades within the housing fixed to a vertical output shaft. An angle on the order of between 5 to 85/sup 0/, in the direction of rotation of the shaft, exists between the upper (Leading) and lower (Trailing) edges of each blade. The blades are manufactured from a plurality of aerodynamically-shaped, radially spaced ribs covered with a skin. The leading edge of each rib is curved, while the trailing edge is straight. The straight edge of the ribs in each blade approach a vertical plane through the vertical axis of the housing output shaft as the ribs progress radially inwardly towards the output shaft. The housing has fluid exit passages in its base so that deenergized fluid can be quickly flushed from the housing by the downwardly directed flow in combination with the novel blade configuration, which acts as a screw or force multiplier, to expel deenergized fluid. The airfoil shaped ribs also provide the blades with a contour for increasing the fluid velocity on the underside of the blades adjacent the fluid exit passage to aid in expelling the deenergized air while providing the turbine with both impulse and axial-flow, fluid impingement on the blades, resulting in a force vector of increased magnitude. A downwardly directed, substantially semi-cylindrical deflector frame connected to the housing blocks the path of flow of ambient fluid to create a low pressure area beneath the base to aid in continuously drawing fluid into the housing at high velocity to impinge on the rotor blades. The increased flow velocity and force on the blades along with the enhanced removal of deenergized fluid results in increased power output of the turbine.

Lebost, B.A.

1980-11-18T23:59:59.000Z

359

A Novel Hyperbolization Procedure for The Two-Phase Six-Equation Flow Model  

SciTech Connect

We introduce a novel approach for the hyperbolization of the well-known two-phase six equation flow model. The six-equation model has been frequently used in many two-phase flow applications such as bubbly fluid flows in nuclear reactors. One major drawback of this model is that it can be arbitrarily non-hyperbolic resulting in difficulties such as numerical instability issues. Non-hyperbolic behavior can be associated with complex eigenvalues that correspond to characteristic matrix of the system. Complex eigenvalues are often due to certain flow parameter choices such as the definition of inter-facial pressure terms. In our method, we prevent the characteristic matrix receiving complex eigenvalues by fine tuning the inter-facial pressure terms with an iterative procedure. In this way, the characteristic matrix possesses all real eigenvalues meaning that the characteristic wave speeds are all real therefore the overall two-phase flowmodel becomes hyperbolic. The main advantage of this is that one can apply less diffusive highly accurate high resolution numerical schemes that often rely on explicit calculations of real eigenvalues. We note that existing non-hyperbolic models are discretized mainly based on low order highly dissipative numerical techniques in order to avoid stability issues.

Samet Y. Kadioglu; Robert Nourgaliev; Nam Dinh

2011-10-01T23:59:59.000Z

360

Fluid Metrology Calibration Services - Gas, Water, or Liquid ...  

Science Conference Proceedings (OSTI)

Fluid Metrology Calibration Services - Gas, Water, Natural Gas, or Liquid Hydrocarbon Flows Special Tests. Fluid Metrology ...

2013-01-25T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Modeling and design of semi-solid flow batteries  

E-Print Network (OSTI)

A three-dimensional dynamic model of the recently introduced semi-solid flow battery system is developed and applied to address issues with important design and operation implications. Because of the high viscosity of ...

Brunini, Victor Eric

2012-01-01T23:59:59.000Z

362

ESS 2012 Peer Review - Flow Battery Modeling - Mario Martinez...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

in horizontal position with even amount of white space between photos and header Flow Battery Modeling Energy Storage Systems Peer Review September 26-28, 2012 MJ Martinez (PI), J...

363

Numerical models for high beta magnetohydrodynamic flow  

Science Conference Proceedings (OSTI)

The fundamentals of numerical magnetohydrodynamics for highly conducting, high-beta plasmas are outlined. The discussions emphasize the physical properties of the flow, and how elementary concepts in numerical analysis can be applied to the construction of finite difference approximations that capture these features. The linear and nonlinear stability of explicit and implicit differencing in time is examined, the origin and effect of numerical diffusion in the calculation of convective transport is described, and a technique for maintaining solenoidality in the magnetic field is developed. Many of the points are illustrated by numerical examples. The techniques described are applicable to the time-dependent, high-beta flows normally encountered in magnetically confined plasmas, plasma switches, and space and astrophysical plasmas. 40 refs.

Brackbill, J.U.

1987-01-01T23:59:59.000Z

364

Perturbative analysis of sheared flow Kelvin-Helmholtz instability in a weakly relativistic magnetized electron fluid  

Science Conference Proceedings (OSTI)

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.

Sundar, Sita; Das, Amita; Kaw, Predhiman [Institute for Plasma Research, Bhat, Gandhinagar-382428 (India)

2012-05-15T23:59:59.000Z

365

Modeling of material and energy flow in an EBCHR casting system  

Science Conference Proceedings (OSTI)

A numerical and experimental analysis is made of fluid flow and heat transfer in a continuous casting system with an electron-beam energy source. For a cylindrical ingot confined in a water-cooled crucible, a two-dimensional, steady-state model is developed which includes the effects of free convection in the pool and conduction in the two-phase and solid regions. A modified Galerkin finite element method is used to solve for the flow and temperature fields simultaneously with the upper and lower boundaries of the pool. The calculation grid deforms along vertical spines as these phase boundaries move. Heat flows are measured in a steady-state experiment involving a short ingot and no pouring. Heat transfer coefficients representing contact resistance are determined, and measured heat flows are compared with model values. Flow and temperature fields along with solidification-zone boundaries are calculated for the experimental case and a case in which the ingot cooling is improved.

Westerberg, K.W. [Aspen Technology, Inc., Cambridge, MA (United States); McClelland, M.A. [Lawrence Livermore National Lab., CA (United States)

1994-11-01T23:59:59.000Z

366

Incorporation of aqueous reaction kinetics and biodegradation into TOUGHREACT: Application of a multi-region model to hydrobiogeoChemical transport of denitrification and sulfate reduction  

E-Print Network (OSTI)

for modeling fluid and heat flow in fractured porous media:1985) for fluid and heat flow in fractured porous media. Theflows of multiphase fluids in porous and fractured media.

Xu, Tianfu

2008-01-01T23:59:59.000Z

367

Under consideration for publication in J. Fluid Mech. 1 Inviscid mean flow through and around  

E-Print Network (OSTI)

velocity is negligible (as the void fraction of the bodies, 0). Within wide and short rectangular arrays of bodies, the average velocity of bubbly flows as a function of void fraction, and the tendency of clouds for void fractions close to 0.1 (Couet, Brown & Hunt 1991). The distinction between different contributions

Reading, University of

368

Microsoft PowerPoint - Development of a Two-Fluid_Gokaltun  

NLE Websites -- All DOE Office Websites (Extended Search)

M., Particle-Fluid Two-Phase Flow: the Energy-Minimization Multi-Scale Method; Metallurgy. Beijing: Industry Press, 1994. (2) Benyahia, S., Analysis of Model Parameters...

