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1

Demonstration of a Computational Fluid Dynamics (CFD) Tool Used...  

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

Demonstration of a Computational Fluid Dynamics (CFD) Tool Used for Data Center Modeling, Thermal Analysis and Operational Management Speaker(s): Saket Karajgikar Date: November...

2

Computational fluid dynamic (CFD) optimization of microfluidic mixing in a MEMS steam generator  

E-Print Network (OSTI)

The challenge of achieving rapid mixing in microchannels is addressed through a computational fluid dynamics (CFD) study using the ADINA-F finite element program. The study is motivated by the need to design an adequate ...

Collins, Kimberlee C. (Kimberlee Chiyoko)

2008-01-01T23:59:59.000Z

3

Computational Fluid Dynamics (CFD) Simulation of Air Dense ...  

Science Conference Proceedings (OSTI)

In current study, the experimental results of coal beneficiation in a cylindrical bed are used to set up and evaluate the results of a CFD simulation software.

4

Demonstration of a Computational Fluid Dynamics (CFD) Tool Used for Data  

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

Demonstration of a Computational Fluid Dynamics (CFD) Tool Used for Data Demonstration of a Computational Fluid Dynamics (CFD) Tool Used for Data Center Modeling, Thermal Analysis and Operational Management Speaker(s): Saket Karajgikar Date: November 11, 2010 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Henry Coles Every Data Center built today is designed with a total capacity in mind, as well as a plan to grow into this final-day load. On a daily basis, Data Center Operations/Management professionals work toward keeping their Data Center as close to this plan as possible by concurrently managing the available power, space, cooling and airflow resources. Unfortunately, lack of communication and information, the pace of change and difficulty in coping with the ever growing power densities of IT equipment can prevent a

5

Radiation-cooled Dew Water Condensers Studied by Computational Fluid Dynamic (CFD)  

E-Print Network (OSTI)

Harvesting condensed atmospheric vapour as dew water can be an alternative or complementary potable water resource in specific arid or insular areas. Such radiation-cooled condensing devices use already existing flat surfaces (roofs) or innovative structures with more complex shapes to enhance the dew yield. The Computational Fluid Dynamic - CFD - software PHOENICS has been programmed and applied to such radiation cooled condensers. For this purpose, the sky radiation is previously integrated and averaged for each structure. The radiative balance is then included in the CFD simulation tool to compare the efficiency of the different structures under various meteorological parameters, for complex or simple shapes and at various scales. It has been used to precise different structures before construction. (1) a 7.32 m^2 funnel shape was studied; a 30 degree tilted angle (60 degree cone half-angle) was computed to be the best compromise for funnel cooling. Compared to a 1 m^2 flat condenser, the cooling efficienc...

Clus, O; Muselli, M; Nikolayev, Vadim; Sharan, Girja; Beysens, D

2007-01-01T23:59:59.000Z

6

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

7

Computational fluid dynamics (CFD) simulations of aerosol in a u-shaped steam generator tube  

E-Print Network (OSTI)

To quantify primary side aerosol retention, an Eulerian/Lagrangian approach was used to investigate aerosol transport in a compressible, turbulent, adiabatic, internal, wall-bounded flow. The ARTIST experimental project (Phase I) served as the physical model replicated for numerical simulation. Realizable k-? and standard k-? turbulence models were selected from the computational fluid dynamics (CFD) code, FLUENT, to provide the Eulerian description of the gaseous phase. Flow field simulation results exhibited: a) onset of weak secondary flow accelerated at bend entrance towards the inner wall; b) flow separation zone development on the convex wall that persisted from the point of onset; c) centrifugal force concentrated high velocity flow in the direction of the concave wall; d) formation of vortices throughout the flow domain resulted from rotational (Dean-type) flow; e) weakened secondary flow assisted the formation of twin vortices in the outflow cross section; and f) perturbations induced by the bend influenced flow recovery several pipe diameters upstream of the bend. These observations were consistent with those of previous investigators. The Lagrangian discrete random walk model, with and without turbulent dispersion, simulated the dispersed phase behavior, incorrectly. Accurate deposition predictions in wall-bounded flow require modification of the Eddy Impaction Model (EIM). Thus, to circumvent shortcomings of the EIM, the Lagrangian time scale was changed to a wall function and the root-mean-square (RMS) fluctuating velocities were modified to account for the strong anisotropic nature of flow in the immediate vicinity of the wall (boundary layer). Subsequent computed trajectories suggest a precision that ranges from 0.1% to 0.7%, statistical sampling error. The aerodynamic mass median diameter (AMMD) at the inlet (5.5 ?m) was consistent with the ARTIST experimental findings. The geometric standard deviation (GSD) varied depending on the scenario evaluated but ranged from 1.61 to 3.2. At the outlet, the computed AMMD (1.9 ?m) had GSD between 1.12 and 2.76. Decontamination factors (DF), computed based on deposition from trajectory calculations, were just over 3.5 for the bend and 4.4 at the outlet. Computed DFs were consistent with expert elicitation cited in NUREG-1150 for aerosol retention in steam generators.

Longmire, Pamela

2007-05-01T23:59:59.000Z

8

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

9

CFD [computational fluid dynamics] And Safety Factors. Computer modeling of complex processes needs old-fashioned experiments to stay in touch with reality.  

SciTech Connect

Computational fluid dynamics (CFD) is recognized as a powerful engineering tool. That is, CFD has advanced over the years to the point where it can now give us deep insight into the analysis of very complex processes. There is a danger, though, that an engineer can place too much confidence in a simulation. If a user is not careful, it is easy to believe that if you plug in the numbers, the answer comes out, and you are done. This assumption can lead to significant errors. As we discovered in the course of a study on behalf of the Department of Energy's Savannah River Site in South Carolina, CFD models fail to capture some of the large variations inherent in complex processes. These variations, or scatter, in experimental data emerge from physical tests and are inadequately captured or expressed by calculated mean values for a process. This anomaly between experiment and theory can lead to serious errors in engineering analysis and design unless a correction factor, or safety factor, is experimentally validated. For this study, blending times for the mixing of salt solutions in large storage tanks were the process of concern under investigation. This study focused on the blending processes needed to mix salt solutions to ensure homogeneity within waste tanks, where homogeneity is required to control radioactivity levels during subsequent processing. Two of the requirements for this task were to determine the minimum number of submerged, centrifugal pumps required to blend the salt mixtures in a full-scale tank in half a day or less, and to recommend reasonable blending times to achieve nearly homogeneous salt mixtures. A full-scale, low-flow pump with a total discharge flow rate of 500 to 800 gpm was recommended with two opposing 2.27-inch diameter nozzles. To make this recommendation, both experimental and CFD modeling were performed. Lab researchers found that, although CFD provided good estimates of an average blending time, experimental blending times varied significantly from the average.

Leishear, Robert A.; Lee, Si Y.; Poirier, Michael R.; Steeper, Timothy J.; Ervin, Robert C.; Giddings, Billy J.; Stefanko, David B.; Harp, Keith D.; Fowley, Mark D.; Van Pelt, William B.

2012-10-07T23:59:59.000Z

10

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

11

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

12

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

13

Applied Computation 274: Computational Fluid Dynamics Lecturer: David Knezevic  

E-Print Network (OSTI)

, nuclear reactor modeling and blood flow simulation. With major advances in CFD algorithms and computer: With Applications in Incompressible Fluid Dynamics, Oxford University Press, 2005. A. Ern, J.-L. Guermond, Theory

Chen, Yiling

14

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

15

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

16

Computational fluid dynamics applications to improve crop production systems  

Science Conference Proceedings (OSTI)

Computational fluid dynamics (CFD), numerical analysis and simulation tools of fluid flow processes have emerged from the development stage and become nowadays a robust design tool. It is widely used to study various transport phenomena which involve ... Keywords: Decision support tools, Greenhouse, Harvesting machines, Sprayers, Tillage

T. Bartzanas; M. Kacira; H. Zhu; S. Karmakar; E. Tamimi; N. Katsoulas; In Bok Lee; C. Kittas

2013-04-01T23:59:59.000Z

17

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.

18

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

19

Two-dimensional computational fluid dynamics and conduction simulations of heat transfer in window frames with internal cavities - Part 1: Cavities only  

E-Print Network (OSTI)

of heat fluxes from CFD and conduction simulations for theapproach to solve the conduction heat-transfer equation. TheFluid Dynamics and Conduction Simulations of Heat Transfer

Gustavsen, Arild; Kohler, Christian; Arasteh, Dariush; Curcija, Dragan

2003-01-01T23:59:59.000Z

20

Developing an integrated building design tool by coupling building energy simulation and computational fluid dynamics programs  

E-Print Network (OSTI)

Building energy simulation (ES) and computational fluid dynamics (CFD) can play important roles in building design by providing essential information to help design energy-efficient, thermally comfortable and healthy ...

Zhai, Zhiqiang, 1971-

2003-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

Coupling of a multizone airflow simulation program with computational fluid dynamics for indoor environmental analysis  

E-Print Network (OSTI)

Current design of building indoor environment comprises macroscopIC approaches, such as CONT AM multizone airflow analysis tool, and microscopic approaches that apply Computational Fluid Dynamics (CFD). Each has certain ...

Gao, Yang, 1974-

2002-01-01T23:59:59.000Z

22

The role of computational fluid dynamics in the management of unruptured intracranial aneurysms: a clinicians' view  

Science Conference Proceedings (OSTI)

Objective. The importance of hemodynamics in the etiopathogenesis of intracranial aneurysms (IAs) is widely accepted. Computational fluid dynamics (CFD) is being used increasingly for hemodynamic predictions. However, alogn with the continuing development ...

Pankaj K. Singh; Alberto Marzo; Stuart C. Coley; Guntram Berti; Philippe Bijlenga; Patricia V. Lawford; Mari-Cruz Villa-Uriol; Daniel A. Rufenacht; Keith M. McCormack; Alejandro Frangi; Umang J. Patel; D. Rodney Hose

2009-01-01T23:59:59.000Z

23

Combustion Chamber Fluid Dynamics and Hypergolic Gel Propellant Chemistry Simulations for Selectable Thrust Rocket Engines  

Science Conference Proceedings (OSTI)

This paper describes the development and application of high performance computing for the acceleration of tactical missile hypergolic propulsion system development. Computational fluid dynamics (CFD) is employed to model the chemically reacting flow ...

Michael J. Nusca; Michael J. McQuaid

2005-06-01T23:59:59.000Z

24

Computational fluid dynamics modelling and experimental study on a single silica gel type B  

Science Conference Proceedings (OSTI)

The application of computational fluid dynamics (CFDs) in the area of porous media and adsorption cooling system is becoming more practical due to the significant improvement in computer power. The results from previous studies have shown that CFD can ...

John White

2012-01-01T23:59:59.000Z

25

National Ignition Facility computational fluid dynamics modeling and light fixture case studies  

SciTech Connect

This report serves as a guide to the use of computational fluid dynamics (CFD) as a design tool for the National Ignition Facility (NIF) program Title I and Title II design phases at Lawrence Livermore National Laboratory. In particular, this report provides general guidelines on the technical approach to performing and interpreting any and all CFD calculations. In addition, a complete CFD analysis is presented to illustrate these guidelines on a NIF-related thermal problem.

Martin, R.; Bernardin, J.; Parietti, L.; Dennison, B.

1998-02-01T23:59:59.000Z

26

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

27

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

28

Comparison between experiments and CFD predictions of mixed convection...  

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

results from a computational fluid dynamics (CFD) simulation of airflow and pollutant dispersion under mixed-convection conditions with experimental data obtained in our 7m x...

29

Petascale Adaptive Computational Fluid Dynamics | Argonne Leadership  

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

Petascale Adaptive Computational Fluid Dynamics Petascale Adaptive Computational Fluid Dynamics PI Name: Kenneth Jansen PI Email: jansen@rpi.edu Institution: Rensselaer Polytechnic Institute The specific aim of this request for resources is to examine scalability and robustness of our code on BG/P. We have confirmed that, during the flow solve phase, our CFD flow solver does exhibit perfect strong scaling to the full 32k cores on our local machine (CCNI-BG/L at RPI) but this will be our first access to BG/P. We are also eager to study the performance of the adaptive phase of our code. Some aspects have scaled well on BG/L (e.g., refinement has produced adaptive meshes that take a 17 million element mesh and perform local adaptivity on 16k cores to match a requested size field to produce a mesh exceeding 1 billion elements) but other aspects (e.g.,

30

Air Reverse Circulation Bit Internal Fluid Simulation Based on CFD  

Science Conference Proceedings (OSTI)

The article instructs the work principle of the injector device and its application in the reverse-circulation sampling drilling bit. Then use the fluent fluid engineering emulator software to simulate the internal fluid territory of the injector when ... Keywords: air reverse circulation, bit, injector hole, optimization

Shuqing Hao; Hong-wei Huang; Kun Yin

2009-07-01T23:59:59.000Z

31

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

32

CFD optimization for GDI spray model tuning and enhancement of engine performance  

Science Conference Proceedings (OSTI)

Coupling a 3D Computational Fluid Dynamics (CFD) tool with a rigorous method of decision making is becoming indispensable in the design process of complex systems, as internal combustion engines. CFD based optimization (CFD-O) is here carried out on ... Keywords: CFD based optimization, Charge stratification, Gasoline direct injection, Multidimensional modelling, Spark ignition engines, Split injection

M. Costa; U. Sorge; L. Allocca

2012-07-01T23:59:59.000Z

33

Issues in computational fluid dynamics code verification and validation  

SciTech Connect

A broad range of mathematical modeling errors of fluid flow physics and numerical approximation errors are addressed in computational fluid dynamics (CFD). It is strongly believed that if CFD is to have a major impact on the design of engineering hardware and flight systems, the level of confidence in complex simulations must substantially improve. To better understand the present limitations of CFD simulations, a wide variety of physical modeling, discretization, and solution errors are identified and discussed. Here, discretization and solution errors refer to all errors caused by conversion of the original partial differential, or integral, conservation equations representing the physical process, to algebraic equations and their solution on a computer. The impact of boundary conditions on the solution of the partial differential equations and their discrete representation will also be discussed. Throughout the article, clear distinctions are made between the analytical mathematical models of fluid dynamics and the numerical models. Lax`s Equivalence Theorem and its frailties in practical CFD solutions are pointed out. Distinctions are also made between the existence and uniqueness of solutions to the partial differential equations as opposed to the discrete equations. Two techniques are briefly discussed for the detection and quantification of certain types of discretization and grid resolution errors.

Oberkampf, W.L.; Blottner, F.G.

1997-09-01T23:59:59.000Z

34

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

35

Distributed computational fluid dynamics  

E-Print Network (OSTI)

that arises in these practical turbulent combustion pro- cesses is a strong coupling between turbulence, chemical kinetics and heat release. These interactions are generally three dimensional and time de- pendent, and are not easily accessible to experimental... and at university and national level by very large massively-parallel supercomputers. Therefore, CFD offers a major opportunity for the development and application of Grid technology in engineering and forms the motivation for the present study. A difficulty...

Jenkins, K; Yang, Xiaobo; Hayes, Mark; Cant, Stewart R

2008-06-26T23:59:59.000Z

36

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

37

A CFD simulation on how the different sizes of silica gel will affect the adsorption performance of silica gel  

Science Conference Proceedings (OSTI)

The application of computational fluid dynamics (CFD) in the area of porous media and adsorption cooling system is becoming more practical due to the significant improvement in computer power. The results from previous studies have shown that CFD can ...

John White

2012-01-01T23:59:59.000Z

38

Computational Fluid Dynamics of rising droplets  

SciTech Connect

The main goal of this study is to perform simulations of droplet dynamics using Truchas, a LANL-developed computational fluid dynamics (CFD) software, and compare them to a computational study of Hysing et al.[IJNMF, 2009, 60:1259]. Understanding droplet dynamics is of fundamental importance in liquid-liquid extraction, a process used in the nuclear fuel cycle to separate various components. Simulations of a single droplet rising by buoyancy are conducted in two-dimensions. Multiple parametric studies are carried out to ensure the problem set-up is optimized. An Interface Smoothing Length (ISL) study and mesh resolution study are performed to verify convergence of the calculations. ISL is a parameter for the interface curvature calculation. Further, wall effects are investigated and checked against existing correlations. The ISL study found that the optimal ISL value is 2.5{Delta}x, with {Delta}x being the mesh cell spacing. The mesh resolution study found that the optimal mesh resolution is d/h=40, for d=drop diameter and h={Delta}x. In order for wall effects on terminal velocity to be insignificant, a conservative wall width of 9d or a nonconservative wall width of 7d can be used. The percentage difference between Hysing et al.[IJNMF, 2009, 60:1259] and Truchas for the velocity profiles vary from 7.9% to 9.9%. The computed droplet velocity and interface profiles are found in agreement with the study. The CFD calculations are performed on multiple cores, using LANL's Institutional High Performance Computing.

Wagner, Matthew [Lake Superior State University; Francois, Marianne M. [Los Alamos National Laboratory

2012-09-05T23:59:59.000Z

39

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

40

Nonlinear Fluid Dynamics from Gravity  

E-Print Network (OSTI)

Black branes in AdS5 appear in a four parameter family labeled by their velocity and temperature. Promoting these parameters to Goldstone modes or collective coordinate fields -- arbitrary functions of the coordinates on the boundary of AdS5 -- we use Einstein's equations together with regularity requirements and boundary conditions to determine their dynamics. The resultant equations turn out to be those of boundary fluid dynamics, with specific values for fluid parameters. Our analysis is perturbative in the boundary derivative expansion but is valid for arbitrary amplitudes. Our work may be regarded as a derivation of the nonlinear equations of boundary fluid dynamics from gravity. As a concrete application we find an explicit expression for the expansion of this fluid stress tensor including terms up to second order in the derivative expansion.

Sayantani Bhattacharyya; Veronika E Hubeny; Shiraz Minwalla; Mukund Rangamani

2007-12-14T23:59:59.000Z

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

The past, present and future of CFD for agro-environmental applications  

Science Conference Proceedings (OSTI)

Computational fluid dynamics (CFD) is a proven simulation tool which caters to almost any field of study. The CFD technique is utilized to simulate, analyze, and optimize various engineering designs. In this review, the discussion is focused on the application ... Keywords: Agriculture, Air, CFD, Environment, Soil, Water

In-Bok Lee; Jessie Pascual P. Bitog; Se-Woon Hong; Il-Hwan Seo; Kyeong-Seok Kwon; Thomas Bartzanas; Murat Kacira

2013-04-01T23:59:59.000Z

42

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

43

Technical Review of the CENWP Computational Fluid Dynamics Model of the John Day Dam Forebay  

Science Conference Proceedings (OSTI)

The US Army Corps of Engineers Portland District (CENWP) has developed a computational fluid dynamics (CFD) model of the John Day forebay on the Columbia River to aid in the development and design of alternatives to improve juvenile salmon passage at the John Day Project. At the request of CENWP, Pacific Northwest National Laboratory (PNNL) Hydrology Group has conducted a technical review of CENWP's CFD model run in CFD solver software, STAR-CD. PNNL has extensive experience developing and applying 3D CFD models run in STAR-CD for Columbia River hydroelectric projects. The John Day forebay model developed by CENWP is adequately configured and validated. The model is ready for use simulating forebay hydraulics for structural and operational alternatives. The approach and method are sound, however CENWP has identified some improvements that need to be made for future models and for modifications to this existing model.

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

2010-12-01T23:59:59.000Z

44

Fluid dynamics of bacterial turbulence  

E-Print Network (OSTI)

Self-sustained turbulent structures have been observed in a wide range of living fluids, yet no quantitative theory exists to explain their properties. We report experiments on active turbulence in highly concentrated 3D suspensions of Bacillus subtilis and compare them with a minimal fourth-order vector-field theory for incompressible bacterial dynamics. Velocimetry of bacteria and surrounding fluid, determined by imaging cells and tracking colloidal tracers, yields consistent results for velocity statistics and correlations over two orders of magnitude in kinetic energy, revealing a decrease of fluid memory with increasing swimming activity and linear scaling between energy and enstrophy. The best-fit model parameters allow for quantitative agreement with experimental data.

Jörn Dunkel; Sebastian Heidenreich; Knut Drescher; Henricus H. Wensink; Markus Bär; Raymond E. Goldstein

2013-02-21T23:59:59.000Z

45

On the application of computational fluid dynamics codes for liquefied natural gas dispersion.  

SciTech Connect

Computational fluid dynamics (CFD) codes are increasingly being used in the liquefied natural gas (LNG) industry to predict natural gas dispersion distances. This paper addresses several issues regarding the use of CFD for LNG dispersion such as specification of the domain, grid, boundary and initial conditions. A description of the k-{var_epsilon} model is presented, along with modifications required for atmospheric flows. Validation issues pertaining to the experimental data from the Burro, Coyote, and Falcon series of LNG dispersion experiments are also discussed. A description of the atmosphere is provided as well as discussion on the inclusion of the Coriolis force to model very large LNG spills.

Luketa-Hanlin, Anay Josephine; Koopman, Ronald P. (Lawrence Livermore National Laboratory, Livermore, CA); Ermak, Donald (Lawrence Livermore National Laboratory, Livermore, CA)

2006-02-01T23:59:59.000Z

46

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

47

Computational Fluid Dynamics (CFD) Modelling on Soot Yield for Fire  

E-Print Network (OSTI)

) , CIBSE Guide E(iii) , etc. All design parameters of the smoke control strategy and architectural design Fire Protection Association, Quincy, MA, USA, 2007. iii CIBSE Guide E, Fire Engineering, 2nd Edition

48

European Conference on Computational Fluid Dynamics ECCOMAS CFD 2006  

E-Print Network (OSTI)

will be applied from 2009, it requires a further 80% reduction in PM and a further 20% reduction in NOx. In order. Shimo, M. Kataoka and H. Fujimoto, "Effect of Cooling of Burned Gas by Vertical Vortex on NOx Reduction://www.ifs.tohoku.ac.jp/edge Key words: Diesel Engine, Exhaust emission reduction, Kriging model Abstract. Diesel engine combustion

Obayashi, Shigeru

49

Applications of Grid techniques in the CFD field  

E-Print Network (OSTI)

up fundermental CFD study in fluid dynamics, for example, mechanism of turbulence. (2) Grid resources 1 can also be used to solve large numbers of small tasks. By modifying one or some parameters like Mach number, angle of attach, iteration steps, CFD... Server MyProxy Server Computing Resources Cambridge CFD Web Portal (CamCFDWP) Fig. 6 Architecture of Cambridge CFD Web Por- tal (CamCFDWP) A successful login window shown in Fig.7. Once the 5 user logs in, it is time for him to submit jobs to remote...

Yang, Xiaobo; Hayes, Mark

2008-06-26T23:59:59.000Z

50

Using a CFD simulation in designing a smoke management system in a building  

Science Conference Proceedings (OSTI)

This paper presents a study on the effectiveness of a smoke exhaust system in a complex building using the Computational Fluid Dynamics (CFD) models. The CFD model FDS (Fire Dynamics Simulator) was used for this study. To simulate fires in the building ...

George Hadjisophocleous; Yoon J. Ko

2006-12-01T23:59:59.000Z

51

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

52

Development and Verification of a Computational Fluid Dynamics Model of a Horizontal-Axis Tidal Current Turbine  

DOE Green Energy (OSTI)

This paper describes the development of a computational fluid dynamics (CFD) methodology to simulate the hydrodynamics of horizontal-axis tidal current turbines. Qualitative measures of the CFD solutions were independent of the grid resolution. Conversely, quantitative comparisons of the results indicated that the use of coarse computational grids results in an under prediction of the hydrodynamic forces on the turbine blade in comparison to the forces predicted using more resolved grids. For the turbine operating conditions considered in this study, the effect of the computational timestep on the CFD solution was found to be minimal, and the results from steady and transient simulations were in good agreement. Additionally, the CFD results were compared to corresponding blade element momentum method calculations and reasonable agreement was shown. Nevertheless, we expect that for other turbine operating conditions, where the flow over the blade is separated, transient simulations will be required.

Lawson, M. J.; Li, Y.; Sale, D. C.

2011-10-01T23:59:59.000Z

53

Computational Fluid Dynamics Framework for Turbine Biological Performance Assessment  

SciTech Connect

In this paper, a method for turbine biological performance assessment is introduced to bridge the gap between field and laboratory studies on fish injury and turbine design. Using this method, a suite of biological performance indicators is computed based on simulated data from a computational fluid dynamics (CFD) model of a proposed turbine design. Each performance indicator is a measure of the probability of exposure to a certain dose of an injury mechanism. If the relationship between the dose of an injury mechanism and frequency of injury (dose-response) is known from laboratory or field studies, the likelihood of fish injury for a turbine design can be computed from the performance indicator. By comparing the values of the indicators from various turbine designs, the engineer can identify the more-promising designs. Discussion here is focused on Kaplan-type turbines, although the method could be extended to other designs. Following the description of the general methodology, we will present sample risk assessment calculations based on CFD data from a model of the John Day Dam on the Columbia River in the USA.

Richmond, Marshall C.; Serkowski, John A.; Carlson, Thomas J.; Ebner, Laurie L.; Sick, Mirjam; Cada, G. F.

2011-05-04T23:59:59.000Z

54

Comparative Evaluation of an Eulerian CFD and Gaussian Plume Models Based on Prairie Grass Dispersion Experiment  

Science Conference Proceedings (OSTI)

A theoretical and statistical comparison of a three-dimensional computational fluid dynamics (CFD) model with two Gaussian plume models is proposed on the Prairie Grass data field experiment for neutral conditions, using both maximum arcwise ...

E. Demael; B. Carissimo

2008-03-01T23:59:59.000Z

55

Dynamical instability of collapsing radiating fluid  

SciTech Connect

We take the collapsing radiative fluid to investigate the dynamical instability with cylindrical symmetry. We match the interior and exterior cylindrical geometries. Dynamical instability is explored at radiative and non-radiative perturbations. We conclude that the dynamical instability of the collapsing cylinder depends on the critical value {gamma} < 1 for both radiative and nonradiative perturbations.

Sharif, M., E-mail: msharif.math@pu.edu.pk; Azam, M., E-mail: azammath@gmail.com [University of the Punjab, Department of Mathematics (Pakistan)

2013-06-15T23:59:59.000Z

56

Computational Fluid Dynamic Analysis of the VHTR Lower Plenum Standard Problem  

DOE Green Energy (OSTI)

The United States Department of Energy is promoting the resurgence of nuclear power in the U. S. for both electrical power generation and production of process heat required for industrial processes such as the manufacture of hydrogen for use as a fuel in automobiles. The DOE project is called the next generation nuclear plant (NGNP) and is based on a Generation IV reactor concept called the very high temperature reactor (VHTR), which will use helium as the coolant at temperatures ranging from 450 ºC to perhaps 1000 ºC. While computational fluid dynamics (CFD) has not been used for past safety analysis for nuclear reactors in the U. S., it is being considered for safety analysis for existing and future reactors. It is fully recognized that CFD simulation codes will have to be validated for flow physics reasonably close to actual fluid dynamic conditions expected in normal and accident operational situations. To this end, experimental data have been obtained in a scaled model of a narrow slice of the lower plenum of a prismatic VHTR. The present report presents results of CFD examinations of these data to explore potential issues with the geometry, the initial conditions, the flow dynamics and the data needed to fully specify the inlet and boundary conditions; results for several turbulence models are examined. Issues are addressed and recommendations about the data are made.

Richard W. Johnson; Richard R. Schultz

2009-07-01T23:59:59.000Z

57

Hydrogen Sulfide Dispersion Consequences Analysis in Different Wind Speeds: A CFD Based Approach  

Science Conference Proceedings (OSTI)

Hydrogen sulfide (h2s) leakage and dispersion from a sulfide recycle installation in different wind speeds are simulated by implementing a 3D Computational Fluid Dynamics (CFD) model. H2s concentrations of monitor points which represent dispersion contours ... Keywords: CFD, hydrogen Sulfide, dispersion, concenquences analysis, different wind speeds

Bo Zhang; Guo-ming Chen

2009-10-01T23:59:59.000Z

58

Formal Calibration Methodology for CFD Model Development to Support the Operation of Energy Efficient Buildings  

E-Print Network (OSTI)

Computational Fluid Dynamics (CFD) is a robust tool for modeling interactions within and between fluids and solids. CFD can help understand and predict phenomena that are difficult to test experimentally leading to cleaner, healthier, and better controlled internal environments. In this research a CFD model of the internal environment of an office space will be developed. The CFD model will then be calibrated using real data taken from a well-positioned wireless sensor network and weather station. The work focuses on developing systematically calibrated CFD models for controlled environments that include clean rooms, health environments, pharmaceutical storage rooms and information and communication technology locations, utilizing wireless sensor networks. The calibrated CFD model will be used to optimize the positions of the physical sensors for the control of energy efficient internal environments by building operators. This could result in significant energy and economic savings and lead to more accurately controlled internal environments.

Hajdukiewicz, M.; Keane, M.; O'Flynn, B.; O'Grady, W.

2010-01-01T23:59:59.000Z

59

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

60

Computational Fluid Dynamics in Support of the SNS Liquid Mercury Thermal-Hydraulic Analysis  

SciTech Connect

Experimental and computational thermal-hydraulic research is underway to support the liquid mercury target design for the Spallation Neutron Source (SNS) facility. The SNS target will be subjected to internal nuclear heat generation that results from pulsed proton beam collisions with the mercury nuclei. Recirculation and stagnation zones within the target are of particular concern because of the likelihood that they will result in local hot spots and diminished heat removal from the target structure. Computational fluid dynamics (CFD) models are being used as a part of this research. Recent improvements to the 3D target model include the addition of the flow adapter which joins the inlet/outlet coolant pipes to the target body and an updated heat load distribution at the new baseline proton beam power level of 2 MW. Two thermal-hydraulic experiments are planned to validate the CFD model.

Siman-Tov, M.; Wendel, M.W.; Yoder, G.L.

1999-11-14T23:59:59.000Z

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

Computational Fluid Dynamics for Engineering Design  

Science Conference Proceedings (OSTI)

Table 2   Examples of CFD software available in the United States...several computer hardware and software companies on the Internet early

62

Original papers: Aerodynamic analysis and CFD simulation of several cellulose evaporative cooling pads used in Mediterranean greenhouses  

Science Conference Proceedings (OSTI)

The present work makes an aerodynamic analysis and computational fluid dynamics (CFD) simulation of the four commercial models of corrugated cellulose evaporative cooling pads that are most widely used in Mediterranean greenhouses. The geometric characteristics ... Keywords: Aerodynamic analysis, CFD, Evaporative cooling, Fan and pad, Greenhouse, Pressure drop

A. Franco; D. L. Valera; A. Peña; A. M. Pérez

2011-05-01T23:59:59.000Z

63

Advances in the use of CFD to characterize, design and optimize bioenergy systems  

Science Conference Proceedings (OSTI)

This article is a critical review of the state-of-the-art of computational fluid dynamics (CFD) used to investigate bioreactors that produce biomethane and biohydrogen by means of biochemical conversion technology. First, the issue on rheology of biomaterials ... Keywords: Bioreactor, Computational fluid dynamics, Heat transfer, Light transfer, Mass transfer, Mixing

Binxin Wu

2013-04-01T23:59:59.000Z

64

Spinodal phase decomposition with dissipative fluid dynamics  

SciTech Connect

The spinodal amplification of density fluctuations is treated perturbatively within dissipative fluid dynamics including not only shear and bulk viscosity but also heat conduction, as well as a gradient term in the local pressure. The degree of spinodal amplification is calculated along specific dynamical phase trajectories and the results suggest that the effect can be greatly enhanced by tuning the collision energy so that maximum compression occurs inside the region of spinodal instability.

Randrup, J., E-mail: JRandrup@LBL.gov [Lawrence Berkeley Laboratory, Nuclear Science Division (United States)

2012-06-15T23:59:59.000Z

65

Development and Verification of a Computational Fluid Dynamics Model of a Horizontal-Axis Tidal Current Turbine  

SciTech Connect

This paper describes the development of a computational fluid dynamics (CFD) methodology to simulate the hydrodynamics of horizontal-axis tidal current turbines (HATTs). First, an HATT blade was designed using the blade element momentum method in conjunction with a genetic optimization algorithm. Several unstructured computational grids were generated using this blade geometry and steady CFD simulations were used to perform a grid resolution study. Transient simulations were then performed to determine the effect of time-dependent flow phenomena and the size of the computational timestep on the numerical solution. Qualitative measures of the CFD solutions were independent of the grid resolution. Conversely, quantitative comparisons of the results indicated that the use of coarse computational grids results in an under prediction of the hydrodynamic forces on the turbine blade in comparison to the forces predicted using more resolved grids. For the turbine operating conditions considered in this study, the effect of the computational timestep on the CFD solution was found to be minimal, and the results from steady and transient simulations were in good agreement. Additionally, the CFD results were compared to corresponding blade element momentum method calculations and reasonable agreement was shown. Nevertheless, we expect that for other turbine operating conditions, where the flow over the blade is separated, transient simulations will be required.

Lawson, Mi. J.; Li, Y.; Sale, D. C.

2011-01-01T23:59:59.000Z

66

Transdisciplinary Fluid Integration Research Center  

E-Print Network (OSTI)

Environment Reality-Coupled Computation Energy Dynamics Integrated Visual Informatics Super-Real-Time Medical of Fluid Science, Tohoku University, in April 2003. The next generation transdisciplinary research Research focus is to advance utilization of Computer Fluid Dynamics (CFD) for solving engineering problems

Obayashi, Shigeru

67

Code Verification of the HIGRAD Computational Fluid Dynamics Solver  

DOE Green Energy (OSTI)

The purpose of this report is to outline code and solution verification activities applied to HIGRAD, a Computational Fluid Dynamics (CFD) solver of the compressible Navier-Stokes equations developed at the Los Alamos National Laboratory, and used to simulate various phenomena such as the propagation of wildfires and atmospheric hydrodynamics. Code verification efforts, as described in this report, are an important first step to establish the credibility of numerical simulations. They provide evidence that the mathematical formulation is properly implemented without significant mistakes that would adversely impact the application of interest. Highly accurate analytical solutions are derived for four code verification test problems that exercise different aspects of the code. These test problems are referred to as: (i) the quiet start, (ii) the passive advection, (iii) the passive diffusion, and (iv) the piston-like problem. These problems are simulated using HIGRAD with different levels of mesh discretization and the numerical solutions are compared to their analytical counterparts. In addition, the rates of convergence are estimated to verify the numerical performance of the solver. The first three test problems produce numerical approximations as expected. The fourth test problem (piston-like) indicates the extent to which the code is able to simulate a 'mild' discontinuity, which is a condition that would typically be better handled by a Lagrangian formulation. The current investigation concludes that the numerical implementation of the solver performs as expected. The quality of solutions is sufficient to provide credible simulations of fluid flows around wind turbines. The main caveat associated to these findings is the low coverage provided by these four problems, and somewhat limited verification activities. A more comprehensive evaluation of HIGRAD may be beneficial for future studies.

Van Buren, Kendra L. [Los Alamos National Laboratory; Canfield, Jesse M. [Los Alamos National Laboratory; Hemez, Francois M. [Los Alamos National Laboratory; Sauer, Jeremy A. [Los Alamos National Laboratory

2012-05-04T23:59:59.000Z

68

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

69

Computational Fluid Dynamics Analyses on Very High Temperature Reactor Air Ingress  

SciTech Connect

A preliminary computational fluid dynamics (CFD) analysis was performed to understand density-gradient-induced stratified flow in a Very High Temperature Reactor (VHTR) air-ingress accident. Various parameters were taken into consideration, including turbulence model, core temperature, initial air mole-fraction, and flow resistance in the core. The gas turbine modular helium reactor (GT-MHR) 600 MWt was selected as the reference reactor and it was simplified to be 2-D geometry in modeling. The core and the lower plenum were assumed to be porous bodies. Following the preliminary CFD results, the analysis of the air-ingress accident has been performed by two different codes: GAMMA code (system analysis code, Oh et al. 2006) and FLUENT CFD code (Fluent 2007). Eventually, the analysis results showed that the actual onset time of natural convection (~160 sec) would be significantly earlier than the previous predictions (~150 hours) calculated based on the molecular diffusion air-ingress mechanism. This leads to the conclusion that the consequences of this accident will be much more serious than previously expected.

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

2009-07-01T23:59:59.000Z

70

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

71

A Molecular Dynamics  

Science Conference Proceedings (OSTI)

A Tale of Two States and More: Modeling of New Generation of Lattice Stability from Zero ... Analysis of Nano Fluid Using CFD-A Hybrid Approach for Cooling Purpose ... Molecular Dynamics Simulations of Grain Boundary Free Energy and

72

A Molecular Dynamic Study  

Science Conference Proceedings (OSTI)

A Tale of Two States and More: Modeling of New Generation of Lattice Stability from Zero ... Analysis of Nano Fluid Using CFD-A Hybrid Approach for Cooling Purpose ... Molecular Dynamics Simulations of Grain Boundary Free Energy and

73

Fluid dynamics in group T-3 Los Alamos national laboratory  

Science Conference Proceedings (OSTI)

The development of computer fluid dynamics has been closely associated with the evolution of large high-speed computers. At first the principal incentive was to produce numerical techniques for solving problems related to national defense. Soon, however, ... Keywords: computational fluid dynamics, history of computing, incompressible flow, multi-field flow, relativistic fluids, strong distortions, turbulence

Francis H. Harlow

2004-04-01T23:59:59.000Z

74

SDI CFD MODELING ANALYSIS  

SciTech Connect

The Savannah River Remediation (SRR) Organization requested that Savannah River National Laboratory (SRNL) develop a Computational Fluid Dynamics (CFD) method to mix and blend the miscible contents of the blend tanks to ensure the contents are properly blended before they are transferred from the blend tank; such as, Tank 50H, to the Salt Waste Processing Facility (SWPF) feed tank. The work described here consists of two modeling areas. They are the mixing modeling analysis during miscible liquid blending operation, and the flow pattern analysis during transfer operation of the blended liquid. The transient CFD governing equations consisting of three momentum equations, one mass balance, two turbulence transport equations for kinetic energy and dissipation rate, and one species transport were solved by an iterative technique until the species concentrations of tank fluid were in equilibrium. The steady-state flow solutions for the entire tank fluid were used for flow pattern analysis, for velocity scaling analysis, and the initial conditions for transient blending calculations. A series of the modeling calculations were performed to estimate the blending times for various jet flow conditions, and to investigate the impact of the cooling coils on the blending time of the tank contents. The modeling results were benchmarked against the pilot scale test results. All of the flow and mixing models were performed with the nozzles installed at the mid-elevation, and parallel to the tank wall. From the CFD modeling calculations, the main results are summarized as follows: (1) The benchmark analyses for the CFD flow velocity and blending models demonstrate their consistency with Engineering Development Laboratory (EDL) and literature test results in terms of local velocity measurements and experimental observations. Thus, an application of the established criterion to SRS full scale tank will provide a better, physically-based estimate of the required mixing time, and elevation of transfer pump for minimum sludge disturbance. (2) An empirical equation for a tank with no cooling coils agrees reasonably with the current modeling results for the dual jet. (3) From the sensitivity study of the cooling coils, it was found that the tank mixing time for the coiled tank was about two times longer than that of the tank fluid with no coils under the 1/10th scale, while the coiled tank required only 50% longer than the one without coils under the full scale Tank 50H. In addition, the time difference is reduced when the pumping U{sub o}d{sub o} value is increased for a given tank. (4) The blending time for T-shape dual jet pump is about 20% longer than that of 15{sup o} upward V-shape pump under the 1/10th pilot-scale tank, while the time difference between the two pumps is about 12% for the full-scale Tank 50H. These results are consistent with the literature information. (5) A transfer pump with a solid-plate suction screen operating at 130 gpm can be located 9.5 inches above settled sludge for 2 in screen height in a 85 ft waste tank without disturbing any sludge. Detailed results are summarized in Table 13. Final pump performance calculations were made by using the established CW pump design, and operating conditions to satisfy the two requirements of minimum sludge disturbance, and adequate blending of tank contents. The final calculation results show that the blending times for the coiled and uncoiled tanks coupled with the CW pump design are 159 and 83 minutes, respectively. All the results are provided in Table 16.

