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1

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

E-Print Network [OSTI]

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...

Longmire, Pamela

2009-05-15T23:59:59.000Z

2

Computational Fluid Dynamics (CFD) Modeling for High Rate Pulverized Coal Injection (PCI) into the Blast Furnace  

SciTech Connect (OSTI)

Pulverized coal injection (PCI) into the blast furnace (BF) has been recognized as an effective way to decrease the coke and total energy consumption along with minimization of environmental impacts. However, increasing the amount of coal injected into the BF is currently limited by the lack of knowledge of some issues related to the process. It is therefore important to understand the complex physical and chemical phenomena in the PCI process. Due to the difficulty in attaining trus BF measurements, Computational fluid dynamics (CFD) modeling has been identified as a useful technology to provide such knowledge. CFD simulation is powerful for providing detailed information on flow properties and performing parametric studies for process design and optimization. In this project, comprehensive 3-D CFD models have been developed to simulate the PCI process under actual furnace conditions. These models provide raceway size and flow property distributions. The results have provided guidance for optimizing the PCI process.

Dr. Chenn Zhou

2008-10-15T23:59:59.000Z

3

Designing high power targets with computational fluid dynamics (CFD)  

SciTech Connect (OSTI)

High power liquid hydrogen (LH2) targets, up to 850 W, have been widely used at Jefferson Lab for the 6 GeV physics program. The typical luminosity loss of a 20 cm long LH2 target was 20% for a beam current of 100 ?A rastered on a square of side 2 mm on the target. The 35 cm long, 2500 W LH2 target for the Qweak experiment had a luminosity loss of 0.8% at 180 ?A beam rastered on a square of side 4 mm at the target. The Qweak target was the highest power liquid hydrogen target in the world and with the lowest noise figure. The Qweak target was the first one designed with CFD at Jefferson Lab. A CFD facility is being established at Jefferson Lab to design, build and test a new generation of low noise high power targets.

Covrig, S. D. [Thomas Jefferson National Laboratory, Newport News, VA 23606 (United States)

2013-11-07T23:59:59.000Z

4

With faster processors and better numerical techniques, computational fluid dynamics (CFD) tools have revolutionized engineering design and optimization--  

E-Print Network [OSTI]

With faster processors and better numerical techniques, computational fluid dynamics (CFD) tools have revolutionized engineering design and optimization-- limiting expensive experimentation and Engineering Division (GED) at Southwest Research Institute® (SwRI®) has extensive experience and capabilities

Chapman, Clark R.

5

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

6

Three-dimensional Computational Fluid Dynamics (CFD) modeling of dry spent nuclear fuel storage canisters  

SciTech Connect (OSTI)

One of the interim storage configurations being considered for aluminum-clad foreign research reactor fuel, such as the Material and Testing Reactor (MTR) design, is in a dry storage facility. To support design studies of storage options, a computational and experimental program was conducted at the Savannah River Site (SRS). The objective was to develop computational fluid dynamics (CFD) models which would be benchmarked using data obtained from a full scale heat transfer experiment conducted in the SRS Experimental Thermal Fluids Laboratory. The current work documents the CFD approach and presents comparison of results with experimental data. CFDS-FLOW3D (version 3.3) CFD code has been used to model the 3-dimensional convective velocity and temperature distributions within a single dry storage canister of MTR fuel elements. For the present analysis, the Boussinesq approximation was used for the consideration of buoyancy-driven natural convection. Comparison of the CFD code can be used to predict reasonably accurate flow and thermal behavior of a typical foreign research reactor fuel stored in a dry storage facility.

Lee, S.Y.

1997-06-01T23:59:59.000Z

7

Application of computational fluid dynamics (CFD) to nuclear applications.  

SciTech Connect (OSTI)

Detailed analysis of a quarter channel was performed using VIPRE and CFX. Results show that VIPRE and CFX agree closely in both cross-sectionally averaged axial temperature and cross-sectionally averaged axial velocity profiles. Detailed temperature distributions in the radial direction over 1mm from the clad surface towards the center of the channel were calculated using CFX, showing significant local variation. This information can be used for example, to determine if this temperature will lead to bubble nucleation. Quarter subassembly calculations were made with both VIPRE and STAR-CD. Comparison between the solutions show that the two codes yield very similar solutions under comparable conditions. However, the STAR-CD CFD calculation provides the analyst with much more detailed flow and temperature distributions than can be predicted by a one-dimensional code such as VIPRE. In addition, a 60 million cell one-eighth reactor core calculation was made using STAR-CD. This analysis showed the importance of accurately predicting the flow and temperature fields in all assemblies simultaneously with modern parallel processing technology, practical turnaround for these types of calculation can be obtained.