369

Multiphase fluid flow and subsequent geochemical transport in variably saturated fractured rocks: 1. Approaches  

E-Print Network (OSTI)

dissolution and precipitation. Here we present a comprehensive modeling approach and numerical methods

Xu, Tianfu; Pruess, Karsten

2000-01-01T23:59:59.000Z

370

A stochastic index flow model of flow duration curves Attilio Castellarin  

E-Print Network (OSTI)

2004; published 10 March 2004. [1] Annual flow duration curves (AFDCs) are used increasingly because for the median AFDC, they enable one to assign return periods to individual AFDCs, and they offer opportunities for developing a generalized stochastic model of daily streamflow. Previous stochastic models of FDCs and AFDCs

Vogel, Richard M.

371

A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic simulations  

E-Print Network (OSTI)

A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic conditions with turbine models covering the range of scales important for wind plant dynamics to help address the impacts that upwind turbines have on turbines in their wake and give greater insight into overall wind

372

Coupling remote sensing with computational fluid dynamics modelling to estimate lake chlorophyll-a concentration  

E-Print Network (OSTI)

Coupling remote sensing with computational fluid dynamics modelling to estimate lake chlorophyll form 17 October 2000; accepted 1 June 2001 Abstract A remotely sensed image of Loch Leven, a shallow in the remotely sensed image. It is proposed that CFD modelling benefits the interpretation of remotely sensed

373

A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic simulations  

E-Print Network (OSTI)

A next-generation modeling capability assesses wind turbine array fluid dynamics and aeroelastic of multi-megawatt turbines requires a new generation of modeling capability to assess individual turbine performance as well as detailed turbine- turbine and turbine-atmosphere interactions. Scientists

374

Efficient Algorithms for Modeling Reacting Flows  

NLE Websites -- All DOE Office Websites (Extended Search)

the development of efficient numerical algorithms that reduce the time required to model combustion phenomena are of great interest. In this talk I will present the development...

375

Design of a continuous-flow reactor for in situ x-ray absorption spectroscopy of solids in supercritical fluids  

Science Conference Proceedings (OSTI)

This paper presents the design and performance of a novel high-temperature and high-pressure continuous-flow reactor, which allows for x-ray absorption spectroscopy or diffraction in supercritical water and other fluids under high pressure and temperature. The in situ cell consists of a tube of sintered, polycrystalline aluminum nitride, which is tolerant to corrosive chemical media, and was designed to be stable at temperatures up to 500 deg. C and pressures up to 30 MPa. The performance of the reactor is demonstrated by the measurement of extended x-ray absorption fine structure spectra of a carbon-supported ruthenium catalyst during the continuous hydrothermal gasification of ethanol in supercritical water at 400 deg. C and 24 MPa.

Dreher, M.; De Boni, E.; Nachtegaal, M.; Wambach, J.; Vogel, F. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)

2012-05-15T23:59:59.000Z

376

Proceedings: Joint DOE/NSF Workshop on flow of particulates and fluids  

Science Conference Proceedings (OSTI)

These proceedings are the result of the Fifth DOR-NSF Workshop on fundamental research in the area of particulate two-phase flow and granular flow. The present collection of twenty contributions from universities and national laboratories is based on research projects sponsored by either the Department of Energy or the National Science Foundation. These papers illustrate some of the latest advances in theory, simulations, and experiments. The papers from the Workshop held September 29--October 1, 1993 have been separated into three basic areas: experiments, theory, and numerical simulations. A list of attendees at the workshop is included at the end of the proceedings. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

Not Available

1993-12-31T23:59:59.000Z

377

Fluid-based analysis of a network of AQM routers supporting TCP flows with an application to RED  

Science Conference Proceedings (OSTI)

In this paper we use jump process driven Stochastic Differential Equations to model the interactions of a set of TCP flows and Active Queue Management routers in a network setting. We show how the SDEs can be transformed into a set of Ordinary Differential ...

Vishal Misra; Wei-Bo Gong; Don Towsley

2000-08-01T23:59:59.000Z

378

Modeling and Simulation of Fluid Mixing Laser Experiments and Supernova  

SciTech Connect

The three year plan for this project is to develop novel theories and advanced simulation methods leading to a systematic understanding of turbulent mixing. A primary focus is the comparison of simulation models (both Direct Numerical Simulation and subgrid averaged models) to experiments. The comprehension and reduction of experimental and simulation data are central goals of this proposal. We will model 2D and 3D perturbations of planar interfaces. We will compare these tests with models derived from averaged equations (our own and those of others). As a second focus, we will develop physics based subgrid simulation models of diffusion across an interface, with physical but no numerical mass diffusion. We will conduct analytic studies of mix, in support of these objectives. Advanced issues, including multiple layers and reshock, will be considered.

Glimm, James

2008-06-24T23:59:59.000Z

379

Towards improved methods for determining porous media multiphase flow functions.  

E-Print Network (OSTI)

??The mathematical modeling and simulation of the flow of fluid through porous media are important in many areas. Relative permeability and capillary pressure functions are… (more)

Xue, Song

2004-01-01T23:59:59.000Z

380

Flow Model Development for the Idaho National Laboratory OU 10-08 Sitewide Groundwater Model  

SciTech Connect

A two-dimensional (2D), steady-state groundwater flow model was developed for the Idaho National Laboratory (INL) sitewide groundwater model. A total of 224 wells inside the model domain were used to calibrate the 2D flow model. Three different calibration techniques, zonation approach, pilot point approach and coupled zonation/pilot point approach, were explored and applied during the model development. The pilot point approach allows modelers to model aquifer heterogeneities at various scales, and extract the maximum amount of data from available monitoring data, permitting the best possible representation of flow and transport at the INL.

Hai Huang; Swen Magnuson; Thomas Wood

2005-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Energy stability analysis for a hybrid fluid-kinetic plasma model  

E-Print Network (OSTI)

In plasma physics, a hybrid fluid-kinetic model is composed of a magnetohydrodynamics (MHD) part that describes a bulk fluid component and a Vlasov kinetic theory part that describes an energetic plasma component. While most hybrid models in the plasma literature are non-Hamiltonian, this paper investigates a recent Hamiltonian variant in its two-dimensional configuration. The corresponding Hamiltonian structure is described along with its Casimir invariants. Then, the energy-Casimir method is used to derive explicit sufficient stability conditions, which imply a stable spectrum and suggest nonlinear stability.