Lee, S.

2011-05-05T23:59:59.000Z

75

Computational Fluid Dynamics University of Leeds  

E-Print Network (OSTI)

simulations to be calculated, or more detailed simulations of present CFD problems; (c) The numerical schemes from a burst tyre led to a ruptured fuel tank on the underside of the left wing. The emerging fuel flow into electricity and can drastically reduce the greenhouse emissions in power plants by using a SOFC and gas

Haase, Markus

76

A validation process for multi-phase reacting flow CFD code  

DOE Green Energy (OSTI)

Computational fluid dynamic (CFD) code calculates flow properties for the analysis of a flow system. Flow properties are computed based on conservation principles and various phenomenological models. The accuracy of the computed flow properties highly depends on the validity of the models and the degree of numerical convergence. Validation of a CFD code is essential for application of an engineering system. Multiphase reacting flows are common in industrial applications and few CFD code are available. A CFD code was developed for the simulation of multiphase reacting flows. A validation process was also developed for such a CFD code. The validation was performed for several cases. Examples of industrial devices which are multiphase reacting flow systems include catalytic cracking reactors, glass melting furnaces, coal-fired combustors, and diesel engines.

Chang, S. L.; Zhou, C. Q.; Petrick, M.

2000-05-09T23:59:59.000Z

77

Computational Fluid Dynamic Simulations of a Regenerative Process...  

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

Fluid Dynamic Simulations of a Regenerative Process for Carbon Dioxide Capture in Advanced Gasification Based Power Systems Background The Department of Energy (DOE) National...

78

Two-Dimensional Computational Fluid Dynamics and Conduction Simulation...  

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

Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer in Horizontal Window Frames with Internal Cavities Title Two-Dimensional Computational...

79

Molecular Dynamics Simulations of Microscale Fluid Transport  

E-Print Network (OSTI)

Recent advances in micro-science and technology, like Micro-ElectroMechanical Systems (MEMS), have generated a group of unique liquid flow problems that involve characteristic length scales of a micron. Also, in manufacturing processes such as coatings, current continuum models are unable to predict microscale physical phenomena that appear in these nonequilibrium systems. It is suspected that in these systems, molecular-level processes can control the interfacial energy and viscoelastic properties at the liquid/solid boundary. A massively parallel molecular dynamics (MD) code has been developed to better understand microscale transport mechanisms, fluid-structure interactions, and scale effects in micro-domains. Specifically, this MD code has been used to analyze liquid channel flow problems for a variety of channel widths, e.g. 0.005-0.05 microns. This report presents results from MD simulations of Poiseuille flow and Couette flow problems and address both scaling and modeling issues...

C. C. Wong; A. R. Lopez; M.J. Stevens; S. J. Plimpton; Category Uc; Like Micro-electro

1998-01-01T23:59:59.000Z

80

Three Important Theorems for Fluid Dynamics  

E-Print Network (OSTI)

The new proposed "energy gradient theory," which physically explains the phenomena of flow instability and turbulent transition in shear flows and has been shown to be valid for parallel flows, is extended to curved flows in this study. Then, three important theorems for fluid dynamics are deduced. These theorems are (1) Potential flow (inviscid and irrotational) is stable. (2) Inviscid rotational (vorticity is not zero) flow is unstable. (3) Velocity profile with an inflectional point is unstable when there is no work input or output to the system, for both inviscid and viscous flows. These theorems are, for the first time, deduced, and are of great significance for the understanding of generation of turbulence and the explanation of complex flows. From these results, it is concluded that the classical Rayleigh theorem (1880) on inflectional velocity instability of inviscid flows is incorrect which has last for more than a century. It is demonstrated that existence of inflection point on velocity profile is ...

Dou, H S

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid dynamics cfd" from the National Library of EnergyBeta (NLEBeta).
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81

Modeling and analysis of transient vehicle underhood thermo- hydrodynamic events using computational fluid dynamics and high performance computing.  

DOE Green Energy (OSTI)

This work has explored the preliminary design of a Computational Fluid Dynamics (CFD) tool for the analysis of transient vehicle underhood thermo-hydrodynamic events using high performance computing platforms. The goal of this tool will be to extend the capabilities of an existing established CFD code, STAR-CD, allowing the car manufacturers to analyze the impact of transient operational events on the underhood thermal management by exploiting the computational efficiency of modern high performance computing systems. In particular, the project has focused on the CFD modeling of the radiator behavior during a specified transient. The 3-D radiator calculations were performed using STAR-CD, which can perform both steady-state and transient calculations, on the cluster computer available at ANL in the Nuclear Engineering Division. Specified transient boundary conditions, based on experimental data provided by Adapco and DaimlerChrysler were used. The possibility of using STAR-CD in a transient mode for the entire period of time analyzed has been compared with other strategies which involve the use of STAR-CD in a steady-state mode at specified time intervals, while transient heat transfer calculations would be performed for the rest of the time. The results of these calculations have been compared with the experimental data provided by Adapco/DaimlerChrysler and recommendations for future development of an optimal strategy for the CFD modeling of transient thermo-hydrodynamic events have been made. The results of this work open the way for the development of a CFD tool for the transient analysis of underhood thermo-hydrodynamic events, which will allow the integrated transient thermal analysis of the entire cooling system, including both the engine block and the radiator, on high performance computing systems.

Tentner, A.; Froehle, P.; Wang, C.; Nuclear Engineering Division

2004-01-01T23:59:59.000Z

82

Modeling and analysis of transient vehicle underhood thermo - hydrodynamic events using computational fluid dynamics and high performance computing.  

DOE Green Energy (OSTI)

This work has explored the preliminary design of a Computational Fluid Dynamics (CFD) tool for the analysis of transient vehicle underhood thermo-hydrodynamic events using high performance computing platforms. The goal of this tool will be to extend the capabilities of an existing established CFD code, STAR-CD, allowing the car manufacturers to analyze the impact of transient operational events on the underhood thermal management by exploiting the computational efficiency of modern high performance computing systems. In particular, the project has focused on the CFD modeling of the radiator behavior during a specified transient. The 3-D radiator calculations were performed using STAR-CD, which can perform both steady-state and transient calculations, on the cluster computer available at ANL in the Nuclear Engineering Division. Specified transient boundary conditions, based on experimental data provided by Adapco and DaimlerChrysler were used. The possibility of using STAR-CD in a transient mode for the entire period of time analyzed has been compared with other strategies which involve the use of STAR-CD in a steady-state mode at specified time intervals, while transient heat transfer calculations would be performed for the rest of the time. The results of these calculations have been compared with the experimental data provided by Adapco/DaimlerChrysler and recommendations for future development of an optimal strategy for the CFD modeling of transient thermo-hydrodynamic events have been made. The results of this work open the way for the development of a CFD tool for the transient analysis of underhood thermo-hydrodynamic events, which will allow the integrated transient thermal analysis of the entire cooling system, including both the engine block and the radiator, on high performance computing systems.

Froehle, P.; Tentner, A.; Wang, C.

2003-09-05T23:59:59.000Z

83

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

84

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

85

Molecular Dynamics Study of Nucleation during Crystallization  

Science Conference Proceedings (OSTI)

A Tale of Two States and More: Modeling of New Generation of Lattice Stability from Zero ... Analysis of Nano Fluid Using CFD-A Hybrid Approach for Cooling Purpose ... Molecular Dynamics Simulations of Grain Boundary Free Energy and

86

CFD analysis of the effect of elbow radius on pressure drop in multiphase flow  

Science Conference Proceedings (OSTI)

Computational fluid dynamics (CFD) analysis was performed in four different 90 degree elbows with air-water two-phase flows. The inside diameters of the elbows were 6.35mm and 12.7mm with radius to diameter ratios (r/D) of 1.5 to 3. The pressure drops ...

Quamrul H. Mazumder

2012-01-01T23:59:59.000Z

87

Noncommutative fluid dynamics in the Kähler parametrization  

E-Print Network (OSTI)

In this paper, we propose a first order action functional for a large class of systems that generalize the relativistic perfect fluids in the K\\"{a}hler parametrization to noncommutative spacetimes. We calculate the equations of motion for the fluid potentials and the energy-momentum tensor in the first order in the noncommutative parameter. The density current does not receive any noncommutative corrections and it is conserved under the action of the commutative generators $P_{\\mu}$ but the energy-momentum tensor is not. Therefore, we determine the set of constraints under which the energy-momentum tensor is divergenceless. Another set of constraints on the fluid potentials is obtained from the requirement of the invariance of the action under the generalization of the volume preserving transformations of the noncommutative spacetime. We show that the proposed action describes noncommutative fluid models by casting the energy-momentum tensor in the familiar fluid form and identifying the corresponding energy and momentum densities. In the commutative limit, they are identical to the corresponding quantities of the relativistic perfect fluids. The energy-momentum tensor contains a dissipative term that is due to the noncommutative spacetime and vanishes in the commutative limit. Finally, we particularize the theory to the case when the complex fluid potentials are characterized by a function $K(z,\\bar{z})$ that is a deformation of the complex plane and show that this model has important common features with the commutative fluid such as infinitely many conserved currents and a conserved axial current that in the commutative case is associated to the topologically conserved linking number.

L. Holender; M. A. Santos; M. T. D. Orlando; I. V. Vancea

2011-09-08T23:59:59.000Z

88

Hard Sphere Dynamics for Normal and Granular Fluids  

E-Print Network (OSTI)

A fluid of N smooth, hard spheres is considered as a model for normal (elastic collisions) and granular (inelastic collisions) fluids. The potential energy is discontinuous for hard spheres so the pairwise forces are singular and the usual forms of Newtonian and Hamiltonian mechanics do not apply. Nevertheless, particle trajectories in the N particle phase space are well defined and the generators for these trajectories can be identified. The first part of this presentation is a review of the generators for the dynamics of observables and probability densities. The new results presented in the second part refer to applications of these generators to the Liouville dynamics for granular fluids. A set of eigenvalues and eigenfunctions of the generator for this Liouville dynamics is identified in a special "stationary representation". This provides a class of exact solutions to the Liouville equation that are closely related to hydrodynamics for granular fluids.

James W. Dufty; Aparna Baskaran

2005-03-08T23:59:59.000Z

89

Reducing Toxic Exposure In Buildings: Application of Computational Fluid  

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

Reducing Toxic Exposure In Buildings: Application of Computational Fluid Reducing Toxic Exposure In Buildings: Application of Computational Fluid Dynamics (CFD) Speaker(s): Buvana Jayaraman Date: December 8, 2005 - 12:00pm Location: Bldg. 90 I investigate three applications related to toxic exposure in buildings and demonstrate the use of Computational Fluid Dynamics (CFD) to address important issues: 1. Improving containment of airborne hazardous materials in an existing room containing a downdraft table. CFD is used to find a ventilation configuration that ensures better containment of the hazardous material and hence improved worker safety. 2. Modeling gas transport in a large indoor space. The goal of this study is to understand how the level of detail of the CFD model affects its accuracy. Comparison of predictions with experimental data will be presented. 3. Understanding

90

A CFD/CSD interaction methodology for aircraft wings  

DOE Green Energy (OSTI)

With advanced subsonic transports and military aircraft operating in the transonic regime, it is becoming important to determine the effects of the coupling between aerodynamic loads and elastic forces. Since aeroelastic effects can significantly impact the design of these aircraft, there is a strong need in the aerospace industry to predict these interactions computationally. Such an analysis in the transonic regime requires high fidelity computational fluid dynamics (CFD) analysis tools, due to the nonlinear behavior of the aerodynamics in the transonic regime and also high fidelity computational structural dynamics (CSD) analysis tools. Also, there is a need to be able to use a wide variety of CFD and CSD methods to predict aeroelastic effects. Since source codes are not always available, it is necessary to couple the CFD and CSD codes without alteration of the source codes. In this study, an aeroelastic coupling procedure is developed to determine the static aeroelastic response of aircraft wings using any CFD and CSD code with little code integration. The aeroelastic coupling procedure is demonstrated on an F/A-18 Stabilator using NASTD (an in-house McDonnell Douglas CFD code) and NASTRAN. In addition, the Aeroelastic Research Wing (ARW-2) is used for demonstration of the aeroelastic coupling procedure by using ENSAERO (NASA Ames Research Center CFD code) and a finite element wing-box code. The results obtained from the present study are compared with those available from an experimental study conducted at NASA Langley Research Center and a study conducted at NASA Ames Research Center using ENSAERO and modal superposition. The results compare well with experimental data.

Bhardwaj, M.K.; Kapania, R.K. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States); Reichenbach, E. [Boeing Co., St. Louis, MO (United States); Guruswamy, G.P. [NASA, Moffett Field, CA (United States). Ames Research Center

1998-01-01T23:59:59.000Z

91

Molecular Dynamics Simulations of Vacancy and Oxygen Diffusion ...  

Science Conference Proceedings (OSTI)

A Tale of Two States and More: Modeling of New Generation of Lattice Stability from Zero ... Analysis of Nano Fluid Using CFD-A Hybrid Approach for Cooling Purpose ... Molecular Dynamics Simulations of Grain Boundary Free Energy and

92

EXAMINATION OF A PROPOSED VALIDATION DATA SET USING CFD CALCULATIONS  

DOE Green Energy (OSTI)

The United States Department of Energy is promoting the resurgence of nuclear power in the U. S. for both electrical power generation and production of process heat required for industrial processes such as the manufacture of hydrogen for use as a fuel in automobiles. The DOE project is called the next generation nuclear plant (NGNP) and is based on a Generation IV reactor concept called the very high temperature reactor (VHTR), which will use helium as the coolant at temperatures ranging from 450 ºC to perhaps 1000 ºC. While computational fluid dynamics (CFD) has not been used for past safety analysis for nuclear reactors in the U. S., it is being considered for such for future reactors. It is fully recognized that CFD simulation codes will have to be validated for flow physics reasonably close to actual fluid dynamic conditions expected in normal and accident operational situations. To this end, experimental data have been obtained in a scaled model of a narrow slice of the lower plenum of a prismatic VHTR. The present article presents new results of CFD examinations of these data to explore potential issues with the geometry, the initial conditions, the flow dynamics and the data needed to fully specify the inlet and boundary conditions; results for several turbulence models are examined. Issues are addressed and recommendations about the data are made.

Richard W. Johnson

2009-08-01T23:59:59.000Z

93

Computational fluid dynamics for LNG vapor dispersion modeling: a key parameters study  

E-Print Network (OSTI)

The increased demand for liquefied natural gas (LNG) has led to the construction of several new LNG terminals in the United States (US) and around the world. To ensure the safety of the public, consequence modeling is used to estimate the exclusion distances. The purpose of having these exclusion distances is to protect the public from being reached by flammable vapors during a release. For LNG industry, the exclusion zones are determined by the half lower flammability limits (half LFL, 2.5% V/V). Since LNG vapors are heavier?than?air when released into atmosphere, it goes through stages, negative, neutral and positive buoyant effect. In this process, it may reach the half LFL. The primary objective of this dissertation is to advance the status of LNG vapor dispersion modeling, especially for complex scenarios (i.e. including obstacle effects). The most used software, box models, cannot assess these complex scenarios. Box models simulate the vapor in a free?obstacle environment. Due to the advancement in computing, this conservative approach has become questionable. New codes as computational fluid dynamics (CFD) have been proven viable and more efficient than box models. The use of such advance tool in consequence modeling requires the refinement of some of the parameters. In these dissertation, these parameters were identified and refine through a series of field tests at the Brayton Firefighter Training Field (BFTF) as part of the Texas A&M University System (TAMUS). A total of five tests contributed to this dissertation, which three of them were designed and executed by the LNG team of the Mary Kay O'Connor Process Safety Center (MKOPSC) and the financial support from BP Global SPU Gas (BP). The data collected were used as calibration for a commercial CFD code called CFX from ANSYS. Once the CFD code was tuned, it was used in a sensitivity analysis to assess the effects of parameters in the LFL distance and the concentration levels. The dissertation discusses also the validity range for the key parameters.

Cormier, Benjamin Rodolphe

2008-08-01T23:59:59.000Z

94

Static and dynamic response of a fluid-fluid interface to electric point and line charge  

SciTech Connect

We consider the behavior of a dielectric fluid-fluid interface in the presence of a strong electric field from a point charge and line charge, respectively, both statically and, in the latter case, dynamically. The fluid surface is elevated above its undisturbed level until balance is reached between the electromagnetic lifting force, gravity and surface tension. We derive ordinary differential equations for the shape of the fluid-fluid interface which are solved numerically with standard means, demonstrating how the elevation depends on field strength and surface tension coefficient. In the dynamic case of a moving line charge, the surface of an inviscid liquid-liquid interface is left to oscillate behind the moving charge after it has been lifted against the force of gravity. We show how the wavelength of the oscillations depends on the relative strength of the forces of gravity and inertia, whereas the amplitude of the oscillations is a nontrivial function of the velocity at which the line charge moves. - Highlights: Black-Right-Pointing-Pointer Fluid surface elevation analyzed near a static point and line charge. Black-Right-Pointing-Pointer Elevation determined by interaction of gravity, dielectric force and surface tension. Black-Right-Pointing-Pointer Dynamic equation of motion for the moving line charge is derived. Black-Right-Pointing-Pointer Surface waves behind moving charge calculated and analysed for different velocities.

Ellingsen, Simen A, E-mail: simen.a.ellingsen@ntnu.no; Brevik, Iver, E-mail: iver.h.brevik@ntnu.no

2012-12-15T23:59:59.000Z

97

The Dalles Dam, Columbia River: Spillway Improvement CFD Study  

DOE Green Energy (OSTI)

This report documents development of computational fluid dynamics (CFD) models that were applied to The Dalles spillway for the US Army Corps of Engineers, Portland District. The models have been successfully validated against physical models and prototype data, and are suitable to support biological research and operations management. The CFD models have been proven to provide reliable information in the turbulent high-velocity flow field downstream of the spillway face that is typically difficult to monitor in the prototype. In addition, CFD data provides hydraulic information throughout the solution domain that can be easily extracted from archived simulations for later use if necessary. This project is part of an ongoing program at the Portland District to improve spillway survival conditions for juvenile salmon at The Dalles. Biological data collected at The Dalles spillway have shown that for the original spillway configuration juvenile salmon passage survival is lower than desired. Therefore, the Portland District is seeking to identify operational and/or structural changes that might be implemented to improve fish passage survival. Pacific Northwest National Laboratory (PNNL) went through a sequence of steps to develop a CFD model of The Dalles spillway and tailrace. The first step was to identify a preferred CFD modeling package. In the case of The Dalles spillway, Flow-3D was as selected because of its ability to simulate the turbulent free-surface flows that occur downstream of each spilling bay. The second step in development of The Dalles CFD model was to assemble bathymetric datasets and structural drawings sufficient to describe the dam (powerhouse, non-overflow dam, spillway, fish ladder entrances, etc.) and tailrace. These datasets are documented in this report as are various 3-D graphical representations of The Dalles spillway and tailrace. The performance of the CFD model was then validated for several cases as the third step. The validated model was then applied to address specific SIS design questions. Specifically, the CFD models were used to evaluate flow deflectors, baffle block removal and the effects of spillwalls. The CFD models were also used to evaluate downstream differences at other locations, such as at the Highway 197 bridge piers and Oregon shore islands, due to alterations in spill pattern. CFD model results were analyzed to quantitatively compare impacts of the spillwall that has subsequently been constructed between bays 6 and 7. CFD model results provided detailed information about how the spillwall would impact downstream flow patterns that complemented results from the 1:80 scale physical model. The CFD model was also used to examine relative differences between the juvenile spill pattern used in previous years and the anticipated spill pattern that will be applied once the wall is complete. In addition, the CFD model examined velocity magnitudes over the downstream basalt shelf to investigate potential for erosion under high flow conditions (e.g., 21 kcfs/bay for bays 1 through 6) with the spillwall in place. Several appendices follow the results and discussion sections of this report. These appendices document the large number of CFD simulations that have been performed by PNNL; both spillway improvement study (SIS) related and those performed for related biological tests.

Cook, Chris B.; Richmond, Marshall C.; Serkowski, John A.

2006-06-01T23:59:59.000Z

98

Nonequilibrium chiral fluid dynamics including dissipation and noise  

E-Print Network (OSTI)

We present a consistent theoretical approach for the study of nonequilibrium effects in chiral fluid dynamics within the framework of the linear sigma model with constituent quarks. Treating the quarks as an equilibrated heat bath we use the influence functional formalism to obtain a Langevin equation for the sigma field. This allows us to calculate the explicit form of the damping coefficient and the noise correlators. For a selfconsistent derivation of both the dynamics of the sigma field and the quark fluid we have to employ the 2PI (two-particle irreducible) effective action formalism. The energy dissipation from the field to the fluid is treated in the exact formalism of the 2PI effective action where a conserved energy-momentum tensor can be constructed. We derive its form and comment on approximations generating additional terms in the energy-momentum balance of the entire system.

Marlene Nahrgang; Stefan Leupold; Christoph Herold; Marcus Bleicher

2011-05-03T23:59:59.000Z

99

Nonequilibrium chiral fluid dynamics including dissipation and noise  

E-Print Network (OSTI)

We present a consistent theoretical approach for the study of nonequilibrium effects in chiral fluid dynamics within the framework of the linear sigma model with constituent quarks. Treating the quarks as an equilibrated heat bath we use the influence functional formalism to obtain a Langevin equation for the sigma field. This allows us to calculate the explicit form of the damping coefficient and the noise correlators. For a selfconsistent derivation of both the dynamics of the sigma field and the quark fluid we have to employ the 2PI (two-particle irreducible) effective action formalism. The energy dissipation from the field to the fluid is treated in the exact formalism of the 2PI effective action where a conserved energy-momentum tensor can be constructed. We derive its form and comment on approximations generating additional terms in the energy-momentum balance of the entire system.

Nahrgang, Marlene; Herold, Christoph; Bleicher, Marcus

2011-01-01T23:59:59.000Z

100

Introduction to Computational Fluid Dynamics 424512 E #4Introduction to Computational Fluid Dynamics 424512 E #4 --rzrz IntroductionIntroduction toto ComputationalComputational Fluid DynamicsFluid DynamicsIntroductionIntroduction toto ComputationalComputa  

E-Print Network (OSTI)

.rwth-aachen.de/fileadmin/LehreSeminar/Combustion/SummerSchool97_ueberarbeitet.pdf W93 Wil D C "T b l d lli f CFD" DCW I d t i I L C ñ d april 2012 �bo Akademi modelling for CFD", DCW Industries Inc., La Cañada (CA), 1993 #12;

Zevenhoven, Ron

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

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

102

Computational fluid dynamics simulation of chemical reactors: Application of in situ adaptive tabulation to methane thermochlorination chemistry  

SciTech Connect

Recently, a novel algorithm--in situ adaptive tabulation--has been proposed to effectively incorporate detailed chemistry in computational fluid dynamics (CFD) simulations for turbulent reacting flows. In this work, detailed tests performed on a pairwise-mixing stirred reactor (PMSR) model are presented implementing methane thermochlorination chemistry to validate the in situ adaptive tabulation (ISAT) algorithm. The detailed kinetic scheme involves 3 elements (H, C, Cl) and 38 chemical species undergoing a total of 152 elementary reactions. The various performance issues (error control, accuracy, storage requirements, speed-up) involved in the implementation of detailed chemistry in particle-based methods (full PDF methods) are discussed. Using an error tolerance of {epsilon}{sub tol} = 2 x 10{sup {minus}4}, sufficiently accurate results with minimal storage requirements and significantly less computational time than would be required with direct integration are obtained. Based on numerous test simulations, an error tolerance in the range of 10{sup {minus}3}--10{sup {minus}4} is found to be satisfactory for carrying out full PDF simulations of methane thermochlorination reactors. The results presented here demonstrate that the implementation of ISAT makes possible the hitherto formidable task of implementing detailed chemistry in CFD simulations of methane thermochlorination reactors.

Shah, J.J.; Fox, R.O.

1999-11-01T23:59:59.000Z

103

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

104

Reaction Engineering International and Pacific Northwest Laboratory staff exchange: Addressing computational fluid dynamics needs of the chemical process industry  

SciTech Connect

Staff exchanges, such as the one described in this report, are intended to facilitate communications and collaboration among scientists and engineers at Department of Energy (DOE) laboratories, in US industry, and academia. Funding support for these exchanges is provided by the DOE, Office of Energy Research, Laboratory Technology Transfer Program. Funding levels for each exchange typically range from $20,000 to $40,000. The exchanges offer the opportunity for the laboratories to transfer technology and expertise to industry, gain a perspective to industry`s problems, and develop the basis for further cooperative efforts through Cooperative Research and Development Agreements (CRADAS) or other mechanisms. Information in this report on the staff exchange of the Pacific Northwest Laboratory (PNL) staff with Reaction Engineering International (REI) includes the significant accomplishments, significant problems, industry benefits realized, recommended follow-on work and potential benefit of that work. The objectives of this project were as follows: Work with REI to develop an understanding of the computational fluid dynamics (CFD) needs of the chemical process industry; assess the combined capabilities of the PNL and REI software analysis tools to address these needs; and establish a strategy for a future programmatically funded, joint effort to develop a new CFD tool for the chemical process industry.

Fort, J.A.

1995-07-01T23:59:59.000Z

105

Gasification CFD Modeling for Advanced Power Plant Simulations  

Science Conference Proceedings (OSTI)

In this paper we have described recent progress on developing CFD models for two commercial-scale gasifiers, including a two-stage, coal slurry-fed, oxygen-blown, pressurized, entrained-flow gasifier and a scaled-up design of the PSDF transport gasifier. Also highlighted was NETL’s Advanced Process Engineering Co-Simulator for coupling high-fidelity equipment models with process simulation for the design, analysis, and optimization of advanced power plants. Using APECS, we have coupled the entrained-flow gasifier CFD model into a coal-fired, gasification-based FutureGen power and hydrogen production plant. The results for the FutureGen co-simulation illustrate how the APECS technology can help engineers better understand and optimize gasifier fluid dynamics and related phenomena that impact overall power plant performance.

Zitney, S.E.; Guenther, C.P.

2005-09-01T23:59:59.000Z

106

Predicting aerodynamic characteristic of typical wind turbine airfoils using CFD  

DOE Green Energy (OSTI)

An investigation was conducted into the capabilities and accuracy of a representative computational fluid dynamics code to predict the flow field and aerodynamic characteristics of typical wind-turbine airfoils. Comparisons of the computed pressure and aerodynamic coefficients were made with wind tunnel data. This work highlights two areas in CFD that require further investigation and development in order to enable accurate numerical simulations of flow about current generation wind-turbine airfoils: transition prediction and turbulence modeling. The results show that the laminar-to turbulent transition point must be modeled correctly to get accurate simulations for attached flow. Calculations also show that the standard turbulence model used in most commercial CFD codes, the k-e model, is not appropriate at angles of attack with flow separation. 14 refs., 28 figs., 4 tabs.

Wolfe, W.P. [Sandia National Labs., Albuquerque, NM (United States); Ochs, S.S. [Iowa State Univ., Ames, IA (United States). Aerospace Engineering Dept.

1997-09-01T23:59:59.000Z

107

Nek5000: Computational Fluid Dynamics Code | Argonne National Laboratory  

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

Nek5000: Computational Fluid Dynamics Code Nek5000: Computational Fluid Dynamics Code Nuclear reactor simulation: An elevation plot of the highest energy neutron flux distributions from an axial slice of a nuclear reactor core is shown superimposed over the same slice of the underlying geometry. This figure shows the rapid spatial variation in the high energy neutron distribution between within each plate along with the more slowly varying, global distribution. The figure is significant since UNIC allows researchers to capture both of these effects simultaneously. Nuclear reactor simulation: An elevation plot of the highest energy neutron flux distributions from an axial slice of a nuclear reactor core is shown superimposed over the same slice of the underlying geometry. This figure shows the rapid spatial variation in the high energy neutron distribution

108

CFD Simulation and Experimental Testing of Multiphase Flow Inside the MVP Electrical Submersible Pump  

E-Print Network (OSTI)

The MVP is a special type of Electrical Submersible Pumps (ESPs) manufactured by Baker Hughes, model no. G470, and is capable of handling multiphase flow up to 70% Gas Volume Fraction (GVF). Flows at high GVF cause conventional ESPs to surge. However, the special design of the impeller blades of the MVP ESP enables it to handle higher GVF. Dynamic behavior of the multiphase flow is studied experimentally and theoretically for this pump for the first time. In this work, a Computational Fluid Dynamics (CFD) simulation of an entire pump and detailed experimental analysis are performed. Meshing and CFD simulations are performed using the commercially available software ANSYS Fluent. An experimental facility has been designed and constructed to test the pump at different operating conditions. The pump is modeled and tested at two speeds; 3300 and 3600 rpm, using air-water mixtures with GVFs of 0, 5, 10, 25, 32 and 35%. The flow loop is controlled to produce different suction pressures up to 300psi. Pump pressure head is used to validate the CFD model for both single and two phase flows. Single phase CFD model was validated at 100 psi inlet pressure, while two phase models were validated at 200 psi inlet pressure. CFD simulations can predict the behavior of the pump at different speeds, flow rates, GVFs, and inlet pressures. Different diffuser designs are studied and simulated to improve the multistage pump performance. Enhanced diffuser designs increased the pump pressure head to up to 3.2%.

Rasmy Marsis, Emanuel 1983-

2012-12-01T23:59:59.000Z

109

Geophysical Fluid Dynamics Laboratory Portal | Data.gov  

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

Geophysical Fluid Dynamics Laboratory Portal Geophysical Fluid Dynamics Laboratory Portal Agriculture Community Menu DATA APPS EVENTS DEVELOPER STATISTICS COLLABORATE ABOUT Agriculture You are here Data.gov » Communities » Agriculture » Data Geophysical Fluid Dynamics Laboratory Portal Dataset Summary Description Output and documentation from a set of multi-century experiments performed using NOAA/GFDL's climate models. Users can download files, display data file attributes, and graphically display the data. Data sets include those from CM2.X experiments associated with the Intergovernmental Panel on Climate Change Assessment Report (IPCC) and the US Climate Change Science Program (US CCSP). Tags {climate,IPCC,CCSP,pressure,SLP," sea ice","upper-level winds",ozone,"meridional winds","zonal winds",u-wind,v-wind," carbon dioxide"," volcanic",aerosol,grids,"soil moisture"," IPCC",flux,"radiation flux",thickness,radiation,emissivity,longwave,sensible,"latent heat",downwelling,upwelling,temperature,convective,runoff,"water vapor",humidity,cloudiness,transport,"geopotential height",assimilation,salinity,evaporation,freshwater}

110

OpenMP parallelism for fluid and fluid-particulate systems  

Science Conference Proceedings (OSTI)

In order to exploit the flexibility of OpenMP in parallelizing large scale multi-physics applications where different modes of parallelism are needed for efficient computation, it is first necessary to be able to scale OpenMP codes as well as MPI on ... Keywords: Computational fluid dynamics (CFD), Hybrid parallelization, MPI, Multiphase flows, OpenMP, Performance tools

Amit Amritkar; Danesh Tafti; Rui Liu; Rick Kufrin; Barbara Chapman

2012-09-01T23:59:59.000Z

111

Development of a Laboratory Verified Single-Duct VAV System Model with Fan Powered Terminal Units Optimized Using Computational Fluid Dynamics  

E-Print Network (OSTI)

Single Duct Variable Air Volume (SDVAV) systems use series and parallel Fan Powered Terminal Units to control the air flow in conditioned spaces. This research developed a laboratory verified model of SDVAV systems that used series and parallel fan terminal units where the fan speeds were controlled by either Silicon Controlled Rectifiers (SCR) or Electronically Commutated Motors (ECM) motors. As part of the research, the model was used to compare the performance of the systems and to predict the harmonics generated by ECM systems. All research objectives were achieved. The CFD model, which was verified with laboratory measurements, showed the potential to identify opportunities for improvement in the design of the FPTU and accurately predicted the static pressure drop as air passed through the unit over the full operating range of the FPTU. Computational fluid dynamics (CFD) models of typical a FPTU were developed and used to investigate opportunities for optimizing the design of FPTUs. The CFD model identified key parameters required to conduct numerical simulations of FPTU and some of the internal components used to manufacture the units. One key internal component was a porous baffle used to enhance mixing when primary air and induced air entered the mixing chamber. The CFD analysis showed that a pressure-drop based on face velocity model could be used to accurately predict the performance of the FPTU. The SDVAV simulation results showed that parallel FPTUs used less energy overall than series systems that used SCR motors as long as primary air leakage was not considered. Simulation results also showed that series ECM FPTUs used about the same amount of energy, within 3 percent, of parallel FPTU even when leakage was not considered. A leakage rate of 10 percent was enough to reduce the performance of the parallel FPTU to the level of the series SCR system and the series ECM FPTUs outperformed the parallel FPTUs at all weather locations used in the study.

Davis, Michael A.

2010-08-01T23:59:59.000Z

112

Research on Ammonium Bisulfate Formation in Air Preheaters - Experimental Investigation and CFD Modeling  

Science Conference Proceedings (OSTI)

Ammonium bisulfate (ABS) formation and deposition is the most common operating problem affecting air preheaters (APHs) in fossil power plants with post combustion NOx controls that use selective noncatalytic reduction (SNCR) or selective catalytic reduction (SCR). This report describes pilot-scale experiments conducted to better understand ABS chemistry and efforts to develop a computational fluid dynamics (CFD) model of an APH to identify the key phenomena that may affect ABS formation and deposition.

2008-06-30T23:59:59.000Z

113

TANK48 CFD MODELING ANALYSIS  

SciTech Connect

The process of recovering the waste in storage tanks at the Savannah River Site (SRS) typically requires mixing the contents of the tank to ensure uniformity of the discharge stream. Mixing is accomplished with one to four dual-nozzle slurry pumps located within the tank liquid. For the work, a Tank 48 simulation model with a maximum of four slurry pumps in operation has been developed to estimate flow patterns for efficient solid mixing. The modeling calculations were performed by using two modeling approaches. One approach is a single-phase Computational Fluid Dynamics (CFD) model to evaluate the flow patterns and qualitative mixing behaviors for a range of different modeling conditions since the model was previously benchmarked against the test results. The other is a two-phase CFD model to estimate solid concentrations in a quantitative way by solving the Eulerian governing equations for the continuous fluid and discrete solid phases over the entire fluid domain of Tank 48. The two-phase results should be considered as the preliminary scoping calculations since the model was not validated against the test results yet. A series of sensitivity calculations for different numbers of pumps and operating conditions has been performed to provide operational guidance for solids suspension and mixing in the tank. In the analysis, the pump was assumed to be stationary. Major solid obstructions including the pump housing, the pump columns, and the 82 inch central support column were included. The steady state and three-dimensional analyses with a two-equation turbulence model were performed with FLUENT{trademark} for the single-phase approach and CFX for the two-phase approach. Recommended operational guidance was developed assuming that local fluid velocity can be used as a measure of sludge suspension and spatial mixing under single-phase tank model. For quantitative analysis, a two-phase fluid-solid model was developed for the same modeling conditions as the single-phase model. The modeling results show that the flow patterns driven by four pump operation satisfy the solid suspension requirement, and the average solid concentration at the plane of the transfer pump inlet is about 12% higher than the tank average concentrations for the 70 inch tank level and about the same as the tank average value for the 29 inch liquid level. When one of the four pumps is not operated, the flow patterns are satisfied with the minimum suspension velocity criterion. However, the solid concentration near the tank bottom is increased by about 30%, although the average solid concentrations near the transfer pump inlet have about the same value as the four-pump baseline results. The flow pattern results show that although the two-pump case satisfies the minimum velocity requirement to suspend the sludge particles, it provides the marginal mixing results for the heavier or larger insoluble materials such as MST and KTPB particles. The results demonstrated that when more than one jet are aiming at the same position of the mixing tank domain, inefficient flow patterns are provided due to the highly localized momentum dissipation, resulting in inactive suspension zone. Thus, after completion of the indexed solids suspension, pump rotations are recommended to avoid producing the nonuniform flow patterns. It is noted that when tank liquid level is reduced from the highest level of 70 inches to the minimum level of 29 inches for a given number of operating pumps, the solid mixing efficiency becomes better since the ratio of the pump power to the mixing volume becomes larger. These results are consistent with the literature results.

Lee, S.

2011-05-17T23:59:59.000Z

114

Mesoscale Structures at Complex Fluid-Fluid Interfaces: a Novel Lattice Boltzmann / Molecular Dynamics Coupling  

E-Print Network (OSTI)

Complex fluid-fluid interfaces featuring mesoscale structures with adsorbed particles are key components of newly designed materials which are continuously enriching the field of soft matter. Simulation tools which are able to cope with the different scales characterizing these systems are a fundamental requirement for efficient theoretical investigations. In this paper we present a novel simulation method, based on the approach of Ahlrichs and D\\"unweg [Ahlrichs and D\\"unweg, Int. J. Mod. Phys. C, 1998, 9, 1429], that couples the "Shan-Chen" multicomponent Lattice Boltzmann technique to off-lattice molecular dynamics. We demonstrate how this approach can be used to solve a wide class of challenging problems. Several examples are given, with an accent on bicontinuous phases formation in polyelectrolyte solutions and ferrofluid emulsions. We show also that the introduction of solvation free energies in the particle-fluid interaction unveils the hidden, multiscale nature of the particle-fluid coupling, allowing to treat symmetrically (and interchangeably) the on-lattice and off-lattice components of the system.

Marcello Sega; Mauro Sbragaglia; Sofia Sergeevna Kantorovich; Alexey Olegovich Ivanov

2013-06-04T23:59:59.000Z

115

CFD simulation for pedestrian wind comfort and wind safety in urban areas: General decision framework and case study for the Eindhoven University campus  

Science Conference Proceedings (OSTI)

Wind comfort and wind safety for pedestrians are important requirements in urban areas. Many city authorities request studies of pedestrian wind comfort and wind safety for new buildings and new urban areas. These studies involve combining statistical ... Keywords: Building aerodynamics, Built environment, Computational fluid dynamics (CFD), Discomfort and danger, Experimental validation, Guidelines, Wind flow

B. Blocken; W. D. Janssen; T. van Hooff

2012-04-01T23:59:59.000Z

116

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

117

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

118

Dynamic Multiscaling in Two-dimensional Fluid Turbulence  

E-Print Network (OSTI)

We obtain, by extensive direct numerical simulations, time-dependent and equal-time structure functions for the vorticity, in both quasi-Lagrangian and Eulerian frames, for the direct-cascade regime in two-dimensional fluid turbulence with air-drag-induced friction. We show that different ways of extracting time scales from these time-dependent structure functions lead to different dynamic-multiscaling exponents, which are related to equal-time multiscaling exponents by different classes of bridge relations; for a representative value of the friction we verify that, given our error bars, these bridge relations hold.