Brewster, R. A.; Jonnavithula, S.; Rizwan-Uddin; Rock, D. T.; Weber, D. P.; Wei, T. Y. C.

1999-02-08T23:59:59.000Z

8

European Conference on Computational Fluid Dynamics ECCOMAS CFD 2006  

E-Print Network [OSTI]

aluminum tubes due to the passage of ethylene-oxygen detonation waves is presented. 1 INTRODUCTION The Center for Simulation of Dynamic Response of Materials at the California In- stitute of Technology has reliably with such a "weakly coupled" method, when the evolving interface geometry and velocities

Barr, Al

9

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

SciTech Connect (OSTI)

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

10

Performance of a municipal solid waste (MSW) incinerator predicted with a computational fluid dynamics (CFD) code  

SciTech Connect (OSTI)

The purpose of this paper is to investigate by the means of numerical simulation the performance of the MSW incinerator with of Vercelli (Italy). FLUENT, a finite-volumes commercial code for Fluid Dynamics has been used to predict the 3-D reacting flows (gaseous phase) within the incinerator geometry, in order to estimate if the three conditions settled by the Italian law (P.D. 915 / 82) are respected: (a) Flue gas temperature at the input of the secondary combustion chamber must exceed 950 C. (b) Oxygen concentration in the same section must exceed 6 %. (c) Residence time for the flue gas in the secondary combustion chamber must exceed 2 seconds. The model of the incinerator has been created using the software pre-processing facilities (wall, input, outlet and live cells), together with the set-up of boundary conditions. There are also imposed the combustion constants (stoichiometry, heat of combustion, air excess). The solving procedure transforms at the level of each live cell the partial derivative equations in algebraic equations, computing the velocities field, the temperatures, gases concentration, etc. These predicted values were compared with the design properties, and the conclusion was that the conditions (a), (b), (c), are respected in normal operation. The powerful graphic interface helps the user to visualize the magnitude of the computed parameters. These results may be successfully used for the design and operation improvements for MSW incinerators. This fact will substantially increase the efficiency, reduce pollutant emissions and optimize the plant overall performance.

Anglesio, P.; Negreanu, G.P.

1998-07-01T23:59:59.000Z

11

Semester project Lattice Boltzmann simulations of fluid flow: An unconventional approach to CFD  

E-Print Network [OSTI]

Semester project Lattice Boltzmann simulations of fluid flow: An unconventional approach to CFD Background: The lattice Boltzmann method is a new numerical method of computational fluid dynamics (CFD). Con on a continuous picture of matter. The lattice Boltzmann method instead relies on discrete particles having

Müller,Bernhard

12

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

SciTech Connect (OSTI)

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

13

Three-Dimensional Computational Fluid Dynamics  

SciTech Connect (OSTI)

Computational fluid dynamics (CFD) is one discipline falling under the broad heading of computer-aided engineering (CAE). CAE, together with computer-aided design (CAD) and computer-aided manufacturing (CAM), comprise a mathematical-based approach to engineering product and process design, analysis and fabrication. In this overview of CFD for the design engineer, our purposes are three-fold: (1) to define the scope of CFD and motivate its utility for engineering, (2) to provide a basic technical foundation for CFD, and (3) to convey how CFD is incorporated into engineering product and process design.

Haworth, D.C.; O'Rourke, P.J.; Ranganathan, R.

1998-09-01T23:59:59.000Z

14

Computational fluid dynamic applications  

SciTech Connect (OSTI)

The rapid advancement of computational capability including speed and memory size has prompted the wide use of computational fluid dynamics (CFD) codes to simulate complex flow systems. CFD simulations are used to study the operating problems encountered in system, to evaluate the impacts of operation/design parameters on the performance of a system, and to investigate novel design concepts. CFD codes are generally developed based on the conservation laws of mass, momentum, and energy that govern the characteristics of a flow. The governing equations are simplified and discretized for a selected computational grid system. Numerical methods are selected to simplify and calculate approximate flow properties. For turbulent, reacting, and multiphase flow systems the complex processes relating to these aspects of the flow, i.e., turbulent diffusion, combustion kinetics, interfacial drag and heat and mass transfer, etc., are described in mathematical models, based on a combination of fundamental physics and empirical data, that are incorporated into the code. CFD simulation has been applied to a large variety of practical and industrial scale flow systems.