Philip J. Morrison; Emanuele Tassi; Cesare Tronci

2013-06-11T23:59:59.000Z

382

Power flow management of microgrid networks using model predictive control  

Science Conference Proceedings (OSTI)

In this paper, we present a power flow management method for a network of cooperating microgrids within the context of a smart grid by formulating the problem in a model predictive control framework. In order to reliably and economically provide the ... Keywords: Microgrid, Model predictive control, Renewable energy sources, Smart grid, Storage devices

A. Hooshmand; H. A. Malki; J. Mohammadpour

2012-09-01T23:59:59.000Z

383

A Laboratory Model of Urban Street-Canyon Flows  

Science Conference Proceedings (OSTI)

A circulating water channel is constructed to examine urban street-canyon flow. In the cases of an even-notch street canyon in which model buildings on both sides of the street have equal heights, one vortex is observed in model canyons with ...

Jong-Jin Baik; Rae-Seol Park; Hye-Yeong Chun; Jae-Jin Kim

2000-09-01T23:59:59.000Z

384

Introduction Application of numerical models of ground water flow  

E-Print Network (OSTI)

Introduction Application of numerical models of ground water flow almost always involves some sort (Yeh 1986; Poeter and Hill 1997; Hill et al. 1998). Other data beside hydraulic head have been used in calibration of ground water models, including rates of ground water exchange with streams and other surface

Saiers, James

385

Wetting and free surface flow modeling for potting and encapsulation.  

Science Conference Proceedings (OSTI)

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.

Brooks, Carlton, F.; Brooks, Michael J. (Los Alamos National Laboratory, Los Alamos, NM); Graham, Alan Lyman (Los Alamos National Laboratory, Los Alamos, NM); Noble, David F. (David Frederick) (.; )); Notz, Patrick K.; Hopkins, Matthew Morgan; Castaneda, Jaime N.; Mahoney, Leo James (Kansas City Plant, Kansas City, MO); Baer, Thomas A.; Berchtold, Kathryn (Los Alamos National Laboratory, Los Alamos, NM); 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

2007-06-01T23:59:59.000Z

386

Fluid flow and reactive transport around potential nuclear waste emplacement tunnels at Yucca Mountain, Nevada  

E-Print Network (OSTI)

Unsaturated Zone at Yucca Mountain, Nevada. U.S. Geologicalzone model at Yucca Mountain, Nevada. J. Contaminantinvesti- gations at Yucca Mountain - the potential

Spycher, N.F.; Sonnenthal, E.L.; Apps, J.A.

2002-01-01T23:59:59.000Z

387

U-Sr isotopic speedometer: Fluid flow and chemical weathering rates inaquifers  

E-Print Network (OSTI)

as the infiltration rate increases, the inferred dissolutioninferred infiltration rate increases in the model, the bulkthat as infiltration rates increase in the system, the pore

Maher, Kate; DePaolo, Donald J.; Christensen, John N.

2005-01-01T23:59:59.000Z

388

(RTD) of Fluid Flows in a Four Strand Delta-shaped Tundish  

Science Conference Proceedings (OSTI)

Abstract Scope, In this one third scale water model study of a four strand billet casting operation, residence time distribution (RTD) curves under steady state ...

389

CFD modeling of commercial-scale entrained-flow coal gasifiers  

SciTech Connect

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 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 system-wide design and optimization.

Ma, J.; Zitney, S.

2012-01-01T23:59:59.000Z

390

Tree-Shaped Fluid Flow and Heat Storage in a Conducting Solid  

Science Conference Proceedings (OSTI)

This paper documents the time-dependent thermal interaction between a fluid stream configured as a plane tree of varying complexity embedded in a conducting solid with finite volume and insulated boundaries. The time scales of the convection-conduction phenomenon are identified. Two-dimensional and three-dimensional configurations are simulated numerically. The number of length scales of the tree architecture varies from one to four. The results show that the heat transfer density increases, and the time of approach to equilibrium decreases as the complexity of the tree designs increases. These results are then formulated in the classical notation of energy storage by sensible heating, which shows that the effective number of heat transfer units increases as the complexity of the tree design increases. The complexity of heat transfer designs in many applications is constrained by first cost and operating cost considerations. This work provides a fundamental basis for objective evaluation of cost and performance tradeoffs in thermal design of energy systems with complexity as an unconstrained parameter that can be actively varied over a broad range to determine the optimum system design.

Combelles, L.; Lorente, S.; Anderson, R.; Bejan, A.

2012-01-01T23:59:59.000Z

391

Fluid-Structure Interaction Modeling of High-Aspect Ratio Nuclear Fuel Plates Using COMSOL  

SciTech Connect

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.

Curtis, Franklin G [ORNL] ORNL; Ekici, Kivanc [ORNL] ORNL; Freels, James D [ORNL] ORNL

2013-01-01T23:59:59.000Z

392

GIS-BASED 1-D DIFFUSIVE WAVE OVERLAND FLOW MODEL  

Science Conference Proceedings (OSTI)

This paper presents a GIS-based 1-d distributed overland flow model and summarizes an application to simulate a flood event. The model estimates infiltration using the Green-Ampt approach and routes excess rainfall using the 1-d diffusive wave approximation. The model was designed to use readily available topographic, soils, and land use/land cover data and rainfall predictions from a meteorological model. An assessment of model performance was performed for a small catchment and a large watershed, both in urban environments. Simulated runoff hydrographs were compared to observations for a selected set of validation events. Results confirmed the model provides reasonable predictions in a short period of time.

KALYANAPU, ALFRED [Los Alamos National Laboratory; MCPHERSON, TIMOTHY N. [Los Alamos National Laboratory; BURIAN, STEVEN J. [NON LANL

2007-01-17T23:59:59.000Z

393

Advanced Conceptual Models for Unsaturated and Two-Phase Flow in Fractured Rock  

DOE Green Energy (OSTI)