Ray, Samriddhi Sankar; Perlekar, Prasad; Pandit, Rahul

2011-01-01T23:59:59.000Z

119

Nuclear Energy CFD Application Management System  

Science Conference Proceedings (OSTI)

In modeling and simulation (M&S), it is virtually impossible to separately evaluate the effectiveness of the model from the data used because the results produced rely heavily on the interaction between the two. Both the data and the simulation are responsible for achieving the ultimate goal of providing defensible research and development (R&D) products and decisions. It is therefore vital that data verification and validation (V&V) activities, along with stringent configuration management, be considered part of the overall M&S accreditation process. In support of these goals is the Nuclear Energy CFD Application Management System (NE-CAMS) for nuclear system design and safety analysis. Working with Bettis Laboratory and Utah State University, a plan of action is being developed by the Idaho National Laboratory (INL) that will address the highest and most immediate needs to track and manage computational fluid dynamics (CFD) models and experimental data in an electronic database. The database will intrinsically incorporate the Nuclear Regulatory Commission (NRC) approved policies and procedures for quality. The quality requirements will be such that the model and data must conform to the quality specifications outlined by the NRC before they can be entered into the database. The primary focus of this database is CFD V&V for nuclear industry needs and will, in practice, serve as the best practice guideline that will accommodate NRC regulations. Such a database, along with a prescriptive methodology for how to utilize it, will provide the NRC with accepted CFD results that could potentially be used for licensing. NE-CAMS will incorporate data V&V as key precursors to the distribution of nuclear systems design and safety data, ensuring that these data are appropriate for use in a particular M&S application. Verification will be conducted to provide a level of confidence that the data selected are the most appropriate for the simulation and are properly prepared, i.e., they are complete, correct and conform to predefined procedures and requirements. Validation will ensure that the data accurately represent the real world activity that is being simulated, ensuring the analytical quality of the data. The level of detail and stringency applied against the data V&V activities will be based on a graded approach principle; the higher the risk, the more rigorous the V&V activities. For the V&V activities to be complete, it will be necessary to scrutinize the physical and statistical properties of the extracted data during the overall process. Regardless of the specific technique or methodology, data V&V will be an important component of NE-CAMS.

Hyung Lee; Kimberlyn C. Mousseau

2001-09-01T23:59:59.000Z

120

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

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121

Introduction to Computational Fluid Dynamics 424512 E #4Introduction to Computational Fluid Dynamics 424512 E #4 --rzrz IntroductionIntroduction toto ComputationalComputational Fluid DynamicsFluid DynamicsIntroductionIntroduction toto ComputationalComputa  

E-Print Network (OSTI)

://www.itm.rwth-aachen.de/Downloadarea/Summerschool97 W93 Wil D C "T b l d lli f CFD" DCW I d t i I L C ñ d mars 2011 �bo Akademi Univ - Thermal", DCW Industries Inc., La Cañada (CA), 1993 #12;

Zevenhoven, Ron

122

Air Ingress Benchmarking with Computational Fluid Dynamics Analysis  

E-Print Network (OSTI)

Temperature Reactor Technology Institute of Nuclear and New Energy Technology Friendship Hotel, Haidian by a CFD benchmarking program based on experimental work performed by JAERI (Japanese Atomic Energy Energy Research Institute) had been set up to study the ingress of air into the core as a result

123

Dissipative particle dynamics simulation of fluid motion through an unsaturated fracture and fracture junction  

Science Conference Proceedings (OSTI)

Multiphase fluid motion in unsaturated fractures and fracture networks involves complicated fluid dynamics, which is difficult to model using grid-based continuum methods. In this paper, the application of dissipative particle dynamics (DPD), a relatively ... Keywords: Dissipative particle dynamics (DPD), Fracture, Fracture flow, Smoothed particle hydrodynamics (SPH), Weight functions

Moubin Liu; Paul Meakin; Hai Huang

2007-03-01T23:59:59.000Z

124

A texture-based framework for improving CFD data visualization in a virtual environment  

Science Conference Proceedings (OSTI)

In the field of computational fluid dynamics (CFD) accurate representations of fluid phenomena can be simulated hut require large amounts of data to represent the flow domain. Most datasets generated from a CFD simulation can be coarse, {approx}10,000 nodes or cells, or very fine with node counts on the order of 1,000,000. A typical dataset solution can also contain multiple solutions for each node, pertaining to various properties of the flow at a particular node. Scalar properties such as density, temperature, pressure, and velocity magnitude are properties that are typically calculated and stored in a dataset solution. Solutions are not limited to just scalar properties. Vector quantities, such as velocity, are also often calculated and stored for a CFD simulation. Accessing all of this data efficiently during runtime is a key problem for visualization in an interactive application. Understanding simulation solutions requires a post-processing tool to convert the data into something more meaningful. Ideally, the application would present an interactive visual representation of the numerical data for any dataset that was simulated while maintaining the accuracy of the calculated solution. Most CFD applications currently sacrifice interactivity for accuracy, yielding highly detailed flow descriptions hut limiting interaction for investigating the field.

Gerrick O'Ron Bivins

2005-05-05T23:59:59.000Z

125

A texture-based frameowrk for improving CFD data visualization in a virtual environment  

SciTech Connect

In the field of computational fluid dynamics (CFD) accurate representations of fluid phenomena can be simulated but require large amounts of data to represent the flow domain. Most datasets generated from a CFD simulation can be coarse, {approx} 10,000 nodes or cells, or very fine with node counts on the order of 1,000,000. A typical dataset solution can also contain multiple solutions for each node, pertaining to various properties of the flow at a particular node. Scalar properties such as density, temperature, pressure, and velocity magnitude are properties that are typically calculated and stored in a dataset solution. Solutions are not limited to just scalar properties. Vector quantities, such as velocity, are also often calculated and stored for a CFD simulation. Accessing all of this data efficiently during runtime is a key problem for visualization in an interactive application. Understanding simulation solutions requires a post-processing tool to convert the data into something more meaningful. Ideally, the application would present an interactive visual representation of the numerical data for any dataset that was simulated while maintaining the accuracy of the calculated solution. Most CFD applications currently sacrifice interactivity for accuracy, yielding highly detailed flow descriptions but limiting interaction for investigating the field.

Biveins, Gerrick O'Ron

2005-05-01T23:59:59.000Z

126

Apparatus for characterizing the temporo-spatial properties of a dynamic fluid front and method thereof  

SciTech Connect

Methods and apparatus are described for characterizing the temporal-spatial properties of a dynamic fluid front within a mold space while the mold space is being filled with fluid. A method includes providing a mold defining a mold space and having one or more openings into the mold space; heating a plurality of temperature sensors that extend into the mold space; injecting a fluid into th emold space through the openings, the fluid experiencing a dynamic fluid front while filling the mold space with a fluid; and characterizing temporal-spatial properties of the dynamic fluid front by monitoring a termperature of each of the plurality of heated temperature sensors while the mold space is being filled with the fluid. An apparatus includes a mold defining a mold space; one or more openings for introducing a fluid into th emold space and filling the mold space with the fluid, the fluid experiencing a dynamic fluid front while filling the mold space; a plurality of heated temperature sensors extending into the mold space; and a computer coupled to the plurality of heated temperature sensors for characterizing the temporal-spatial properties of the dynamic fluid front.

Battiste, Richard L

2013-12-31T23:59:59.000Z

127

Fluid Dynamics of Carbon Dioxide Disposal into Saline Aquifers  

SciTech Connect

Injection of carbon dioxide (CO{sub 2}) into saline aquifers has been proposed as a means to reduce greenhouse gas emissions (geological carbon sequestration). Large-scale injection of CO{sub 2} will induce a variety of coupled physical and chemical processes, including multiphase fluid flow, fluid pressurization and changes in effective stress, solute transport, and chemical reactions between fluids and formation minerals. This work addresses some of these issues with special emphasis given to the physics of fluid flow in brine formations. An investigation of the thermophysical properties of pure carbon dioxide, water and aqueous solutions of CO{sub 2} and NaCl has been conducted. As a result, accurate representations and models for predicting the overall thermophysical behavior of the system CO{sub 2}-H{sub 2}O-NaCl are proposed and incorporated into the numerical simulator TOUGH2/ECO{sub 2}. The basic problem of CO{sub 2} injection into a radially symmetric brine aquifer is used to validate the results of TOUGH2/ECO2. The numerical simulator has been applied to more complex flow problem including the CO{sub 2} injection project at the Sleipner Vest Field in the Norwegian sector of the North Sea and the evaluation of fluid flow dynamics effects of CO{sub 2} injection into aquifers. Numerical simulation results show that the transport at Sleipner is dominated by buoyancy effects and that shale layers control vertical migration of CO{sub 2}. These results are in good qualitative agreement with time lapse surveys performed at the site. High-resolution numerical simulation experiments have been conducted to study the onset of instabilities (viscous fingering) during injection of CO{sub 2} into saline aquifers. The injection process can be classified as immiscible displacement of an aqueous phase by a less dense and less viscous gas phase. Under disposal conditions (supercritical CO{sub 2}) the viscosity of carbon dioxide can be less than the viscosity of the aqueous phase by a factor of 15. Because of the lower viscosity, the CO{sub 2} displacement front will have a tendency towards instability. Preliminary simulation results show good agreement between classical instability solutions and numerical predictions of finger growth and spacing obtained using different gas/liquid viscosity ratios, relative permeability and capillary pressure models. Further studies are recommended to validate these results over a broader range of conditions.

Garcia, Julio Enrique

2003-12-18T23:59:59.000Z

128

Coupled computational fluid dynamics and heat transfer analysis of the VHTR lower plenum.  

SciTech Connect

The very high temperature reactor (VHTR) concept is being developed by the US Department of Energy (DOE) and other groups around the world for the future generation of electricity at high thermal efficiency (> 48%) and co-generation of hydrogen and process heat. This Generation-IV reactor would operate at elevated exit temperatures of 1,000-1,273 K, and the fueled core would be cooled by forced convection helium gas. For the prismatic-core VHTR, which is the focus of this analysis, the velocity of the hot helium flow exiting the core into the lower plenum (LP) could be 35-70 m/s. The impingement of the resulting gas jets onto the adiabatic plate at the bottom of the LP could develop hot spots and thermal stratification and inadequate mixing of the gas exiting the vessel to the turbo-machinery for energy conversion. The complex flow field in the LP is further complicated by the presence of large cylindrical graphite posts that support the massive core and inner and outer graphite reflectors. Because there are approximately 276 channels in the VHTR core from which helium exits into the LP and a total of 155 support posts, the flow field in the LP includes cross flow, multiple jet flow interaction, flow stagnation zones, vortex interaction, vortex shedding, entrainment, large variation in Reynolds number (Re), recirculation, and mixing enhancement and suppression regions. For such a complex flow field, experimental results at operating conditions are not currently available. Instead, the objective of this paper is to numerically simulate the flow field in the LP of a prismatic core VHTR using the Sandia National Laboratories Fuego, which is a 3D, massively parallel generalized computational fluid dynamics (CFD) code with numerous turbulence and buoyancy models and simulation capabilities for complex gas flow fields, with and without thermal effects. The code predictions for simpler flow fields of single and swirling gas jets, with and without a cross flow, are validated using reported experimental data and theory. The key processes in the LP are identified using phenomena identification and ranking table (PIRT). It may be argued that a CFD code that accurately simulates simplified, single-effect flow fields with increasing complexity is likely to adequately model the complex flow field in the VHTR LP, subject to a future experimental validation. The PIRT process and spatial and temporal discretizations implemented in the present analysis using Fuego established confidence in the validation and verification (V and V) calculations and in the conclusions reached based on the simulation results. The performed calculations included the helicoid vortex swirl model, the dynamic Smagorinsky large eddy simulation (LES) turbulence model, participating media radiation (PMR), and 1D conjugate heat transfer (CHT). The full-scale, half-symmetry LP mesh used in the LP simulation included unstructured hexahedral elements and accounted for the graphite posts, the helium jets, the exterior walls, and the bottom plate with an adiabatic outer surface. Results indicated significant enhancements in heat transfer, flow mixing, and entrainment in the VHTR LP when using swirling inserts at the exit of the helium flow channels into the LP. The impact of using various swirl angles on the flow mixing and heat transfer in the LP is qualified, including the formation of the central recirculation zone (CRZ), and the effect of LP height. Results also showed that in addition to the enhanced mixing, the swirling inserts result in negligible additional pressure losses and are likely to eliminate the formation of hot spots.

El-Genk, Mohamed S. (University of New Mexico, Albuquerque, NM); Rodriguez, Salvador B.

2010-12-01T23:59:59.000Z

129

CFD MODELING OF ITER CABLE-IN-CONDUIT SUPERCONDUCTORS. PART V: COMBINED MOMENTUM AND HEAT TRANSFER IN RIB ROUGHENED PIPES  

Science Conference Proceedings (OSTI)

Computational Fluid Dynamics (CFD) techniques have been proposed and applied in a series of papers to analyze cable-in-conduit conductors (CICC) for the International Thermonuclear Experimental Reactor (ITER). Previous work on the pressure drop in the central channel of ITER CICC is extended here to the problem of combined heat and momentum transfer. The CFD model, solved by the FLUENT commercial code, is first validated against 2D and 3D data from compact heat exchangers, showing good agreement. The Colburn analogy between the friction factor f and the Nusselt number Nu is not verified in the considered 2D geometries, as shown by both experiment and simulation. The validated CFD model is finally applied to the 3D analysis of central channel-like geometries relevant for ITER CICC. It is shown that the heat transfer coefficient on the central channel side stays relatively close to the smooth-pipe (Dittus-Boelter) value.

Zanino, R.; Giors, S. [Dipartimento di Energetica, Politecnico Torino, I-10129 (Italy)

2008-03-16T23:59:59.000Z

130

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

131

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

132

Dynamic Self-Consistent Field Theory for Unentangled Homopolymer Fluids  

E-Print Network (OSTI)

We present a lattice formulation of a dynamic self-consistent field (DSCF) theory that is capable of resolving interfacial structure, dynamics and rheology in inhomogeneous, compressible melts and blends of unentangled homopolymer chains. The joint probability distribution of all the Kuhn segments in the fluid, interacting with adjacent segments and walls, is approximated by a product of one-body probabilities for free segments interacting solely with an external potential field that is determined self-consistently. The effect of flow on ideal chain conformations is modeled with FENE-P dumbbells, and related to stepping probabilities in a random walk. Free segment and stepping probabilities generate statistical weights for chain conformations in a self-consistent field, and determine local volume fractions of chain segments. Flux balance across unit lattice cells yields mean-field transport equations for the evolution of free segment probabilities and of momentum densities on the Kuhn length scale. Diffusive and viscous contributions to the fluxes arise from segmental hops modeled as a Markov process, with transition rates reflecting changes in segmental interaction, kinetic energy, and entropic contributions to the free energy under flow.

Maja Mihajlovic; Tak Shing Lo; Yitzhak Shnidman

2004-11-10T23:59:59.000Z

133

Dynamic fluid loss in hydraulic fracturing under realistic shear conditions in high-permeability rocks  

SciTech Connect

A study of the dynamic fluid loss of hydraulic fracturing fluids under realistic shear conditions is presented. During a hydraulic fracturing treatment, a polymeric solution is pumped under pressure down the well to create and propagate a fracture. Part of the fluid leaks into the rock formation, leaving a skin layer of polymer or polymer filter cake, at the rock surface or in the pore space. This study focuses on the effects of shear rate and permeability on dynamic fluid-loss behavior of crosslinked and linear fracturing gels. Previous studies of dynamic fluid loss have mainly been with low-permeability cores and constant shear rates. Here, the effect of shear history and fluid-loss additive on the dynamic leakoff of high-permeability cores is examined.

Navarrete, R.C.; Cawiezel, K.E.; Constien, V.G. [Dowell Schlumberger, Tulsa, OK (United States)

1996-08-01T23:59:59.000Z

134

Molecular to fluid dynamics: The consequences of stochastic molecular motion Stefan Heinz*  

E-Print Network (OSTI)

Molecular to fluid dynamics: The consequences of stochastic molecular motion Stefan Heinz) The derivation of fluid dynamic equations from molecular equations is considered. This is done on the basis of a stochastic model for the molecular motion which can be obtained by a projection of underlying determin- istic

Heinz, Stefan

135

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

136

Advanced process engineering co-simulation using CFD-based reduced order models  

Science Conference Proceedings (OSTI)

The process and energy industries face the challenge of designing the next generation of plants to operate with unprecedented efficiency and near-zero emissions, while performing profitably amid fluctuations in costs for raw materials, finished products, and energy. To achieve these targets, the designers of future plants are increasingly relying upon modeling and simulation to create virtual plants that allow them to evaluate design concepts without the expense of pilot-scale and demonstration facilities. Two of the more commonly used simulation tools include process simulators for describing the entire plant as a network of simplified equipment models and computational fluid dynamic (CFD) packages for modeling an isolated equipment item in great detail by accounting for complex thermal and fluid flow phenomena. The Advanced Process Engineering Co-Simulator (APECS) sponsored by the U.S. Department of Energy’s (DOE) National Energy Technology Laboratory (NETL) has been developed to combine process simulation software with CFD-based equipment simulation software so that design engineers can analyze and optimize the coupled fluid flow, heat and mass transfer, and chemical reactions that drive overall plant performance (Zitney et al., 2006). The process/CFD software integration was accomplished using the process-industry standard CAPE-OPEN interfaces.

Lang, Y.-D.; Biegler, L.T.; Munteanu, S.; Madsen, J.I.; Zitney, S.E.

2007-11-04T23:59:59.000Z

137

Bonneville Project: CFD of the Spillway Tailrace  

SciTech Connect

US Army Corps of Engineers, Portland District (CENWP) operates the Bonneville Lock and Dam Project on the Columbia River. High spill flows that occurred during 2011 moved a large volume of rock from downstream of the spillway apron to the stilling basin and apron. Although 400 cubic yards of rocks were removed from the stilling basin, there are still large volumes of rock downstream of the apron that could, under certain flow conditions, move upstream into the stilling basin. CENWP is investigating operational changes that could be implemented to minimize future movement of rock into the stilling basin. A key analysis tool to develop these operational changes is a computational fluid dynamics (CFD) model of the spillway. A free-surface CFD model of the Bonneville spillway tailrace was developed and applied for four flow scenarios. These scenarios looked at the impact of flow volume and flow distribution on tailrace hydraulics. The simulation results showed that areas of upstream flow existed near the river bed downstream of the apron, on the apron, and within the stilling basin for all flows. For spill flows of 300 kcfs, the cross-stream and downstream extent of the recirculation zones along Cascade and Bradford Island was very dependent on the spill pattern. The center-loaded pattern had much larger recirculation zones than the flat or bi-modal pattern. The lower flow (200 kcfs) with a flat pattern had a very large recirculation zone that extended half way across the channel near the river bed. A single flow scenario (300 kcfs of flow in a relatively flat spill pattern) was further interrogated using Lagrangian particle tracking. The tracked particles (with size and mass) showed the upstream movement of sediments onto the concrete apron and against the vertical wall between the apron and the stilling basin from seed locations downstream of the apron and on the apron.

Rakowski, Cynthia L.; Serkowski, John A.; Richmond, Marshall C.; Romero Gomez, Pedro DJ

2012-11-19T23:59:59.000Z

138

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

139

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

140

Multi-Phase CFD Modeling of Solid Sorbent Carbon Capture System  

Science Conference Proceedings (OSTI)

Computational fluid dynamics (CFD) simulations are used to investigate a low temperature post-combustion carbon capture reactor. The CFD models are based on a small scale solid sorbent carbon capture reactor design from ADA-ES and Southern Company. The reactor is a fluidized bed design based on a silica-supported amine sorbent. CFD models using both Eulerian-Eulerian and Eulerian-Lagrangian multi-phase modeling methods are developed to investigate the hydrodynamics and adsorption of carbon dioxide in the reactor. Models developed in both FLUENT® and BARRACUDA are presented to explore the strengths and weaknesses of state of the art CFD codes for modeling multi-phase carbon capture reactors. The results of the simulations show that the FLUENT® Eulerian-Lagrangian simulations (DDPM) are unstable for the given reactor design; while the BARRACUDA Eulerian-Lagrangian model is able to simulate the system given appropriate simplifying assumptions. FLUENT® Eulerian-Eulerian simulations also provide a stable solution for the carbon capture reactor given the appropriate simplifying assumptions.

Ryan, Emily M.; DeCroix, David; Breault, Ronald W.; Xu, Wei; Huckaby, E. D.; Saha, Kringan; Darteville, Sebastien; Sun, Xin

2013-07-30T23:59:59.000Z

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141

The Piecewise Parabolic Method for Multidimensional Relativistic Fluid Dynamics  

E-Print Network (OSTI)

We present an extension of the Piecewise Parabolic Method to special relativistic fluid dynamics in multidimensions. The scheme is conservative, dimensionally unsplit, and suitable for a general equation of state. Temporal evolution is second-order accurate and employs characteristic projection operators; spatial interpolation is piece-wise parabolic making the scheme third-order accurate in smooth regions of the flow away from discontinuities. The algorithm is written for a general system of orthogonal curvilinear coordinates and can be used for computations in non-cartesian geometries. A non-linear iterative Riemann solver based on the two-shock approximation is used in flux calculation. In this approximation, an initial discontinuity decays into a set of discontinuous waves only implying that, in particular, rarefaction waves are treated as flow discontinuities. We also present a new and simple equation of state which approximates the exact result for the relativistic perfect gas with high accuracy. The strength of the new method is demonstrated in a series of numerical tests and more complex simulations in one, two and three dimensions.

A. Mignone; T. Plewa; G. Bodo

2005-05-10T23:59:59.000Z

142

Petascale, Adaptive CFD | Argonne Leadership Computing Facility  

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

Petascale, Adaptive CFD Petascale, Adaptive CFD Petascale, Adaptive CFD PI Name: Kenneth Jansen PI Email: jansenke@colorado.edu Institution: U. Colorado-Boulder Allocation Program: ESP Allocation Hours at ALCF: 150 Million Year: 2010 to 2013 Research Domain: Engineering The aerodynamic simulations proposed will involve modeling of active flow control based on synthetic jet actuation that has been shown experimentally to produce large-scale flow changes (e.g., re-attachment of separated flow or virtual aerodynamic shaping of lifting surfaces) from micro-scale input (e.g., a 0.1 W piezoelectric disk resonating in a cavity alternately pushes/pulls out/in the fluid through a small slit to create small-scale vortical structures that interact with, and thereby dramatically alter, the cross flow). This is a process that has yet to be understood fundamentally.

143

COMPARISON OF EXPERIMENTS TO CFD MODELS FOR MIXING USING DUAL OPPOSING JETS IN TANKS WITH AND WITHOUT INTERNAL OBSTRUCTIONS  

SciTech Connect

This paper documents testing methods, statistical data analysis, and a comparison of experimental results to CFD models for blending of fluids, which were blended using a single pump designed with dual opposing nozzles in an eight foot diameter tank. Overall, this research presents new findings in the field of mixing research. Specifically, blending processes were clearly shown to have random, chaotic effects, where possible causal factors such as turbulence, pump fluctuations, and eddies required future evaluation. CFD models were shown to provide reasonable estimates for the average blending times, but large variations -- or scatter -- occurred for blending times during similar tests. Using this experimental blending time data, the chaotic nature of blending was demonstrated and the variability of blending times with respect to average blending times were shown to increase with system complexity. Prior to this research, the variation in blending times caused discrepancies between CFD models and experiments. This research addressed this discrepancy, and determined statistical correction factors that can be applied to CFD models, and thereby quantified techniques to permit the application of CFD models to complex systems, such as blending. These blending time correction factors for CFD models are comparable to safety factors used in structural design, and compensate variability that cannot be theoretically calculated. To determine these correction factors, research was performed to investigate blending, using a pump with dual opposing jets which re-circulate fluids in the tank to promote blending when fluids are added to the tank. In all, eighty-five tests were performed both in a tank without internal obstructions and a tank with vertical obstructions similar to a tube bank in a heat exchanger. These obstructions provided scale models of vertical cooling coils below the liquid surface for a full scale, liquid radioactive waste storage tank. Also, different jet diameters and different horizontal orientations of the jets were investigated with respect to blending. Two types of blending tests were performed. The first set of eighty-one tests blended small quantities of tracer fluids into solution. Data from these tests were statistically evaluated to determine blending times for the addition of tracer solution to tanks, and blending times were successfully compared to Computational Fluid Dynamics (CFD) models. The second set of four tests blended bulk quantities of solutions of different density and viscosity. For example, in one test a quarter tank of water was added to a three quarters of a tank of a more viscous salt solution. In this case, the blending process was noted to significantly change due to stratification of fluids, and blending times increased substantially. However, CFD models for stratification and the variability of blending times for different density fluids was not pursued, and further research is recommended in the area of blending bulk quantities of fluids. All in all, testing showed that CFD models can be effectively applied if statistically validated through experimental testing, but in the absence of experimental validation CFD model scan be extremely misleading as a basis for design and operation decisions.

Leishear, R.; Poirier, M.; Lee, S.; Fowley, M.

2012-06-26T23:59:59.000Z

144

COMPARISON OF EXPERIMENTAL RESULTS TO CFD MODELS FOR BLENDING IN A TANK USING DUAL OPPOSING JETS  

Science Conference Proceedings (OSTI)

Research has been completed in a pilot scale, eight foot diameter tank to investigate blending, using a pump with dual opposing jets. The jets re-circulate fluids in the tank to promote blending when fluids are added to the tank. Different jet diameters and different horizontal and vertical orientations of the jets were investigated. In all, eighty five tests were performed both in a tank without internal obstructions and a tank with vertical obstructions similar to a tube bank in a heat exchanger. These obstructions provided scale models of several miles of two inch diameter, serpentine, vertical cooling coils below the liquid surface for a full scale, 1.3 million gallon, liquid radioactive waste storage tank. Two types of tests were performed. One type of test used a tracer fluid, which was homogeneously blended into solution. Data were statistically evaluated to determine blending times for solutions of different density and viscosity, and the blending times were successfully compared to computational fluid dynamics (CFD) models. The other type of test blended solutions of different viscosity. For example, in one test a half tank of water was added to a half tank of a more viscous, concentrated salt solution. In this case, the fluid mechanics of the blending process was noted to significantly change due to stratification of fluids. CFD models for stratification were not investigated. This paper is the fourth in a series of papers resulting from this research (Leishear, et.al. [1- 4]), and this paper documents final test results, statistical analysis of the data, a comparison of experimental results to CFD models, and scale-up of the results to a full scale tank.

Leishear, R.

2011-08-07T23:59:59.000Z

145

Processes and Procedures for Application of CFD to Nuclear Reactor Safety Analysis  

SciTech Connect

Traditionally, nuclear reactor safety analysis has been performed using systems analysis codes such as RELAP5, which was developed at the INL. However, goals established by the Generation IV program, especially the desire to increase efficiency, has lead to an increase in operating temperatures for the reactors. This increase pushes reactor materials to operate towards their upper temperature limits relative to structural integrity. Because there will be some finite variation of the power density in the reactor core, there will be a potential for local hot spots to occur in the reactor vessel. Hence, it has become apparent that detailed analysis will be required to ensure that local ‘hot spots’ do not exceed safety limits. It is generally accepted that computational fluid dynamics (CFD) codes are intrinsically capable of simulating fluid dynamics and heat transport locally because they are based on ‘first principles.’ Indeed, CFD analysis has reached a fairly mature level of development, including the commercial level. However, CFD experts are aware that even though commercial codes are capable of simulating local fluid and thermal physics, great care must be taken in their application to avoid errors caused by such things as inappropriate grid meshing, low-order discretization schemes, lack of iterative convergence and inaccurate time-stepping. Just as important is the choice of a turbulence model for turbulent flow simulation. Turbulence models model the effects of turbulent transport of mass, momentum and energy, but are not necessarily applicable for wide ranges of flow types. Therefore, there is a well-recognized need to establish practices and procedures for the proper application of CFD to simulate flow physics accurately and establish the level of uncertainty of such computations. The present document represents contributions of CFD experts on what the basic practices, procedures and guidelines should be to aid CFD analysts to obtain accurate estimates of the flow and energy transport as applied to nuclear reactor safety. However, it is expected that these practices and procedures will require updating from time to time as research and development affect them or replace them with better procedures. The practices and procedures are categorized into five groups. These are: 1.Code Verification 2.Code and Calculation Documentation 3.Reduction of Numerical Error 4.Quantification of Numerical Uncertainty (Calculation Verification) 5.Calculation Validation. These five categories have been identified from procedures currently required of CFD simulations such as those required for publication of a paper in the ASME Journal of Fluids Engineering and from the literature such as Roache [1998]. Code verification refers to the demonstration that the equations of fluid and energy transport have been correctly coded in the CFD code. Code and calculation documentation simply means that the equations and their discretizations, etc., and boundary and initial conditions used to pose the fluid flow problem are fully described in available documentation. Reduction of numerical error refers to practices and procedures to lower numerical errors to negligible or very low levels as is reasonably possible (such as avoiding use of first-order discretizations). The quantification of numerical uncertainty is also known as calculation verification. This means that estimates are made of numerical error to allow the characterization of the numerical

Richard W. Johnson; Richard R. Schultz; Patrick J. Roache; Ismail B. Celik; William D. Pointer; Yassin A. Hassan

2006-09-01T23:59:59.000Z

146

Dynamics of Nanoparticle-Based Complex Fluids in Porous Media  

Science Conference Proceedings (OSTI)

Abstract Scope, Advances in the use of nanoparticle-based complex fluids are likely to transform exploration and production of oil and gas. The dependence of  ...

147

CFD analysis and experimental investigation associated with the design of the Los Alamos nuclear materials storage facility  

Science Conference Proceedings (OSTI)

The Nuclear Materials Storage Facility (NMSF) at the Los Alamos National Laboratory is being renovated for long-term storage of canisters designed to hold heat-generating nuclear materials, such as powders, ingots, and other components. The continual heat generation within the canisters necessitates a reliable cooling scheme of sufficient magnitude which maintains the stored material temperatures within acceptable limits. The primary goal of this study was to develop both an experimental facility and a computational fluid dynamics (CFD) model of a subsection of the NMSF which could be used to observe general performance trends of a proposed passive cooling scheme and serve as a design tool for canister holding fixtures. Comparisons of numerical temperature and velocity predictions with empirical data indicate that the CFD model provides an accurate representation of the NMSF experimental facility. Minor modifications in the model geometry and boundary conditions are needed to enhance its accuracy, however, the various fluid and thermal models correctly capture the basic physics.

Bernardin, J.D.; Hopkins, S.; Gregory, W.S.; Martin, R.A. [and others

1997-06-01T23:59:59.000Z

148

Noncommutative fluid dynamics in the K\\"{a}hler parametrization  

E-Print Network (OSTI)

In this paper, we propose a first order action functional for a large class of systems that generalize the relativistic perfect fluids in the K\\"{a}hler parametrization to noncommutative spacetimes. We calculate the equations of motion for the fluid potentials and the energy-momentum tensor in the first order in the noncommutative parameter. The density current does not receive any noncommutative corrections and it is conserved under the action of the commutative generators $P_{\\mu}$ but the energy-momentum tensor is not. Therefore, we determine the set of constraints under which the energy-momentum tensor is divergenceless. Another set of constraints on the fluid potentials is obtained from the requirement of the invariance of the action under the generalization of the volume preserving transformations of the noncommutative spacetime. We show that the proposed action describes noncommutative fluid models by casting the energy-momentum tensor in the familiar fluid form and identifying the corresponding energy...

Holender, L; Orlando, M T D; Vancea, I V

2011-01-01T23:59:59.000Z

149

Design and Construction of an Affordable Rotating Table for Classroom Demonstrations of Geophysical Fluid Dynamics Principles  

Science Conference Proceedings (OSTI)

Rotating tables have been in use for many years because of their ability to demonstrate fluid dynamical phenomena, shedding insight on the sometimes complicated or esoteric mathematics used to describe such processes. A small team of students at ...

Brian D. McNoldy; Anning Cheng; Zachary A. Eitzen; Richard W. Moore; John Persing; Kevin Schaefer; Wayne H. Schubert

2003-12-01T23:59:59.000Z

150

Combustion Chamber Fluid Dynamics and Hypergolic Gel Propellant Chemistry Simulations for Selectable Thrust Rocket Engines  

Science Conference Proceedings (OSTI)

This paper describes the application of high performance computing to accelerate the development of hypergolic propulsion systems for tactical missiles. Computational fluid dynamics is employed to model the chemically reacting flow within a system's ...

M. Nusca; C.-C. Chen; M. McQuaid

2007-06-01T23:59:59.000Z

151

Combustion Chamber Fluid Dynamics and Hypergolic Gel Propellant Chemistry Simulations for Selectable Thrust Rocket Engines  

Science Conference Proceedings (OSTI)

This paper describes the development and application of high performance computing for the acceleration of tactical missile hypergolic propulsion system development. Computational fluid dynamics is employed to model the chemically reacting flow within ...

Michael J. Nusca; Michael J. McQuaid

2006-06-01T23:59:59.000Z

152

Combustion Chamber Fluid Dynamics and Hypergolic Gel Propellant Chemistry Simulations for Selectable Thrust Rocket Engines  

Science Conference Proceedings (OSTI)

This paper describes the application of high performance computing to accelerate the development of hypergolic propulsion systems for tactical missiles. Computational fluid dynamics is employed to model the chemically reacting flow within a system’s ...

Michael J. Nusca; Chiung-Chu Chen; Michael J. McQuaid

2008-07-01T23:59:59.000Z

153

Computational Fluid Dynamic Simulations of Plume Dispersion in Urban Oklahoma City  

Science Conference Proceedings (OSTI)

A 3D computational fluid dynamics study using Reynolds-averaged Navier–Stokes modeling was conducted and validated with field data from the Joint Urban 2003 dispersion study in Oklahoma City, Oklahoma. The modeled flow field indicated that the ...

Julia E. Flaherty; David Stock; Brian Lamb

2007-12-01T23:59:59.000Z

154

Consequences of Urban Stability Conditions for Computational Fluid Dynamics Simulations of Urban Dispersion  

Science Conference Proceedings (OSTI)

The validity of omitting stability considerations when simulating transport and dispersion in the urban environment is explored using observations from the Joint Urban 2003 field experiment and computational fluid dynamics simulations of that ...

Julie K. Lundquist; Stevens T. Chan

2007-07-01T23:59:59.000Z

155

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

156

Scaling studies and conceptual experiment designs for NGNP CFD assessment  

SciTech Connect

The objective of this report is to document scaling studies and conceptual designs for flow and heat transfer experiments intended to assess CFD codes and their turbulence models proposed for application to prismatic NGNP concepts. The general approach of the project is to develop new benchmark experiments for assessment in parallel with CFD and coupled CFD/systems code calculations for the same geometry. Two aspects of the complex flow in an NGNP are being addressed: (1) flow and thermal mixing in the lower plenum ("hot streaking" issue) and (2) turbulence and resulting temperature distributions in reactor cooling channels ("hot channel" issue). Current prismatic NGNP concepts are being examined to identify their proposed flow conditions and geometries over the range from normal operation to decay heat removal in a pressurized cooldown. Approximate analyses have been applied to determine key non-dimensional parameters and their magnitudes over this operating range. For normal operation, the flow in the coolant channels can be considered to be dominant turbulent forced convection with slight transverse property variation. In a pressurized cooldown (LOFA) simulation, the flow quickly becomes laminar with some possible buoyancy influences. The flow in the lower plenum can locally be considered to be a situation of multiple hot jets into a confined crossflow -- with obstructions. Flow is expected to be turbulent with momentumdominated turbulent jets entering; buoyancy influences are estimated to be negligible in normal full power operation. Experiments are needed for the combined features of the lower plenum flows. Missing from the typical jet experiments available are interactions with nearby circular posts and with vertical posts in the vicinity of vertical walls - with near stagnant surroundings at one extreme and significant crossflow at the other. Two types of heat transfer experiments are being considered. One addresses the "hot channel" problem, if necessary. The second type will treat heated jets entering a model plenum. Unheated MIR (Matched-Index-of-Refraction) experiments are first steps when the geometry is complicated. One does not want to use a computational technique which will not even handle constant properties properly. The purpose of the fluid dynamics experiments is to develop benchmark databases for the assessment of CFD solutions of the momentum equations, scalar mixing and turbulence models for typical NGNP plenum geometries in the limiting case of negligible buoyancy and constant fluid properties. As indicated by the scaling studies, in normal full power operation of a typical NGNP conceptual design, buoyancy influences should be negligible in the lower plenum. The MIR experiment will simulate flow features of the paths of jets as they mix in flowing through the array of posts in a lower plenum en route to the single exit duct. Conceptual designs for such experiments are described.

D. M. McEligot; G. E. McCreery

2004-11-01T23:59:59.000Z

157

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

158

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

159

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

160

Computational fluid dynamics analyses of lateral heat conduction, coolant azimuthal mixing and heat transfer predictions in a BR2 fuel assembly geometry.  

SciTech Connect

To support the analyses related to the conversion of the BR2 core from highly-enriched (HEU) to low-enriched (LEU) fuel, the thermal-hydraulics codes PLTEMP and RELAP-3D are used to evaluate the safety margins during steady-state operation (PLTEMP), as well as after a loss-of-flow, loss-of-pressure, or a loss of coolant event (RELAP). In the 1-D PLTEMP and RELAP simulations, conduction in the azimuthal and axial directions is not accounted. The very good thermal conductivity of the cladding and the fuel meat and significant temperature gradients in the lateral directions (axial and azimuthal directions) could lead to a heat flux distribution that is significantly different than the power distribution. To evaluate the significance of the lateral heat conduction, 3-D computational fluid dynamics (CFD) simulations, using the CFD code STAR-CD, were performed. Safety margin calculations are typically performed for a hot stripe, i.e., an azimuthal region of the fuel plates/coolant channel containing the power peak. In a RELAP model, for example, a channel between two plates could be divided into a number of RELAP channels (stripes) in the azimuthal direction. In a PLTEMP model, the effect of azimuthal power peaking could be taken into account by using engineering factors. However, if the thermal mixing in the azimuthal direction of a coolant channel is significant, a stripping approach could be overly conservative by not taking into account this mixing. STAR-CD simulations were also performed to study the thermal mixing in the coolant. Section II of this document presents the results of the analyses of the lateral heat conduction and azimuthal thermal mixing in a coolant channel. Finally, PLTEMP and RELAP simulations rely on the use of correlations to determine heat transfer coefficients. Previous analyses showed that the Dittus-Boelter correlation gives significantly more conservative (lower) predictions than the correlations of Sieder-Tate and Petukhov. STAR-CD 3-D simulations were performed to compare heat transfer predictions from CFD and the correlations. Section III of this document presents the results of this analysis.

Tzanos, C. P.; Dionne, B. (Nuclear Engineering Division)

2011-05-23T23:59:59.000Z

Note: This page contains sample records for the topic "fluid dynamics cfd" 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
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161

Design sensitivity analysis and optimization of steady fluid-thermal systems  

E-Print Network (OSTI)

Design optimization of fluid-thermal systems has been an area of significant research interest for the aerospace and automotive industry. The subject studies the modification of internal and external flow passages under certain specified objective constraints while satisfying the governing flow equations. Amongst various available optimization procedures the analytical sensitivity analyses-based optimization is arguably the most efficient design tool for complex multi-dimensional practical problems. In this paper, we augmented the analysis capabilities of the computational fluid dynamics (CFD) code with design sensitivity analysis (DSA). The design sensitivities are computed efficiently via analytical differentiation methods. The CFD DSA codes are then combined with numerical optimization schemes. Finally, CFD DSA design optimization algorithm is applied to the optimization of heat exchanger fin and HVAC duct systems. 2001 Elsevier Science B.V. All rights reserved.