Chang, S.-L.; Lottes, S. A.; Zhou, C. Q.

2000-04-03T23:59:59.000Z

15

Computational Fluid Dynamics Study of Aerosol Transport and Deposition Mechanisms  

E-Print Network [OSTI]

In this work, various aerosol particle transport and deposition mechanisms were studied through the computational fluid dynamics (CFD) modeling, including inertial impaction, gravitational effect, lift force, interception, and turbophoresis, within...

Tang, Yingjie

2012-07-16T23:59:59.000Z

16

Seventh International Conference on Computational Fluid Dynamics (ICCFD7),  

E-Print Network [OSTI]

industrial purpose CFD codes, such as TONUS [7], to investigate turbulent combustion flows. The main drawback-diffusive scheme, upwind downwind-controlled splitting 1 Introduction The use of Computational Fluids Dynamics (CFD: the reaction zone in a laminar deflagration at atmospheric condition can vary from about 1 mm to 10 mm

Boyer, Edmond

17

Coupled multi-body dynamics and CFD for wind turbine simulation including explicit wind turbulence  

Science Journals Connector (OSTI)

Abstract A high fidelity approach for wind turbine aero-elastic simulations including explicit representation of the atmospheric wind turbulence is presented. The approach uses a dynamic overset computational fluid dynamics (CFD) code for the aerodynamics coupled with a multi-body dynamics (MBD) code for the motion responses to the aerodynamic loads. Mann's wind turbulence model was implemented into the CFD code as boundary and initial conditions. The wind turbulence model was validated by comparing the theoretical one-point spectrum for the three components of the velocity fluctuations, and by comparing the expected statistics from the CFD simulated wind turbulent field with the explicit wind turbulence inlet boundary from Mann model. Extensive simulations based on the proposed coupled approach were conducted with the conceptual NREL 5-MW offshore wind turbine in an increasing level of complexity, analyzing the turbine behavior as elasticity, wind shear and atmospheric wind turbulence are added to the simulations. Results are compared with the publicly available simulations results from OC3 participants, showing good agreement for the aerodynamic loads and blade tip deflections in time and frequency domains. Wind turbulence/turbine interaction was examined for the wake flow. It was found that explicit turbulence addition results in considerably increased wake diffusion. The coupled CFD/MBD approach can be extended to include multibody models of the shaft, bearings, gearbox and generator, resulting in a promising tool for wind turbine design under complex operational environments.

Y. Li; A.M. Castro; T. Sinokrot; W. Prescott; P.M. Carrica

2015-01-01T23:59:59.000Z

18

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

SciTech Connect (OSTI)

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

19

A computational fluid dynamics model for wind simulation: model implementation and experimental validation  

Science Journals Connector (OSTI)

To provide physically based wind modelling for wind erosion research at regional scale, a 3D computational fluid dynamics (CFD) wind model was developed. The model was programmed ... analysis and modelling tool (...

Zhuo-dong Zhang; Ralf Wieland; Matthias Reiche

2012-04-01T23:59:59.000Z

20

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

Science Journals Connector (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

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

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

22

MAX Fluid Dynamics facility  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

23

View dependent fluid dynamics  

E-Print Network [OSTI]

VIEW DEPENDENT FLUID DYNAMICS A Thesis by BRIAN ARTHUR BARRAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 2006 Major Subject: Visualization... Sciences VIEW DEPENDENT FLUID DYNAMICS A Thesis by BRIAN ARTHUR BARRAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Donald...