This project was initiated in FY03. As of December 2003, we have accomplished the following: (1) We conducted a more detailed evaluation of the preliminary experiments used to develop our investigative approach. In those experiments, water was invaded at a variety of flow rates into an air-filled, two dimensional analog fracture network. Results demonstrated the critical control that fracture intersections place on two-phase flow in fracture networks. At low flows, capillary and gravitational forces combined to create a narrow pulsing flow structure that spanned the system vertically. At higher flows, viscous forces acted to remove the pulsation; however, the flow structure remained narrow. The intersections acted to impose a narrow ''slender ladder'' structure on the flowing phase that did not expand with depth, but instead remained focused. A manuscript documenting this effort has been published in Water Resources Research [Glass et al., 2003a]. (2) We initiated a collaborative relationship with a research group at Seoul National University. This group, which is led by Dr. Kang-Kun Lee is also using a combined experimental numerical approach to consider DNAPL migration in fracture networks. They are particularly interested in the influence of ambient groundwater flows, making their work complementary to ours. The first fruit of that collaboration is an article demonstrating that modification of an Invasion Percolation algorithm to include gravity and the first-order effects of viscous forces shows good agreement with physical experiments in a simplistic fracture network. Results were published in Geophysical Research Letters [Ji et al., 2003a]. (3) We carried out an extensive review of models for fracture networks. These include models developed from observations of networks on outcrops at several scales and stochastic models that are prevalent in the literature from the 1980s to very recent developments. The results of this review were included as par t of a review paper co-authored by Rajaram, which was submitted to Reviews in Geophysics [Molz et al., in press]. (4) We prepared a manuscript based on previous work that will be used to support the development of our new conceptual model(s) for transport in fractured rock. Eight experiments were conducted to evaluate the repeatability of flow under nearly identical conditions and to characterize general patterns in flow behavior. Collected data revealed that flow generally converged to a single fracture in the bottom row of blocks. Periods of pathway switching were observed to be more common than periods with steady, constant flow pathways. We noted the importance of fracture intersections for integrating uniform flow and discharging a ''fluid cascade'', where water advances rapidly to the next capillary barrier creating a stop and start advance of water through the network. The results of this simple experiment suggest that the interaction of multiple fracture intersections in a network creates flow behavior not generally recognized in popular conceptual and numerical models. A manuscript documenting this effort has been accepted for publication in Vadose Zone Journal [Wood et al., 2003]. (5) Slender transport pathways have been found in laboratory and field experiments within unsaturated fractured rock. We considered the simulation of such structures with a Modified form of Invasion Percolation (MIP). Results show that slender pathways form in fracture networks for a wide range of expected conditions, can be maintained when subsequent matrix imbibition is imposed, and may arise even in the context of primarily matrix flow due to the action of fractures as barriers to inter-matrix block transport. A manuscript documenting this effort has been submitted to Geophysical Research Letters [Glass et al., 2003b].

Rajaram, Harihar

2003-06-01T23:59:59.000Z

394

Detector of the flowing of a fluid in a pipe and energy saving device for a hot water system using this detector  

SciTech Connect

A fluid flow sensor, comprising a tubular element having a greater diameter than and vertically mounted on a pipe for serially interconnecting two portions of this pipe. One portion is connected to the upper end of the tubular element while the other portion is connected to its lower end. A magnetic piston is slidably mounted within the tubular element and is therefore free to move along it. A by-pass conduit interconnects the lower portion of the pipe with the upper portion of the pipe. The piston moves upwardly in the tubular element when the fluid flows. Fluid flows from the portion of the pipe connected at the lower end of the tubular element to the one connected at its upper end through the by-pass. The piston moves downwardly by gravity to the lower end of the tubular element when the fluid stops flowing. A coil wound around a portion of the tubular element produces in electrical signal when the piston moves in the tubular element. The piston has a frustroconical element on each end to absorb shocks which result when the piston seats in each position. This detecting device can be mounted on a hot water supply pipe and used in combination with an electronic circuit for saving energy in operating a hot water system. The electronic circuit allows or prevents the thermostat to control the water heating apparatus.

Lawless, J.

1985-02-05T23:59:59.000Z

395

Materials Science and Engineering B 117 (2005) 5361 Finite element analysis-based design of a fluid-flow control nano-valve  

E-Print Network (OSTI)

of a fluid-flow control nano-valve M. Grujicica,, G. Caoa, B. Pandurangana, W.N. Royb a Department A finite element method-based procedure is developed for the design of molecularly functionalized nano-size devices. The procedure is aimed at the single-walled carbon nano-tubes (SWCNTs) used in the construction

Grujicic, Mica

396

Liquid-fluidized-bed heat exchanger flow distribution models  

DOE Green Energy (OSTI)

Allied Chemical Corporation at the Idaho National Engineering Laboratory is developing liquid-fluidized-bed shell-and-tube heat exchangers for geothermal applications. Sand fluidized by geothermal water on the shell side prevents scaling and increases heat transfer coefficients over conventional heat exchangers. Tests were conducted on two instrumented fluidized-bed heat exchanger models, constructed primarily of plexiglass, which differ in tube bundle orientation. 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 uniform flow distribution and higher heat transfer coefficients than the horizontal model. The horizontal heat exchanger experienced piling on top of the tubes and areas of poor fluidization existed in the bed. Geometric considerations show that a horizontal design is more conducive to large flow rates than a vertical design. New design concepts for both vertical and horizontal assemblies and recommendations for further developmental work are presented.

Cole, L.T.; Allen, C.A.

1979-01-01T23:59:59.000Z

397

Two dimensional, two fluid model for sodium boiling in LMFBR fuel assemblies  

Science Conference Proceedings (OSTI)

A two dimensional numerical model for the simulation of sodium boiling transient was developed using the two fluid set of conservation equations. A semiimplicit numerical differencing scheme capable of handling the problems associated with the ill-posedness implied by the complex characteristic roots of the two fluid problems was used, which took advantage of the dumping effect of the exchange terms. Of particular interest in the development of the model was the identification of the numerical problems caused by the strong disparity between the axial and radial dimensions of fuel assemblies. A solution to this problem was found which uses the particular geometry of fuel assemblies to accelerate the convergence of the iterative technique used in the model. Three sodium boiling experiments were simulated with the model, with good agreement between the experimental results and the model predictions.

Granziera, M.R.; Kazimi, M.S.

1980-05-01T23:59:59.000Z

398

TOUGH Simulations of the Updegraff's Set of Fluid and Heat Flow Problems  

E-Print Network (OSTI)

Transport Model (SWIFT), NUREG/CR-3316, SAND83- 1154, SandiaK. , TOUGH User's Guide, NUREG/CR-4645, SAND86-7104, LBL-Media, Release 4.84," NUREG/CR-3328, SAND83-1159, Sandia

Moridis, G.J.

2010-01-01T23:59:59.000Z

399

TOUGH Simulations of the Updegraff's Set of Fluid and Heat Flow Problems  

E-Print Network (OSTI)

A schematic of the heat pipe problem (from Updegraff [1989])19. A schematic of the heat pipe problem (from Updegraff[Numerical Modeling of a Porous Heat Pipe: Comparison with a

Moridis, G.J.