Balagangadhar; Uid-thermal Systems

2001-01-01T23:59:59.000Z

162

A CFD-based wind solver for a fast response transport and dispersion model  

SciTech Connect

In many cities, ambient air quality is deteriorating leading to concerns about the health of city inhabitants. In urban areas with narrow streets surrounded by clusters of tall buildings, called street canyons, air pollution from traffic emissions and other sources is difficult to disperse and may accumulate resulting in high pollutant concentrations. For various situations, including the evacuation of populated areas in the event of an accidental or deliberate release of chemical, biological and radiological agents, it is important that models should be developed that produce urban flow fields quickly. For these reasons it has become important to predict the flow field in urban street canyons. Various computational techniques have been used to calculate these flow fields, but these techniques are often computationally intensive. Most fast response models currently in use are at a disadvantage in these cases as they are unable to correlate highly heterogeneous urban structures with the diagnostic parameterizations on which they are based. In this paper, a fast and reasonably accurate computational fluid dynamics (CFD) technique that solves the Navier-Stokes equations for complex urban areas has been developed called QUIC-CFD (Q-CFD). This technique represents an intermediate balance between fast (on the order of minutes for a several block problem) and reasonably accurate solutions. The paper details the solution procedure and validates this model for various simple and complex urban geometries.

Gowardhan, Akshay A [Los Alamos National Laboratory; Brown, Michael J [Los Alamos National Laboratory; Pardyjak, Eric R [UNIV OF UTAH; Senocak, Inanc [BOISE STATE UNIV

2010-01-01T23:59:59.000Z

163

Stochastic Hard-Sphere Dynamics for Hydrodynamics of Non-Ideal Fluids  

SciTech Connect

A novel stochastic fluid model is proposed with a nonideal structure factor consistent with compressibility, and adjustable transport coefficients. This stochastic hard-sphere dynamics (SHSD) algorithm is a modification of the direct simulation Monte Carlo algorithm and has several computational advantages over event-driven hard-sphere molecular dynamics. Surprisingly, SHSD results in an equation of state and a pair correlation function identical to that of a deterministic Hamiltonian system of penetrable spheres interacting with linear core pair potentials. The fluctuating hydrodynamic behavior of the SHSD fluid is verified for the Brownian motion of a nanoparticle suspended in a compressible solvent.

Donev, A; Alder, B J; Garcia, A L

2008-02-26T23:59:59.000Z

164

CFD Predictions of Severe Accident Steam Generator Flows in a 1/7. Scale Pressurized Water Reactor  

SciTech Connect

Computational Fluid Dynamics (CFD) is applied to steam generator inlet plenum mixing as part of a larger plan covering steam generator tube integrity. The technique is verified by comparing predicted results with severe accident natural circulation data from a 1/7. scale Westinghouse facility. This exercise demonstrates that the technique can predict the natural circulation and mixing phenomena relevant to steam generator tube integrity issues. The model includes primary side flow paths for a single hot leg and steam generator. Qualitatively, the experimentally observed flow phenomena are predicted. The paths of the natural circulation flows and the relative flow proportions are correctly predicted. Quantitatively, comparisons are made with temperatures, mass flows, and other parameters. All predictions are generally within 10% of the experimental values. Overall, there is a high degree of confidence in the CFD technique for prediction of the relevant flow phenomena associated with this type of severe accident sequence. (authors)

Boyd, Christopher; Hardesty, Kelly [U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001 (United States)

2002-07-01T23:59:59.000Z

165

Fluid Dynamics and Solid Mechanics, T-3: Theoretical, T: LANL Inside  

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

Leader Leader Mark Schraad Deputy Group Leader Marianne Francois Administration Crystal Martinez Beverly Corrales Office Location MS B216 TA-3, Bldg 200, Rm 215 Fluid Dynamics and Solid Mechanics, T-3 Conducts basic and applied research in theoretical continuum dynamics, modern hydrodynamic theory, materials modeling, global climate modeling, numerical algorithm development, and large-scale computational simulations. There is an emphasis on developing advanced numerical methods for continuum dynamics at all flow velocities and strain rates, and coupling these methods to constitutive models for solid material response and other physical processes such as turbulence, chemical reactions, combustion, phase change, heat and mass transfer, and plasma behavior. The Fluid Dynamics Group's portfolio of research activities represents fundamental

166

Standard Problems for CFD Validation for NGNP - Status Report  

DOE Green Energy (OSTI)

The U.S. Department of Energy (DOE) is conducting research and development to support the resurgence of nuclear power in the United States for both electrical power generation and production of process heat required for industrial processes such as the manufacture of hydrogen for use as a fuel in automobiles. The project is called the Next Generation Nuclear Plant (NGNP) Project, which is based on a Generation IV reactor concept called the very high temperature reactor (VHTR). The VHTR will be of the prismatic or pebble bed type; the former is considered herein. The VHTR will use helium as the coolant at temperatures ranging from 250°C to perhaps 1000°C. While computational fluid dynamics (CFD) has not previously been used for the safety analysis of nuclear reactors in the United States, it is being considered for existing and future reactors. It is fully recognized that CFD simulation codes will have to be validated for flow physics reasonably close to actual fluid dynamic conditions expected in normal operational and accident situations. The “Standard Problem” is an experimental data set that represents an important physical phenomenon or phenomena, whose selection is based on a phenomena identification and ranking table (PIRT) for the reactor in question. It will be necessary to build a database that contains a number of standard problems for use to validate CFD and systems analysis codes for the many physical problems that will need to be analyzed. The first two standard problems that have been developed for CFD validation consider flow in the lower plenum of the VHTR and bypass flow in the prismatic core. Both involve scaled models built from quartz and designed to be installed in the INL’s matched index of refraction (MIR) test facility. The MIR facility employs mineral oil as the working fluid at a constant temperature. At this temperature, the index of refraction of the mineral oil is the same as that of the quartz. This provides an advantage to the optics used for data gathering. Particle image velocimetry (PIV) is used to take the data. The first standard problem represents several flow physics expected to be present in the lower plenum of the prismatic VHTR. In the lower plenum, heated helium coolant in the form of jets issues downward into the plenum and is then forced to turn ninety degrees and flow toward the exit duct. The lower plenum is filled with cylindrical graphite posts that hold up the core. Figure S-1 provides a plan view of the lower plenum. The red circles represent support posts holding up columns of heated blocks. Grey circles represent support posts under columns of reflector blocks. Helium enters the lower plenum at the junctions of the hexagonal blocks.

Richard W. Johnson; Richard R. Schultz

2010-08-01T23:59:59.000Z

167

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

168

Real-time motion effect enhancement based on fluid dynamics in figure animation  

Science Conference Proceedings (OSTI)

In fast figure animation, motion blur is often employed to generate fantastic effects of figure motion, for exaggerating the atmosphere one wants to convey. In the previous works for long time, the solution based on certain kind of image blending in ... Keywords: GPU geometric processing, fluid dynamics, motion blur, skeletal animation

Tian-Chen Xu; En-Hua Wu; Mo Chen; Ming Xie

2011-12-01T23:59:59.000Z

169

Particle Swarm Optimization of Ceramic Roller Kiln Temperature Field Uniformity Using Computational Fluid Dynamics Tools  

Science Conference Proceedings (OSTI)

In this paper ceramic roller kiln temperature field uniformity is mainly researched using computational fluid dynamics tools and particle swarm optimization (PSO). In consideration of burning and burning temperature control is key technique of burning ... Keywords: PSO, temperature field uniformity, multiple liner regression, uniform design, ceramic roller kiln design

Wenbi Rao; Peng Li

2009-06-01T23:59:59.000Z

170

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

171

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

172

Steam Generator Management Program: Thermal-Hydraulic Analysis of a Recirculating Steam Generator Using Commercial Computational Fluid Dynamics Software  

Science Conference Proceedings (OSTI)

The objective of this research was to demonstrate that a commercial computational fluid dynamics code can be set up to model the thermal-hydraulic physics that occur during the operation of a steam generator. Specific complexities in steam-generator thermal-hydraulic modeling include: phase change and two-phase fluid mechanics, hydrodynamic representation of the tube bundle, and thermal coupling between the primary and secondary sides. A commercial computational fluid dynamics code was used without any s...

2012-02-21T23:59:59.000Z

173

Fluid Dynamic and Performance Behavior of Multiphase Progressive Cavity Pumps  

E-Print Network (OSTI)

It is common for an oil well to produce a mixture of hydrocarbons that flash when exposed to atmospheric pressure. The separation of oil and gas mixtures on site may prove expensive and lead to higher infrastructure and maintenance costs as well. A multiphase pump offers a good alternative with a lower capital cost and increased overall production. A Progressive Cavity Pump (PCP) is a positive displacement pump type that can be used to pump a wide range of multiphase mixtures, including high viscosity fluids with entrained gas and solid particles in suspension. Despite its advantages, a PCP has a reduced ability to handle high gas-liquid ratios due to limitations of its elastomeric stator material required to overcome thermo and mechanical effects. Also the efficiency decreases significantly with increases in gas volume fractions and reduced differential pressures. The current study focuses on studying the behavior of this unique pump in a wide range of GVFs and studying the effect of this ratio on overall efficiency, temperature and pressure distribution on the stator. The pump exhibits vibration issues at specific differential pressures and they have been studied in this work. This can be of critical value as severe vibration issues can damage the pump components such as couplings and bearings leading to high maintenance costs. Another important issue addressed by this research is the behavior of this pump in transient conditions. Oil well production is highly unpredictable with unexpected rises and drops in GVFs. These transient conditions have been simulated by varying the GVF over wide ranges and studying the pump's behavior in terms of load, temperature rises and instantaneous pressure profiles on the pump stator. This thesis provides a comprehensive study of this pump, its operating ranges and behavior in off-design conditions to assist oil and gas exploration ventures in making an informed choice in pump selection for their applications based on field conditions.

Narayanan, Shankar Bhaskaran

2011-08-01T23:59:59.000Z

174

Using Process/CFD Co-Simulation for the Design and Analysis of Advanced Energy Systems  

Science Conference Proceedings (OSTI)

In this presentation we describe the major features and capabilities of NETL’s Advanced Process Engineering Co-Simulator (APECS) and highlight its application to advanced energy systems, ranging from small fuel cell systems to commercial-scale power plants including the coal-fired, gasification-based electricity and hydrogen plant in the DOE’s $1 billion, 10-year FutureGen demonstration project. APECS is an integrated software suite which allows the process and energy industries to optimize overall plant performance with respect to complex thermal and fluid flow phenomena by combining process simulation (e.g., Aspen Plus®) with high-fidelity equipment simulations based on computational fluid dynamics (CFD) models (e.g., FLUENT®).

Zitney, S.E.

2007-04-01T23:59:59.000Z

175

Impact of random obstacles on the dynamics of a dense colloidal fluid  

E-Print Network (OSTI)

Using molecular dynamics simulations we study the slow dynamics of a colloidal fluid annealed within a matrix of obstacles quenched from an equilibrated colloidal fluid. We choose all particles to be of the same size and to interact as hard spheres, thus retaining all features of the porous confinement while limiting the control parameters to the packing fraction of the matrix, {\\Phi}m, and that of the fluid, {\\Phi}f. We conduct detailed investigations on several dynamic properties, including the tagged-particle and collective intermediate scattering functions, the mean-squared displacement, and the van Hove function. We show the confining obstacles to profoundly impact the relaxation pattern of various quantifiers pertinent to the fluid. Varying the type of quantifier (tagged-particle or collective) as well as {\\Phi}m and {\\Phi}f, we unveil both discontinuous and continuous arrest scenarios. Furthermore, we discover subdiffusive behavior and demonstrate its close connection to the matrix structure. Our findings partly confirm the various predictions of a recent extension of mode-coupling theory to the quenched-annealed protocol.

Jan Kurzidim; Daniele Coslovich; Gerhard Kahl

2010-07-02T23:59:59.000Z

176

Liquid phase fluid dynamic (methanol) run in the LaPorte alternative fuels development unit  

DOE Green Energy (OSTI)

A fluid dynamic study was successfully completed in a bubble column at DOE's Alternative Fuels Development Unit (AFDU) in LaPorte, Texas. Significant fluid dynamic information was gathered at pilot scale during three weeks of Liquid Phase Methanol (LPMEOJP) operations in June 1995. In addition to the usual nuclear density and temperature measurements, unique differential pressure data were collected using Sandia's high-speed data acquisition system to gain insight on flow regime characteristics and bubble size distribution. Statistical analysis of the fluctuations in the pressure data suggests that the column was being operated in the churn turbulent regime at most of the velocities considered. Dynamic gas disengagement experiments showed a different behavior than seen in low-pressure, cold-flow work. Operation with a superficial gas velocity of 1.2 ft/sec was achieved during this run, with stable fluid dynamics and catalyst performance. Improvements included for catalyst activation in the design of the Clean Coal III LPMEOH{trademark} plant at Kingsport, Tennessee, were also confirmed. In addition, an alternate catalyst was demonstrated for LPMEOH{trademark}.

Bharat L. Bhatt

1997-05-01T23:59:59.000Z

177

Relativistic Dynamics of Non-ideal Fluids: Viscous and heat-conducting fluids II. Transport properties and microscopic description of relativistic nuclear matter  

E-Print Network (OSTI)

In the causal theory of relativistic dissipative fluid dynamics, there are conditions on the equation of state and other thermodynamic properties such as the second-order coefficients of a fluid that need to be satisfied to guarantee that the fluid perturbations propagate causally and obey hyperbolic equations. The second-order coefficients in the causal theory, which are the relaxation times for the dissipative degrees of freedom and coupling constants between different forms of dissipation (relaxation lengths), are presented for partonic and hadronic systems. These coefficients involves relativistic thermodynamic integrals. The integrals are presented for general case and also for different regimes in the temperature--chemical potential plane. It is shown that for a given equation of state these second-order coefficients are not additional parameters but they are determined by the equation of state. We also present the prescription on the calculation of the freeze-out particle spectra from the dynamics of relativistic non-ideal fluids.

Azwinndini Muronga

2006-11-25T23:59:59.000Z

178

Quantum-fluid-dynamics approach for strong-field processes: Application to the study of multiphoton ionization and high-order harmonic generation of He and Ne atoms  

E-Print Network (OSTI)

Wigner cor- relation energy functionals are used. QUANTUM-FLUID-DYNAMICS APPROACH FOR STRONGQuantum-fluid-dynamics approach for strong-field processes: Application to the study of multiphoton; published 18 March 2002 We explore the feasibility of extending the quantum-fluid dynamics QFD approach

Chu, Shih-I

179

Performance Evaluation and CFD Simulation of Multiphase Twin-Screw Pumps  

E-Print Network (OSTI)

Twin-screw pumps are economical alternatives to the conventional multiphase system and are increasingly used in the oil and gas industry due to their versatility in transferring the multiphase mixture with varying Gas Void Fraction (GVF). Present work focuses on the experimental and numerical analysis of twin-screw pumps for different operating conditions. Experimental evaluation aims to understand steady state and transient behavior of twin-screw pumps. Detailed steady state evaluation helped form better understanding of twin-screw pumps under different operating conditions. A comparative study of twin-screw pumps and compressors contradicted the common belief that compressor efficiency is better than the efficiency of twin-screw pumps. Transient analysis at high GVF helped incorporate necessary changes in the design of sealflush recirculation loop to improve the efficiency of the pump. The effect of viscosity of the sealflush fluid at high GVF on pump performance was studied. Volumetric efficiency was found to be decreased with increase in viscosity. Flow visualization was aimed to characterize phase distribution along cavities and clearances at low to high GVF. Dynamic pressure variation was studied along the axis of the screw which helped correlate the GVF, velocity and pressure distribution. Complicated fluid flow behavior due to enclosed fluid pockets and interconnecting clearances makes it difficult to numerically simulate the pump. Hence design optimization and performance prediction incorporates only analytical approach and experimental evaluation. Current work represents an attempt to numerically simulate a multiphase twin-screw pump as a whole. Single phase 3D CFD simulation was performed for different pressure rise. The pressure and velocity profile agreed well with previous studies. Results are validated using an analytical approach as well as experimental data. A two-phase CFD simulation was performed for 50% GVF. An Eulerian approach was employed to evaluate multiphase flow behavior. Pressure, velocity, temperature and GVF distributions were successfully predicted using CFD simulation. Bubble size was found to be most dominant parameter, significantly affecting phase separation and leakage flow rate. Better phase separation was realized with increased bubble size, which resulted in decrease in leakage flow rate. CFD results agreed well with experimental data for the bubble size higher than 0.08 mm.

Patil, Abhay

2013-08-01T23:59:59.000Z

180

Investigation of Coal-biomass Catalytic Gasification using Experiments, Reaction Kinetics, and Computational Fluid Dynamics  

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

Coal-biomass Catalytic Coal-biomass Catalytic Gasification using Experiments, Reaction Kinetics, and Computational Fluid Dynamics Background The U.S. Department of Energy (DOE) supports research and development efforts targeted to improve efficiency and reduce the negative environmental effects of the use of fossil fuels. One way to achieve these goals is to combine coal with biomass to create synthesis gas (syngas) for use in turbines and refineries to produce energy, fuels,

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

Measurement techniques for local and global fluid dynamic quantities in two and three phase systems  

SciTech Connect

This report presents a critical review of the methods available for assessing the fluid dynamic parameters in large industrial two and three phase bubble column and slurry bubble column reactors operated at high pressure and temperature. The physical principles behind various methods are explained, and the basic design of the instrumentation needed to implement each measurement principle is discussed. Fluid dynamic properties of interest are: gas, liquid and solids holdup and their axial and radial distribution as well as the velocity distribution of the two (bubble column) or three phases (slurry bubble column). This information on operating pilot plant and plant reactors is essential to verify the computational fluid dynamic codes as well as scale-up rules used in reactor design. Without such information extensive and costly scale-up to large reactors that exploit syngas chemistries, and other reactors in production of fuels and chemicals, cannot be avoided. In this report, available measurement techniques for evaluation of global and local phase holdups, instantaneous and average phase velocities and for the determination of bubble sizes in gas-liquid and gas-liquid-solid systems are reviewed. Advantages and disadvantages of various techniques are discussed. Particular emphasis is placed on identifying methods that can be employed on large scale, thick wall, high pressure and high temperature reactors used in the manufacture of fuels and chemicals from synthesis gas and its derivatives.

Kumar, S.; Dudukovic, M.P. [Washington Univ., St. Louis, MO (United States). Chemical Reaction Engineering Lab.; Toseland, B.A. [Air Products and Chemicals, Inc., Lehigh Valley, PA (United States)

1996-03-01T23:59:59.000Z

182

Complete CFD analysis of a Velocity XL-5 RG with flight-test verification  

E-Print Network (OSTI)

The Texas A&M Flight Research Laboratory (FRL) recently received delivery of its newest aircraft, the Velocity XL-5 RG. The Velocity can fly faster than the other aircraft owned by the FRL and does not have a propeller in the front of the aircraft to disrupt the air flow. These are definite advantages that make the Velocity an attractive addition to the FRL inventory to be used in boundary-layer stability and transition control. Possible mounting locations built into the aircraft for future projects include hard points in the wings and roof of the fuselage. One of the drawbacks of the aircraft is that it has a canard ahead of the main wing that could disrupt the incoming flow for a wing glove or research requiring test pieces mounted to the hard point in the wing. Therefore, it is necessary to understand the influence the canard and the impact of its wake on the wing of the aircraft before any in-depth aerodynamic research could be completed on the aircraft. A combination of in-flight measurements of the canard wake and Computational Fluid Dynamics (CFD) were used to provide a clear picture of the flowfield around the aircraft. The first step of the project consisted of making a 3-D CAD model of the aircraft. This model was then used for the CFD simulations in Fluent. 2-D, 3-D, inviscid, and viscous simulations were preformed on the aircraft. A pressure rake was designed to house a 5-hole probe and 18 Pitot probes that extended forward of the main wing to measure the location and strength of the canard wake at various flight conditions. There were five primary test points that were recorded at multiple times over the course of three flights. Once all of the data were collected from the flights, the freestream conditions became the inputs into the final, 3-D CFD simulations on the aircraft. The good agreement between the CFD results and the in-flight measurements provided the necessary verification of the CFD model of the aircraft. These results can be used in the future planning and execution of experiments involving the Velocity XL-5 RG.

Schouten, Shane Michael

2008-05-01T23:59:59.000Z

183

Proceedings of the International Symposium on Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances  

DOE Green Energy (OSTI)

This publication contains extended abstracts of papers presented at the International Symposium ''Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances'' held at Ernest Orlando Lawrence Berkeley National Laboratory on February 10-12, 1999. This Symposium is organized in Honor of the 80th Birthday of Paul A. Witherspoon, who initiated some of the early investigations on flow and transport in fractured rocks at the University of California, Berkeley, and at Lawrence Berkeley National Laboratory. He is a key figure in the development of basic concepts, modeling, and field measurements of fluid flow and contaminant transport in fractured rock systems. The technical problems of assessing fluid flow, radionuclide transport, site characterization, modeling, and performance assessment in fractured rocks remain the most challenging aspects of subsurface flow and transport investigations. An understanding of these important aspects of hydrogeology is needed to assess disposal of nu clear wastes, development of geothermal resources, production of oil and gas resources, and remediation of contaminated sites. These Proceedings of more than 100 papers from 12 countries discuss recent scientific and practical developments and the status of our understanding of fluid flow and radionuclide transport in fractured rocks. The main topics of the papers are: Theoretical studies of fluid flow in fractured rocks; Multi-phase flow and reactive chemical transport in fractured rocks; Fracture/matrix interactions; Hydrogeological and transport testing; Fracture flow models; Vadose zone studies; Isotopic studies of flow in fractured systems; Fractures in geothermal systems; Remediation and colloid transport in fractured systems; and Nuclear waste disposal in fractured rocks.

Faybishenko, B. (ed.)

1999-02-01T23:59:59.000Z

184

Proceedings of the International Symposium on Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances  

SciTech Connect

This publication contains extended abstracts of papers presented at the International Symposium ''Dynamics of Fluids in Fractured Rocks: Concepts and Recent Advances'' held at Ernest Orlando Lawrence Berkeley National Laboratory on February 10-12, 1999. This Symposium is organized in Honor of the 80th Birthday of Paul A. Witherspoon, who initiated some of the early investigations on flow and transport in fractured rocks at the University of California, Berkeley, and at Lawrence Berkeley National Laboratory. He is a key figure in the development of basic concepts, modeling, and field measurements of fluid flow and contaminant transport in fractured rock systems. The technical problems of assessing fluid flow, radionuclide transport, site characterization, modeling, and performance assessment in fractured rocks remain the most challenging aspects of subsurface flow and transport investigations. An understanding of these important aspects of hydrogeology is needed to assess disposal of nu clear wastes, development of geothermal resources, production of oil and gas resources, and remediation of contaminated sites. These Proceedings of more than 100 papers from 12 countries discuss recent scientific and practical developments and the status of our understanding of fluid flow and radionuclide transport in fractured rocks. The main topics of the papers are: Theoretical studies of fluid flow in fractured rocks; Multi-phase flow and reactive chemical transport in fractured rocks; Fracture/matrix interactions; Hydrogeological and transport testing; Fracture flow models; Vadose zone studies; Isotopic studies of flow in fractured systems; Fractures in geothermal systems; Remediation and colloid transport in fractured systems; and Nuclear waste disposal in fractured rocks.

Faybishenko, B. (ed.)

1999-02-01T23:59:59.000Z

185

Study of ebullated bed fluid dynamics. Final progress report, September 1980-July 1983  

Science Conference Proceedings (OSTI)

The fluid dynamics occurring in HRI's H-coal process development unit coal liquefaction reactor during Run PDU-10 were measured and compared with Amoco Oil cold-flow fluidization results. It was found that catalyst bed expansions and gas holdups are higher in the PDU than those observed in the cold-flow tests for slurries having the same nominal viscosity. Comparison of PDU results with cold-flow results shows that the bulk of the operating reactor gas flow lies in the ideal bubbly regime. It also appears that the gas bubbles in these PDU tests are rising quite slowly. Only two of the operating points in our test program on the PDU were found to lie in the churn turbulent regime. Existence of churn turbulent behavior during these two experiments is consistent with trends observed in earlier cold-flow experiments. Two- and three-phase fluidization experiments were carried out in Amoco's cold-flow fluid dynamics unit. The data base now includes fluidization results for coal char/kerosene slurry concentrations of 4.0, 9.8, and 20.7 vol% in addition to the 15.5 and 17.8 vol% data from our earlier work. Both HDS-2A and Amocat-1A catalysts were used in the tests. Bed expansion is primarily a function of slurry velocity, with gas velocity having only a weak effect. Bed contractions have been observed in some cases at sufficiently high gas velocity. Gas and liquid holdups were found to be uniform across the cross-section of the Amoco cold-flow fluid dynamics pilot plant. A viscometer was adapted for measurement of the viscosity of coal slurries at high temperature and pressure. Based on experiments carried out in the Amoco cold-flow unit, a significant degree of backmixing was found to occur in the H-Coal system. 70 references, 93 figures, 32 tables.

Schaefer, R.J.; Rundell, D.N.; Shou, J.K.

1983-07-01T23:59:59.000Z

186

TEMPEST: A computer code for three-dimensional analysis of transient fluid dynamics  

SciTech Connect

TEMPEST (Transient Energy Momentum and Pressure Equations Solutions in Three dimensions) is a powerful tool for solving engineering problems in nuclear energy, waste processing, chemical processing, and environmental restoration because it analyzes and illustrates 3-D time-dependent computational fluid dynamics and heat transfer analysis. It is a family of codes with two primary versions, a N- Version (available to public) and a T-Version (not currently available to public). This handout discusses its capabilities, applications, numerical algorithms, development status, and availability and assistance.

Fort, J.A.

1995-06-01T23:59:59.000Z

187

GTRF Calculations Using Hydra-TH (L3 Milestone THM.CFD.P5.05)  

SciTech Connect

This report describes the work carried out for completion of the Thermal Hydraulics Methods (THM) Level 3 Milestone THM.CFD.P5.05 for the Consortium for Advanced Simulation of Light Water Reactors (CASL). A series of body-fitted computational meshes have been generated by Numeca's Hexpress/Hybrid, a.k.a. 'Spider', meshing technology for the V5H 3 x 3 and 5 x 5 rod bundle geometries and subsequently used to compute the fluid dynamics of grid-to-rod fretting (GTRF). Spider is easy to use, fast, and automatically generates high-quality meshes for extremely complex geometries, required for the GTRF problem. Hydra-TH has been used to carry out large-eddy simulations on both 3 x 3 and 5 x 5 geometries, using different mesh resolutions. The results analyzed show good agreement with Star-CCM+ simulations and experimental data.

Bakosi, Jozsef [Los Alamos National Laboratory; Christon, Mark A. [Los Alamos National Laboratory; Francois, Marianne M. [Los Alamos National Laboratory; Lowrie, Robert B. [Los Alamos National Laboratory; Nourgaliev, Robert [Los Alamos National Laboratory

2012-09-05T23:59:59.000Z

188

PIV Uncertainty Methodologies for CFD Code Validation at the MIR Facility  

SciTech Connect

Currently, computational fluid dynamics (CFD) is widely used in the nuclear thermal hydraulics field for design and safety analyses. To validate CFD codes, high quality multi dimensional flow field data are essential. The Matched Index of Refraction (MIR) Flow Facility at Idaho National Laboratory has a unique capability to contribute to the development of validated CFD codes through the use of Particle Image Velocimetry (PIV). The significance of the MIR facility is that it permits non intrusive velocity measurement techniques, such as PIV, through complex models without requiring probes and other instrumentation that disturb the flow. At the heart of any PIV calculation is the cross-correlation, which is used to estimate the displacement of particles in some small part of the image over the time span between two images. This image displacement is indicated by the location of the largest peak. In the MIR facility, uncertainty quantification is a challenging task due to the use of optical measurement techniques. Currently, this study is developing a reliable method to analyze uncertainty and sensitivity of the measured data and develop a computer code to automatically analyze the uncertainty/sensitivity of the measured data. The main objective of this study is to develop a well established uncertainty quantification method for the MIR Flow Facility, which consists of many complicated uncertainty factors. In this study, the uncertainty sources are resolved in depth by categorizing them into uncertainties from the MIR flow loop and PIV system (including particle motion, image distortion, and data processing). Then, each uncertainty source is mathematically modeled or adequately defined. Finally, this study will provide a method and procedure to quantify the experimental uncertainty in the MIR Flow Facility with sample test results.

Piyush Sabharwall; Richard Skifton; Carl Stoots; Eung Soo Kim; Thomas Conder

2013-12-01T23:59:59.000Z

189

Compilation of CFD Models of Various Solid Oxide Electrolyzers Analyzed at the Idaho National Laboratory  

SciTech Connect

Various three dimensional computational fluid dynamics (CFD) models of solid oxide electrolyzers have been created and analyzed at the Idaho National Laboratory since the inception of the Nuclear Hydrogen Initiative in 2004. Three models presented herein include: a 60 cell planar cross flow with inlet and outlet plenums, 10 cell integrated planar cross flow, and internally manifolded five cell planar cross flow. 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) module 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 SOEC 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. 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 indicated the effects of heat transfer, endothermic reaction, Ohmic heating, and change in local gas composition. Results are discussed for using these models in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production is reported herein. Contour plots and discussion show areas of likely cell degradation, flow distribution in inlet plenum, and flow distribution across and along the flow channels of the current collectors

Grant Hawkes; James O'Brien

2012-06-01T23:59:59.000Z

190

3D CFD Model of a Multi-Cell High Temperature Electrolysis Stack  

DOE Green Energy (OSTI)

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis stack performance and steam electrolysis in the Idaho National Laboratory Integrated Lab Scale (ILS) experiment. The model is made of 60 planar cells stacked on top of each other operated as Solid Oxide Electrolysis Cells (SOEC). Details of the model geometry are specific to a stack that was fabricated by Ceramatec, Inc1. and tested at the Idaho National Laboratory. Inlet and outlet plenum flow and distribution are considered. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT2. 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 userdefined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation overpotential, 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.

G.L. Hawkes; J. E. O'Brien; C. M. Stoots

2007-11-01T23:59:59.000Z

191

3-D CFD MODEL OF A MULTI-CELL HIGH TEMPERATURE ELECTROLYSIS STACK  

DOE Green Energy (OSTI)

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis stack performance and steam electrolysis in the Idaho National Laboratory (INL) Integrated Lab Scale (ILS) experiment. The model is made of 60 planar cells stacked on top of each other operated as Solid Oxide Electrolysis Cells (SOEC). Details of the model geometry are specific to a stack that was fabricated by Ceramatec, Inc. and tested at INL. Inlet and outlet plenum flow and distribution are considered. 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 SOEC 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.

Grant Hawkes; James O'Brien; Carl Stoots; Brian Hawkes

2009-05-01T23:59:59.000Z

192

Study of the Effects of Obstacles in Liquefied Natural Gas (LNG) Vapor Dispersion using CFD Modeling  

E-Print Network (OSTI)

The evaluation of the potential hazards related with the operation of an LNG terminal includes possible release scenarios with the consequent flammable vapor dispersion within the facility; therefore, it is important to know the behavior of this phenomenon through the application of advanced simulation tools. Computational Fluid Dynamic (CFD) tools are often used to estimate the exclusion zones in an event of accidental LNG spill. In practice these releases are more likely to occur in the confines of complex geometries with solid obstacles such as LNG terminals, and LNG processing plants. The objective of this research is to study the effects that different obstacles have over the LNG vapor dispersion and the safety distance reduction caused by enhanced mixing. Through parametric analysis it is demonstrated that height, width and shape of the obstacles play an important role in the vapor concentration reduction. The findings of this research may be applied in the design stage of an LNG terminal, to improve the design of passive barriers, and for designing better layout configurations for storage tanks. Simulations results performed with FLACS (Flame Acceleration Simulator), a CFD solver, confirmed that these applications help to reduce safety distances.

Ruiz Vasquez, Roberto

2012-08-01T23:59:59.000Z

193

Sandia National Laboratories environmental fluid dynamics code : pH effects user manual.  

Science Conference Proceedings (OSTI)

This document describes the implementation level changes in the source code and input files of Sandia National Laboratories Environmental Fluid Dynamics Code (SNL-EFDC) that are necessary for including pH effects into algae-growth dynamics. The document also gives a brief introduction to how pH effects are modeled into the algae-growth model. The document assumes that the reader is aware of the existing algae-growth model in SNL-EFDC. The existing model is described by James, Jarardhanam and more theoretical considerations behind modeling pH effects are presented therein. This document should be used in conjunction with the original EFDC manual and the original water-quality manual.

Janardhanam, Vijay (University of New Mexico, Albuquerque, NM); James, Scott Carlton

2012-02-01T23:59:59.000Z

194

CFD SIMULATION OF PROPOSED VALIDATION DATA FOR A FLOW PROBLEM RECONFIGURED TO ELIMINATE AN UNDESIRABLE FLOW INSTABILITY  

DOE Green Energy (OSTI)

The U. S. Department of Energy (DOE) is supporting the development of a next generation nuclear plant (NGNP), which will be based on a very high temperature reactor (VHTR) design. The VHTR is a single-phase helium-cooled reactor wherein the helium will be heated initially to 750 °C and later to temperatures approaching 1000 °C. The high temperatures are desired to increase reactor efficiency and to provide a heat source for the manufacture of hydrogen and other applications. While computational fluid dynamics (CFD) has not been used in the past to design or license nuclear reactors in the U. S., it is expected that CFD will be used in the design and safety analysis of forthcoming designs. This is partly because of the maturity of CFD and partly because detailed information is desired of the flow and heat transfer inside the reactor to avoid hot spots and other conditions that might compromise reactor safety. Numerical computations of turbulent flow should be validated against experimental data for flow conditions that contain some or all of the physics expected in the thermal fluid machinery of interest. To this end, a scaled model of a narrow slice of the lower plenum of the prismatic VHTR was constructed and installed in the Idaho National Laboratory’s (INL) matched index of refraction (MIR) test facility and data were taken. The data were then studied and compared to CFD calculations to help determine their suitability for validation data. One of the main findings was that the inlet data, which were measured and controlled by calibrated mass flow rotameters and were also measured using detailed stereo particle image velocimetry (PIV) showed considerable discrepancies in mass flow rate between the two methods. The other finding was that a randomly unstable recirculation zone occurs in the flow. This instability has a very significant effect on the flow field in the vicinity of the inlet jets. Because its time scale is long and because it is apparently a random instability, it was deemed undesirable for a validation data set. It was predicted using CFD that by eliminating the first of the four jets, the recirculation zone could be stabilized. The present paper reports detailed results for the three-jet case with comparisons to the four-jet data inasmuch as three-jet data are still unavailable. Hence, the present simulations are true or blind predictions.

Richard W. Johnson; Hugh M. McIlroy

2010-08-01T23:59:59.000Z

195

Molecular Dynamics Study of Freezing Point and Solid-Liquid Interfacial Free Energy of Stockmayer Fluids  

SciTech Connect

Freezing temperatures of Stockmayer fluids with different dipolar strength at zero pressure are estimated and computed using three independent molecular-dynamics (MD) simulation methods, namely, the superheating-undercooling method, the constant-pressure and constant-temperature (NPT) two phase coexistence method, and the constant-pressure and constant-enthalpy (NPH) coexistence method. The best estimate of the freezing temperature (in reduced unit) for the Stockmayer (SM) fluid with a reduced dipole moment is 0.656 0.001, 0.726 0.002 and 0.835 0.005, respectively. The freezing temperature increases with the dipolar strength. The solid-liquid interfacial free energies of the (111), (110) and (100) interface are calculated for the first time using two independent methods, namely, the cleaving-wall method and the interfacial fluctuation method. Both methods predict that the interfacial free energy increases with the dipole moment. Although the interfacial fluctuation method suggests a weaker interfacial anisotropy, particularly for strongly dipolar SM fluids, both methods predicted the same trend of interfacial anisotropy, that is, .

Wang, J. [University of Nebraska, Lincoln; Apte, Pankaj [Indian Institute of Technology, Kanpur; Morris, James R [ORNL; Zeng, X.C. [University of Nebraska, Lincoln

2013-01-01T23:59:59.000Z

196

On the relative importance of second-order terms in relativistic dissipative fluid dynamics  

E-Print Network (OSTI)

In Denicol et al., Phys. Rev. D 85, 114047 (2012), the equations of motion of relativistic dissipative fluid dynamics were derived from the relativistic Boltzmann equation. These equations contain a multitude of terms of second order in Knudsen number, in inverse Reynolds number, or their product. Terms of second order in Knudsen number give rise to non-hyperbolic (and thus acausal) behavior and must be neglected in (numerical) solutions of relativistic dissipative fluid dynamics. The coefficients of the terms which are of the order of the product of Knudsen and inverse Reynolds numbers have been explicitly computed in the above reference, in the limit of a massless Boltzmann gas. Terms of second order in inverse Reynolds number arise from the collision term in the Boltzmann equation, upon expansion to second order in deviations from the single-particle distribution function in local thermodynamical equilibrium. In this work, we compute these second-order terms for a massless Boltzmann gas with constant scattering cross section. Consequently, we assess their relative importance in comparison to the terms which are of the order of the product of Knudsen and inverse Reynolds numbers.

E. Molnár; H. Niemi; G. S. Denicol; D. H. Rischke

2013-08-04T23:59:59.000Z

197

A B-Spline-Based Colocation Method to Approximate the Solutions to the Equations of Fluid Dynamics  

SciTech Connect

The potential of a B-spline collocation method for numerically solving the equations of fluid dynamics is discussed. It is known that B-splines can resolve curves with drastically fewer data than can their standard shape function counterparts. This feature promises to allow much faster numerical simulations of fluid flow than standard finite volume/finite element methods without sacrificing accuracy. An example channel flow problem is solved using the method.

Johnson, Richard Wayne; Landon, Mark Dee

1999-07-01T23:59:59.000Z

198

A B-Spline-Based Colocation Method to Approximate the Solutions to the Equations of Fluid Dynamics  

SciTech Connect

The potential of a B-spline collocation method for numerically solving the equations of fluid dynamics is discussed. It is known that B-splines can resolve complex curves with drastically fewer data than can their standard shape function counterparts. This feature promises to allow much faster numerical simulations of fluid flow than standard finite volume/finite element methods without sacrificing accuracy. An example channel flow problem is solved using the method.

M. D. Landon; R. W. Johnson

1999-07-01T23:59:59.000Z

199

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

200

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

E-Print Network (OSTI)

If water is used as a drilling fluid or in hydraulic packerfrom above or the drilling fluid. Little is known about theFluids in the Upper Continental Crust – Results from the German Continental Deep Drilling

Faybishenko, Boris; Witherspoon, Paul A.

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer in Horizontal Window Frames with Internal Cavities  

E-Print Network (OSTI)

the two-dimensional heat transfer through building products.Gustavsen, A. 2001. Heat transfer in window frames withand CFD Simulations of Heat Transfer in Horizontal Window

Gustavsen, Arlid

2008-01-01T23:59:59.000Z

202

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

203

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

204

The 3D Quasigeostrophic Fluid Dynamics under Random Forcing on Boundary  

E-Print Network (OSTI)

The three-dimensional baroclinic quasigeostrophic flow model has been widely used to study basic mechanisms in oceanic flows and climate dynamics. In this paper, we consider this flow model under random wind forcing and time-periodic fluctuations on fluid boundary (the interface between the oceans and the atmosphere). The time-periodic fluctuations are due to periodic rotation of the earth and thus periodic exposure of the earth to the solar radiation. After establishing the well-posedness of the baroclinic quasigeostrophic flow model in the state space, we demonstrate the existence of the random attractors, again in the state space. We also discuss the relevance of our result to climate modeling.