Barran, Brian Arthur

2006-08-16T23:59:59.000Z

24

Computational fluid dynamics modeling of coal gasification in a pressurized spout-fluid bed  

SciTech Connect (OSTI)

Computational fluid dynamics (CFD) modeling, which has recently proven to be an effective means of analysis and optimization of energy-conversion processes, has been extended to coal gasification in this paper. A 3D mathematical model has been developed to simulate the coal gasification process in a pressurized spout-fluid bed. This CFD model is composed of gas-solid hydrodynamics, coal pyrolysis, char gasification, and gas phase reaction submodels. The rates of heterogeneous reactions are determined by combining Arrhenius rate and diffusion rate. The homogeneous reactions of gas phase can be treated as secondary reactions. A comparison of the calculated and experimental data shows that most gasification performance parameters can be predicted accurately. This good agreement indicates that CFD modeling can be used for complex fluidized beds coal gasification processes. 37 refs., 7 figs., 5 tabs.

Zhongyi Deng; Rui Xiao; Baosheng Jin; He Huang; Laihong Shen; Qilei Song; Qianjun Li [Southeast University, Nanjing (China). Key Laboratory of Clean Coal Power Generation and Combustion Technology of Ministry of Education

2008-05-15T23:59:59.000Z

25

Petascale Adaptive Computational Fluid Dynamics | Argonne Leadership  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.,

26

Ship hull resistance calculations using CFD methods  

E-Print Network [OSTI]

In past years, the computational power and run-time required by Computational Fluid Dynamics (CFD) codes restricted their use in ship design space exploration. Increases in computational power available to designers, in ...

Voxakis, Petros

2012-01-01T23:59:59.000Z

27

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

Science Journals Connector (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

28

MR-driven Computational Fluid Dynamics J-F. Nielsen1  

E-Print Network [OSTI]

MR-driven Computational Fluid Dynamics J-F. Nielsen1 , and K. S. Nayak2 1 Biomedical Engineering-encoding gradient pulse (VENC=1.6 m/s) was placed on the x, y, or z-gradient axis, or was turned off. MR-driven CFD component (vertical in Fig. 1) was incorporated into the MR-driven CFD solver. Hence, vx and vy were

Southern California, University of

29

Computational Fluid Dynamics of rising droplets  

SciTech Connect (OSTI)

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

30

Improving the representation of thermal boundary conditions of livestock during CFD modelling of the indoor environment  

Science Journals Connector (OSTI)

The use of computational fluid dynamics (CFD) to evaluate the climate distribution in agricultural buildings has grown in importance in recent years. Convection and radiation are the dominant forms of heat transfer from an animal's body, and accurately ... Keywords: Airflow, Animal house, CFD, Computational fluid dynamics, Livestock building, Optimisation, Simulation, Temperature, Ventilation

Toms Norton; Jim Grant; Richard Fallon; Da-Wen Sun

2010-07-01T23:59:59.000Z

31

Experimental methodology for computational fluid dynamics code validation  

SciTech Connect (OSTI)

Validation of Computational Fluid Dynamics (CFD) codes is an essential element of the code development process. Typically, CFD code validation is accomplished through comparison of computed results to previously published experimental data that were obtained for some other purpose, unrelated to code validation. As a result, it is a near certainty that not all of the information required by the code, particularly the boundary conditions, will be available. The common approach is therefore unsatisfactory, and a different method is required. This paper describes a methodology developed specifically for experimental validation of CFD codes. The methodology requires teamwork and cooperation between code developers and experimentalists throughout the validation process, and takes advantage of certain synergisms between CFD and experiment. The methodology employs a novel uncertainty analysis technique which helps to define the experimental plan for code validation wind tunnel experiments, and to distinguish between and quantify various types of experimental error. The methodology is demonstrated with an example of surface pressure measurements over a model of varying geometrical complexity in laminar, hypersonic, near perfect gas, 3-dimensional flow.

Aeschliman, D.P.; Oberkampf, W.L.

1997-09-01T23:59:59.000Z

32

LECTURES IN ELEMENTARY FLUID DYNAMICS  

E-Print Network [OSTI]

LECTURES IN ELEMENTARY FLUID DYNAMICS: Physics, Mathematics and Applications J. M. McDonough Departments of Mechanical Engineering and Mathematics University of Kentucky, Lexington, KY 40506-0503 c 1987, 1990, 2002, 2004, 2009 #12;Contents 1 Introduction 1 1.1 Importance of Fluids

McDonough, James M.