2010-01-01T23:59:59.000Z

400

Multiphase Flow Modeling of Biofuel Production Processes  

Science Conference Proceedings (OSTI)

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 advantages over other biomass processing methods with respect to separations. These 'green' alternatives employ a hybrid medium that, when operated supercritically, offers the prospect of tunable physicochemical properties. Solubility can be rapidly altered and phases partitioned selectively to precipitate or dissolve certain components by altering temperature or pressure in the near-critical region. The ability to tune the solvation properties of water in the highly compressible near-critical region facilitates partitioning of products or by-products into separate phases to separate and purify products. Since most challenges related to lipid extraction are associated with the industrial scale-up of integrated extraction systems, the new modeling capability offers the prospect of addressing previously untenable scaling issues.

D. Gaston; D. P. Guillen; J. Tester

2011-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Geothermal loan guaranty cash flow model: description and users' manual  

SciTech Connect

This is the users guide for the Geothermal Loan Guaranty Cash Flow Model (GCFM). GCFM is a Fortran code which designs and costs geothermal fields and electric power plants. It contains a financial analysis module which performs life cycle costing analysis taking into account various types of taxes, costs and financial structures. The financial module includes a discounted cash flow feature which calculates a levelized breakeven price for each run. The user's guide contains descriptions of the data requirements and instructions for using the model.

Keimig, M.A.; Rosenberg, J.I.; Entingh, D.J.

1980-11-01T23:59:59.000Z

402

Circular hydraulic jump in generalized-Newtonian fluids  

E-Print Network (OSTI)

We carry out an analytical study of laminar circular hydraulic jumps, in generalized-Newtonian fluids obeying the two-parametric power-law model of Ostwald-de Waele. Under the boundary-layer approximation we obtained exact expressions determining the flow, an implicit relation for the jump radius is derived. Corresponding results for Newtonian fluids can be retrieved as a limiting case for the flow behavior index n=1, predictions are made for fluids deviating from Newtonian behavior.

Rai, Ashutosh; Poria, Swarup

2008-01-01T23:59:59.000Z

403

Fluid Queue Models of Battery Life Gareth L. Jones, Peter G. Harrison, Uli Harder, Tony Field  

E-Print Network (OSTI)

Fluid Queue Models of Battery Life Gareth L. Jones, Peter G. Harrison, Uli Harder, Tony Field-mail:{gljones,uh,ajf,pgh}@doc.ic.ac.uk Abstract--We investigate how a power-save mode affects the battery life of a device subject transform of the battery life's probability density function is found and inverted numerically in particular

Imperial College, London

404

Bulk viscous fluid hypersurface - homogeneous cosmological models with time varying G and ?  

Science Conference Proceedings (OSTI)

Hypersurface - homogeneous cosmological models containing a bulk viscous fluid with time varying G and ? have been presented. We have shown that the field equations are solvable for any arbitrary cosmic scale function. The viscosity coefficient ... Keywords: bulk viscosity, hypersurface - homogeneous, variable G and ?. LATEX

Shri Ram; M. K. Verma

2010-02-01T23:59:59.000Z

405

Vorton dynamics: a case study of developing a fluid dynamics model for a vector processor  

Science Conference Proceedings (OSTI)

The raw performance of vector processors such as the CDC CYBER-205 has been well documented. The ability to apply this raw power to ever more complex algebraic algorithms has been reported in [9]. The final step in making computers of this class truly ... Keywords: CYBER-205, computational fluid dynamics, programming, vorton model

M. J. Kascic, Jr.

1984-08-01T23:59:59.000Z

406

An Integrated Modeling Analysis of Unsaturated Flow Patterns in Fractured Rock  

E-Print Network (OSTI)

study, heat flow simulations use a 3-D thermal model grid (model grid, which is used for gas flow and ambient heat-flowgrid showing a smaller model domain, used for modeling gas and heat

Wu, Yu-Shu; Lu, Guoping; Zhang, Keni; Pan, Lehua; Bodvarsson, Gudmundur S.

2008-01-01T23:59:59.000Z

407

Fluid flow, element migration, and petrotectonic evolution of the Early Mesozoic central Klamath Island arc, northwesternmost California. Progress report  

SciTech Connect

Investigations in the central Klamath Mountains (KM) have documented the presence of a polymetamorphosed suite of highly magnesian basaltic rocks, the Yellow Dog greenstones, in the Sawyers Bar (SB) terrane of the western Triassic and Paleozoic belt. The assemblage was laid down, altered and metasomatized during the hypothesized collapse of a Phillipine Sea-type back-arc basin which brought the westerly SB oceanic arc terrane into juxtaposition with the inboard, pre-existing Stuart Fork subduction complex, and more easterly KM terranes in an immature island arc setting. Supporting research has concentrated on elucidating the areal extent and structural/stratigraphic relations of these mafic/ultramafic Yellow Dog metavolcanic units, and has documented the insignificant degree of crustal contamination of the melts by associated terrigenous metasediments. The thermal structure and its evolution in the central KM evidently reflects surfaceward advective transport of magmatic energy derived from the partly fused downgoing oceanic slab, as well as hydrothermal fluid circulation. Clarification of the thermal evolution of this crust-constructional event in the immature basaltic island arc are the goals of the research now underway, emptying both field and geochemical methods. Continuing work is documenting the flow and P-T history of aqueous fluids through the evolving KM arc, utilizing electron microprobe and oxygen isotopic data. The authors have nearly finished a regional reconnaissance map showing the distribution of the lavas throughout the California part of the KM. Application of the terrane concept to the central KM has also been reevaluated in the light of regional petrotectonic relationships. Investigations of the regional and contact metamorphism/metasomatism of the SB metasedimentary pile are in progress.

Ernst, W.G.

1992-12-11T23:59:59.000Z

408

Measuring and Modeling Flow in Welded Fractured Tuffs  

SciTech Connect

We have carried out a series of in situ liquid-release experiments in conjunction with a numerical modeling study to examine the effect of the rock matrix on liquid flow and transport occurring primarily through the fracture network. Field experiments were conducted in the highly fractured Topopah Spring welded tuff at a site accessed from the Exploratory Studies Facility (ESFS), an underground laboratory in the unsaturated zone at Yucca Mountain, Nevada. During the experiment, wetting-front movement, flow-field evolution, and drainage of fracture flow paths were evaluated. Modeling was used to aid in experimental design, predict experimental results, and study the physical processes accompanying liquid flow through unsaturated fractured welded tuff. Field experiments and modeling suggest that it may not be sufficient to conceptualize the fractured tuff as consisting of a single network of high-permeability fractures embedded in a low-permeability matrix. The need to include a secondary fracture network is demonstrated by comparison to the liquid flow observed in the field.