Jinqiao Duan; Bjorn Schmalfuss

2000-12-30T23:59:59.000Z

205

Circulating fluidized bed hydrodynamics experiments for the multiphase fluid dynamics research consortium (MFDRC).  

Science Conference Proceedings (OSTI)

An experimental program was conducted to study the multiphase gas-solid flow in a pilot-scale circulating fluidized bed (CFB). This report describes the CFB experimental facility assembled for this program, the diagnostics developed and/or applied to make measurements in the riser section of the CFB, and the data acquired for several different flow conditions. Primary data acquired included pressures around the flow loop and solids loadings at selected locations in the riser. Tomographic techniques using gamma radiation and electrical capacitance were used to determine radial profiles of solids volume fraction in the riser, and axial profiles of the integrated solids volume fraction were produced. Computer Aided Radioactive Particle Tracking was used to measure solids velocities, fluxes, and residence time distributions. In addition, a series of computational fluid dynamics simulations was performed using the commercial code Arenaflow{trademark}.

Oelfke, John Barry; Torczynski, John Robert; O'Hern, Timothy John; Tortora, Paul Richard; Bhusarapu, Satish (; ); Trujillo, Steven Mathew

2006-08-01T23:59:59.000Z

206

Relativistic Dynamics of Non-ideal Fluids: Viscous and heat-conducting fluids I. General Aspects and 3+1 Formulation for Nuclear Collisions  

E-Print Network (OSTI)

Relativistic non-ideal fluid dynamics is formulated in 3+1 space--time dimensions. The equations governing dissipative relativistic hydrodynamics are given in terms of the time and the 3-space quantities which correspond to those familiar from non-relativistic physics. Dissipation is accounted for by applying the causal theory of relativistic dissipative fluid dynamics. As a special case we consider a fluid without viscous/heat couplings in the causal system of transport/relaxation equations. For the study of physical systems we consider pure (1+1)-dimensional expansion in planar geometry, (1+1)-dimensional spherically symmetric ({\\em fireball}) expansion, (1+1)-dimensional cylindrically symmetric expansion and a (2+1)-dimensional expansion with cylindrical symmetry in the transverse plane ({\\em firebarell} expansion). The transport/relaxation equations are given in terms of the spatial components of the dissipative fluxes, since these are not independent. The choice for the independent components is analogous to the non-relativistic equations.

Azwinndini Muronga

2006-11-25T23:59:59.000Z

207

CFD MODELING ANALYSIS OF MECHANICAL DRAFT COOLING TOWER  

Science Conference Proceedings (OSTI)

Industrial processes use mechanical draft cooling towers (MDCT's) to dissipate waste heat by transferring heat from water to air via evaporative cooling, which causes air humidification. The Savannah River Site (SRS) has a MDCT consisting of four independent compartments called cells. Each cell has its own fan to help maximize heat transfer between ambient air and circulated water. The primary objective of the work is to conduct a parametric study for cooling tower performance under different fan speeds and ambient air conditions. The Savannah River National Laboratory (SRNL) developed a computational fluid dynamics (CFD) model to achieve the objective. The model uses three-dimensional steady-state momentum, continuity equations, air-vapor species balance equation, and two-equation turbulence as the basic governing equations. It was assumed that vapor phase is always transported by the continuous air phase with no slip velocity. In this case, water droplet component was considered as discrete phase for the interfacial heat and mass transfer via Lagrangian approach. Thus, the air-vapor mixture model with discrete water droplet phase is used for the analysis. A series of the modeling calculations was performed to investigate the impact of ambient and operating conditions on the thermal performance of the cooling tower when fans were operating and when they were turned off. The model was benchmarked against the literature data and the SRS test results for key parameters such as air temperature and humidity at the tower exit and water temperature for given ambient conditions. Detailed results will be presented here.

Lee, S; Alfred Garrett, A; James02 Bollinger, J; Larry Koffman, L

2008-03-03T23:59:59.000Z

208

Pollutant Dispersion in a Large Indoor Space Part 2 -- Computational Fluid  

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

Pollutant Dispersion in a Large Indoor Space Part 2 -- Computational Fluid Pollutant Dispersion in a Large Indoor Space Part 2 -- Computational Fluid Dyamics (CF) Predictions and Comparisons with a Model Experiment for Isothermal Flow Title Pollutant Dispersion in a Large Indoor Space Part 2 -- Computational Fluid Dyamics (CF) Predictions and Comparisons with a Model Experiment for Isothermal Flow Publication Type Journal Article Year of Publication 2004 Authors Finlayson, Elizabeth U., Ashok J. Gadgil, Tracy L. Thatcher, and Richard G. Sextro Journal Indoor Air Volume 14 Start Page Chapter Pagination 272-283 Abstract 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

209

GASFLOW: A Computational Fluid Dynamics Code for Gases, Aerosols, and Combustion, Volume 2: User's Manual  

Science Conference Proceedings (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 containment 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 in low-speed, buoyancy-driven flows, as well as sonic flows or diffusion dominated flows; and 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.

B. D. Nichols; C. Müller; G. A. Necker; J. R. Travis; J. W. Spore; K. L. Lam; P. Royl; T. L. Wilson

1998-10-01T23:59:59.000Z

210

Abstract A COUPLED CFD FINITE ELEMENT ANALYSIS METHODOLOGY IN A BIFURCATION PIPE IN A NUCLEAR PLANT HEAT EXCHANGER  

E-Print Network (OSTI)

The accurate calculation of temperature distribution in key parts of a nuclear plant plays a crucial role in maximising the power output and the plant efficiency, whilst ensuring safe operation. The need for making the most profitable use of the available sources of energy requires the full exploitation of plant operational capacity. Temperature dependent material properties mean that increasing the power output in a nuclear plant may reduce the life of the welds in the pipes of the heat exchanger (boiler), operating in very demanding conditions. Rolls-Royce plc was requested to come up with a suitable solution that shielded critical pipe weld locations, reducing local temperatures, so allowing a useful increase in power output from the plant. Part of the heat shield design process was a comprehensive thermal analysis of the installation. Traditionally fluid and solid simulations are conducted separately or using conjugate analysis. Standard methods rely on the application of boundary conditions to the wall surface, which are commonly based on empirical heat transfer coefficient correlations or approximate read across of the CFD results. An alternative approach using conjugate calculations can be adopted, but the computational cost and meshing difficulties in matching the fluid and solid grids makes this unaffordable in terms of analysis time. This paper presents the application of an improved method using a communication library (SC89) between the in-house finite element (FE) code SC03, and the commercial computational fluid dynamics (CFD) code FLUENT. The method has been validated using test data from a Perspex model, where heat transfer coefficients were measured using a transient liquid crystal technique.

J. A. Dixon; A. Guijarro Valencia; P. Irel; P. Ridl; N. Hills

2010-01-01T23:59:59.000Z

211

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

212

Understanding Fuming during Metal Refining by CFD  

Science Conference Proceedings (OSTI)

The model accounts for conservation of mass, momentum and energy by the classical ... CFD–Based Modelling on Interfacial Heat Transfer for Water Quenching.

213

CFD Modeling and Simulation in Materials Processing  

Science Conference Proceedings (OSTI)

Jul 31, 2011 ... A Coupled CFD-Thermodynamic-Kinetic Model to Simulate a Gas Stirred ... on Thermal and Thermosolutal Natural Convection in Liquid Alloys.

214

Three-dimensional fluid-structure interaction dynamics of a pool-reactor in-tank component. [LMFBR  

SciTech Connect

The safety evaluation of reactor-components often involves the analysis of various types of fluid/structural components interacting in three-dimensional space. For example, in the design of a pool-type reactor several vital in-tank components such as the primary pumps and the intermediate heat exchangers are contained within the primary tank. Typically, these components are suspended from the deck structure and largely submersed in the sodium pool. Because of this positioning these components are vulnerable to structural damage due to pressure wave propagation in the tank during a CDA. In order to assess the structural integrity of these components it is necessary to perform a dynamic analysis in three-dimensional space which accounts for the fluid-structure coupling. A model is developed which has many of the salient features of this fluid-structural component system.

Kulak, R.F.

1979-01-01T23:59:59.000Z

215

Molecular Dynamics Simulations of Grain Boundary Free Energy ...  

Science Conference Proceedings (OSTI)

A Tale of Two States and More: Modeling of New Generation of Lattice Stability ... Analysis of Nano Fluid Using CFD-A Hybrid Approach for Cooling Purpose.

216

3D CFD ELECTROCHEMICAL AND HEAT TRANSFER MODEL OF AN INTERNALLY MANIFOLDED SOLID OXIDE ELECTROLYSIS CELL  

DOE Green Energy (OSTI)

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in an internally manifolded planar solid oxide electrolysis cell (SOEC) stack. This design is being evaluated at the Idaho National Laboratory for hydrogen production from nuclear power and process heat. 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 SOEC mode. Model results provide detailed profiles of temperature, operating potential, steam-electrode gas composition, oxygen-electrode gas composition, current density and hydrogen production over a range of stack operating conditions. Single-cell and five-cell results will be presented. Flow distribution through both models is discussed. Flow enters from the bottom, distributes through the inlet plenum, flows across the cells, gathers in the outlet plenum and flows downward making an upside-down ''U'' shaped flow pattern. Flow and concentration variations exist downstream of the inlet holes. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, oxygen-electrode and steam-electrode current density, and contact resistance from the base case are presented. 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. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

Grant L. Hawkes; James E. O'Brien; Greg Tao

2011-11-01T23:59:59.000Z

217

A method for enhancing the stability and robustness of explicit schemes in astrophysical fluid dynamics  

E-Print Network (OSTI)

A method for enhancing the stability and robustness of explicit schemes in computational fluid dynamics is presented. The method is based in reformulating explicit schemes in matrix form, which cane modified gradually into semi or strongly-implicit schemes. From the point of view of matrix-algebra, explicit numerical methods are special cases in which the global matrix of coefficients is reduced to the identity matrix $I$. This extreme simplification leads to severer stability range, hence of their robustness. In this paper it is shown that a condition, which is similar to the Courant-Friedrich-Levy (CFL) condition can be obtained from the stability requirement of inversion of the coefficient matrix. This condition is shown to be relax-able, and that a class of methods that range from explicit to strongly implicit methods can be constructed, whose degree of implicitness depends on the number of coefficients used in constructing the corresponding coefficient-matrices. Special attention is given to a simple and tractable semi-explicit method, which is obtained by modifying the coefficient matrix from the identity matrix $I$ into a diagonal-matrix $D$. This method is shown to be stable, robust and it can be applied to search for stationary solutions using large CFL-numbers, though it converges slower than its implicit counterpart. Moreover, the method can be applied to follow the evolution of strongly time-dependent flows, though it is not as efficient as normal explicit methods. In addition, we find that the residual smoothing method accelerates convergene toward steady state solutions considerably and improves the efficiency of the solution procedure.

A. A. Hujeirat

2004-10-26T23:59:59.000Z

218

CFD Simulation of Airflow in Ventilated Wall System Report #9  

DOE Green Energy (OSTI)

The objective of this report was to examine air movements in vinyl and brick ventilation cavities in detail, using a state of the art CFD commercial modeling tool. The CFD activity was planned to proceed the other activities in order to develop insight on the important magnitudes of scales occurring during ventilation air flow. This information generated by the CFD model was to be used to modify (if necessary) and to validate the air flow dynamics already imbedded in the hygrothermal model for the computer-based air flow simulation procedures. A comprehensive program of advanced, state-of-the-art hygrothermal modeling was then envisaged mainly to extend the knowledge to other wall systems and at least six representative climatic areas. These data were then to be used to provide the basis for the development of design guidelines. CFD results provided timely and much needed answers to many of the concerns and questions related to ventilation flows due to thermal buoyancy and wind-driven flow scenarios. The relative strength between these two mechanisms. Simple correlations were developed and are presented in the report providing the overall pressure drop, and flow through various cavities under different exterior solar and temperature scenarios. Brick Rainscreen Wall: It was initially expected that a 50 mm cavity would offer reduced pressure drops and increased air flow compared to a 19 mm cavity. However, these models showed that the size of the ventilation slots through the wall are the limiting factor rather than the cavity depth. Of course, once the slots are enlarged beyond a certain point, this could change. The effects of natural convection within the air cavities, driven by the temperature difference across the cavity, were shown to be less important than the external wind speed (for a wind direction normal to the wall surface), when wind action is present. Vinyl Rainscreen Wall: The CFD model of the vinyl rainscreen wall was simpler than that for the brick wall. Constant wall temperatures were used rather than conjugate heat transfer. Although this is appropriate for a thin surface with little heat capacity, it does mean that an empirical correlation between solar radiation (and perhaps wind speed) and vinyl temperature is required to use these results appropriately. The results developed from this CFD model were correlated to weather parameters and construction details so that they can be incorporated into ORNL s advanced hygrothermal models MOISTURE- EXPERT.

Stovall, Therese K [ORNL; Karagiozis, Achilles N [ORNL

2004-01-01T23:59:59.000Z

219

Development of CFD-Based Simulation Tools for In-Situ Thermal Processing of Oil Shale/Sands  

Science Conference Proceedings (OSTI)

In our research, we are taking the novel approach of developing and applying high performance computing, computational fluid dynamics (CFD)-based simulation tools to a modified in-situ process for production of oil from oil shale. The simulation tools being developed capture the relevant physical processes and data from a large-scale system. The modified in-situ application is a pilot-scale heat transfer process inside Red Leaf Resourcesâ?? EcoShale capsule. We demonstrate the need to understand fluid flow behavior in the convective channels of the rubblized shale bed as convective heating greatly decreases the time required to heat the oil shale to the production temperature when compared with conductive heating alone. We have developed and implemented a geometry creation strategy for a representative section of the EcoShale capsule, developed a meshing approach to deal with the complicated geometry and produce a well-behaved mesh, analyzed the effects of boundary conditions on the simulation results, and devised a new operator splitting solution algorithm that reduces computational costs by taking advantage of the differing convective and conductive time scales occurring in the simulation. These simulation tools can be applied to a wide range of processes involving convective fluid flow heating in rubblized beds.

None

2012-04-30T23:59:59.000Z

220

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

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221

REVIEW OF EXPERIMENTAL CAPABILITIES AND HYDRODYNAMIC DATA FOR VALIDATION OF CFD BASED PREDICTIONS FOR SLURRY BUBBLE COLUMN REACTORS  

DOE Green Energy (OSTI)

The purpose of this paper is to document the review of several open-literature sources of both experimental capabilities and published hydrodynamic data to aid in the validation of a Computational Fluid Dynamics (CFD) based model of a slurry bubble column (SBC). The review included searching the Web of Science, ISI Proceedings, and Inspec databases, internet searches as well as other open literature sources. The goal of this study was to identify available experimental facilities and relevant data. Integral (i.e., pertaining to the SBC system), as well as fundamental (i.e., separate effects are considered), data are included in the scope of this effort. The fundamental data is needed to validate the individual mechanistic models or closure laws used in a Computational Multiphase Fluid Dynamics (CMFD) simulation of a SBC. The fundamental data is generally focused on simple geometries (i.e., flow between parallel plates or cylindrical pipes) or custom-designed tests to focus on selected interfacial phenomena. Integral data covers the operation of a SBC as a system with coupled effects. This work highlights selected experimental capabilities and data for the purpose of SBC model validation, and is not meant to be an exhaustive summary.

Donna Post Guillen; Daniel S. Wendt

2007-11-01T23:59:59.000Z

222

REVIEW OF EXPERIMENTAL CAPABILITIES AND HYDRODYNAMIC DATA FOR VALIDATION OF CFD-BASED PREDICTIONS FOR SLURRY BUBBLE COLUMN REACTORS  

DOE Green Energy (OSTI)

The purpose of this paper is to document the review of several open-literature sources of both experimental capabilities and published hydrodynamic data to aid in the validation of a Computational Fluid Dynamics (CFD) based model of a slurry bubble column (SBC). The review included searching the Web of Science, ISI Proceedings, and Inspec databases, internet searches as well as other open literature sources. The goal of this study was to identify available experimental facilities and relevant data. Integral (i.e., pertaining to the SBC system), as well as fundamental (i.e., separate effects are considered), data are included in the scope of this effort. The fundamental data is needed to validate the individual mechanistic models or closure laws used in a Computational Multiphase Fluid Dynamics (CMFD) simulation of a SBC. The fundamental data is generally focused on simple geometries (i.e., flow between parallel plates or cylindrical pipes) or custom-designed tests to focus on selected interfacial phenomena. Integral data covers the operation of a SBC as a system with coupled effects. This work highlights selected experimental capabilities and data for the purpose of SBC model validation, and is not meant to be an exhaustive summary.

Donna Post Guillen; Daniel S. Wendt; Steven P. Antal; Michael Z. Podowski

2007-11-01T23:59:59.000Z

223

Recent CFD-Related Activities at the High  

E-Print Network (OSTI)

· early CFD activities at HFIR · cold-source (and other upgrades)CFD activities at HFIR · LEU Conversion this then at a research reactor ? · 1991 started at HFIR · 1992 graduation · ~ 2003 COMSOL becomes the tool of choice (Freels) Early CFD Activities at HFIR #12;Freels ,CFD Colloquium at UTK,in honor of A, J. Baker, 05

Tennessee, University of

224

OMAE2009-79052 CFD SIMULATION OF WAVE RUN-UP ON A SEMI-SUBMERSIBLE AND COMPARISON WITH EXPERIMENT  

E-Print Network (OSTI)

Use of CFD tools for industrial offshore applications is a common practice nowadays. So is the need for validation of such tools against experimental results. This paper presents one of the CFD tools, ComFLOW, which solves Navier-Stokes equations and employs an improved Volume of Fluid (iVOF) method to find temporary location of fluid’s free surface. The code is used to simulate flow around a semi-submersible offshore platform due to an incoming regular wave. In particular, wave run-up on the semi’s columns and under-deck fluid impact phenomena are investigated on high-accuracy computational grids with number of cells being in range of 10 millions. Results of numerical simulations are compared with experimental data and focus is on local fluid flow details in immediate vicinity of the platform. Wave run-up on the platform’s columns

Bogdan Iwanowski; Marc Lefranc; Rik Wemmenhove

2009-01-01T23:59:59.000Z

225

Characterization of Filter Cake Buildup and Cleanup under Dynamic Fluid Loss Conditions  

E-Print Network (OSTI)

Hydraulic fracturing is a popular stimulation method in tight gas and shale gas reservoirs that uses a viscous fluid to fracture the reservoir rock and uniformly transport proppant to create a highly conductive path that is kept open by the proppant after fracturing. This method is used to improve the productivity of the otherwise low permeability reservoirs. Hydraulic fracturing, though in general beneficial, is a complex process that has a number of challenges in fracturing design and execution. This research focuses on studying the damage caused by the fracturing fluid (gel) to the fracture and the conditions to remove the damage. Guar gum and its derivatives have been the most commonly used polymers to increase the viscosity of fracturing fluids. The fracturing fluid gets dehydrated under pressure leaving behind a highly concentrated unbroken residue called filter cake which causes permeability impairment in the proppant pack, resulting in low fracture conductivity and decreased effective fracture length. This study seeks to characterize filter cakes. By measuring its thickness and with the leak off volume, the concentration and yield stress of the filter cake can be estimated. The thickness of the filter cake was measured with a precise laser profilometer. Correlations are proposed to estimate filter cake properties (thickness, concentration and yield stress) based on pumping conditions (pump rate, time and net pressure) and rock properties. With these properties known, a required flow back rate of the reservoir fluid can be estimated to clean up the filter cake modeled as a non-newtonian fluid exhibiting a yield stress. Typical field conditions were referenced and scaled down in the lab to closely represent the field conditions. Recommendations are provided on gel damage based on the observation of the study.

Yango, Takwe

2011-08-01T23:59:59.000Z

226

CFD calculations of S809 aerodynamic characteristics  

DOE Green Energy (OSTI)

Steady-state, two-dimensional CFD calculations were made for the S809 laminar-flow, wind-turbine airfoil using the commercial code CFD-ACE. Comparisons of the computed pressure and aerodynamic coefficients were made with wind tunnel data from the Delft University 1.8 m x 1.25 m low-turbulence wind tunnel. This work highlights two areas in CFD that require further investigation and development in order to enable accurate numerical simulations of flow about current generation wind-turbine airfoils: transition prediction and turbulence modeling. The results show that the laminar-to-turbulent transition point must be modeled correctly to get accurate simulations for attached flow. Calculations also show that the standard turbulence model used in most commercial CFD codes, the k-{epsilon} model, is not appropriate at angles of attack with flow separation.

Wolfe, W.P. [Sandia National Labs., Albuquerque, NM (United States); Ochs, S.S. [Iowa State Univ., Ames, IA (United States)

1997-01-01T23:59:59.000Z

227

Multiscale CFD simulations of entrained flow gasification  

E-Print Network (OSTI)

The design of entrained flow gasifiers and their operation has largely been an experience based enterprise. Most, if not all, industrial scale gasifiers were designed before it was practical to apply CFD models. Moreover, ...

Kumar, Mayank, Ph. D. Massachusetts Institute of Technology

2011-01-01T23:59:59.000Z

228

Dissipative Particle Dynamics and Other Particle Methods for Multiphase Fluid Flow in Fractured and Porous Media  

Science Conference Proceedings (OSTI)

Particle methods are less computationally efficient than grid based numerical solution of the Navier Stokes equation. However, they have important advantages including rigorous mass conservation, momentum conservation and isotropy. In addition, there is no need for explicit interface tracking/capturing and code development effort is relatively low. We describe applications of three particle methods: molecular dynamics, dissipative particle dynamics and smoothed particle hydrodynamics. The mesoscale (between the molecular and continuum scales) dissipative particle dynamics method can be used to simulate systems that are too large to simulate using molecular dynamics but small enough for thermal fluctuations to play an important role.

Paul Meakin; Zhijie Xu

2009-08-01T23:59:59.000Z

229

Thermo-fluid Dynamics of Flash Atomizing Sprays and Single Droplet Impacts.  

E-Print Network (OSTI)

??Spray atomization and droplet dynamics are research topics that have existed for many decades. Their prevalence in manufacturing, energy generation and other practical applications is… (more)

Vu, Henry

2010-01-01T23:59:59.000Z

230

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

231

Pre-test CFD Calculations for a Bypass Flow Standard Problem  

SciTech Connect

The bypass flow in a prismatic high temperature gas-cooled reactor (HTGR) is the flow that occurs between adjacent graphite blocks. Gaps exist between blocks due to variances in their manufacture and installation and because of the expansion and shrinkage of the blocks from heating and irradiation. Although the temperature of fuel compacts and graphite is sensitive to the presence of bypass flow, there is great uncertainty in the level and effects of the bypass flow. The Next Generation Nuclear Plant (NGNP) program at the Idaho National Laboratory has undertaken to produce experimental data of isothermal bypass flow between three adjacent graphite blocks. These data are intended to provide validation for computational fluid dynamic (CFD) analyses of the bypass flow. Such validation data sets are called Standard Problems in the nuclear safety analysis field. Details of the experimental apparatus as well as several pre-test calculations of the bypass flow are provided. Pre-test calculations are useful in examining the nature of the flow and to see if there are any problems associated with the flow and its measurement. The apparatus is designed to be able to provide three different gap widths in the vertical direction (the direction of the normal coolant flow) and two gap widths in the horizontal direction. It is expected that the vertical bypass flow will range from laminar to transitional to turbulent flow for the different gap widths that will be available.

Rich Johnson

2011-11-01T23:59:59.000Z

232

Development of CFD models to support LEU Conversion of ORNL s High Flux Isotope Reactor  

SciTech Connect

The US Department of Energy s National Nuclear Security Administration (NNSA) is participating in the Global Threat Reduction Initiative to reduce and protect vulnerable nuclear and radiological materials located at civilian sites worldwide. As an integral part of one of NNSA s subprograms, Reduced Enrichment for Research and Test Reactors, HFIR is being converted from the present HEU core to a low enriched uranium (LEU) core with less than 20% of U-235 by weight. Because of HFIR s importance for condensed matter research in the United States, its conversion to a high-density, U-Mo-based, LEU fuel should not significantly impact its existing performance. Furthermore, cost and availability considerations suggest making only minimal changes to the overall HFIR facility. Therefore, the goal of this conversion program is only to substitute LEU for the fuel type in the existing fuel plate design, retaining the same number of fuel plates, with the same physical dimensions, as in the current HFIR HEU core. Because LEU-specific testing and experiments will be limited, COMSOL Multiphysics was chosen to provide the needed simulation capability to validate against the HEU design data and previous calculations, and predict the performance of the proposed LEU fuel for design and safety analyses. To achieve it, advanced COMSOL-based multiphysics simulations, including computational fluid dynamics (CFD), are being developed to capture the turbulent flows and associated heat transfer in fine detail and to improve predictive accuracy [2].

Khane, Vaibhav B [ORNL; Jain, Prashant K [ORNL; Freels, James D [ORNL

2012-01-01T23:59:59.000Z

233

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 ...

234

3D CFD Electrochemical and Heat Transfer Model of an Integrated-Planar Solid Oxide Electrolysis Cells  

DOE Green Energy (OSTI)

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in a new novel integrated planar porous-tube supported solid oxide electrolysis cell (SOEC). The model is of several integrated planar cells attached to a ceramic support tube. This design is being evaluated with modeling at the Idaho National Laboratory. 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 SOEC 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. Mean per-cell area-specific-resistance (ASR) values decrease with increasing current density. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, cathode and anode exchange current density, and contact resistance from the base case are presented. Contour plots of local electrolyte temperature, current density, and Nernst potential indicated the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

Grant Hawkes; James E. O'Brien

2008-10-01T23:59:59.000Z

235

Detailed CFD modelling of open refrigerated display cabinets  

Science Conference Proceedings (OSTI)

A comprehensive and detailed computational fluid dynamics (CFDs) modelling of air flow and heat transfer in an open refrigerated display cabinet (ORDC) is performed in this study. The physical-mathematical model considers the flow through the internal ...

Pedro Dinis Gaspar; L. C. Carrilho Gonçalves; R. A. Pitarma

2012-01-01T23:59:59.000Z

236

Analogies of Ocean/Atmosphere Rotating Fluid Dynamics with Gyroscopes: Teaching Opportunities  

Science Conference Proceedings (OSTI)

The dynamics of the rotating shallow-water (RSW) system include geostrophic f low and inertial oscillation. These classes of motion are ubiquitous in the ocean and atmosphere. They are often surprising to people at first because intuition about rotating f ...

Thomas W. N. Haine; Deepak A. Cherian

2013-05-01T23:59:59.000Z

237

Development and Verification of a Computational Fluid Dynamics Model of a Horizontal-Axis Tidal Current Turbine  

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

Development and Verification of Development and Verification of a Computational Fluid Dynamics Model of a Horizontal-Axis Tidal Current Turbine M.J. Lawson and Y. Li. National Renewable Energy Laboratory D.C. Sale University of Washington Presented at the 30 th International Conference on Ocean, Offshore, and Arctic Engineering Rotterdam, The Netherlands June 19-24, 2011 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. Conference Paper NREL/CP-5000-50981 October 2011 Contract No. DE-AC36-08GO28308 NOTICE The submitted manuscript has been offered by an employee of the Alliance for Sustainable Energy, LLC (Alliance), a contractor of the US Government under Contract No. DE-AC36-08GO28308. Accordingly, the US

238

Gasificaton Transport: A Multiphase CFD Approach & Measurements  

DOE Green Energy (OSTI)

The objective of this project was to develop predictive theories for the dispersion and mass transfer coefficients and to measure them in the turbulent fluidization regime, using existing facilities. A second objective was to use our multiphase CFD tools to suggest optimized gasifier designs consistent with aims of Future Gen. We have shown that the kinetic theory based CFD codes correctly compute: (1) Dispersion coefficients; and (2) Mass transfer coefficients. Hence, the kinetic theory based CFD codes can be used for fluidized bed reactor design without any such inputs. We have also suggested a new energy efficient method of gasifying coal and producing electricity using a molten carbonate fuel cell. The principal product of this new scheme is carbon dioxide which can be converted into useful products such as marble, as is done very slowly in nature. We believe this scheme is a lot better than the canceled FutureGen, since the carbon dioxide is safely sequestered.

Dimitri Gidaspow; Veeraya Jiradilok; Mayank Kashyap; Benjapon Chalermsinsuwan

2009-02-14T23:59:59.000Z

239

A 2-D Test Problem for CFD Modeling Heat Transfer in Spent Fuel Transfer Cask Neutron Shields  

SciTech Connect

In the United States, commercial spent nuclear fuel is typically moved from spent fuel pools to outdoor dry storage pads within a transfer cask system that provides radiation shielding to protect personnel and the surrounding environment. The transfer casks are cylindrical steel enclosures with integral gamma and neutron radiation shields. Since the transfer cask system must be passively cooled, decay heat removal from spent nuclear fuel canister is limited by the rate of heat transfer through the cask components, and natural convection from the transfer cask surface. The primary mode of heat transfer within the transfer cask system is conduction, but some cask designs incorporate a liquid neutron shield tank surrounding the transfer cask structural shell. In these systems, accurate prediction of natural convection within the neutron shield tank is an important part of assessing the overall thermal performance of the transfer cask system. The large-scale geometry of the neutron shield tank, which is typically an annulus approximately 2 meters in diameter but only 5-10 cm in thickness, and the relatively small scale velocities (typically less than 5 cm/s) represent a wide range of spatial and temporal scales that contribute to making this a challenging problem for computational fluid dynamics (CFD) modeling. Relevant experimental data at these scales are not available in the literature, but some recent modeling studies offer insights into numerical issues and solutions; however, the geometries in these studies, and for the experimental data in the literature at smaller scales, all have large annular gaps that are not prototypic of the transfer cask neutron shield. This paper presents results for a simple 2-D problem that is an effective numerical analog for the neutron shield application. Because it is 2-D, solutions can be obtained relatively quickly allowing a comparison and assessment of sensitivity to model parameter changes. Turbulence models are considered as well as the tradeoff between steady state and transient solutions. Solutions are compared for two commercial CFD codes, FLUENT and STAR-CCM+. The results can be used to provide input to the CFD Best Practices for this application. Following study results for the 2-D test problem, a comparison of simulation results is provided for a high Rayleigh number experiment with large annular gap. Because the geometry of this validation is significantly different from the neutron shield, and due to the critical nature of this application, the argument is made for new experiments at representative scales

Zigh, Ghani; Solis, Jorge; Fort, James A.

2011-01-14T23:59:59.000Z

240

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

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

Optics and Fluid Dynamics Ris-R-1227(EN) Annual Progress Report for 2000  

E-Print Network (OSTI)

of polymer films by laser ablation 12 2.3 New laser systems 13 2.3.1 A new high-power 1.5 µm laser diode thickness determination and cutting of plants by lasers 22 3. Optical diagnostics and information processing dynamics 49 4.1 Introduction 49 4.2 Fusion plasma physics 49 4.2.1 Taming drift-wave turbulence 49 4

242

MEASUREMENT OF INTERFACIAL TENSION IN FLUID-FLUID SYSTEMS  

E-Print Network (OSTI)

Interfacial tension at fluid-fluid interfaces is a reflection of the excess energy associated with unsaturated in parts per million concentration (27). DYNAMIC INTERFACIAL TENSION MEASUREMENTS In fluid-fluid systems, detergency, foam or froth generation, and stability (3). In these pro- cesses, dynamic interfacial tensions

Loh, Watson

243

CFD Research Overview Dr. Chris Roy  

E-Print Network (OSTI)

/gallon, resulting in a total consumption of 26 billion gallons of diesel fuel · With diesel at $2.33/gallon high-efficiency CFD predictions (Roy) and conducting wind tunnel experiments (Devenport) · Auburn were not optimized to minimize drag Tractor-Trailer with Base Flaps Wind-Averaged Drag Coefficient #12

Roy, Chris

244

Evaluation and Effect of Fracturing Fluids on Fracture Conductivity in Tight Gas Reservoirs Using Dynamic Fracture Conductivity Test  

E-Print Network (OSTI)

Unconventional gas has become an important resource to help meet our future energy demands. Although plentiful, it is difficult to produce this resource, when locked in a massive sedimentary formation. Among all unconventional gas resources, tight gas sands represent a big fraction and are often characterized by very low porosity and permeability associated with their producing formations, resulting in extremely low production rate. The low flow properties and the recovery factors of these sands make necessary continuous efforts to reduce costs and improve efficiency in all aspects of drilling, completion and production techniques. Many of the recent improvements have been in well completions and hydraulic fracturing. Thus, the main goal of a hydraulic fracture is to create a long, highly conductive fracture to facilitate the gas flow from the reservoir to the wellbore to obtain commercial production rates. Fracture conductivity depends on several factors, such as like the damage created by the gel during the treatment and the gel clean-up after the treatment. This research is focused on predicting more accurately the fracture conductivity, the gel damage created in fractures, and the fracture cleanup after a hydraulic fracture treatment under certain pressure and temperature conditions. Parameters that alter fracture conductivity, such as polymer concentration, breaker concentration and gas flow rate, are also examined in this study. A series of experiments, using a procedure of “dynamical fracture conductivity test”, were carried out. This procedure simulates the proppant/frac fluid slurries flow into the fractures in a low-permeability rock, as it occurs in the field, using different combinations of polymer and breaker concentrations under reservoirs conditions. The result of this study provides the basis to optimize the fracturing fluids and the polymer loading at different reservoir conditions, which may result in a clean and conductive fracture. Success in improving this process will help to decrease capital expenditures and increase the production in unconventional tight gas reservoirs.

Correa Castro, Juan

2011-05-01T23:59:59.000Z

245

MODELING STRATEGIES TO COMPUTE NATURAL CIRCULATION USING CFD IN A VHTR AFTER A LOFA  

Science Conference Proceedings (OSTI)

A prismatic gas-cooled very high temperature reactor (VHTR) is being developed under the next generation nuclear plant program (NGNP) of the U.S. Department of Energy, Office of Nuclear Energy. In the design of the prismatic VHTR, hexagonal shaped graphite blocks are drilled to allow insertion of fuel pins, made of compacted TRISO fuel particles, and coolant channels for the helium coolant. One of the concerns for the reactor design is the effects of a loss of flow accident (LOFA) where the coolant circulators are lost for some reason, causing a loss of forced coolant flow through the core. In such an event, it is desired to know what happens to the (reduced) heat still being generated in the core and if it represents a problem for the fuel compacts, the graphite core or the reactor vessel (RV) walls. One of the mechanisms for the transport of heat out of the core is by the natural circulation of the coolant, which is still present. That is, how much heat may be transported by natural circulation through the core and upwards to the top of the upper plenum? It is beyond current capability for a computational fluid dynamic (CFD) analysis to perform a calculation on the whole RV with a sufficiently refined mesh to examine the full potential of natural circulation in the vessel. The present paper reports the investigation of several strategies to model the flow and heat transfer in the RV. It is found that it is necessary to employ representative geometries of the core to estimate the heat transfer. However, by taking advantage of global and local symmetries, a detailed estimate of the strength of the resulting natural circulation and the level of heat transfer to the top of the upper plenum is obtained.

Yu-Hsin Tung; Richard W. Johnson; Ching-Chang Chieng; Yuh-Ming Ferng

2012-11-01T23:59:59.000Z

246

CFD Calculation of Nitrogen Gas Quenching for Steel Ring Gears  

Science Conference Proceedings (OSTI)

In this study, we present CFD calculations of gas quenching process during the ... Exercise on Thermal and Thermosolutal Natural Convection in Liquid Alloys.

247

The Limitations of CFD Modeling for Furnace Atmosphere ... - TMS  

Science Conference Proceedings (OSTI)

Feb 1, 2002 ... The Limitations of CFD Modeling for Furnace Atmosphere Troubleshooting by P.F. Stratton, N. Saxena and M. Huggahalli ...

248

CFD Modeling and Analysis of Casting of Energetic Materials in ...  

Science Conference Proceedings (OSTI)

Multiphase Flow in a Steelmaking Converter Using an Unconventional Lance · Multiphysics CFD Modeling of a Free Falling Jet during Melt-Blowing Slag ...

249

CFD Modeling of Splash in Molten Materials Processing Operations  

Science Conference Proceedings (OSTI)

A Coupled CFD-Thermodynamic-Kinetic Model to Simulate a Gas Stirred Ladle ... Exercise on Thermal and Thermosolutal Natural Convection in Liquid Alloys.

250

CFD Modelling of Heat Transfer in Supersonic Nozzles for ... - TMS  

Science Conference Proceedings (OSTI)

May 1, 2007 ... CFD Modelling of Heat Transfer in Supersonic Nozzles for Magnesium Production by Peter Witt, M.N.H. Khan, and Geoffrey Brooks ...

251

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

252

A General Strategy for Physics-Based Model Validation Illustrated with Earthquake Phenomenology, Atmospheric Radiative Transfer, and Computational Fluid Dynamics  

E-Print Network (OSTI)

Validation is often defined as the process of determining the degree to which a model is an accurate representation of the real world from the perspective of its intended uses. Validation is crucial as industries and governments depend increasingly on predictions by computer models to justify their decisions. In this article, we survey the model validation literature and propose to formulate validation as an iterative construction process that mimics the process occurring implicitly in the minds of scientists. We thus offer a formal representation of the progressive build-up of trust in the model, and thereby replace incapacitating claims on the impossibility of validating a given model by an adaptive process of constructive approximation. This approach is better adapted to the fuzzy, coarse-grained nature of validation. Our procedure factors in the degree of redundancy versus novelty of the experiments used for validation as well as the degree to which the model predicts the observations. We illustrate the new methodology first with the maturation of Quantum Mechanics as the arguably best established physics theory and then with several concrete examples drawn from some of our primary scientific interests: a cellular automaton model for earthquakes, an anomalous diffusion model for solar radiation transport in the cloudy atmosphere, and a computational fluid dynamics code for the Richtmyer-Meshkov instability. This article is an augmented version of Sornette et al. [2007] that appeared in Proceedings of the National Academy of Sciences in 2007 (doi: 10.1073/pnas.0611677104), with an electronic supplement at URL http://www.pnas.org/cgi/content/full/0611677104/DC1. Sornette et al. [2007] is also available in preprint form at physics/0511219.

Didier Sornette; Anthony B. Davis; James R. Kamm; Kayo Ide

2007-10-01T23:59:59.000Z

253

CFD Simulation of Infiltration Heat Recovery  

E-Print Network (OSTI)

residential buildings with dynamic insulation”, 16* AIVCas dynamic insulation, air is drawn through the building

Buchanan, C.R.

2011-01-01T23:59:59.000Z

254

Lecture notes Ideal fluid mechanics  

E-Print Network (OSTI)

involves energy loss--such fluids are known as viscous fluids--we will not consider them here. Some fluids of the basic equations underlying the dynamics of ideal fluids is based on three basic principles (see Chorin. Conservation of energy, energy is neither created nor destroyed. In turn these principles generate the: 1

Malham, Simon J.A.

255

Using CFD Capabilities of CONTAM 3.0 for Simulating Airflow ...  

Science Conference Proceedings (OSTI)

... CFD0 was a CFD program originally developed for ASHRAE research project RP-927 (Chen et al. 1999), and improved by Wang (2007). ...