33

A Simple Interface to Computational Fluid Dynamics Programs for Building Environment Simulations  

E-Print Network [OSTI]

. SCI can be easily integrated into new CFD programs. Introduction Advanced building design requests and pressure distributions that are crucial for thermal comfort and building structure designs. TraditionallyA Simple Interface to Computational Fluid Dynamics Programs for Building Environment Simulations

Chen, Qingyan "Yan"

34

Computational fluid dynamic simulations of chemical looping fuel reactors utilizing gaseous fuels  

SciTech Connect (OSTI)

A computational fluid dynamic(CFD) model for the fuel reactor of chemical looping combustion technology has been developed,withspecialfocusonaccuratelyrepresentingtheheterogeneous chemicalreactions.Acontinuumtwo-fluidmodelwasusedtodescribeboththegasandsolidphases. Detailedsub-modelstoaccountforfluidparticleandparticleparticleinteractionforceswerealso incorporated.Twoexperimentalcaseswereanalyzedinthisstudy(Son andKim,2006; Mattisonetal., 2001). SimulationswerecarriedouttotestthecapabilityoftheCFDmodeltocapturechangesinoutletgas concentrationswithchangesinnumberofparameterssuchassuperficialvelocity,metaloxide concentration,reactortemperature,etc.Fortheexperimentsof Mattissonetal.(2001), detailedtime varyingoutletconcentrationvalueswerecompared,anditwasfoundthatCFDsimulationsprovideda reasonablematchwiththisdata.

Mahalatkar, K.; Kuhlman, J.; Huckaby, E.D.; O'Brien, T.

2011-01-01T23:59:59.000Z

35

Uncovering MIT wind myths through micro-climatological CFD analysis  

E-Print Network [OSTI]

Popular campus myths of unusually strong pedestrian level winds are investigated with a Computational Fluid Dynamics (CFD) approach. The numerical simulations confirm the existence of the reported phenomena and provide a qualitative explanation of their physical mechanisms.

Kalmikov, Alexander

2013-01-01T23:59:59.000Z

36

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

SciTech Connect (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

37

Visualization of the recovery-bioler flow fields predicted by computational fluid dynamics  

SciTech Connect (OSTI)

Flow patterns in the kraft recovery furnace can be simulated using models based on computational fluid dynamics (CFD). The use of CFD is becoming increasingly common as computer workstations become more powerful and CFD software is improved. In this article, the authors present simulated results for flow fields in the lower furnace. Because the flows in the lower furnace are dominated by the air system, the authors chose to simulate flow fields under isothermal conditions. The predicted flow fields were used to supplement results obtained from physical modeling. When a physical model is used for testing, each air-system configuration is typically evaluated based on air and gas velocities and the mixing distribution as measured at a limited number of test planes. Such measurements are commonly used to quantitatively assess air-system configurations for modeling studies or to validate CFD models.

Chapman, P.J.; Janik, S.G. (Kreisinger Development Lab. ABB Combustion Engineering Systems, Windsor, CT (United States)); Jones, A.K. (ABB Canada, Ottawa, ON (Canada))

1992-03-01T23:59:59.000Z

38

Validation of a Fast-Fluid-Dynamics Model for Predicting Distribution of Particles with Low Stokes Number  

SciTech Connect (OSTI)

To design a healthy indoor environment, it is important to study airborne particle distribution indoors. As an intermediate model between multizone models and computational fluid dynamics (CFD), a fast fluid dynamics (FFD) model can be used to provide temporal and spatial information of particle dispersion in real time. This study evaluated the accuracy of the FFD for predicting transportation of particles with low Stokes number in a duct and in a room with mixed convection. The evaluation was to compare the numerical results calculated by the FFD with the corresponding experimental data and the results obtained by the CFD. The comparison showed that the FFD could capture major pattern of particle dispersion, which is missed in models with well-mixed assumptions. Although the FFD was less accurate than the CFD partially due to its simplification in numeric schemes, it was 53 times faster than the CFD.