R. Salve; C. Doughty; J.S. Wang

2001-10-03T23:59:59.000Z

409

Development, Verification, and Validation of Multiphase Models for Polydisperse Flows  

Science Conference Proceedings (OSTI)

This report describes in detail the technical findings of the DOE Award entitled 'Development, Verification, and Validation of Multiphase Models for Polydisperse Flows.' The focus was on high-velocity, gas-solid flows with a range of particle sizes. A complete mathematical model was developed based on first principles and incorporated into MFIX. The solid-phase description took two forms: the Kinetic Theory of Granular Flows (KTGF) and Discrete Quadrature Method of Moments (DQMOM). The gas-solid drag law for polydisperse flows was developed over a range of flow conditions using Discrete Numerical Simulations (DNS). These models were verified via examination of a range of limiting cases and comparison with Discrete Element Method (DEM) data. Validation took the form of comparison with both DEM and experimental data. Experiments were conducted in three separate circulating fluidized beds (CFB's), with emphasis on the riser section. Measurements included bulk quantities like pressure drop and elutriation, as well as axial and radial measurements of bubble characteristics, cluster characteristics, solids flux, and differential pressure drops (axial only). Monodisperse systems were compared to their binary and continuous particle size distribution (PSD) counterparts. The continuous distributions examined included Gaussian, lognormal, and NETL-provided data for a coal gasifier.

Christine Hrenya; Ray Cocco; Rodney Fox; Shankar Subramaniam; Sankaran Sundaresan

2011-12-31T23:59:59.000Z

410

A finite element approach for multiphase fluid flow in porous media  

Science Conference Proceedings (OSTI)

The main scope of this work is to carry out a mathematical framework and its corresponding finite element (FE) discretization for the partially saturated soil consolidation modelling in presence of an immiscible pollutant. A multiphase system with the ... Keywords: Consolidation, Finite elements, Immiscible pollutants, Mixture theory, Multiphase porous media

Javier L. Mroginski; H.Ariel Di Rado; Pablo A. Beneyto; Armando M. Awruch

2010-09-01T23:59:59.000Z

411

Numerical Simulation Of Gas-Droplet Flow Around A Nozzle In A Cylindrical Chamber Using A Lagrangian Model Based On A Multigrid Navier-Stokes Solver  

E-Print Network (OSTI)

A numerical simulation of an upward directed, 2-- dimensional, turbulent gas--droplet flow around an axisymmetric nozzle in a cylindrical chamber was made. We use a Lagrangian method, where trajectories of many droplets are calculated from the equations of motion along with the continuity and momentum equations of fluid. Strong coupling effects between the two phases are dealt with. Special algorithms were introduced for particle tracking and interpolation of the fluid flow data at the particle location on the numerical grid, which use multigrid structure for improvement of the speed of droplet trajectory calculation. The Lagrangian solver for the calculation of the trajectory and particle momentum source term was parallelised on a workstation cluster using a host--node programming model. The resulting droplet and fluid velocities at different cross sections of the cylindrical chamber are reported and compared with measurements. 2. INTRODUCTION In many engineering flow situations par...

Thomas Frank; Ingvelde Schulze

1994-01-01T23:59:59.000Z

412

A viscosity counteracting approach in the lattice Boltzmann BGK model for low viscosity flow: Preliminary verification  

Science Conference Proceedings (OSTI)

Due to numerical instability, the lattice Boltzmann model (LBM) with the Bhatnagar-Gross-Krook (BGK) collision operator has some limitations in the simulation of low viscosity flows. In this paper, we propose a viscosity counteracting approach for simulating ... Keywords: Couette flow, Lattice Boltzmann BGK model, Lid-driven cavity flow, Poiseuille flow, Taylor-Green vortex flow, Verification, Viscosity counteracting

Yongguang Cheng; Hui Zhang

2011-06-01T23:59:59.000Z

413

A comparison study of multi-component Lattice Boltzmann models for flow in porous media applications  

Science Conference Proceedings (OSTI)

A comparison study of three different multi-component Lattice Boltzmann models is carried out to explore their capability of describing binary immiscible fluid systems. The Shan-Chen pseudo potential model, the Oxford free energy model and the colour ... Keywords: Binary fluids, Lattice Boltzmann, Multi-component models

Jianhui Yang; Edo S. Boek

2013-03-01T23:59:59.000Z

414

One- and two-dimensional Stirling machine simulation using experimentally generated reversing flow turbuulence models  

DOE Green Energy (OSTI)

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.

Goldberg, L.F. [Univ. of Minnesota, Minneapolis, MN (United States)

1990-08-01T23:59:59.000Z

415

Isotropic singularities in shear-free perfect fluid cosmologies  

E-Print Network (OSTI)

We investigate barotropic perfect fluid cosmologies which admit an isotropic singularity. From the General Vorticity Result of Scott, it is known that these cosmologies must be irrotational. In this paper we prove, using two different methods, that if we make the additional assumption that the perfect fluid is shear-free, then the fluid flow must be geodesic. This then implies that the only shear-free, barotropic, perfect fluid cosmologies which admit an isotropic singularity are the FRW models.

Geoffery Ericksson; Susan M. Scott

2001-08-02T23:59:59.000Z

416

Two-phase flow in a vertical pipe and the phenomenon of choking: Homogeneous diffusion model. Part I. Homogeneous flow models  

DOE Green Energy (OSTI)

The paper examines the topologic structure of all possible solutions which can exist in flows through adiabatic constant-area ducts for which the homogeneous diffusion model has been assumed. The conservation equations are one-dimensional with the single space variable z, but gravity effects are included. The conservation equations are coupled with three equations of state: a pure substance, a perfect gas with constant specific heats, and a homogeneous two-phase system in thermodynamic equilibrium. The preferred state variables are pressure P, enthalpy h, and mass flux G{sup 2}. The three conservation equations are first-order but nonlinear. They induce a family of solutions which are interpreted as curves in a four-dimensional phase space conceived as a union of three-dimensional spaces (h, G{sup 2};z) with G{sup 2} = const treated as a parameter. It is shown that all points in these spaces are regular, so that no singular solutions need to be considered. The existence and uniqueness theorem leads to the conclusion that through every point in phase space there passes one and only one solution-curve. The set of differential equations, treated as a system of algebraic equations at each point of the phase space, determines the components of a rate-of-change vector which are obtained explicitly by Cramer's rule. This vector is tangent to the solution curve. Each solution curve turns downward in z at some specific elevation z*, and this determines the condition for choking. Choking occurs always when the exit flow velocity at L=z* is equal to the local velocity of propagation of small plane disturbances of sufficiently large wavelength, that is when the flow rate G becomes equal to a specified, critical flow rate, G*. A criterion, analogous to the Mach number, which indicates the presence or absence of choking in a cross-section is the ratio K=G/G** of the mass-flow rate G to the local critical mass flow rate, G**, K=1 denoting choking. The critical parameters depend only on the thermodynamic properties of the fluid and are independent of the gravitational acceleration and shearing stress at the wall. The topological characteristics of the solutions allow us to study all flow patterns which can, and which cannot, occur in a pipe of given length L into which fluid is discharged through a rounded entrance from a stagnation reservoir and whose back-pressure is slowly lowered. The set of flow patterns is analogous to that which occurs with a perfect gas, except that the characteristic numerical values are different. They must be obtained by numerical integration and the influence of gravity must be allowed for. The preceding conclusions are valid for all assumptions concerning the shearing stress at the wall which make it dependent on the state parameters only, but not on their derivatives with respect to z. However, the study is limited to upward flows for which the shearing stress at the wall and the gravitational acceleration are codirectional.