2010-11-09T23:59:59.000Z

256

Practical issues on CFD use and some industry aspects on research with CFD  

E-Print Network (OSTI)

of non-catalytic NOx reduction in FBC freeboard CFD project planning Fast pyrolysis model, 18.6.2010 2-catalytic NOx reduction in FBC freeboard target: Finding optimal locations for urea injection Injections temperature for NOx reduction is between blue and red areas. Courtesy Metso Power Oy #12;Geometry Fast

Zevenhoven, Ron

257

Spinning fluid cosmology  

E-Print Network (OSTI)

The dynamics of a spinning fluid in a flat cosmological model is investigated. The space-time is itself generated by the spinning fluid which is characterized by an energy-momentum tensor consisting a sum of the usual perfect-fluid energy-momentum tensor and some Belinfante-Rosenfeld tensors. It is shown that the equations of motion admit a solution for which the fluid four-velocity and four-momentum are not co-linear in general. The momentum and spin densities of the fluid are expressed in terms of the scale factor.

Morteza Mohseni

2008-07-22T23:59:59.000Z

258

Spinning fluid cosmology  

E-Print Network (OSTI)

The dynamics of a spinning fluid in a flat cosmological model is investigated. The space-time is itself generated by the spinning fluid which is characterized by an energy-momentum tensor consisting a sum of the usual perfect-fluid energy-momentum tensor and some Belinfante-Rosenfeld tensors. It is shown that the equations of motion admit a solution for which the fluid four-velocity and four-momentum are not co-linear in general. The momentum and spin densities of the fluid are expressed in terms of the scale factor.

Mohseni, Morteza

2008-01-01T23:59:59.000Z

259

Computational fluid dynamics study on the decomposition of ammonia in a selective porous membrane - article no. 42  

SciTech Connect

The development of alternative technologies for the removal of gas pollutants is an important aspect for the environmental friendliness of energy production. During coal gasification, N{sub 2} contained in coal is converted to NH{sub 3} and, as much as 50% of the ammonia in the fuel gas can be converted to nitrogen oxides (NOx). At these conditions, decomposition seems to be the only applicable solution for the removal of NH{sub 3}. The application of a high temperature catalytic membrane reactor process appears to offer an efficient and cost effective method of removing the NH{sub 3} from coal gasification gas streams. The present work examines the operation of such a selective membrane, used for the decomposition of NH{sub 3}, under a 2-D axissymetric CFD approach where the flow field, the chemical reactions and the selective porous membrane behavior are being modeled and computed. The main target of this effort was to obtain a more detailed view of the flow field and to investigate the decomposition of ammonia in comparison with a simpler 1-D modeling approach and, thus, to evaluate the advantages and disadvantages of each method.

Athanasios Sideridis; Dimitrios Koutsonikolas; Dimitrios Missirlis [Aristotle University of Thessaloniki (Greece)

2008-07-01T23:59:59.000Z

260

Applications of automatic differentiation in CFD  

DOE Green Energy (OSTI)

Automated multidisciplinary design of aircraft requires the optimization of complex performance objectives with respect to a number of design parameters and constraints. The effect of these independent design variables on the system performance criteria can be quantified in terms of sensitivity derivatives for the individual discipline simulation codes. Typical advanced CFD codes do not provide such derivatives as part of a flow solution. These derivatives are expensive to obtain by divided differences from perturbed solutions, and may be unreliable, particularly for noisy functions. In this paper, automatic differentiation has been investigated as a means of extending iterative CFD codes with sensitivity derivatives. In particular, the ADIFOR automatic differentiator has been applied to the 3-D, thin-layer Navier-Stokes, multigrid flow solver called TLNS3D coupled with the WTCO wing grid generator. Results of a sequence of efforts in which TLNS3D has been successfully augmented to compute a variety of sensitivities are presented. It is shown that sensitivity derivatives can be obtained accurately and efficiently using ADIFOR, although significant advances are necessary for the efficiency of ADIFOR-generated derivative code to become truly competitive with hand-differentiated code.

Carle, A. [Rice Univ., Houston, TX (United States); Green, L.L.; Newman, P.A. [National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center; Bischof, C.H. [Argonne National Lab., IL (United States)

1994-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

Development of CFD Software To Support the Engineering of Lost Foam Pattern Blowing and Steaming  

SciTech Connect

This CFD Project has led to a new commercial software package (Arena-flow-eps) for advanced engineering of lost foam pattern formation. Specifically, the new software models all fluid/particle/thermal phenomena during both the bead-blowing and the pattern-fusing cycles--within a single, integrated computational tool. Engineering analysis with Arena-flow-eps will enable foundries to now obtain desirable foam pattern characteristics in a reliable (consistent) manner, aided by an understanding of the fundamental fluid/thermal physics of the process. This will lead to significant reductions in casting scrap and energy usage, as well as enable future castings to satisfy stringent requirements on high-power-density and low-emissions in tomorrow's automotive and watercraft engines.

Dr. Kenneth A. Williams; Dr. Dale M. Snider

2003-02-04T23:59:59.000Z

262

CFD MODELING AND ANALYSIS FOR A-AREA AND H-AREA COOLING TOWERS  

Science Conference Proceedings (OSTI)

Mechanical draft cooling towers are designed to cool process water via sensible and latent heat transfer to air. Heat and mass transfer take place simultaneously. Heat is transferred as sensible heat due to the temperature difference between liquid and gas phases, and as the latent heat of the water as it evaporates. Mass of water vapor is transferred due to the difference between the vapor pressure at the air-liquid interface and the partial pressure of water vapor in the bulk of the air. Equations to govern these phenomena are discussed here. The governing equations are solved by taking a computational fluid dynamics (CFD) approach. The purpose of the work is to develop a three-dimensional CFD model to evaluate the flow patterns inside the cooling tower cell driven by cooling fan and wind, considering the cooling fans to be on or off. Two types of the cooling towers are considered here. One is cross-flow type cooling tower located in A-Area, and the other is counterflow type cooling tower located in H-Area. The cooling tower located in A-Area is mechanical draft cooling tower (MDCT) consisting of four compartment cells as shown in Fig. 1. It is 13.7m wide, 36.8m long, and 9.4m high. Each cell has its own cooling fan and shroud without any flow communications between two adjacent cells. There are water distribution decks on both sides of the fan shroud. The deck floor has an array of about 25mm size holes through which water droplet falls into the cell region cooled by the ambient air driven by fan and wind, and it is eventually collected in basin area. As shown in Fig. 1, about 0.15-m thick drift eliminator allows ambient air to be humidified through the evaporative cooling process without entrainment of water droplets into the shroud exit. The H-Area cooling tower is about 7.3 m wide, 29.3 m long, and 9.0 m high. Each cell has its own cooling fan and shroud, but each of two corner cells has two panels to shield wind at the bottom of the cells. There is some degree of flow communications between adjacent cells through the 9-in gap at the bottom of the tower cells as shown in Fig. 2. Detailed geometrical dimensions for the H-Area tower configurations are presented in the figure. The model was benchmarked and verified against off-site and on-site test results. The verified model was applied to the investigation of cooling fan and wind effects on water cooling in cells when fans are off and on. This report will discuss the modeling and test results.

Lee, S.; Garrett, A.; Bollinger, J.

2009-09-02T23:59:59.000Z

263

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. Dørum; S. T. Munkejord

2012-03-01T23:59:59.000Z

264

Fluid and drift-kinetic description of a magnetized plasma with low collisionality and slow dynamics orderings. II. Ion theory  

SciTech Connect

The ion side of a closed, fluid and drift-kinetic theoretical model to describe slow and macroscopic plasma processes in a fusion-relevant, low collisionality regime is presented. It follows the ordering assumptions and the methodology adopted in the companion electron theory [Ramos, Phys. Plasmas 17, 082502 (2010)]. To reach the frequency scale where collisions begin to play a role, the drift-kinetic equation for the ion distribution function perturbation away from a Maxwellian must be accurate to the second order in the Larmor radius. The macroscopic density, flow velocity and temperature are accounted for in the Maxwellian, and are evolved by a fluid system which includes consistently the gyroviscous part of the stress tensor and second-order contributions to the collisionless perpendicular heat flux involving non-Maxwellian fluid moments. The precise compatibility among these coupled high-order fluid and drift-kinetic equations is made manifest by showing that the evolution of the non-Maxwellian part of the distribution function is such that its first three velocity moments remain equal to zero.

Ramos, J. J. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (United States)

2011-10-15T23:59:59.000Z

265

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

266

CFD Modeling of Methane Production from Hydrate-Bearing Reservoir  

Science Conference Proceedings (OSTI)

Methane hydrate is being examined as a next-generation energy resource to replace oil and natural gas. The U.S. Geological Survey estimates that methane hydrate may contain more organic carbon the the world's coal, oil, and natural gas combined. To assist in developing this unfamiliar resource, the National Energy Technology Laboratory has undertaken intensive research in understanding the fate of methane hydrate in geological reservoirs. This presentation reports preliminary computational fluid dynamics predictions of methane production from a subsurface reservoir.

Gamwo, I.K.; Myshakin, E.M.; Warzinski, R.P.

2007-04-01T23:59:59.000Z

267

Organization of IGCC processes with reduced order CFD models  

SciTech Connect

Integrated gasificationcombinedcycle(IGCC)plantshavesignificantadvantagesforefficientpowergen- eration withcarboncapture.Moreover,withthedevelopmentofaccurateCFDmodelsforgasificationand combined cyclecombustion,keyunitsoftheseprocessescannowbemodeledmoreaccurately.However, the integrationofCFDmodelswithinsteady-stateprocesssimulators,andsubsequentoptimizationof the integratedsystem,stillpresentssignificantchallenges.Thisstudydescribesthedevelopmentand demonstration ofareducedordermodeling(ROM)frameworkforthesetasks.Theapproachbuildson the conceptsofco-simulationandROMdevelopmentforprocessunitsdescribedinearlierstudies.Here we showhowtheROMsderivedfrombothgasificationandcombustionunitscanbeintegratedwithin an equation-orientedsimulationenvironmentfortheoveralloptimizationofanIGCCprocess.Inaddi- tion toasystematicapproachtoROMdevelopment,theapproachincludesvalidationtasksfortheCFD model aswellasclosed-looptestsfortheintegratedflowsheet.Thisapproachallowstheapplicationof equation-based nonlinearprogrammingalgorithmsandleadstofastoptimizationofCFD-basedprocess flowsheets. TheapproachisillustratedontwoflowsheetsbasedonIGCCtechnology.

Lang, Y.; Zitney, S.; Biegler, L.

2011-01-01T23:59:59.000Z

268

The Dynamic Compressive Response of an Open-Cell Foam Impregnated With a Non-Newtonian Fluid  

E-Print Network (OSTI)

The response of a reticulated, elastomeric foam filled with colloidal silica under dynamic compression is studied. Under compression beyond local strain rates on the order of 1 s[superscript ?1], the non-Newtonian, colloidal ...

Dawson, Matthew A.

269

Office of Fossil EnergyTOPICAL REPORT: DEVELOPMENT OF CFD_BASED SIMULATION TOOLS FOR IN SITU THERMAL PROCESSING OF OIL SHALE/SANDS  

E-Print Network (OSTI)

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. In our research, we are taking the novel approach of developing and applying high performance computing, computational fluid dynamics (CFD)-based simulation tools to a modified in-situ process for production of oil from oil shale. The simulation tools being developed capture the relevant physical processes and data from a large-scale system. The modified in-situ application

Michal Hradisky; Philip J. Smith; Doe Award; No. De-fe

2009-01-01T23:59:59.000Z

270

SRM -? Fluids  

Science Conference Proceedings (OSTI)

... These reference fluid formulations characterize the behavior of broad ranges of chemically similar fluids; in this way data on propane, for example ...

2012-10-01T23:59:59.000Z

271

Physics-Based Simulations for Fluid Mixtures Dongwoon Lee  

E-Print Network (OSTI)

experience a chemical reaction which produces a new type of fluid or generates heat energy. When heat energy knowledge of fluids. He helped me to understand dynamics of fluids through his lectures and experiments. I Interaction . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3 Fluid Models 10 3.1 Fluid Dynamics

Toronto, University of

272

Building Energy Software Tools Directory: Virtualwind  

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

training in computational fluid dynamics (CFD) or fluid dynamics is necessary; however, a learning curve is associated with fully understanding the software. Several tutorials and...

273

Fluid dynamics, particulate segregation, chemical processes, and natural ore analog discussions that relate to the potential for criticality in Hanford tanks  

SciTech Connect

This report presents an in-depth review of the potential for nuclear criticality to occur in Hanford defense waste tanks during past, current and future safe storage and maintenance operations. The report also briefly discusses the potential impacts of proposed retrieval activities, although retrieval was not a main focus of scope. After thorough review of fluid dynamic aspects that focus on particle segregation, chemical aspects that focus on solubility and adsorption processes that might concentrate plutonium and/or separate plutonium from the neutron absorbers in the tank waste, and ore-body formation and mining operations, the interdisciplinary team has come to the conclusion that there is negligible risk of nuclear critically under existing storage conditions in Hanford site underground waste storage tanks. Further, for the accident scenarios considered an accidental criticality is incredible.

Barney, G.S.

1996-09-27T23:59:59.000Z

274

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

275

Phase separation of an asymmetric binary fluid mixture confined in a nanoscopic slit pore: Molecular-dynamics simulations  

E-Print Network (OSTI)

As a generic model system of an asymmetric binary fluid mixture, hexadecane dissolved in carbon dioxide is considered, using a coarse-grained bead-spring model for the short polymer, and a simple spherical particle with Lennard-Jones interactions for the carbon dioxide molecules. In previous work, it has been shown that this model reproduces the real phase diagram reasonable well, and also the initial stages of spinodal decomposition in the bulk following a sudden expansion of the system could be studied. Using the parallelized simulation package ESPResSo on a multiprocessor supercomputer, phase separation of thin fluid films confined between parallel walls that are repulsive for both types of molecules are simulated in a rather large system (1356 x 1356 x 67.8 A^3, corresponding to about 3.2 million atoms). Following the sudden system expansion, a complicated interplay between phase separation in the directions perpendicular and parallel to the walls is found: in the early stages the hexadecane molecules accumulate mostly in the center of the slit pore, but as the coarsening of the structure in the parallel direction proceeds, the inhomogeneity in the perpendicular direction gets much reduced. Studying then the structure factors and correlation functions at fixed distances from the wall, the densities are essentially not conserved at these distances, and hence the behavior differs strongly from spinodal decomposition in the bulk. Some of the characteristic lengths show a nonmonotonic variation with time, and simple coarsening described by power-law growth is only observed if the domain sizes are much larger than the film thickness.

K. Bucior; L. Yelash; K. Binder

2008-04-09T23:59:59.000Z

276

A localised subgrid scale model for fluid dynamical simulations in astrophysics II: Application to type Ia supernovae  

E-Print Network (OSTI)

The dynamics of the explosive burning process is highly sensitive to the flame speed model in numerical simulations of type Ia supernovae. Based upon the hypothesis that the effective flame speed is determined by the unresolved turbulent velocity fluctuations, we employ a new subgrid scale model which includes a localised treatment of the energy transfer through the turbulence cascade in combination with semi-statistical closures for the dissipation and non-local transport of turbulence energy. In addition, subgrid scale buoyancy effects are included. In the limit of negligible energy transfer and transport, the dynamical model reduces to the Sharp-Wheeler relation. According to our findings, the Sharp-Wheeler relation is insuffcient to account for the complicated turbulent dynamics of flames in thermonuclear supernovae. The application of a co-moving grid technique enables us to achieve very high spatial resolution in the burning region. Turbulence is produced mostly at the flame surface and in the interior ash regions. Consequently, there is a pronounced anisotropy in the vicinity of the flame fronts. The localised subgrid scale model predicts significantly enhanced energy generation and less unburnt carbon and oxygen at low velocities compared to earlier simulations.

W. Schmidt; J. C. Niemeyer; W. Hillebrandt; F. K. Roepke

2006-01-23T23:59:59.000Z

277

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

278

Experimental reconsideration of spatio-temporal dynamics observed in fluid-elastic oscillator arrays from complex system viewpoint: From vibrating pipes in heat exchangers to waving plants in agricultural fields: Research Articles  

Science Conference Proceedings (OSTI)

Transition from local complexity to global spatio-temporal dynamics in a two-dimensional array of fluid-elastic oscillators is examined experimentally with an apparatus comprising 90-1000 cantilevered rods in a wind tunnel as the Reynolds number (based ... Keywords: impact, nonlinear vibration, self-organization, spatio-temporal pattern, wave

Masaharu Kuroda; Francis C. Moon

2007-03-01T23:59:59.000Z

279

CFD-based application of the Nyquist criterion to thermo-acoustic instabilities  

Science Conference Proceedings (OSTI)

A novel approach for the analysis of self-excited instabilities in thermo-acoustic systems is proposed. Combining computational fluid dynamics with low-order acoustic modeling, the open-loop transfer function of the system under investigation is computed. ... Keywords: 02.30.Yy, 43.28.Kt, 43.35.Ud, 43.60.Bf, 47.50.Gj, 52.35.Dm, Computational fluid dynamics, Control theory, Instabilities, Thermo-acoustics

J. Kopitz; W. Polifke

2008-07-01T23:59:59.000Z

280

Water at a hydrophilic solid surface probed by ab-initio molecular dynamics: inhomogeneous thin layers of dense fluid  

DOE Green Energy (OSTI)

We present a microscopic model of the interface between liquid water and a hydrophilic, solid surface, as obtained from ab-initio molecular dynamics simulations. In particular, we focused on the (100)surface of cubic SiC, a leading candidate semiconductor for bio-compatible devices. Our results show that, in the liquid in contact with the clean substrate, molecular dissociation occurs in a manner unexpectedly similar to that observed in the gas phase. After full hydroxylation takes place, the formation of a thin ({approx}3 {angstrom})interfacial layer is observed, which has higher density than bulk water and forms stable hydrogen bonds with the substrate. The liquid does not uniformly wet the surface, rather molecules preferably bind along directions parallel to the Si dimer rows. Our calculations also predict that one dimensional confinement between two hydrophilic surfaces at about 1.3 nm distance does not affect the structural and electronic properties of the whole water sample.

Cicero, G; Grossman, J; Galli, G; Catellani, A

2005-01-28T23:59:59.000Z

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281

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. Heat transfer coefficient fairly agreed with the data for 1.03 and 2.01 mm ID tubes when j{sub l} was relatively high. But it became lower than that for larger diameter tubes when j{sub l} was low. Analogy between heat transfer and frictional pressure drop was proved to hold roughly for the two-phase flow in micro-channel. But satisfactory relation was not obtained under the condition of low liquid superficial velocity. (author)

Kaji, Masuo; Sawai, Toru; Kagi, Yosuke [Department of Mechanical Engineering, School of Biology-Oriented Science and Technology, Kinki University, 930 Nishi-mitani, Kinokawa, Wakayama 649-6493 (Japan); Ueda, Tadanobu [Toyota Central R and D Laboratory, Incorporated, 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan)

2010-05-15T23:59:59.000Z

282

Investigations of the Application of CFD to Flow Expected in the Lower Plenum of the Prismatic VHTR  

Science Conference Proceedings (OSTI)

The Generation IV (Gen IV) very high temperature reactor (VHTR) will either be a prismatic (block) or pebble bed design. However, a prismatic VHTR reference design, based on the General Atomics Gas Turbine-Modular Helium Reactor (GT-MHR) [General Atomics, 1996] has been developed for preliminary analysis purposes [MacDonald, et al., 2003]. Numerical simulation studies reported herein are based on this reference design. In the lower plenum of the prismatic reference design, the flow will be introduced by dozens of turbulent jets from the core above. The jet flow will encounter rows of columns that support the core. The flow from the core will have to turn ninety degrees and flow toward the exit duct as it passed through the forest of support columns. Due to the radial variation of the power density in the core, the jets will be at various temperatures at the inlet to the lower plenum. This presents some concerns, including that local hot spots may occur in the lower plenum. This may have a deleterious effect on the materials present as well as cause a variation in temperature to be present as the flow enters the power conversion system machinery, which could cause problems with the operation of the machinery. In the past, systems analysis codes have been used to model flow in nuclear reactor systems. It is recognized, however, that such codes are not capable of modeling the local physics of the flow to be able to analyze for local mixing and temperature variations. This has led to the determination that computational fluid dynamic (CFD) codes be used, which are generally regarded as having the capability of accurately simulating local flow physics. Accurate flow modeling involves determining appropriate modeling strategies needed to obtain accurate analyses. These include determining the fineness of the grid needed, the required iterative convergence tolerance, which numerical discretization method to use, and which turbulence model and wall treatment should be employed. It also involves validating the computer code and turbulence model against a series of separate and combined flow phenomena and selecting the data used for the validation. This report describes progress made to identify proper modeling strategies for simulating the lower plenum flow for the task entitled “CFD software validation of jets in crossflow,” which was designed to investigate the issues pertaining to the validation process. The flow phenomenon previously chosen to investigate is flow in a staggered tube bank because it is shown by preliminary simulations to be the location of the highest turbulence intensity in the lower plenum Numerical simulations were previously obtained assuming that the flow is steady. Various turbulence models were employed along with strategies to reduce numerical error to allow appropriate comparisons of the results. It was determined that the sophisticated Reynolds stress model (RSM) provided the best results. It was later determined that the flow is an unsteady flow wherein circulating eddies grow behind the tube and ‘peel off’ alternately from the top and the bottom of the tube. Additional calculations show that the mean velocity is well predicted when the flow is modeled as an unsteady flow. The results for U are clearly superior for the unsteady computations; the unsteady computations for the turbulence stress are similar to those for the steady calculations, showing the same trends. It is clear that strategie

Richard W.Johnson; Tara Gallaway; Donna P. Guillen

2006-09-01T23:59:59.000Z

283

The identification of inflow fluid dynamics parameters that can be used to scale fatigue loading spectra of wind turbine structural components  

DOE Green Energy (OSTI)

We have recently shown that the alternating load fatigue distributions measured at several locations on a wind turbine operating in a turbulent flow can be described by a mixture of at least three parametric statistical models. The rainflow cycle counting of the horizontal and vertical inflow components results in a similar mixture describing the cyclic content of the wind. We believe such a description highlights the degree of non-Gaussian characteristics of the flow. We present evidence that the severity of the low-cycle, high-amplitude alternating stress loads seen by wind turbine components are a direct consequence of the degree of departure from normality in the inflow. We have examined the details of the turbulent inflow associated with series large loading events that took place on two adjacent wind turbines installed in a large wind park in San Gorgonio Pass, California. In this paper, we describe what we believe to be the agents in the flow that induced such events. We also discuss the atmospheric mechanisms that influence the low-cycle, high-amplitude range loading seen by a number of critical wind turbine components. We further present results that can be used to scale the specific distribution shape as functions of measured inflow fluid dynamics parameters.

Kelley, N.D.

1993-11-01T23:59:59.000Z

284

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

285

FRACTURING FLUID CHARACTERIZATION FACILITY  

SciTech Connect

Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids and slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.

Subhash Shah

2000-08-01T23:59:59.000Z

286

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

287

Microsoft Word - CFD MHD Post Grad Researcher.docx  

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

Postgraduate Researcher Postgraduate Researcher DEPARTMENT, AGENCY: Department of Energy, National Energy Technology Laboratory SALARY RANGE: Depends on level of experience OPEN PERIOD: Until Filled LEVEL: Post-graduate POSITION INFORMATION: Temporary Appointment: 1 year with potential for extension; Full-Time (40 hours per week); Starting as soon as possible. DUTY LOCATION: Morgantown, WV WHO MAY BE CONSIDERED: United States Citizens & Foreign Nationals with appropriate approval JOB SUMMARY: Computational Fluid Dynamics of Magneto-Hydrodynamic Generators. Applications are sought for a post-graduate research fellowship in computational energy sciences at the National Energy Technology Laboratory (NETL) as part of the ORISE post-graduate fellowship program. The research engineer would be part of a multidisciplinary team

288

Low Energy Buildings: CFD Techniques for Natural Ventilation and Thermal  

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

Low Energy Buildings: CFD Techniques for Natural Ventilation and Thermal Low Energy Buildings: CFD Techniques for Natural Ventilation and Thermal Comfort Prediction Speaker(s): Malcolm Cook Date: February 14, 2013 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Michael Wetter Malcolm's presentation will cover both his research and consultancy activities. This will cover the work he has undertaken during his time spent working with architects on low energy building design, with a particular focus on natural ventilation and passive cooling strategies, and the role computer simulation can play in this design process. Malcolm will talk about the simulation techniques employed, as well as the innovative passive design principles that have led to some of the UK's most energy efficient buildings. In addition to UK building projects, the talk will

289

Cutting Fluids  

Science Conference Proceedings (OSTI)

Table 6   Cutting fluids for aluminum...Table 6 Cutting fluids for aluminum Type of lubricant Principal ingredients Viscosity range Application; maintenance Relative effectiveness Necessary precautions Mineral oils (fatty-additive type preferred) Mineral oil, lard, or neats-foot oil; oleic acid

290

Supercritical fluid reverse micelle separation  

DOE Patents (OSTI)

A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

Fulton, J.L.; Smith, R.D.

1993-11-30T23:59:59.000Z

291

Supercritical fluid reverse micelle separation  

DOE Patents (OSTI)

A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W.sub.o that determines the maximum size of the reverse micelles. The maximum ratio W.sub.o of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions.

Fulton, John L. (Richland, WA); Smith, Richard D. (Richland, WA)

1993-01-01T23:59:59.000Z

292

Wavelet Turbulence for Fluid Simulation Theodore Kim  

E-Print Network (OSTI)

in the running time. We instead propose an algorithm that generates small-scale fluid de- tail procedurally. We of the key results of Kolmogorov the- ory is that the energy spectrum of a turbulent fluid approaches a five spectra [Perrier et al. 1995], and the sub- stitution is common in fluid dynamics [Farge et al. 1996

California at Santa Barbara, University of

293

HYDRAULIC FLUIDS  

E-Print Network (OSTI)

This fact sheet answers the most frequently asked health questions (FAQs) about hydraulic fluids. For more information, call the ATSDR Information Center at 1-888-422-8737. This fact sheet is one in a series of summaries about hazardous substances and their health effects. This information is important because this substance may harm you. The effects of exposure to any hazardous substance depend on the dose, the duration, how you are exposed, personal traits and habits, and whether other chemicals are present. HIGHLIGHTS: Exposure to hydraulic fluids occurs mainly in the workplace. Drinking certain types of hydraulic fluids can cause death in humans, and swallowing or inhaling certain types of hydraulic fluids has caused nerve damage in animals. Contact with some types of hydraulic fluids can irritate your skin or eyes. These substances have been found in at least 10 of the 1,428 National Priorities List sites identified by the Environmental Protection Agency (EPA). What are hydraulic fluids? (Pronounced ?????ô????????????) Hydraulic fluids are a large group of liquids made of many kinds of chemicals. They are used in automobile automatic

unknown authors

1997-01-01T23:59:59.000Z

294

Multiphysics CFD Modeling of a Free Falling Jet during Melt-Blowing ...  

Science Conference Proceedings (OSTI)

Presentation Title, Multiphysics CFD Modeling of a Free Falling Jet during Melt- Blowing Slag Fiberization ... A Micro-Macro Model of a PEM Fuel Cell System.

295

KINETIC MODELING OF A FISCHER-TROPSCH REACTION OVER A COBALT CATALYST IN A SLURRY BUBBLE COLUMN REACTOR FOR INCORPORATION INTO A COMPUTATIONAL MULTIPHASE FLUID DYNAMICS MODEL  

DOE Green Energy (OSTI)

Currently multi-tubular fixed bed reactors, fluidized bed reactors, and slurry bubble column reactors (SBCRs) are used in commercial Fischer Tropsch (FT) synthesis. There are a number of advantages of the SBCR compared to fixed and fluidized bed reactors. The main advantage of the SBCR is that temperature control and heat recovery are more easily achieved. The SBCR is a multiphase chemical reactor where a synthesis gas, comprised mainly of H2 and CO, is bubbled through a liquid hydrocarbon wax containing solid catalyst particles to produce specialty chemicals, lubricants, or fuels. The FT synthesis reaction is the polymerization of methylene groups [-(CH2)-] forming mainly linear alkanes and alkenes, ranging from methane to high molecular weight waxes. The Idaho National Laboratory is developing a computational multiphase fluid dynamics (CMFD) model of the FT process in a SBCR. This paper discusses the incorporation of absorption and reaction kinetics into the current hydrodynamic model. A phased approach for incorporation of the reaction kinetics into a CMFD model is presented here. Initially, a simple kinetic model is coupled to the hydrodynamic model, with increasing levels of complexity added in stages. The first phase of the model includes incorporation of the absorption of gas species from both large and small bubbles into the bulk liquid phase. The driving force for the gas across the gas liquid interface into the bulk liquid is dependent upon the interfacial gas concentration in both small and large bubbles. However, because it is difficult to measure the concentration at the gas-liquid interface, coefficients for convective mass transfer have been developed for the overall driving force between the bulk concentrations in the gas and liquid phases. It is assumed that there are no temperature effects from mass transfer of the gas phases to the bulk liquid phase, since there are only small amounts of dissolved gas in the liquid phase. The product from the incorporation of absorption is the steady state concentration profile of the absorbed gas species in the bulk liquid phase. The second phase of the model incorporates a simplified macrokinetic model to the mass balance equation in the CMFD code. Initially, the model assumes that the catalyst particles are sufficiently small such that external and internal mass and heat transfer are not rate limiting. The model is developed utilizing the macrokinetic rate expression developed by Yates and Satterfield (1991). Initially, the model assumes that the only species formed other than water in the FT reaction is C27H56. Change in moles of the reacting species and the resulting temperature of the catalyst and fluid phases is solved simultaneously. The macrokinetic model is solved in conjunction with the species transport equations in a separate module which is incorporated into the CMFD code.

Anastasia Gribik; Doona Guillen, PhD; Daniel Ginosar, PhD

2008-09-01T23:59:59.000Z

296

Dynamic  

Office of Legacy Management (LM)

Dynamic Dynamic , and Static , Res.ponse of the Government Oil Shale Mine at ' , . , Rifle, Colorado, to the Rulison Event. , . ; . . DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. p ( y c - - a 2-1 0 -4- REPORT AT (29-2) 914 USBM 1 0 0 1 UNITED STATES DEPARTMENT O F THE I NTERIOR BUREAU OF MINES e s.09 P. L. R U S S E L L RESEARCH D l RECTOR Februory 2, lB7O DYNAMIC AND STATIC RESPONSE 'OF THE GOVERNMENT OIL SHALE MINE A T RIFLE, COLORADO, T O THE, RULISON EVENT ORDER FROM CFSTl A S ~ B ~ &J C / This page intentionally left blank CONTENTS Page . . . . . . . . . . . . . . . . . . . . . . . . . H i s t o r i c . a l Des c r i p t i o n 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Summary 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction 3

297

Computational simulation of aerosol behaviour.  

E-Print Network (OSTI)

??In this thesis, computational methods have been developed for the simulation of aerosol dynamics and transport. Two different coupled aerosol-computational fluid dynamics (CFD) models are… (more)

Pyykönen, Jouni

2002-01-01T23:59:59.000Z

298

Project: Greenhouse Gas Emissions and Transport  

Science Conference Proceedings (OSTI)

... and an easy-to-use tool for estimating ... fluid dynamics (CFD) software tools such as Fire Dynamics Simulator (FDS) and Weather Research and ...

2012-12-27T23:59:59.000Z

299

A study of the location of the entrance of a fishway in a regulated river with CFD and ADCP  

Science Conference Proceedings (OSTI)

Simulation-driven design with computational fluid dynamics has been used to evaluate the flow downstream of a hydropower plant with regards to upstream migrating fish. Fieldmeasurements with an Acoustic Doppler Current Profiler were performed, and the ...

Anders G. Andersson; Dan-Erik Lindberg; Elianne M. Lindmark; Kjell Leonardsson; Patrik Andreasson; Hans Lundqvist; T. Staffan Lundström

2012-01-01T23:59:59.000Z

300

Dynamics  

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

Hydration Hydration Water on Rutile Studied by Backscattering Neutron Spectroscopy and Molecular Dynamics Simulation E. Mamontov,* ,† D. J. Wesolowski, ‡ L. Vlcek, § P. T. Cummings, §,| J. Rosenqvist, ‡ W. Wang, ⊥ and D. R. Cole ‡ Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6473, Chemical Sciences DiVision, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6110, Department of Chemical Engineering, Vanderbilt UniVersity, NashVille, Tennessee 37235-1604, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6496, and EnVironmental Sciences DiVision, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6036 ReceiVed: December 20, 2007; ReVised Manuscript ReceiVed: June 4, 2008 The high energy resolution, coupled with the wide dynamic range, of the new backscattering

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

CFD-based operational thermal efficiency improvement of a production data center  

Science Conference Proceedings (OSTI)

Effective cooling of data centers presents a dual challenge: increased cooling power to meet the ever increasing device heat loads, and the need for energy efficient cooling. Detailed analysis of the thermal and flow conditions within a data center are ... Keywords: computational fluid dynamics, energy efficiency, production data center, thermal management

Umesh Singh; Amarendra K. Singh; S. Parvez; Anand Sivasubramaniam

2010-02-01T23:59:59.000Z

302

Automatic differentiation of advanced CFD codes for multidisciplinary design  

SciTech Connect

Automated multidisciplinary design of aircraft and other flight vehicles requires the optimization of complex performance objectives with respect to a number of design parameters and constraints. The effect of these independent design variables on the system performance criteria can be quantified in terms of sensitivity derivatives which must be calculated and propagated by the individual discipline simulation codes. Typical advanced CFD analysis codes do not provide such derivatives as part of a flow solution; these derivatives are very expensive to obtain by divided (finite) differences from perturbed solutions. It is shown here that sensitivity derivatives can be obtained accurately and efficiently using the ADIFOR source translator for automatic differentiation. In particular, it is demonstrated that the 3-D, thin-layer Navier-Stokes, multigrid flow solver called TLNS3D is amenable to automatic differentiation in the forward mode even with its implicit iterative solution algorithm and complex turbulence modeling. It is significant that using computational differentiation, consistent discrete nongeometric sensitivity derivatives have been obtained from an aerodynamic 3-D CFD code in a relatively short time, e.g. O(man-week) not O(man-year).

Bischof, C.; Corliss, G.; Griewank, A. (Argonne National Lab., IL (United States)); Green, L.; Haigler, K.; Newman, P. (National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center)

1992-01-01T23:59:59.000Z

303

Automatic differentiation of advanced CFD codes for multidisciplinary design  

SciTech Connect

Automated multidisciplinary design of aircraft and other flight vehicles requires the optimization of complex performance objectives with respect to a number of design parameters and constraints. The effect of these independent design variables on the system performance criteria can be quantified in terms of sensitivity derivatives which must be calculated and propagated by the individual discipline simulation codes. Typical advanced CFD analysis codes do not provide such derivatives as part of a flow solution; these derivatives are very expensive to obtain by divided (finite) differences from perturbed solutions. It is shown here that sensitivity derivatives can be obtained accurately and efficiently using the ADIFOR source translator for automatic differentiation. In particular, it is demonstrated that the 3-D, thin-layer Navier-Stokes, multigrid flow solver called TLNS3D is amenable to automatic differentiation in the forward mode even with its implicit iterative solution algorithm and complex turbulence modeling. It is significant that using computational differentiation, consistent discrete nongeometric sensitivity derivatives have been obtained from an aerodynamic 3-D CFD code in a relatively short time, e.g. O(man-week) not O(man-year).

Bischof, C.; Corliss, G.; Griewank, A. [Argonne National Lab., IL (United States); Green, L.; Haigler, K.; Newman, P. [National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center

1992-12-31T23:59:59.000Z

304

R fluids  

E-Print Network (OSTI)

A theory of collisionless fluids is developed in a unified picture, where nonrotating figures with anisotropic random velocity component distributions and rotating figures with isotropic random velocity component distributions, make adjoints configurations to the same system. R fluids are defined and mean and rms angular velocities and mean and rms tangential velocity components are expressed, by weighting on the moment of inertia and the mass, respectively. The definition of figure rotation is extended to R fluids. The generalized tensor virial equations are formulated for R fluids and further attention is devoted to axisymmetric configurations where, for selected coordinate axes, a variation in figure rotation has to be counterbalanced by a variation in anisotropy excess and vice versa. A microscopical analysis of systematic and random motions is performed under a few general hypotheses, by reversing the sign of tangential or axial velocity components of an assigned fraction of particles, leaving the distribution function and other parameters unchanged (Meza 2002). The application of the reversion process to tangential velocity components, implies the conversion of random motion rotation kinetic energy into systematic motion rotation kinetic energy. The application of the reversion process to axial velocity components, implies the conversion of random motion translation kinetic energy into systematic motion translation kinetic energy, and the loss related to a change of reference frame is expressed in terms of systematic (imaginary) motion rotation kinetic energy. A procedure is sketched for deriving the spin parameter distribution (including imaginary rotation) from a sample of observed or simulated large-scale collisionless fluids i.e. galaxies and galaxy clusters.

R. Caimmi

2007-10-20T23:59:59.000Z

305

Controlling the fluid-fluid mixing-demixing phase transition with electric fields  

E-Print Network (OSTI)

We review recent theoretical advances on controlling the fluid-fluid phase transition with electric fields. Using a mean-field approach, we compare the effects of uniform versus non-uniform electric fields, and show how non-uniform fields are better at altering the phase diagram. Focusing on non-uniform fields, we then discuss the behavior of the fluid concentration profile and the parameters (temperature, fluid concentration, etc.) that control the location of the fluid-fluid interface from both equilibrium and dynamic perspectives.

Jennifer Galanis; Sela Samin; Yoav Tsori

2012-12-06T23:59:59.000Z

306

A Class of Semi-Lagrangian Approximations for Fluids  

Science Conference Proceedings (OSTI)

This paper discusses a class of finite-difference approximations to the evolution equations of fluid dynamics. These approximations derive from elementary properties of differential forms. Values of a fluid variable ? at any two points of a space-...

Piotr K. Smolarkiewicz; Janusz A. Pudykiewicz

1992-11-01T23:59:59.000Z

307

Fluid extraction  

DOE Patents (OSTI)

A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

Wai, Chien M. (Moscow, ID); Laintz, Kenneth E. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

308

CFD Analyses for Water-Air Flow With the Euler-Euler Two-Phase Model in the Fluent4 CFD Code  

SciTech Connect

Framatome ANP develops a new boiling water reactor called SWR 1000. For the case of a hypothetical core melt accident it is designed in such a way that the core melt is retained in the Reactor Pressure Vessel (RPV) at low pressure owing to cooling of the RPV exterior and high reliable depressurization devices. Framatome ANP performs - in co-operation with VTT - tests to quantify the safety margins of the exterior cooling concept for the SWR 1000, for determining the limits to avoid the critical heat fluxes (CHFs). The three step procedure has been set up to investigate the phenomenon: 1. Water-air study for a 1:10 scaled global model, with the aim to investigate the global flow conditions 2. Water-air study for a 1:10 scaled, 10 % sector model, with the aim to find a flow sector with almost similar flow conditions as in the global model. 3. Final CHF experiments for a 1:1-scaled, 10 % sector., the boarders of this model have been selected based on the first two steps. The instrumentation for the water/air experiments included velocity profiles, the vertically averaged average void fraction and void fraction profiles in selected positions. The experimental results from the air-water experiments have been analyzed at VTT using the Fluent-4.5.2 code with its Eulerian multiphase flow modeling capability. The aim of the calculations was to learn how to model complex two-phase flow conditions. The structural mesh required by Fluent-4 is a strong limitation in the complex geometry, but modeling of the 1/4 sector from the facility was possible, when the GAMBIT pre-processor was used for the mesh generation. The experiments were analyzed with the 150 x 150 x 18 grid for the geometry. In the analysis the fluid viscosity was the main dials for adjusting the vertical liquid velocity profiles and the bubble diameter for adjusting the phase separation. The viscosity ranged between 1 to 10000 times the molecular viscosity, and bubble diameter between 3 to 100 mm, when the calculation results were adjusted for a good agreement with the experimental data. The analysis results were very valuable for designing the final water/steam facility for final CHF tests. The validation against data from the air-water experiments proved that the present CFD codes approach to the state where they can be used for simulating such two-phase experiments, where the fraction of both phases is essential and the flow is strongly affected by the density differences. It is still too early to predict, if the CFD calculation of the 1:1 scale critical heat flux experiments is successful, could the result be used for formulating a new type of a critical heat flux correlation, where the effects of CRD's on the flow patterns and gap dimensions are model parameters. (authors)

Miettinen, Jaakko [VTT Process, P.O. Box 1000 Tietatie 3 Espoo FIN-02044 (Finland); Schmidt, Holger [Framatome ANP GmbH, Department FANP NT31, Freyeslebenstrasse 1, D-91058 Erlangen (Germany)

2002-07-01T23:59:59.000Z

309

Microsoft PowerPoint - UCR-2013-presentation sent to doe [Compatibilit...  

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

Singh (PhD Student) The overall objective of the program is to develop a Computational Fluid Dynamic (CFD) model and to perform CFD simulations to describe the heterogeneous...

310

Visually simulating realistic fluid motion  

E-Print Network (OSTI)

In this thesis we investigate various methods for visually simulating fluid flow. The focus is on implementing effective fluid simulation within an interactive animation system. Two implementations have been developed based on derivations and simplifications of the Navier-Stokes' equations. The first implementation is the most accurate and follows the physics of fluid dynamics more closely. However, the high computation times incurred by this implementation make it inappropriate as an interactive method. The second approach is not as accurate as the first one, however it incurs lower computation times. This second method is only able to model a subset of the total fluid behavior. The second method has been integrated into an interactive modeling and animation environment. Several examples are included.

Naithani, Priyanka

2002-01-01T23:59:59.000Z

311

Inkjet printing of non-Newtonian fluids  

E-Print Network (OSTI)

G. Harlen; Department of Applied Mathematics; University of Leeds, Leeds, LS2 9JT, U.K. Abstract Jet breakup is strongly affected by fluid rheology. In par- ticular, small amounts of polymer can cause substantially differ- ent breakup dynamics... fluid dynamics (2008) from the University of Cambridge. Since then he has worked at the Department of Applied Mathematics at the University of Leeds. His recent research involves the development of computational techniques for the simulation of flows...

Morrison, N.F.; Harlen, O.G.

2011-01-01T23:59:59.000Z

312

CFD modeling of a gas turbine combustor from compressor exit to turbine inlet  

SciTech Connect

Gas turbine combustor CFD modeling has become an important combustor design tool in the past few years, but CFD models are generally limited to the flow field inside the combustor liner at the diffuser/combustor annulus region. Although strongly coupled in reality, the two regions have rarely been coupled in CFD modeling. A CFD calculation for a full model combustor from compressor diffuser exit to turbine inlet is described. The coupled model accomplishes the following two main objectives: (1) implicit description of flow splits and flow conditions for openings into the combustor liner, and (2) prediction of liner wall temperatures. Conjugate heat transfer with nonluminous gas radiation (appropriate for lean, low emission combustors) is utilized to predict wall temperatures compared to the conventional approach of predicting only near wall gas temperatures. Remaining difficult issues such as generating the grid, modeling swirler vane passages, and modeling effusion cooling are also discussed.

Crocker, D.S.; Nickolaus, D.; Smith, C.E. [CFD Research Corp., Huntsville, AL (United States)

1999-01-01T23:59:59.000Z

313

A Coupled CFD-Thermodynamic-Kinetic Model to Simulate a Gas ...  

Science Conference Proceedings (OSTI)

For this purpose, argon gas stirring is commonly used. ... Modeling of Solidification Benchmark of Sn-3% Pb Wt. Alloy under Natural Convection ... CFD Model for Prediction of Liquid Steel Temperature in Ladle during Steel Making and Casting.

314

Extending the Photon Mapping Method for Realistic Rendering of Hot Gaseous Fluids  

E-Print Network (OSTI)

fluid dynamics have proved very successful. As a result, diverse physically based fluid animation fluids. In addition to the generation of ap- pealing motions of gaseous fluids, several inter- esting, they are gen- erated within the gaseous fluid, but an energy value is assigned to each one according to the to

Texas at Austin, University of

315

CFD Simulation and Measurement Validation of Air Distribution at the Hunan International Exhibition Center  

E-Print Network (OSTI)

The Hunan International Exhibition Center (HIEC) is a large space building. A stratified air-conditioning system on the second floor of the building has been adopted. Due to some problems with the air supply jet diffuser, CFD simulations were carried out to predict air distribution. Meanwhile, field measurement results were used to validate the CFD simulation results. A good agreement of simulated and test results was obtained. Based on simulation results, some analyses and suggestions are put forward to improve air distribution.

Deng, T.; Zhang, Q.; Zhang, G.; Yuan, H.

2006-01-01T23:59:59.000Z

316

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

317

Mesh Requirement Investigation for 2D and 3D Aerodynamic Simulation of Vertical Axis Wind Turbines.  

E-Print Network (OSTI)

??The accuracy of a Computational Fluid Dynamics (CFD) model to capture the complex flow around a small vertical axis wind turbine (VAWT) on 2D and… (more)

Naghib Zadeh, Saman

2013-01-01T23:59:59.000Z

318

Illinois | Department of Energy  

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

Categorical Exclusion Determination Computational Fluid Dynamics (CFD) Simulations of a Regenerative Process for Carbon Dioxide Capture in Advanced Gasification Based Systems...

319

Categorical Exclusion Determinations: National Energy Technology...  

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

Categorical Exclusion Determination Computational Fluid Dynamics (CFD) Simulations of a Regenerative Process for Carbon Dioxide Capture in Advanced Gasification Based Systems...

320

KIVA-4: Los Alamos National Laboratory  

The KIVA family of Computational Fluid Dynamics (CFD) software predicts complex fuel and air flows as well as ignition, combustion, and ...

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

Argonne Software Licensing: Glass Furnace Model (GFM)  

The Glass Furnace Model (GFM) The Glass Furnace Model (GFM) Version 4.0, a computational fluid dynamic (CFD) glass furnace simulation code was developed at Argonne ...

322

Microsoft Word - BBI Retrofit Handbook MDS Rev Sep 19.docx  

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

thermal unit CFD Computational Fluid Dynamics ECM Energy Conservation Measure EIS Energy Information System Envelope Physical separator between the interior and the exterior...

323

Numerical Simulation of an Open Channel Ultraviolet Waste-water Disinfection Reactor.  

E-Print Network (OSTI)

??The disinfection characteristics of an open channel ultra-violet (UV) wastewater disinfection reactor are investigated using a computational fluid dynamics (CFD) model. The model is based… (more)

Saha, Rajib Kumar

2013-01-01T23:59:59.000Z

324

Mobile Ice Nucleus Spectrometer  

SciTech Connect

This first year report presents results from a computational fluid dynamics (CFD) study to assess the flow and temperature profiles within the mobile ice nucleus spectrometer.

Kulkarni, Gourihar R.; Kok, G. L.

2012-05-07T23:59:59.000Z

325

TEMPLATE FOR EES DIRECTORATE QUARTERLY HIGHLIGHTS  

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

limiting the practical application of dual-fuel operation. This project will utilize Titan to perform massively parallel computational fluid dynamic (CFD) engine simulations...

326

NETL: LabNotes -January 2013  

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

equipment. At NETL, scientists have developed in-house multiphase computational fluid dynamic (CFD) model MFIX (Multiphase Flow with Interphase eXchanges) as well as the...

327

Building Energy Software Tools Directory: FLOVENT  

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

FLOVENT FLOVENT logo. Calculates airflow, heat transfer and contamination distribution for built environments. FLOVENT uses techniques of Computational Fluid Dynamics (CFD)...

328

NETL F 451.1-1/1 Categorical Exclusion (CX) Designation Form  

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

DE-FE0000699 University of Kentucky FE DE-FE0000699 315 10 Donald Krastman 5110 -10112 Lexington, Fayette County, KY COMPUTATIONAL FLUID DYNAMICS (CFD) ANALYSIS DENSITY...

329

Simulation of the atmospheric behavior for the environment of a small-scale wind turbine.  

E-Print Network (OSTI)

??This study investigates a method using computational fluid dynamics (CFD) to model low-elevation atmospheric conditions. There are three goals in this research: to analyze the… (more)

Nguyen, Viet

2011-01-01T23:59:59.000Z

330

Dynamic modeling of a single-stage downward firing, entrained flow gasifier  

SciTech Connect

The gasifier is the heart of the integrated gasification combined cycle (IGCC), a technology that has emerged as an attractive alternative to conventional coal-fired power plant technology due to its higher efficiency and cleaner environmental performance especially with the option of CO{sub 2} capture and sequestration. Understanding the optimal performance of the gasifier is therefore paramount for the efficient operation of IGCC power plants. Numerous gasifier models of varying complexity have been developed to study the various aspects of gasifier performance. These range from simple one-dimensional (1D) process-type models to rigorous higher order 2-3D models based on computational fluid dynamics (CFD). Whereas high-fidelity CFD models can accurately predict most key aspects of gasifier performance, they are computationally expensive and typically take hours to days to execute on high-performance computers. Therefore, faster 1D partial differential equation (PDE)-based models are required for use in dynamic simulation studies, control system analysis, and training applications. A number of 1D gasifier models can be found in the literature, but most are steady-state models that have limited application in the practical operation of the gasifier. As a result, 1D PDE-based dynamic models are needed to further study and predict gasifier performance under a wide variety of process conditions and disturbances. In the current study, a 1D transient model of a single-stage downward-fired GE/Texaco-type entrained-flow gasifier has been developed. The model comprises mass, momentum and energy balances for the gas and solid phases. The model considers the initial gasification processes of water evaporation and coal devolatilization. In addition, the key heterogeneous and homogeneous chemical reactions have been modeled. The resulting time-dependent PDE model is solved using the well-known method of lines approach in Aspen Custom Modeler®, whereby the PDEs in the spatial domain are discretized and the resulting differential algebraic equations (DAEs) are then integrated over time using a dynamic integrator. The dynamic response results of the gasifier performance parameters to certain disturbances commonly encountered during practical operation are presented. These disturbances include ramp and step changes to input variables such as coal flow rate, oxygen-to-coal ratio and water-to-coal ratio among others. Comparison of model predictions to available dynamic data will also be discussed.

Kasule, J., Turton, R., Bhattacharyya, D., Zitney, S.

2012-01-01T23:59:59.000Z

331

An evaluation of the neutron radiography facility at the Nuclear Science Center for dynamic imaging of two-phase hydrogenous fluids  

E-Print Network (OSTI)

Though both film and video radiographic image techniques are available in neutron radiography, radiographic cameras are commonly used to capture the dynamic flow patterns in a rapid sequence of images. These images may be useful to verify two-phase flow models in small diameter flow channels. An initial series of real-time neutron radiography experiments were performed at the Texas A&M University System, Texas Engineering Experiment Station, Nuclear Science Center Reactor (NSCR) to determined the image resolution of two-phase water and air flow regimes through small diameter metal flow channels. After evaluating these initial images, research was conducted to determine cost effective enhancements that would increase the dimensional accuracy and contrast of these flow images. Modifications were completed to the beam collimator and the radiography camera video processing board was realigned to provide a stronger vidio signal with less noise. Several hydrogenous-media reference standards were designed and constructed to evaluate the effectiveness of the modifications. The beamport collimator was redesigned and the radiography calibration methodology was changed. The post-modification images demonstrate that a smaller, more focused neutron beam and a more sensitive video camera provide clearer images with excellent dimensional characteristics. Specific research to quantify both the resolution and sensitivity limits is proposed and a change in dynamic target imaging methodology is proposed.

Carlisle, Bruce Scott

1994-01-01T23:59:59.000Z

332

NUMERICAL DETERMINATION AND TREATMENT OF CONVECTIVE HEAT TRANSFER COEFFICIENT IN THE COUPLED BUILDING ENERGY AND CFD SIMULATION  

E-Print Network (OSTI)

for the correct prediction of the convective heat. A finer grid resolution in CFD does not always lead to a more conservation equations of flow on these grid cells. As shown in Figure 1(a), CFD calculates convective heat1 NUMERICAL DETERMINATION AND TREATMENT OF CONVECTIVE HEAT TRANSFER COEFFICIENT IN THE COUPLED

Chen, Qingyan "Yan"

333

CFD Simulation of the CANDU-6 Moderator Circulation Under Normal Operating Conditions  

Science Conference Proceedings (OSTI)

A steady-state 3D simulation for predicting the local subcooling of the moderator in the vicinity of the calandria tubes in a CANDU-6 reactor is performed. For the current simulation, a set of grid structures with the same geometry as the CANDU-6 moderator tank, called 'calandria vessel', is generated and the momentum, heat and continuity equations are solved by CFX-4.3, a CFD code developed by AEA technology. The standard k-{epsilon} turbulence model associated with logarithmic wall treatment is used to model turbulence generation and dissipation within the vessel. The moderator fluid is heavy water. Buoyancy forces are modeled using the Boussinesq approximation in which density is assumed to be a linear function of temperature. The matrix of the calandria tubes in the center region of the calandria vessel is simplified by the porous media approach. The anisotropic hydraulic impedance of the calandria tubes is modeled using the frictional pressure drop correlations suggested by Idelchik and Szymanski. The heat load in this steady-state simulation is conservatively set as 103 MW of 103% full power, consisting of 96.7 MW to the core region and 6.3 MW to the reflector region. The total volumetric flow rate through eight inlet nozzles is 940 L/s and the outlet temperature is constantly 71.0 deg. C. The thermal boundary condition of the circumferential vessel wall is assumed a little heat flux out. As a result, the velocity field and temperature distribution of a CANDU-6 moderator in the operating condition are presented. The flow pattern identified in this simulation is the weak jet momentum-dominated flow, which is generated by the interaction between the buoyancy force by heating and the dominant momentum forces by inlet jets. The calculated maximum temperature of the moderator is 83.0 deg. C at the lower center region of the core, which corresponds to the minimum subcooling of 33.0 deg. C considering the boiling point increase due to the hydrostatic pressure change. (authors)

Bo Wook Rhee; Churl Yoon; Byung-Joo Min [Korea Atomic Energy Research Institute, 150, Dukjin-Dong, Yusong-Gu, Taejon 305-353 (Korea, Republic of)

2002-07-01T23:59:59.000Z

334

J. Non-Newtonian Fluid Mech. 166 (2011) 487499 Contents lists available at ScienceDirect  

E-Print Network (OSTI)

framework for complex fluid mixtures where the microstructural dynamics has an energy-based variational to the sur- rounding fluid motion as the plates are set into steady motion to generate a bulk shear flow within the liquid crystal phase with some model of the nematic director dynamics and elastic fluid

Shen, Jie

335

Local rheological probes for complex fluids: Application to Laponite suspensions C. Wilhelm,1,2  

E-Print Network (OSTI)

of the fluid viscosity on the applied stress, and a dynamical yield stress which saturates with the fluid aging . Their constitutive entities are in interaction; the competition between the different energies generates structures to ensure a Stokes flow: Re uR/v 10 2 , where v is the fluid dynamic viscosity. 2 This value of corresponds

Weeks, Eric R.

336

Fluid Interface Reactions, Structures and Transport (FIRST) Center EFRC Director: David J. Wesolowski  

E-Print Network (OSTI)

environment in which to train the next generation of scientists to meet 21st century energy challenges. Fluid computational models relating the nanoscale structures, dynamics and reactivities of fluid-solid interfaces the interfacial region differ in structure, dynamics and reactivity from the bulk properties of the fluid

337

Fluid Simulation using Laplacian Eigenfunctions TYLER DE WITT, CHRISTIAN LESSIG and EUGENE FIUME  

E-Print Network (OSTI)

complement to the methods in the literature. 2. RELATED WORK Incompressible fluid dynamics is a vast subject in computer graphics applications. 2.2 Computational Fluid Dynamics In the 1950's, Silberman presented a fluid conditions, and still dissipates energy. Bridson presented a simple means to generate procedural divergence

Toronto, University of

338

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

339

Fluid transport container  

DOE Patents (OSTI)

An improved fluid container for the transport, collection, and dispensing of a sample fluid that maintains the fluid integrity relative to the conditions of the location at which it is taken. More specifically, the invention is a fluid sample transport container that utilizes a fitting for both penetrating and sealing a storage container under controlled conditions. Additionally, the invention allows for the periodic withdrawal of portions of the sample fluid without contamination or intermixing from the environment surrounding the sample container. 13 figs.

DeRoos, B.G.; Downing, J.P. Jr.; Neal, M.P.

1995-11-14T23:59:59.000Z

340

Fluid transport container  

DOE Patents (OSTI)

An improved fluid container for the transport, collection, and dispensing of a sample fluid that maintains the fluid integrity relative to the conditions of the location at which it is taken. More specifically, the invention is a fluid sample transport container that utilizes a fitment for both penetrating and sealing a storage container under controlled conditions. Additionally, the invention allows for the periodic withdrawal of portions of the sample fluid without contamination or intermixing from the environment surrounding the sample container.

DeRoos, Bradley G. (41 James St., Sequim, WA 98382); Downing, Jr., John P. (260 Kala Heights Dr., Port Townsand, WA 98368); Neal, Michael P. (921 Amberly Pl., Columbus, OH 43220)

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

The use of dynamic adaptive chemistry in combustion simulation of gasoline surrogate fuels  

Science Conference Proceedings (OSTI)

A computationally efficient dynamic adaptive chemistry (DAC) scheme is described that permits on-the-fly mechanism reduction during reactive flow calculations. The scheme reduces a globally valid full mechanism to a locally, instantaneously applicable smaller mechanism. Previously we demonstrated its applicability to homogeneous charge compression ignition (HCCI) problems with n-heptane [L. Liang, J.G. Stevens, J.T. Farrell, Proc. Combust. Inst. 32 (2009) 527-534]. In this work we demonstrate the broader utility of the DAC scheme through the simulation of HCCI and shock tube ignition delay times (IDT) for three gasoline surrogates, including two- and three-component blends of primary reference fuels (PRF) and toluene reference fuels (TRF). Both a detailed 1099-species mechanism and a skeletal 150-species mechanism are investigated as the full mechanism to explore the impact of fuel complexity on the DAC scheme. For all conditions studied, pressure and key species profiles calculated using the DAC scheme are in excellent agreement with the results obtained using the full mechanisms. For the HCCI calculations using the 1099- and 150-species mechanisms, the DAC scheme achieves 70- and 15-fold CPU time reductions, respectively. For the IDT problems, corresponding speed-up factors of 10 and two are obtained. Practical guidance is provided for choosing the search-initiating species set, selecting the threshold, and implementing the DAC scheme in a computational fluid dynamics (CFD) framework. (author)

Liang, Long; Raman, Sumathy; Farrell, John T. [Corporate Strategic Research Laboratories, ExxonMobil Research and Engineering Company, 1545 Route 22 East, Annandale, NJ 08801 (United States); Stevens, John G. [Corporate Strategic Research Laboratories, ExxonMobil Research and Engineering Company, 1545 Route 22 East, Annandale, NJ 08801 (United States); Department of Mathematical Sciences, Montclair State University, Montclair, NJ 07043 (United States)

2009-07-15T23:59:59.000Z

342

Hamiltonian description of the ideal fluid  

SciTech Connect

Fluid mechanics is examined from a Hamiltonian perspective. The Hamiltonian point of view provides a unifying framework; by understanding the Hamiltonian perspective, one knows in advance (within bounds) what answers to expect and what kinds of procedures can be performed. The material is organized into five lectures, on the following topics: rudiments of few-degree-of-freedom Hamiltonian systems illustrated by passive advection in two-dimensional fluids; functional differentiation, two action principles of mechanics, and the action principle and canonical Hamiltonian description of the ideal fluid; noncanonical Hamiltonian dynamics with examples; tutorial on Lie groups and algebras, reduction-realization, and Clebsch variables; and stability and Hamiltonian systems.

Morrison, P.J.

1994-01-01T23:59:59.000Z

343

A Molecular Dynamics Simulation  

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.

344

Wind power resource assessment in complex urban environments: MIT campus case-study using CFD Analysis  

E-Print Network (OSTI)

Wind power resource assessment in complex urban environments: MIT campus case-study using CFD of Technology, 2Meteodyn Objectives Conclusions References [1] TopoWind software, User Manual [2] Wind Resource Assessment Handbook: Fundamentals for Conducting a Successful Wind Monitoring Program, AWS Scientific, Inc

345

Original paper: Validation of CFD simulation for ammonia emissions from an aqueous solution  

Science Conference Proceedings (OSTI)

In order to model and predict ammonia emissions from animal houses, it is important to determine the concentration on the emission surface correctly. In the current literature, Henry's law is usually used to model the mass transfer through the gas-liquid ... Keywords: Ammonia emission, CFD, Concentration boundary condition, Henry's law constant, Vapor-liquid equilibrium

Li Rong; Basman Elhadidi; H. Ezzat Khalifa; Peter V. Nielsen; Guoqiang Zhang

2011-02-01T23:59:59.000Z

346

Control of underactuated fluid-body systems with real-time particle image velocimetry  

E-Print Network (OSTI)

Controlling the interaction of a robot with a fluid, particularly when the desired behavior is intimately related to the dynamics of the fluid, is a difficult and important problem. High-performance aircraft cannot ignore ...

Roberts, John W., Ph. D. Massachusetts Institute of Technology

2012-01-01T23:59:59.000Z

347

Environmentally safe fluid extractor  

DOE Patents (OSTI)

An environmentally safe fluid extraction device for use in mobile laboratory and industrial settings comprising a pump, compressor, valving system, waste recovery tank, fluid tank, and a exhaust filtering system.

Sungaila, Zenon F. (Orland Park, IL)

1993-01-01T23:59:59.000Z

348

Drilling Fluid Corrosion  

Science Conference Proceedings (OSTI)

Table 8   Drilling fluid corrosion control troubleshooting chart...Table 8 Drilling fluid corrosion control troubleshooting chart Corrosion cause Primary source Identification Major corrosion forms Remedies Oxygen Atmosphere, mud conditioning, equipment, oxidizing

349

Fluid Suspensions & Emulsions  

Science Conference Proceedings (OSTI)

Fluid Suspensions & Emulsions. Summary: Our primary interest is protein ... protein solutions? 1. Health & Safety. There is ongoing ...

2013-09-29T23:59:59.000Z

350

Thermal influence indices: Causality metrics for efficient exploration of data center cooling  

Science Conference Proceedings (OSTI)

Cooling is an important issue in data center design and operation. Accurate evaluation of a design or operational parameter choice for cooling is difficult as it requires several runs of computationally intensive Computational Fluid Dynamics (CFD) based ... Keywords: Computational Fluid Dynamics (CFD),Data center,Efficient cooling

Harshad Bhagwat; Amarendra Singh; Arunchandar Vasan; Anand Sivasubramaniam

2012-06-01T23:59:59.000Z

351

Fluid Dynamics of Oceanic Thermocline Ventilation  

Science Conference Proceedings (OSTI)

A flux form of the Potential vorticity (PV) equation is applied to study the creation and transport of potential vorticity in an ocean gyre; generalized PV fluxes (J vectors) and the associated PV flux fines are used to map the creation, by ...

John C. Marshall; A. J. George Nurser

1992-06-01T23:59:59.000Z

352

Fluid dynamics of partially radiative blast waves  

E-Print Network (OSTI)

We derive a self similar solution for the propagation of an extreme relativistic (or Newtonian) radiative spherical blast wave into a surrounding cold medium. The solution is obtained under the assumption that the radiation process is fast, it takes place only in the vicinity of the shock and that it radiates away a fixed fraction of the energy generated by the shock. In the Newtonian regime these solutions generalize the Sedov-Taylor adiabatic solution and the pressure-driven fully radiative solution. In the extreme relativistic case these solutions generalize the Blandford-McKee adiabatic solution. They provide a new fully radiative extreme relativistic solution which is different from the Blandford-McKee fully radiative relativistic solution. This new solution develops a hot interior which causes it to cool faster than previous estimates. We find that the energy of the blast wave behaves as a power law of the location of the shock. The power law index depends on the fraction of the energy emitted by the shock. We obtain an analytic solution for the interior of the blast wave. These new solutions might be applicable to the study of GRB afterglow or SNRs.

Ehud Cohen; Tsvi Piran; Re'em Sari

1998-03-22T23:59:59.000Z

353

table of contents part i: fluid dynamics  

Science Conference Proceedings (OSTI)

CHAPTER 7: HEAT TRANSFER AND THE ENERGY EQUATION. 7.1 Heat ... 7.2 Heat transfer with laminar forced convection over a flat plate [pp. 224-228

354

Three Dimensional CFD Model of a Planar Solid Oxide Electrolysis Cell for Co-Electrolysis of Steam and Carbon-Dioxide  

SciTech Connect

A three-dimensional computational fluid dynamics (CFD) model has been created to model high temperature co-electrolysis of steam and carbon dioxide in a planar solid oxide electrolyzer (SOE). A research program is under way at the Idaho National Laboratory (INL) to simultaneously address the research and scale-up issues associated with the implementation of planar solid-oxide electrolysis cell technology for syn-gas production from CO2 and steam. Various runs have been performed under different run conditions to help assess the performance of the SOE. An experimental study is also being performed at the INL to assess the SOE. Model results provide detailed profiles of temperature, Nernst potential, operating potential, anode-side gas composition, cathode-side gas composition, current density and syn-gas production over a range of stack operating conditions. Typical results of current density versus cell potential, cell current versus H2 and CO production, temperature, and voltage potential are all presented within this paper. Plots of mole fraction of CO2, CO, H2, H2O, O2, are presented. Currently there is strong interest in the large-scale production of syn-gas from CO2 and steam to be reformed into a usable transportation fuel. This process takes the carbon-neutral approach where the amount of CO2 in the atmosphere does not increase. Consequently, there is a high level of interest in production of syn-gas from CO2 and steam electrolysis. Worldwide, the demand for light hydrocarbon fuels like gasoline and diesel oil is increasing. To satisfy this demand, oil companies have begun to utilize oil deposits of lower hydrogen. In the mean time, with the price of oil currently over $70 / barrel, synthetically-derived hydrocarbon fuels (synfuels) have become economical. Synfuels are typically produced from syngas – hydrogen (H2) and carbon monoxide (CO) -- using the Fischer-Tropsch process, discovered by Germany before World War II. South Africa has used synfuels to power a significant number of their buses, trucks, and taxicabs. The Idaho National Laboratory (INL), in conjunction with Ceramatec Inc. (Salt Lake City, USA) has been researching for several years the use of solid-oxide fuel cell technology to electrolyze steam for large-scale nuclear-powered hydrogen production. Now, an experimental research project is underway at the INL to investigate the feasibility of producing syngas by simultaneously electrolyzing at high-temperature steam and carbon dioxide (CO2) using solid oxide fuel cell technology. High-temperature nuclear reactors have the potential for substantially increasing the efficiency of syn-gas production from CO2 and water, with no consumption of fossil fuels, and no production of greenhouse gases. Thermal CO2-splitting and water splitting for syn-gas production can be accomplished via high-temperature electrolysis or thermochemical processes, using high-temperature nuclear process heat. In order to achieve competitive efficiencies, both processes require high-temperature operation (~850°C). High-temperature electrolytic CO2 and water splitting supported by nuclear process heat and electricity has the potential to produce syn-gas with an overall system efficiency near those of the thermochemical processes. Specifically, a high-temperature advanced nuclear reactor coupled with a high-efficiency high-temperature electrolyzer could achieve a competitive thermal-to-syn-gas conversion efficiency of 45 to

G. Hawkes; J. O' Brien; C. Stoots; S. Herring; R. Jones

2006-11-01T23:59:59.000Z

355

Spinning fluids reactor  

SciTech Connect

A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.

Miller, Jan D; Hupka, Jan; Aranowski, Robert

2012-11-20T23:59:59.000Z

356

Entropy production at freeze-out from dissipative fluids  

E-Print Network (OSTI)

Entropy production due to shear viscosity during the continuous freeze-out of a longitudinally expanding dissipative fluid is addressed. Assuming the validity of the fluid dynamical description during the continuous removal of interacting matter we estimated a small entropy production as function of the freeze-out duration and the ratio of dissipative to non-dissipative quantities in case of a relativistic massless pion fluid.

E. Molnar

2007-09-17T23:59:59.000Z

357

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.

358

Lagrangian Motion and Fluid Exchange in a Barotropic Meandering Jet  

Science Conference Proceedings (OSTI)

Kinematic models predict that a coherent structure, such as a jet or an eddy, in an unsteady flow can exchange fluid with its surroundings. The authors consider the significance of this effect for a fully nonlinear, dynamically consistent, ...

A. M. Rogerson; P. D. Miller; L. J. Pratt; C. K. R. T. Jones

1999-10-01T23:59:59.000Z

359

2.25 Advanced Fluid Mechanics, Fall 2002  

E-Print Network (OSTI)

Survey of principal concepts and methods of fluid dynamics. Mass conservation, momentum, and energy equations for continua. Navier-Stokes equation for viscous flows. Similarity and dimensional analysis. Lubrication theory. ...

Sonin, A. A.

360

J. Fluid Mech. (2004) Copyright c 2004 Cambridge University Press  

E-Print Network (OSTI)

(1968) that the depth of an energy-conserving gravity current is half that of the ambient fluid ahead-zero . Apparently, the process of generating these waves dominates the dynamics governing the motion of the gravityJ. Fluid Mech. (2004) Copyright c 2004 Cambridge University Press 1 Intrusive Gravity Currents

Sutherland, Bruce

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

A comparison of grid-based techniques for Navier-Stokes fluid simulation in computer graphics  

E-Print Network (OSTI)

1. Fluid Simulation in Computer Graphics 2. PreviousB. Applications in Computer Graphics II The Navier Stokesstable ?uid dynamics for computer graphics. In SIGGRAPH

Chrisman, Cameron

2008-01-01T23:59:59.000Z

362

Coupling methodology of 1D finite difference and 3D finite volume CFD codes based on the Method of Characteristics  

Science Conference Proceedings (OSTI)

This paper describes the methodology followed to perform a co-simulation between 1D (OpenWAM) and 3D (FLUENT) CFD codes. The Method of Characteristics (MoC) has been chosen to transfer the information between the two domains by properly updating the ... Keywords: 1D modeling, 1D-3D coupling, CFD simulation, Co-simulation, Method of Characteristics, User defined function

J. Galindo; A. Tiseira; P. Fajardo; R. Navarro

2011-10-01T23:59:59.000Z

363

Phenomenology of Rayleigh-Taylor Turbulence If a heavy fluid lies above a light one, the gravity-  

E-Print Network (OSTI)

to surface tension. We examined in [2] the dynamics of two immiscible fluids when the heavier fluid is placed be estimated to be the scale where the kinetic energy density of the fluids, (vl)2 , and the interfacial energy, generating an emulsion that is progres- sively more dispersed. Dynamically, the permanent decrease

364

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

365

Three dimensional analysis of turbulent steam jets in enclosed structures : a CFD approach.  

SciTech Connect

This paper compares the three-dimensional numerical simulation with the experimental data of a steam blowdown event in a light water reactor containment building. The temperature and pressure data of a steam blowdown event was measured at the Purdue University Multi-Dimensional Integrated Test Assembly (PUMA), a scaled model of the General Electric simplified Boiling Water Reactor. A three step approach was used to analyze the steam jet behavior. First, a 1-Dimensional, system level RELAP5/Mod3.2 model of the steam blowdown event was created and the results used to set the initial conditions for the PUMA blowdown experiments. Second, 2-Dimensional CFD models of the discharged steam jets were computed using PHOENICS, a commercially available CFD package. Finally, 3-Dimensional model of the PUMA drywell was created with the boundary conditions based on experimental measurements. The results of the 1-D and 2-D models were reported in the previous meeting. This paper discusses in detail the formulation and the results of the 3-Dimensional PHOENICS model of the PUMA drywell. It is found that the 3-D CFD solutions compared extremely well with the measured data.

Ishii, M.; NguyenLe, Q.

1999-04-20T23:59:59.000Z

366

Towards CFD Modelling of Critical Heat Flux in Fuel Rod Bundles  

SciTech Connect

The paper describes actual CFD approaches to subcooled boiling and investigates their capability to contribute to fuel assembly design. In a prototype version of the CFD code CFX a wall boiling model is implemented based on a wall heat flux partition algorithm. It can be shown, that the wall boiling model is able, to calculate the cross sectional averaged vapour volume fraction with good agreement to published measurements. The most sensitive parameters of the model are identified. Needs for more detailed experiments are established which are necessary to support further model development. Nevertheless in the paper the model is applied for the investigation of the phenomena inside a hot channel in a fuel assembly. Here the essential parameter is the critical heat flux. Although subcooled boiling represents only a preliminary state toward critical heat flux essential parameters like the swirl, the cross flow between adjacent channels and concentration regions of bubbles can be determined. By calculating the temperature at the rod surface the critical regions can be identified which might later on lead to departure from nucleate boiling and possible damage of the fuel pin. The application of up-to-date CFD with a subcooled boiling model for the simulation of a hot channel enables the comparison and the evaluation of different geometrical designs of the spacer grids of a fuel rod bundle. (authors)

Krepper, Eckhard [Forschungszentrum Rossendorf e.V., Institute of Safety Research, D-01314 Dresden, POB 510119 (Germany); Egorov, Yury [ANSYS Germany GmbH Staudenfeldweg 12, D-83624 Otterfing (Germany); Koncar, Bostjan ['Jozef Stefan' Institute Jamova 39, 1000 Ljubljana (Slovenia)

2006-07-01T23:59:59.000Z

367

Fluid velocity fluctuations in a collision of a sphere with a wall J. Rafael Pacheco,1,a)  

E-Print Network (OSTI)

, Arizona State University, Tempe, Arizona 85287, USA and Environmental Fluid Dynamics Laboratories of a combined experimental and numerical study on the fluid motion generated by the controlled approach axisymmetric. The fluid agitation of the fluid related to the kinetic energy is obtained as function of time

Pacheco, Jose Rafael

368

Complex Fluids Group  

Science Conference Proceedings (OSTI)

... applications in energy, sustainability, electronics and medicine. As these materials are typically in the fluid state during their production or end-use ...

2013-05-14T23:59:59.000Z

369

Working/Functional Fluids  

Science Conference Proceedings (OSTI)

... power cycle except that it uses an organic working fluid instead of water to allow operation at lower temperatures, including geothermal or solar ...

2012-10-05T23:59:59.000Z

370

Topical report : CFD analysis for the applicability of the natural convection shutdown heat removal test facility (NSTF) for the simulation of the VHTR RCCS.  

DOE Green Energy (OSTI)

The Very High Temperature gas cooled reactor (VHTR) is one of the GEN IV reactor concepts that have been proposed for thermochemical hydrogen production and other process-heat applications like coal gasification. The United States Department of Energy has selected the VHTR for further research and development, aiming to demonstrate emissions-free electricity and hydrogen production at a future time. One of the major safety advantages of the VHTR is the potential for passive decay heat removal by natural circulation of air in a Reactor Cavity Cooling System (RCCS). The air-side of the RCCS is very similar to the Reactor Vessel Auxiliary Cooling System (RVACS) that has been proposed for the PRISM reactor design. The design and safety analysis of the RVACS have been based on extensive analytical and experimental work performed at ANL. The Natural Convection Shutdown Heat Removal Test Facility (NSTF) at ANL that simulates at full scale the air-side of the RVACS was built to provide experimental support for the design and analysis of the PRISM RVACS system. The objective of this work is to demonstrate that the NSTF facility can be used to generate RCCS experimental data: to validate CFD and systems codes for the analysis of the RCCS; and to support the design and safety analysis of the RCCS. At this time no reference design is available for the NGNP. The General Atomics (GA) gas turbine - modular helium reactor (GT-MHR) has been used in many analyses as a starting reference design. In the GT-MHR the reactor outlet temperature is 850 C, while the target outlet reactor temperature in VHTR is 1000 C. VHTR scoping studies with a reactor outlet temperature of 1000 C have been performed at GA and INEL. Although the reactor outlet temperature in the VHTR is significantly higher than in the GT-MHR, the peak temperature in the reactor vessel (which is the heat source for the RCCS) is not drastically different. In this work, analyses have been performed using reactor vessel temperatures from the GT-MHR design, and the VHTR scoping studies. To demonstrate the applicability of the NSTF facility for full scale simulation of the RCCS the following approach was used. CFD analyses were performed of the RCCS and of its simulation at NSTF to demonstrate that: all significant fluid flow and heat transfer phenomena in the RCCS can be simulated at NSTF; and RCCS simulations at NSTF can cover the whole range of variation of the parameters describing these important phenomena in the RCCS. In CFD analyses, the simulation of turbulence is one of the most significant challenges. Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) of turbulence in large scale systems require excessive computational resources. The use of the Low-Re number k-{var_epsilon} model, which resolves the boundary layer, is computationally expensive in studies where many simulations have to be performed. In Ref. 2 it was shown that in the RCCS, heat transfer coefficient predictions of the high-Re number k-{var_epsilon} model are closer to those of the low-Re number model than those of heat transfer correlations. In this work, the standard high-Re number k-{var_epsilon} was used to simulate turbulence, and all analyses were performed with the CFD code STARCD.

Tzanos, C. P. (Nuclear Engineering Division)

2007-05-16T23:59:59.000Z

371

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

372

Supercritical Fluid Extraction  

E-Print Network (OSTI)

In supercritical fluid extraction, many options are available for achieving and controlling the desired selectivity, which is extremely sensitive to variations in pressure, temperature, and choice of solvent. The ability of supercritical fluids to vaporize relatively nonvolatile compounds at moderate temperatures can reduce the energy requirements compared to distillation and liquid extraction.

Johnston, K. P.; Flarsheim, W. M.

1984-01-01T23:59:59.000Z

373

Nonlinear pressure and temperature waves propagation in fluid-saturated rocks  

Science Conference Proceedings (OSTI)

A numerical study for the simulation of rock deformation due to nonlinear temperature and pressure waves in fluid saturated porous rock is presented. The problem of an homogeneous, thermoelastic, and isotropic fluid-saturated matrix, lying over an aquifer ... Keywords: Fluid dynamics, Geothermics, Nonlinear model, Quasi-Newton solver

M. De' Michieli Vitturi; F. Beux

2005-10-01T23:59:59.000Z

374

2D simulation of fluid-structure interaction using finite element method  

Science Conference Proceedings (OSTI)

This paper deals with pressure-based finite element analysis of fluid-structure systems considering the coupled fluid and structural dynamics. The present method uses two-dimensional fluid elements and structural line elements for the numerical simulation ... Keywords: Finite element, Galerkin weighted residual method, Newmark's predictor-corrector method, Pressure formulation, Sloshing

S. Mitra; K. P. Sinhamahapatra

2008-12-01T23:59:59.000Z

375

DISCRETE AND CONTINUOUS doi:10.3934/dcdss.2010.3.xx DYNAMICAL SYSTEMS SERIES S  

E-Print Network (OSTI)

AND DIMITRIOS MITSOTAKIS where u is the fluid velocity, ± are the fluids densities, µ± are the fluids dynamic is needed for the heavy fluid to acquire the kinetic energy and to enter into the propagation r generation by dynamic displacement of sea bed due to dip-slip faulting. Mathematics and Computers

Paris-Sud XI, Université de

376

TRACING FLUID SOURCES IN THE COSO GEOTHERMAL SYSTEM USING FLUID...  