Bilicki, Z.; Kestin, J.

1982-01-01T23:59:59.000Z

417

Self-Assembling Sup-porosity: The Effect On Fluid Flow And Seismic Wave Propagation  

SciTech Connect

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 â??sub-porosityâ?ť within the fracture void space. This sub-porosity often is composed of material that differs from the fracture walls in mineralogy and morphology. The â??sub-porosityâ?ť 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 topic is contained in the report and the full details of the research and approach are contained in the publications found in the Attachment section of this report. A list of presentation and publications of all work associated with this grant is also provided.

Pyrak-Nolte, Laura J. [Purdue University

2013-04-27T23:59:59.000Z

418

Continental-Scale River Flow in Climate Models  

Science Conference Proceedings (OSTI)

The hydrologic cycle is a major part of the global climate system. There is an atmospheric flux of water from the ocean surface to the continents. The cycle is closed by return flow in rivers. In this paper a river routing model is developed to ...

James R. Miller; Gary L. Russell; Guilherme Caliri

1994-06-01T23:59:59.000Z

419

Sleep scheduling for wireless sensor networks via network flow model  

Science Conference Proceedings (OSTI)

The pervasiveness and operational autonomy of mesh-based wireless sensor networks (WSNs) make them an ideal candidate in offering sustained monitoring functions at reasonable cost over a wide area. There has been a general consensus within the research ... Keywords: Cross-layer design, Integer linear programming, Network flow model, Sleep scheduling, Wireless sensor networks

Rick W. Ha; Pin-Han Ho; X. Sherman Shen; Junshan Zhang

2006-08-01T23:59:59.000Z

420

MATHEMATICAL MODELS OF THERMAL AND CHEMICAL TRANSPORT IN GEOLOGIC MEDIA  

E-Print Network (OSTI)

for Modeling Fluid and Heat Flow in Fractured Porous Media,Fluid Flow in a Single Fracture Because the topology of fractured media is different from that of porous media,

Lai, C.-H.

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "model fluid flow" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Simulation and Modeling  

Science Conference Proceedings (OSTI)

Mar 6, 2013... 5Key Laboratory of Unconventional Metallurgy, Kunming University of ... fluid flow and fuel oil heat and mass transfer mathematical model for ...

422

A numerical study of fluids with pressure dependent viscosity flowing through a rigid porous media  

E-Print Network (OSTI)

In this paper we consider modifications to Darcy's equation wherein the drag coefficient is a function of pressure, which is a realistic model for technological applications like enhanced oil recovery and geological carbon sequestration. We first outline the approximations behind Darcy's equation and the modifications that we propose to Darcy's equation, and derive the governing equations through a systematic approach using mixture theory. We then propose a stabilized mixed finite element formulation for the modified Darcy's equation. To solve the resulting nonlinear equations we present a solution procedure based on the consistent Newton-Raphson method. We solve representative test problems to illustrate the performance of the proposed stabilized formulation. One of the objectives of this paper is also to show that the dependence of viscosity on the pressure can have a significant effect both on the qualitative and quantitative nature of the solution.

Nakshatrala, K B

2009-01-01T23:59:59.000Z

423

Modeling crustal deformation and rupture processes related to upwelling of deep CO2-rich fluids during the 1965-1967 Matsushiro Earthquake Swarm in Japan  

Science Conference Proceedings (OSTI)

In Matsushiro, central Japan, a series of more than 700,000 earthquakes occurred over a 2-year period (1965-1967) associated with a strike-slip faulting sequence. This swarm of earthquakes resulted in ground surface deformations, cracking of the topsoil, and enhanced spring-outflows with changes in chemical compositions as well as carbon dioxide (CO{sub 2}) degassing. Previous investigations of the Matsushiro earthquake swarm have suggested that migration of underground water and/or magma may have had a strong influence on the swarm activity. In this study, employing coupled multiphase flow and geomechanical modelling, we show that observed crustal deformations and seismicity can have been driven by upwelling of deep CO{sub 2}-rich fluids around the intersection of two fault zones - the regional East Nagano earthquake fault and the conjugate Matsushiro fault. We show that the observed spatial evolution of seismicity along the two faults and magnitudes surface uplift, are convincingly explained by a few MPa of pressurization from the upwelling fluid within the critically stressed crust - a crust under a strike-slip stress regime near the frictional strength limit. Our analysis indicates that the most important cause for triggering of seismicity during the Matsushiro swarm was the fluid pressurization with the associated reduction in effective stress and strength in fault segments that were initially near critically stressed for shear failure. Moreover, our analysis indicates that a two order of magnitude permeability enhancement in ruptured fault segments may be necessary to match the observed time evolution of surface uplift. We conclude that our hydromechanical modelling study of the Matsushiro earthquake swarm shows a clear connection between earthquake rupture, deformation, stress, and permeability changes, as well as large-scale fluid flow related to degassing of CO{sub 2} in the shallow seismogenic crust. Thus, our study provides further evidence of the important role of deep fluid sources in earthquake fault dynamics and surface deformations.

Cappa, F.; Rutqvist, J.; Yamamoto, K.

2009-05-15T23:59:59.000Z

424

PARTICLE IMAGE VELOCIMETRY MEASUREMENTS IN A REPRESENTATIVE GAS-COOLED PRISMATIC REACTOR CORE MODEL: FLOW IN THE COOLANT CHANNELS AND INTERSTITIAL BYPASS GAPS  

Science Conference Proceedings (OSTI)

Core bypass flow is one of the key issues with the prismatic Gas Turbine-Modular Helium Reactor, and it refers to the coolant that navigates through the interstitial, non-cooling passages between the graphite fuel blocks instead of traveling through the designated coolant channels. To determine the bypass flow, a double scale representative model was manufactured and installed in the Matched Index-of-Refraction flow facility; after which, stereo Particle Image Velocimetry (PIV) was employed to measure the flow field within. PIV images were analyzed to produce vector maps, and flow rates were calculated by numerically integrating over the velocity field. It was found that the bypass flow varied between 6.9-15.8% for channel Reynolds numbers of 1,746 and 4,618. The results were compared to computational fluid dynamic (CFD) pre-test simulations. When compared to these pretest calculations, the CFD analysis appeared to under predict the flow through the gap.

Thomas E. Conder; Richard Skifton; Ralph Budwig

2012-11-01T23:59:59.000Z

425

New shear-free relativistic models with heat flow  

E-Print Network (OSTI)

We study shear-free spherically symmetric relativistic models with heat flow. Our analysis is based on Lie's theory of extended groups applied to the governing field equations. In particular, we generate a five-parameter family of transformations which enables us to map existing solutions to new solutions. All known solutions of Einstein equations with heat flow can therefore produce infinite families of new solutions. In addition, we provide two new classes of solutions utilising the Lie infinitesimal generators. These solutions generate an infinite class of solutions given any one of the two unknown metric functions.

A. M. Msomi; K. S. Govinder; S. D. Maharaj

2012-12-29T23:59:59.000Z

426

Analyzing flow patterns in unsaturated fractured rock of Yucca Mountain using an integrated modeling approach  

E-Print Network (OSTI)

heat flow simulations use the 3-D thermal model grid (Figuremodel grid, which is used for gas flow and ambient heat flowgrid showing a smaller model domain, used for modeling gas and heat

Wu, Yu-Shu; Lu, Guoping; Zhang, Keni; Pan, Lehua; Bodvarsson, Gudmundur S.

2008-01-01T23:59:59.000Z

427

Laboratory–Numerical Model Comparisons of Flow over a Coastal Canyon  

Science Conference Proceedings (OSTI)

Different modeling approaches are applied to the same geophysical flow in order to assess the ability of laboratory models to provide useful benchmarks in the development of oceanic numerical models. The test case considered here—that of the flow ...

Nicolas Pérenne; Dale B. Haidvogel; Don L. Boyer

2001-02-01T23:59:59.000Z

428

GASFLOW: A Computational Fluid Dynamics Code for Gases, Aerosols, and Combustion, Volume 1: Theory and Computational Model  

DOE Green Energy (OSTI)

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. Volume III contains some of the assessments performed by LANL and FzK. GASFLOW is under continual development, assessment, and application by LANL and FzK. This manual is considered a living document and will be updated as warranted.

Nichols, B.D.; Mueller, C.; Necker, G.A.; Travis, J.R.; Spore, J.W.; Lam, K.L.; Royl, P.; Redlinger, R.; Wilson, T.L.

1998-10-01T23:59:59.000Z

429

Numerical modeling of the wind flow over a transverse dune  

E-Print Network (OSTI)

Transverse dunes, which form under unidirectional winds and have fixed profile in the direction perpendicular to the wind, occur on all celestial objects of our solar system where dunes have been detected. Here we perform a numerical study of the average turbulent wind flow over a transverse dune by means of computational fluid dynamics simulations. We find that the length of the zone of recirculating flow at the dune lee --- the {\\em{separation bubble}} --- displays a surprisingly strong dependence on the wind shear velocity, $u_{\\ast}$: it is nearly independent of $u_{\\ast}$ for shear velocities within the range between $0.2\\,$m$$s and $0.8\\,$m$$s but increases linearly with $u_{\\ast}$ for larger shear velocities. Our calculations show that transport in the direction opposite to dune migration within the separation bubble can be sustained if $u_{\\ast}$ is larger than approximately $0.39\\,$m$$s, whereas a larger value of $u_{\\ast}$ (about $0.49\\,$m$$s) is required to initiate this reverse transport.

Ascânio D. Araújo; Eric J. R. Parteli; Thorsten Poeschel; José S. Andrade Jr.; Hans J. Herrmann

2013-07-26T23:59:59.000Z

430

Cosmological model with viscosity media (dark fluid) described by an effective equation of state  

E-Print Network (OSTI)

A generally parameterized equation of state (EOS) is investigated in the cosmological evolution with bulk viscosity media modelled as dark fluid, which can be regarded as a unification of dark energy and dark matter. Compared with the case of the perfect fluid, this EOS has possessed four additional parameters, which can be interpreted as the case of the non-perfect fluid with time-dependent viscosity or the model with variable cosmological constant. From this general EOS, a completely integrable dynamical equation to the scale factor is obtained with its solution explicitly given out. (i) In this parameterized model of cosmology, for a special choice of the parameters we can explain the late-time accelerating expansion universe in a new view. The early inflation, the median (relatively late time) deceleration, and the recently cosmic acceleration may be unified in a single equation. (ii) A generalized relation of the Hubble parameter scaling with the redshift is obtained for some cosmology interests. (iii) By using the SNe Ia data to fit the effective viscosity model we show that the case of matter described by $p=0$ plus with effective viscosity contributions can fit the observational gold data in an acceptable level

J. Ren; Xin He Meng

2005-11-07T23:59:59.000Z

431

2.853 Manufacturing Systems I: Analytical Methods and Flow Models, Fall 2002  

E-Print Network (OSTI)

Provides ways to conceptualize and analyze manufacturing systems and supply chains in terms of material flow, information flow, capacities, and flow times. Fundamental building blocks: Inventory and Queuing Models, Forecasting ...

Gershwin, S. B.

432

Analytical solution for two-phase flow in a wellbore using the drift-flux model  

E-Print Network (OSTI)

Wellbore flow model for carbon dioxide and brine, EnergyReservoir Flow of Carbon Dioxide and Water. LBNL-4291E. [14]non-isothermal flow of carbon dioxide in wellbores. In: SPE

Pan, L.

2013-01-01T23:59:59.000Z

433

Heat transfer and fluid dynamics of air-water two-phase flow in micro-channels  

SciTech Connect

Heat transfer, pressure drop, and void fraction were simultaneously measured for upward heated air-water non-boiling two-phase flow in 0.51 mm ID tube to investigate thermo-hydro dynamic characteristics of two-phase flow in micro-channels. At low liquid superficial velocity j{sub l} frictional pressure drop agreed with Mishima-Hibiki's correlation, whereas agreed with Chisholm-Laird's correlation at relatively high j{sub l}. Void fraction was lower than the homogeneous model and conventional empirical correlations. To interpret the decrease of void fraction with decrease of tube diameter, a relation among the void fraction, pressure gradient and tube diameter was derived.