Open Energy Info (EERE)

TRACING FLUID SOURCES IN THE COSO GEOTHERMAL SYSTEM USING FLUID-INCLUSION GAS CHEMISTRY Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: TRACING...

377

Annu. Rev. Fluid Mech. 2004. 36:281314 doi: 10.1146/annurev.fluid.36.050802.122121  

E-Print Network (OSTI)

. Dissipative and dynamical mechanisms generate a global average #12;VERTICAL MIXING, ENERGY, AND THE GENERAL on the ocean capable of generating an energy supply to the fluid. They are (a) wind, (b) heating and cooling density variations due to compressibility that have no dynamical effect. #12;VERTICAL MIXING, ENERGY

Wunsch, Carl

378

Supercritical fluid extraction  

DOE Patents (OSTI)

A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated or lipophilic crown ether or fluorinated dithiocarbamate. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

Wai, Chien M. (Moscow, ID); Laintz, Kenneth (Pullman, WA)

1994-01-01T23:59:59.000Z

379

IDENTIFYING FRACTURES AND FLUID TYPES USING FLUID INCLUSION STRATIGRAPHY |  

Open Energy Info (EERE)

IDENTIFYING FRACTURES AND FLUID TYPES USING FLUID INCLUSION STRATIGRAPHY IDENTIFYING FRACTURES AND FLUID TYPES USING FLUID INCLUSION STRATIGRAPHY Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: IDENTIFYING FRACTURES AND FLUID TYPES USING FLUID INCLUSION STRATIGRAPHY Details Activities (1) Areas (1) Regions (0) Abstract: Fluid Inclusion Stratigraphy (FIS) is a method currently being developed for use in geothermal systems to identify fractures and fluid types. This paper is the third in a series of papers on the development of FIS. Fluid inclusion gas chemistry is analyzed and plotted on well log diagrams. The working hypothesis is that select gaseous species and species ratios indicate areas of groundwater and reservoir fluid flow and reservoir seals. Previously we showed that FIS analyses identify fluid types and

380

Application of Cutting Fluids  

Science Conference Proceedings (OSTI)

...is transferred to the drill by a rotating gland and is forced directly into the cutting zone. The fluid flowing from the hole assists in chip removal. Oil-hole drills have become very popular in

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

Basic fluid system trainer  

DOE Patents (OSTI)

This invention, a trainer mounted and housed within a mobile console, is used to teach and reinforce fluid principles to students. The system trainer has two centrifugal pumps, each driven by a corresponding two-speed electric motor. The motors are controlled by motor controllers for operating the pumps to circulate the fluid stored within a supply tank through a closed system. The pumps may be connected in series or in parallel. A number of valves are also included within the system to effect different flow paths for the fluid. In addition, temperature and pressure sensing instruments are installed throughout the closed system for measuring the characteristics of the fluid, as it passes through the different valves and pumps. These measurements are indicated on a front panel mounted to the console, as a teaching aid, to allow the students to observe the characteristics of the system.

Semans, J.P.; Johnson, P.G.; LeBoeuf, R.F. Jr.; Kromka, J.A.; Goron, R.H.; Hay, G.D.

1991-04-30T23:59:59.000Z

382

Basic fluid system trainer  

DOE Patents (OSTI)

A trainer, mounted and housed within a mobile console, is used to teach and reinforce fluid principles to students. The system trainer has two centrifugal pumps, each driven by a corresponding two-speed electric motor. The motors are controlled by motor controllers for operating the pumps to circulate the fluid stored within a supply tank through a closed system. The pumps may be connected in series or in parallel. A number of valves are also included within the system to effect different flow paths for the fluid. In addition, temperature and pressure sensing instruments are installed throughout the closed system for measuring the characteristics of the fluid, as it passes through the different valves and pumps. These measurements are indicated on a front panel mounted to the console, as a teaching aid, to allow the students to observe the characteristics of the system.

Semans, Joseph P. (Uniontown, PA); Johnson, Peter G. (Pittsburgh, PA); LeBoeuf, Jr., Robert F. (Clairton, PA); Kromka, Joseph A. (Idaho Falls, ID); Goron, Ronald H. (Connellsville, PA); Hay, George D. (Venetia, PA)

1993-01-01T23:59:59.000Z

383

Phoresis in fluids  

E-Print Network (OSTI)

This paper presents a unified theory of phoretic phenomena in single-component fluids. Simple formulas are given for the phoretic velocities of small inert force-free non-Brownian particles migrating through otherwise ...

Brenner, Howard

384

Modeling HCCI using CFD and Detailed Chemistry with Experimental Validation and a Focus on CO Emissions  

DOE Green Energy (OSTI)

Multi-zone CFD simulations with detailed kinetics were used to model engine experiments performed on a diesel engine that was converted for single cylinder, HCCI operation, here using iso-octane as the fuel. The modeling goals were to validate the method (multi-zone combustion modeling) and the reaction mechanism (LLNL 857 species iso-octane), both of which performed very well. The purpose of this paper is to document the validation findings and to set the ground work for further analysis of the results by first looking at CO emissions characteristics with varying equivalence ratio.

Hessel, R; Foster, D; Aceves, S; Flowers, D; Pitz, B; Dec, J; Sjoberg, M; Babajimopoulos, A

2007-04-23T23:59:59.000Z

385

GEOTHERMAL FLUID PROPENE AND PROPANE: INDICATORS OF FLUID | Open Energy  

Open Energy Info (EERE)

FLUID PROPENE AND PROPANE: INDICATORS OF FLUID FLUID PROPENE AND PROPANE: INDICATORS OF FLUID Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: GEOTHERMAL FLUID PROPENE AND PROPANE: INDICATORS OF FLUID Details Activities (1) Areas (1) Regions (0) Abstract: The use of fluid inclusion gas analysis propene/propene ratios is investigated. Ratios of these species are affected by geothermal fluid temperature and oxidations state. Our purpose is to determine if analyses of these species in fluid inclusions these species to can be used to interpret fluid type, history, or process. Analyses were performed on drill cuttings at 20ft intervals from four Coso geothermal wells. Two wells are good producers, one has cold-water entrants in the production zone, and the fourth is a non-producer. The ratios show distinct differences between

386

CFD Simulation of 3D Flow field in a Gas Centrifuge  

SciTech Connect

A CFD method was used to study the whole flow field in a gas centrifuge. In this paper, the VSM (Vector Splitting Method) of the FVM (Finite Volume Method) was used to solve the 3D Navier-Stokes equations. An implicit second-order upwind scheme was adopted. The numerical simulation was successfully performed on a parallel cluster computer and a convergence result was obtained. The simulation shows that: in the withdrawal chamber, a strong detached shock wave is formed in front of the scoop; as the radial position increases, the shock becomes stronger and the distance to scoop front surface is smaller. An oblique shock forms in the clearance between the scoop and the centrifuge wall; behind the shock-wave, the radially-inward motion of gas is induced because of the imbalance of the pressure gradient and the centrifugal force. In the separation chamber, a countercurrent is introduced. This indicates that CFD method can be used to study the complex three-dimensional flow field of gas centrifuges. (authors)

Dongjun Jiang; Shi Zeng [Tsinghua University, Beijing, 100084 (China)

2006-07-01T23:59:59.000Z

387

Development of a Consensus Standard for Verification and Validation of Nuclear System Thermal-Fluids Software  

SciTech Connect

With the resurgence of nuclear power and increased interest in advanced nuclear reactors as an option to supply abundant energy without the associated greenhouse gas emissions of the more conventional fossil fuel energy sources, there is a need to establish internationally recognized standards for the verification and validation (V&V) of software used to calculate the thermal-hydraulic behavior of advanced reactor designs for both normal operation and hypothetical accident conditions. To address this need, ASME (American Society of Mechanical Engineers) Standards and Certification has established the V&V 30 Committee, under the jurisdiction of the V&V Standards Committee, to develop a consensus standard for verification and validation of software used for design and analysis of advanced reactor systems. The initial focus of this committee will be on the V&V of system analysis and computational fluid dynamics (CFD) software for nuclear applications. To limit the scope of the effort, the committee will further limit its focus to software to be used in the licensing of High-Temperature Gas-Cooled Reactors. In this framework, the Standard should conform to Nuclear Regulatory Commission (NRC) and other regulatory practices, procedures and methods for licensing of nuclear power plants as embodied in the United States (U.S.) Code of Federal Regulations and other pertinent documents such as Regulatory Guide 1.203, 'Transient and Accident Analysis Methods' and NUREG-0800, 'NRC Standard Review Plan'. In addition, the Standard should be consistent with applicable sections of ASME NQA-1-2008 'Quality Assurance Requirements for Nuclear Facility Applications (QA)'. This paper describes the general requirements for the proposed V&V 30 Standard, which includes; (a) applicable NRC and other regulatory requirements for defining the operational and accident domain of a nuclear system that must be considered if the system is to be licensed, (b) the corresponding calculation domain of the software that should encompass the nuclear operational and accident domain to be used to study the system behavior for licensing purposes, (c) the definition of the scaled experimental data set required to provide the basis for validating the software, (d) the ensemble of experimental data sets required to populate the validation matrix for the software in question, and (e) the practices and procedures to be used when applying a validation standard. Although this initial effort will focus on software for licensing of High-Temperature Gas-Cooled Reactors, it is anticipated that the practices and procedures developed for this Standard can eventually be extended to other nuclear and non-nuclear applications.

Edwin A. Harvego; Richard R. Schultz; Ryan L. Crane

2011-12-01T23:59:59.000Z

388

Boiler using combustible fluid  

DOE Patents (OSTI)

A fluid fuel boiler is described comprising a combustion chamber, a cover on the combustion chamber having an opening for introducing a combustion-supporting gaseous fluid through said openings, means to impart rotation to the gaseous fluid about an axis of the combustion chamber, a burner for introducing a fluid fuel into the chamber mixed with the gaseous fluid for combustion thereof, the cover having a generally frustro-conical configuration diverging from the opening toward the interior of the chamber at an angle of between 15/sup 0/ and 55/sup 0/; means defining said combustion chamber having means defining a plurality of axial hot gas flow paths from a downstream portion of the combustion chamber to flow hot gases into an upstream portion of the combustion chamber, and means for diverting some of the hot gas flow along paths in a direction circumferentially of the combustion chamber, with the latter paths being immersed in the water flow path thereby to improve heat transfer and terminating in a gas outlet, the combustion chamber comprising at least one modular element, joined axially to the frustro-conical cover and coaxial therewith. The modular element comprises an inner ring and means of defining the circumferential, radial, and spiral flow paths of the hot gases.

Baumgartner, H.; Meier, J.G.

1974-07-03T23:59:59.000Z

389

Universal fluid droplet ejector  

DOE Patents (OSTI)

A droplet generator comprises a fluid reservoir having a side wall made of glass or quartz, and an end cap made from a silicon plate. The end cap contains a micromachined aperture through which the fluid is ejected. The side wall is thermally fused to the end cap, and no adhesive is necessary. This means that the fluid only comes into contact with the side wall and the end cap, both of which are chemically inert. Amplitudes of drive pulses received by reservoir determine the horizontal displacements of droplets relative to the ejection aperture. The drive pulses are varied such that the dropper generates a two-dimensional array of vertically-falling droplets. Vertical and horizontal interdroplet spacings may be varied in real time. Applications include droplet analysis experiments such as Millikan fractional charge searches and aerosol characterization, as well as material deposition applications.

Lee, Eric R. (Redwood City, CA); Perl, Martin L. (Palo Alto, CA)

1999-08-24T23:59:59.000Z

390

Full Life Wind Turbine Gearbox Lubricating Fluids  

DOE Green Energy (OSTI)

Industrial gear box lubricants typically are hydrocarbon based mineral oils with considerable amounts of additives to overcome the lack of base fluid properties like wear protection, oxidation stability, load carrying capacity, low temperature solidification and drop of viscosity at higher temperatures. For today's wind turbine gearboxes, the requirements are more severe and synthetic hydrocarbon oils are used to improve on this, but all such hydrocarbon based lubricants require significant amounts of Extreme Pressure (EP) additives to meet performance requirements. Perfluoropolyether (PFPE) fluids provide load carrying capacity as an inherent property. During the course of the project with the main tasks of 'Establish a Benchmark', 'Lubricant Evaluation', 'Full Scale Gearbox Trial' and 'Economic Evaluation', the PAO Reference oil exhibited significant changes after laboratory gear testing, in service operation in the field and full scale gearbox trial. Four hydrocarbon base oils were selected for comparison in the benchmarking exercise and showed variation with respect to meeting the requirements for the laboratory micro-pitting tests, while the PFPE fluid exceeded the requirements even with the material taken after the full scale gear box trial. This is remarkable for a lubricant without EP additives. Laboratory bearing tests performed on the PFPE fluids before and after the full scale gear box trial showed the results met requirements for the industry standard. The PFPE fluid successfully completed the full scale gear box test program which included baseline and progressive staged load testing. The evaluation of gears showed no micro-pitting or objectionable wear. By the final stage, lubricant film thickness had been reduced to just 21% of its original value, this was by design and resulted in a lambda ratio of well below 1. This test design scenario of a low lambda ratio is a very undesirable lubrication condition for real world but creates the ability to test the lubricating fluids performance under the most extreme conditions. The PAO Reference oil also passed its testing without any noticeable deterioration of the gear surface. However the PAO Reference oil was replaced midway through the progressive loading, as the lubricant was burned in an attempt to raise the sump temperature to the same levels as for the PFPE. Both materials experienced a decrease of viscosity during their respective run times. The viscosity index decreased for the PAO there while there was a slight increase for the PFPE. FZG laboratory gear tests and measurements of the drive motor's current during the full scale gear box trial were made to characterize the relative efficiency between the PFPE fluid and the PAO Reference oil. In the FZG laboratory efficiency test, the PFPE fluids show much higher churning losses due to their higher viscosity and density. The analysis seems to show that the efficiency correlates better to dynamic viscosity than any other of the measured metrics such as film thickness. In load stages where the load, speed and temperature are similar, the PFPE fluid has a greater film thickness and theoretical gear protection, but requires a larger current for the drive motor than the PAO. However in load stages where the film thickness is the same, the PFPE fluid's reduced dynamic viscosity gives it a slight efficiency advantage relative to the PAO reference oil. Ultimately, many factors such as temperature, rotational speed, and fluid viscosity combine in a complex fashion to influence the results. However, the PFPE's much lower change of viscosity with respect to temperature, allows variations in designing an optimum viscosity to balance efficiency versus gear protection. Economic analysis was done using Cost of Energy calculations. The results vary from 5.3% for a 'Likely Case' to 16.8% for a 'Best Case' scenario as potential cost improvement by using PFPE as the gearbox lubricating fluid. It is important to note the largest portion of savings comes in Levelized Replacement Cost, which is dictated by the assumption on gearb

Lutz, Glenn A.; Jungk, Manfred; Bryant, Jonathan J.; Lauer, Rebecca S.; Chobot, Anthony; Mayer, Tyler; Palmer, Shane; Kauffman, Robert E.

2012-02-28T23:59:59.000Z

391

Adiabatic and entropy perturbations with interacting fluids and fields  

E-Print Network (OSTI)

We develop a gauge-invariant formalism for the study of density perturbations in a Friedmann-Robertson-Walker universe with multiple interacting fluids and/or scalar fields. We show how N scalar fields may be described by N kinetic fluids (with maximally stiff equation of state) interacting with a non-dynamical potential (with vacuum equation of state). We split generic perturbations into adiabatic and entropic parts, and give the coupled first-order evolution equations on all scales, including energy and momentum exchange. We identify the non-adiabatic effects on large scales, and define adiabatic initial conditions in the presence of multiple fluids and fields.

Karim A. Malik; David Wands

2004-11-25T23:59:59.000Z

392

Unsteady Flow Visualization at Part-Load Conditions of a Radial Diffuser Pump: by PIV and CFD  

Science Conference Proceedings (OSTI)

The present study provides flow visualization on complex internal flows in a radial diffuser pump under part-load conditions by using the three-dimensional Navier-Stokes code CFX-10 with Detached Eddy Simulation (DES) turbulence model. Particle Image ... Keywords: CFD, Flow separation, Flow visualization, PIV, Radial pump

J. Feng; F.-K. Benra; H. J. Dohmen

2009-01-01T23:59:59.000Z

393

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 ...

394

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

395

RayleighTaylor and RichtmyerMeshkov instabilities for fluids with a finite density contrast  

E-Print Network (OSTI)

of the fluid energy concentrates in the large­scale coherent motion. The dynamics of the coherent structure­scale coherent structure, the dynamics of small­scale structures, and the cascades of energy should be understood dynamics [3,4]. The singular aspects of the interface evolution (the generation of vorticity and secondary

New York at Stoney Brook, State University of

396

J. Fluid Mech. (2005), vol. 529, pp. 97116. c 2005 Cambridge University Press doi:10.1017/S0022112004003271 Printed in the United Kingdom  

E-Print Network (OSTI)

energy transfers. 1. Introduction It is well-established in the theory of geophysical fluid dynamics for this is the natural trend of two-dimensional dynamics to generate organized structures, namely coherent shears. & Lifshitz, E. 1971 M´ecanique des Fluides. ´Editions Mir. Lapeyre, G., Hua, B. L. & Klein, P. 2001 Dynamics

Dubos, Thomas

397

Experimental Properties of Fluids Group  

Science Conference Proceedings (OSTI)

The Experimental Properties of Fluids Group, Physical and Chemical Properties Division of the Chemical Science and Technology Laboratory, NIST.

2000-07-24T23:59:59.000Z

398

Supercritical fluid reverse micelle systems  

DOE Patents (OSTI)

of 1 ) United States Patent 5,158,704 Fulton ,   et al. October 27, 1992 Supercritical fluid reverse micelle systems

Fulton, John L. (Richland, WA); Smith, Richard D. (Richland, WA)

1992-01-01T23:59:59.000Z

399

Production of MHD fluid  

SciTech Connect

A hot gaseous fluid of low ash content, suitable for use in open-cycle MHD (magnetohydrodynamic) power generation, is produced by means of a three-stage process comprising (1) partial combustion of a fossil fuel to produce a hot gaseous product comprising CO.sub.2 CO, and H.sub.2 O, (2) reformation of the gaseous product from stage (1) by means of a fluidized char bed, whereby CO.sub.2 and H.sub.2 O are converted to CO and H.sub.2, and (3) combustion of CO and H.sub.2 from stage (2) to produce a low ash-content fluid (flue gas) comprising CO.sub.2 and H.sub.2 O and having a temperature of about 4000.degree. to 5000.degree.F.

Lacey, James J. (Library, PA); Kurtzrock, Roy C. (Bethel Park, PA); Bienstock, Daniel (Pittsburgh, PA)

1976-08-24T23:59:59.000Z

400

Downhole Fluid Analyzer Development  

SciTech Connect

A novel fiber optic downhole fluid analyzer has been developed for operation in production wells. This device will allow real-time determination of the oil, gas and water fractions of fluids from different zones in a multizone or multilateral completion environment. The device uses near infrared spectroscopy and induced fluorescence measurement to unambiguously determine the oil, water and gas concentrations at all but the highest water cuts. The only downhole components of the system are the fiber optic cable and windows. All of the active components--light sources, sensors, detection electronics and software--will be located at the surface, and will be able to operate multiple downhole probes. Laboratory testing has demonstrated that the sensor can accurately determine oil, water and gas fractions with a less than 5 percent standard error. Once installed in an intelligent completion, this sensor will give the operating company timely information about the fluids arising from various zones or multilaterals in a complex completion pattern, allowing informed decisions to be made on controlling production. The research and development tasks are discussed along with a market analysis.

Bill Turner

2006-11-28T23:59:59.000Z

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

Viscous fluid sheets  

E-Print Network (OSTI)

We present a general theory for the dynamics of thin viscous sheets. Employing concepts from differential geometry and tensor calculus we derive the governing equations in terms of a coordinate system that moves with the ...

Savva, Nikos

2007-01-01T23:59:59.000Z

402

Fluid bed material transfer method  

DOE Patents (OSTI)

A fluidized bed apparatus comprising a pair of separated fluid bed enclosures, each enclosing a fluid bed carried on an air distributor plate supplied with fluidizing air from below the plate. At least one equalizing duct extending through sidewalls of both fluid bed enclosures and flexibly engaged therewith to communicate the fluid beds with each other. The equalizing duct being surrounded by insulation which is in turn encased by an outer duct having expansion means and being fixed between the sidewalls of the fluid bed enclosures.

Pinske, Jr., Edward E. (Akron, OH)

1994-01-01T23:59:59.000Z

403

Imperfect fluids, Lorentz violations, and Finsler cosmology  

Science Conference Proceedings (OSTI)

We construct a cosmological toy model based on a Finslerian structure of space-time. In particular, we are interested in a specific Finslerian Lorentz violating theory based on a curved version of Cohen and Glashow's very special relativity. The osculation of a Finslerian manifold to a Riemannian manifold leads to the limit of relativistic cosmology, for a specified observer. A modified flat Friedmann-Robertson-Walker cosmology is produced. The analogue of a zero energy particle unfolds some special properties of the dynamics. The kinematical equations of motion are affected by local anisotropies. Seeds of Lorentz violations may trigger density inhomogeneities to the cosmological fluid.

Kouretsis, A. P.; Stathakopoulos, M.; Stavrinos, P. C. [Section of Astrophysics, Astronomy and Mechanics, Department of Physics, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); 1 Anastasiou Genadiou Street, 11474, Athens (Greece); Department of Mathematics, University of Athens, 15784 Greece (Greece)

2010-09-15T23:59:59.000Z

404

Sounding liquids: Automatic sound synthesis from fluid simulation  

Science Conference Proceedings (OSTI)

We present a novel approach for synthesizing liquid sounds directly from visual simulation of fluid dynamics. Our approach takes advantage of the fact that the sound generated by liquid is mainly due to the vibration of resonating bubbles in the medium ... Keywords: Sound simulation, liquids

William Moss; Hengchin Yeh; Jeong-Mo Hong; Ming C. Lin; Dinesh Manocha

2010-06-01T23:59:59.000Z

405

Proposal of a critical test of the Navier-Stokes-Fourier paradigm for compressible fluid continua  

E-Print Network (OSTI)

A critical, albeit simple experimental and/or molecular-dynamic (MD) simulation test is proposed whose outcome would, in principle, establish the viability of the Navier-Stokes-Fourier (NSF) equations for compressible fluid ...

Brenner, Howard

406

Analytic fluid theory of beam spiraling in high-intensity cyclotrons  

E-Print Network (OSTI)

Using a two-dimensional fluid description, we investigate the nonlinear radial-longitudinal dynamics of intense beams in isochronous cyclotrons in the nonrelativistic limit. With a multiscale analysis separating the time ...

Cerfon, A. J.

407

Drop Formation and Breakup of Low Viscosity Elastic Fluids: Effects of Molecular Weight and Concentration  

E-Print Network (OSTI)

The dynamics of drop formation and pinch-off have been investigated for a series of low viscosity elastic fluids possessing similar shear viscosities, but differing substantially in elastic properties. On initial approach ...

Tirtaatmadja, Viyada

2007-01-23T23:59:59.000Z

408

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

409

Data:3f3cfd22-0dfd-4594-8182-12f67aeb7991 | Open Energy Information  

Open Energy Info (EERE)

cfd22-0dfd-4594-8182-12f67aeb7991 cfd22-0dfd-4594-8182-12f67aeb7991 No revision has been approved for this page. It is currently under review by our subject matter experts. Jump to: navigation, search Loading... 1. Basic Information 2. Demand 3. Energy << Previous 1 2 3 Next >> Basic Information Utility name: Otter Tail Power Co Effective date: 2011/10/01 End date if known: Rate name: Large General Service - Time of Day TRANSMISSION Shoulder Sector: Commercial Description: RULES AND REGULATIONS: Terms and conditions of this electric rate schedule and the General Rules and Regulations govern use of this service. APPLICATION OF SCHEDULE: This schedule is applicable to nonresidential Customers with a measured Demand of at least 80 kW within the most recent 12 months. Source or reference: https://www.otpco.com/RatesPricing/Documents/PDF/MN/MN_10.05.pdf

410

GPA a tool for fluid scalability analysis of massively parallel systems  

E-Print Network (OSTI)

analysis, GPA first generates an abstract representation of the system of ODEs and then dynamically. Hayden, and J. T. Bradley, "Fluid Analysis of Energy Consumption using Rewards in Massively ParallelGPA ­ a tool for fluid scalability analysis of massively parallel systems Anton Stefanek Richard A

Imperial College, London

411

J . Fluid Mech. (1981),vol. 106, pp. 103-130 Printed in Great Britairz  

E-Print Network (OSTI)

small enough, fluid flow generated by the sheet produces forces on the sheet that affect the energy)generating forces in the body of the flow,e.g. extracting energyfromorinjecting energy into the flow work on geo-, astro- and cosmological fluid dynamics is also important pure research which may have

Hunt, Julian

412

J . Fluid Mech. (1989),vol. 207, p p . 133-152 Printed in Great Britain  

E-Print Network (OSTI)

with a fixed randomly generated velocity field. At infinite resolution, the modified dynamics with energyJ . Fluid Mech. (1989),vol. 207, p p . 133-152 Printed in Great Britain 133 Extremal energy) Certain modifications of the Euler equations of fluid motion lead to systems in which the energy decays

Vallis, Geoff

413

J . Fluid Mech. (1990),vol. 213, pp. 54S571 Printed in Great Britain  

E-Print Network (OSTI)

the modified dynamics, (1.4) %l-+5*Vq = 0, at #12;Stable states of inviscid fluids 551 also conserves q on all particles. If the 8 can be chosen at each moment in such a way that the total energy of the fluid must a smoothly distributed, randomly generated vorticity field. 4.1. Energy minimization :Kelvin's sponge Kelvin

Vallis, Geoff

414

It's The Fluids SEG Honorary Lecture  

E-Print Network (OSTI)

T.P. Water Butane CO2 #12;Fluid ­ Density 800 1000 1200FluidDensity[kg/m3] Brine CO2 0 2 4 6 8 10 0 200 400 600 Fluid Pressure [MPa] FluidDensity[kg/m Butane CO2 #12;Fluid ­ Modulus 2000 2500 3000 FluidModulus[MPa] Brine 0 2 4 6 8 10 0 500 1000 1500 Fluid Pressure [MPa] FluidModulus[MPa] Butane CO2 #12;GENERAL PHASE

415

Encapsulated Nanoparticle Synthesis and Characterization for Improved Storage Fluids: Preprint  

DOE Green Energy (OSTI)

Nanoparticles are typically composed of 50--500 atoms and exhibit properties that are significantly different from the properties of larger, macroscale particles that have the same composition. The addition of these particles to traditional fluids may improve the fluids' thermophysical properties. As an example, the addition of a nanoparticle or set of nanoparticles to a storage fluid may double its heat capacity. This increase in heat capacity would allow a sensible thermal energy storage system to store the same amount of thermal energy in half the amount of storage fluid. The benefit is lower costs for the storage fluid and the storage tanks, resulting in lower-cost electricity. The goal of this long-term research is to create a new class of fluids that enable concentrating solar power plants to operate with greater efficiency and lower electricity costs. Initial research on this topic developed molecular dynamic models that predicted the energy states and transition temperatures for these particles. Recent research has extended the modeling work, along with initiating the synthesis and characterization of bare metal nanoparticles and metal nanoparticles that are encapsulated with inert silica coatings. These particles possess properties that make them excellent candidates for enhancing the heat capacity of storage fluids.

Glatzmaier, G. C.; Pradhan, S.; Kang, J.; Curtis, C.; Blake, D.

2010-10-01T23:59:59.000Z

416

Inertial Particle Dynamics in a Hurricane  

E-Print Network (OSTI)

The motion of inertial (i.e., finite-size) particles is analyzed in a three-dimensional unsteady simulation of Hurricane Isabel. As established recently, the long-term dynamics of inertial particles in a fluid is governed ...

Sapsis, Themistoklis

417

Volatiles in hydrothermal fluids- A mass spectrometric study of fluid  

Open Energy Info (EERE)

Volatiles in hydrothermal fluids- A mass spectrometric study of fluid Volatiles in hydrothermal fluids- A mass spectrometric study of fluid inclusions from active geothermal systems Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Volatiles in hydrothermal fluids- A mass spectrometric study of fluid inclusions from active geothermal systems Details Activities (4) Areas (4) Regions (0) Abstract: A system for analysis of inclusion gas contents based upon quadrupole mass spectrometry has been designed, assembled and tested during the first 7 months of funding. The system is currently being tested and calibrated using inclusions with known gas contents from active geothermal systems. Analyses are in progress on inclusions from the Salton Sea, Valles Caldera, Geysers, and Coso geothermal systems. Author(s): Mckibben, M. A.

418

Case study: visual analysis of complex, time-dependent simulation results of a diesel exhaust system  

Science Conference Proceedings (OSTI)

In previous work we have presented visualization techniques that provide engineers with a high degree of interactivity and flexibility for analyzing large, time-dependent, and high-dimensional data sets resulting from CFD (computational fluid dynamics) ...

Helmut Doleisch; Michael Mayer; Martin Gasser; Roland Wanker; Helwig Hauser

2004-05-01T23:59:59.000Z

419

The Net Environmental Effects of Carbon Dioxide Reduction Policies  

E-Print Network (OSTI)

............................................................................................................3 Clean Coal Technology Production of Methane from Hydrates and Unconventional Sources Biofuels production: clean coal, methane production from unconventional sources, biofuels, and renewable energy, including computational fluid dynamics (CFD) modeling and fluidized bed coal-gasification processes

420

Shock capturing with PDE-based artificial viscosity for an adaptive, higher-order discontinuous Galerkin finite element method  

E-Print Network (OSTI)

The accurate simulation of supersonic and hypersonic flows is well suited to higher-order (p > 1), adaptive computational fluid dynamics (CFD). Since these cases involve flow velocities greater than the speed of sound, an ...

Barter, Garrett E. (Garrett Ehud), 1979-

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "fluid dynamics cfd" 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

Shock Capturing with PDE-Based Artificial Viscosity for an Adaptive, Higher-Order Discontinuous Galerkin Finite Element Method  

E-Print Network (OSTI)

The accurate simulation of supersonic and hypersonic flows is well suited to higher-order (p > 1), adaptive computational fluid dynamics (CFD). Since these cases involve flow velocities greater than the speed of sound, an ...

Barter, Garrett Ehud

422

Benchmark calculations with an unstructured grid flow solver on a SIMD computer  

Science Conference Proceedings (OSTI)

An unstructured grid flow solver was implemented on a massively parallel computer, and benchmark computations were performed. The solver was a two-dimensional computational fluid dynamics (CFD) code that performs first-order, steady-state solutions of ...

J. S. Clary; G. A. Howell; Jr. S. L. Karman

1989-08-01T23:59:59.000Z

423

CX-002296: Categorical Exclusion Determination | Department of...  

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

Computational Fluid Dynamics (CFD) Analysis Density Separator of an Air-Based Density Separator CX(s) Applied: B3.6 Date: 05182010 Location(s): Lexington, Kentucky...

424

Simulating the effects of structural parameters on the hydraulic performances of venturi tube  

Science Conference Proceedings (OSTI)

The effects of Venturi structural parameters on its hydraulic performance were studied, which provided theoretical basis for the design of Venturi injector. With an inlet diameter of 50 mm, based on the method of computational fluid dynamics (CFD), the ...

Yanqi Sun; Wenquan Niu

2012-01-01T23:59:59.000Z

425

A study on the use of multiple surrogate models in valve design  

Science Conference Proceedings (OSTI)

Nowadays, the use of computational fluid dynamics (CFD) in the design of valves is very common. Despite the continuing growth of computing capability, the computational cost of complex three-dimensional CFD analysis of butterfly valve maintains high, ... Keywords: DOE, butterfly valve, error analysis, multiple surrogate models, optimization

Xue Guan Song; Jeong Ju Choi; Joon-Ho Lee; Young Chul Park

2011-09-01T23:59:59.000Z

426

Hydrodynamic modes in a confined granular fluid  

E-Print Network (OSTI)

Confined granular fluids, placed in a shallow box that is vibrated vertically, can achieve homogeneous stationary states thanks to energy injection mechanisms that take place throughout the system. These states can be stable even at high densities and inelasticities allowing for a detailed analysis of the hydrodynamic modes that govern the dynamics of granular fluids. Analyzing the decay of the time correlation functions it is shown that there is a crossover between a quasielastic regime in which energy evolves as a slow mode, to a inelastic regime, with energy slaved to the other conserved fields. The two regimes have well differentiated transport properties and, in the inelastic regime, the dynamics can be described by a reduced hydrodynamics with modified longitudinal viscosity and sound speed. The crossover between the two regimes takes place at a wavevector that is proportional to the inelasticity. A two dimensional granular model, with collisions that mimic the energy transfers that take place in a confined system is studied by means of microscopic simulations. The results show excellent agreement with the theoretical framework and allows the validation of hydrodynamic-like models.

Ricardo Brito; Dino Risso; Rodrigo Soto

2013-01-17T23:59:59.000Z

427

Ultrasonic fluid quality sensor system  

SciTech Connect

A system for determining the composition of a multiple-component fluid and for determining linear flow comprising at least one sing-around circuit that determines the velocity of a signal in the multiple-component fluid and that is correlatable to a database for the multiple-component fluid. A system for determining flow uses two of the inventive circuits, one of which is set at an angle that is not perpendicular to the direction of flow.

Gomm, Tyler J. (Meridian, ID); Kraft, Nancy C. (Idaho Falls, ID); Phelps, Larry D. (Pocatello, ID); Taylor, Steven C. (Idaho Falls, ID)

2002-10-08T23:59:59.000Z

428

Ultrasonic Fluid Quality Sensor System  

DOE Patents (OSTI)

A system for determining the composition of a multiple-component fluid and for determining linear flow comprising at least one sing-around circuit that determines the velocity of a signal in the multiple-component fluid and that is correlatable to a database for the multiple-component fluid. A system for determining flow uses two of the inventive circuits, one of which is set at an angle that is not perpendicular to the direction of flow.

Gomm, Tyler J. (Meridian, ID); Kraft, Nancy C. (Idaho Falls, ID); Phelps, Larry D. (Pocatello, ID); Taylor, Steven C. (Idaho Falls, ID)

2003-10-21T23:59:59.000Z

429

CFD Simulation and Analysis of the Combined Evaporative Cooling and Radiant Ceiling Air-conditioning System  

E-Print Network (OSTI)

Due to such disadvantages as large air duct and high energy consumption of the current all- outdoor air evaporative cooling systems used in the dry region of Northwest China, as well as the superiority of the ceiling cooling system in improving thermal comfort and saving energy, a combined system is presented in this paper. It combines an evaporative cooling system with ceiling cooling, in which the evaporative cooling system handles the entire latent load and one part of the sensible loads, and the ceiling cooling system deals with the other part of sensible loads in the air-conditioned zone, so that the condensation on radiant panels and the insufficiency of cooling capacity can be avoided. The cooling water at 18? used in the cooling coils of ceiling cooling system can be ground water, tap water or the cooled water from cooling towers in the summer. This new air-conditioning system and existing all- outdoor air evaporative cooling system are applied to a project in the city of Lanzhou. Energy consumption analysis of the building is carried out using the energy consumption code. Velocity and temperature distribution in the air-conditioned zone is computed using CFD. According to the results, the energy consumption and indoor human thermal comfort of both systems are then compared. It is concluded that the new system occupies less building space, reduces energy consumption, improves indoor human thermal comfort and saves initial investment.

Xiang, H.; Yinming, L.; Junmei, W.

2006-01-01T23:59:59.000Z

430

MOLTEN SALT HEAT TRANSFER FLUID  

thermal energy storage tanks Sandia has developed a heat transfer fluid (HTF) for use at elevated temperatures that has a lower freezing point

431

Fracturing Fluid Characterization Facility  

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

Documentation Page Documentation Page 1. Report No. DE - FC 21 - 92MC29077 2. 3. Recipient's Accession No. 5. Report Date August 31, 2000 4. Title and Subtitle Fracturing Fluid Characterization Facility 6. 7. Author(s) The University of Oklahoma 8. Performing Organization Rept. No. 10. Project/Task/Work Unit No. 9. Performing Organization Name and Address The University of Oklahoma Sarkeys Energy Center T301 100 E Boyd St Norman, OK 73019 11. Contract (C) or Grant (G) No. DOE:DE FC21 92 MC29077 13. Type of Report & Period Covered Final Report 09 30 92 - 03 31 00 12. Sponsoring Organization Name and Address US Dept of Energy - FETL 3610 Collins Ferry Road Morgantown, WV 26505 14. 15. Supplementary Notes Several technical papers were prepared and presented at various Society of Petroleum Engineers Conferences and US

432

Newtonian and Post Newtonian Expansionfree Fluid Evolution in f(R) Gravity  

E-Print Network (OSTI)

We consider a collapsing sphere and discuss its evolution under the vanishing expansion scalar in the framework of $f(R)$ gravity. The fluid is assumed to be locally anisotropic which evolves adiabatically. To study the dynamics of the collapsing fluid, Newtonian and post Newtonian regimes are taken into account. The field equations are investigated for a well-known $f(R)$ model of the form $R+\\delta R^2$ admitting Schwarzschild solution. The perturbation scheme is used on the dynamical equations to explore the instability conditions of expansionfree fluid evolution. We conclude that instability conditions depend upon pressure anisotropy, energy density and some constraints arising from this theory.

M. Sharif; H. Rizwana Kausar

2011-11-11T23:59:59.000Z

433

Fluid equations in the presence of electron cyclotron current drive  

Science Conference Proceedings (OSTI)

Two-fluid equations, which include the physics imparted by an externally applied radiofrequency source near electron cyclotron resonance, are derived in their extended magnetohydrodynamic forms using the formalism of Hegna and Callen [Phys. Plasmas 16, 112501 (2009)]. The equations are compatible with the closed fluid/drift-kinetic model developed by Ramos [Phys. Plasmas 17, 082502 (2010); 18, 102506 (2011)] for fusion-relevant regimes with low collisionality and slow dynamics, and they facilitate the development of advanced computational models for electron cyclotron current drive-induced suppression of neoclassical tearing modes.

Jenkins, Thomas G.; Kruger, Scott E. [Tech-X Corporation, 5621 Arapahoe Avenue, Boulder, Colorado 80303 (United States)

2012-12-15T23:59:59.000Z

434

Parallel adaptive fluid-structure interaction simulation of explosions impacting on building structures  

SciTech Connect

We pursue a level set approach to couple an Eulerian shock-capturing fluid solver with space-time refinement to an explicit solid dynamics solver for large deformations and fracture. The coupling algorithms considering recursively finer fluid time steps as well as overlapping solver updates are discussed in detail. Our ideas are implemented in the AMROC adaptive fluid solver framework and are used for effective fluid-structure coupling to the general purpose solid dynamics code DYNA3D. Beside simulations verifying the coupled fluid-structure solver and assessing its parallel scalability, the detailed structural analysis of a reinforced concrete column under blast loading and the simulation of a prototypical blast explosion in a realistic multistory building are presented.

Deiterding, Ralf [ORNL; Wood, Stephen L [University of Tennessee, Knoxville (UTK)

2013-01-01T23:59:59.000Z