Zuo, Wangda; Chen, Qingyan

2011-06-01T23:59:59.000Z

39

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

SciTech Connect (OSTI)

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

40

European Conference on Computational Fluid Dynamics ECCOMAS CFD 2006  

E-Print Network [OSTI]

in industrialized countries. The major CVD include coronary (or ischaemic) heart disease (heart attack), cerebrovascular disease (stroke), hypertension (high blood pressure), rheumatic heart disease and heart failure. Damage to the heart tissues from CVD or from heart surgery can disrupt the natural electrical impulses

Frangi, Alejandro

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

European Conference on Computational Fluid Dynamics ECCOMAS CFD 2006  

E-Print Network [OSTI]

21 Uppsala, Sweden e-mail: damir.valiev@fysik.uu.se 3UPPMAX, Uppsala University, Box 337, 751 05¨uller, J. Rantakokko, P. L¨otstedt and M.A. Liberman of numerous efforts, the basic mechanisms controlling challenge of the combustion theory [6, 7, 8, 9]. The classical explanation of DDT [1, 2, 3] was due to flame

Müller,Bernhard

42

Modeling an EDC Cracker using Computational Fluid Dynamics (CFD).  

E-Print Network [OSTI]

?? The process used by the Norwegian company Hydro for making Vinyl Chloride Monomer (VCM) from natural gas and sodium chloride has been studied. A (more)

Kaggerud, Torbjrn Herder

2007-01-01T23:59:59.000Z

43

European Conference on Computational Fluid Dynamics ECCOMAS CFD 2006  

E-Print Network [OSTI]

217, 7500 AE Enschede, The Netherlands e-mail: {L.Pesch, J.J.W.vanderVegt}@math.utwente.nl web page. P´eriaux (Eds) c TU Delft, The Netherlands, 2006 A SPACE-TIME DISCONTINUOUS GALERKIN FINITE

Al Hanbali, Ahmad

44

European Conference on Computational Fluid Dynamics ECCOMAS CFD 2006  

E-Print Network [OSTI]

of Twente P.O. Box 217, Enschede, The Netherlands e-mail: o.bokhove@math.utwente.nl web page: google "Onno. P´eriaux (Eds) c TU Delft, The Netherlands, 2006 A (DIS)CONTINUOUS FINITE ELEMENT MODEL of Physics, University of Utrecht, Utrecht, The Netherlands Department of Applied Mathematics, University

Al Hanbali, Ahmad

45

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

SciTech Connect (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

46

Design of Cleanroom Airflows for Particle Control Using CFD Analysis: Case Studies  

Science Journals Connector (OSTI)

This paper describes two case studies involving the use of Computational Fluid Dynamics (CFD) analysis for evaluating the designs of significantly different types (and cleanliness classes) of cleanrooms: a cla...

Ken Goldstein; John Divelbiss

1993-01-01T23:59:59.000Z

47

Sandia National Laboratories: Computational Fluid Dynamics Simulations...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Canal, Yakima Washington Sandia Publishes Five Reports on the Environmental Effects of Wave-Energy Converters Computational Fluid Dynamics Simulations Provide Insight for Rotor...

48

Geophysical Fluid Dynamics Laboratory Presented by  

E-Print Network [OSTI]

Dynamics Laboratory Outline: · Introduction · Software Infrastructure Projects: Completed Current consortium for climate-weather community 3 #12;Geophysical Fluid Dynamics Laboratory Software Infrastructure Projects ­ Completed: · Flexible Modeling System (FMS) · FMS Model: Hybrid programming model Memory

49

Computational Fluid Dynamic Analysis of the VHTR Lower Plenum Standard Problem  

SciTech Connect (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 C to perhaps 1000 C. 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

50

Dynamic stall analysis of horizontal-axis-wind-turbine blades using computational fluid dynamics  

Science Journals Connector (OSTI)

Dynamic stall has been widely known to significantly affect the performance of the wind turbines. In this paper aerodynamic simulation of the unsteady low-speed flow past two-dimensional wind turbine blade profiles developed by the National Renewable Energy Laboratory (NREL) will be performed. The aerodynamic simulation will be performed using Computational Fluid Dynamics (CFD). The governing equations used in the simulations are the Unsteady-Reynolds-Averaged-Navier-Stokes (URANS) equations. The unsteady separated turbulent flow around an oscillating airfoil pitching in a sinusoidal pattern in the regime of low Reynolds number is investigated numerically. The investigation employs the URANS approach with the most suitable turbulence model. The development of the light dynamic stall of the blades under consideration is studied. The S809 blade profile is simulated at different mean wind speeds. Moreover the S826 blade profile is also considered for analysis of wind turbine blade which is the most suitable blade profile for the wind conditions in Egypt over the site of Gulf of El-Zayt. In order to find the best oscillating frequency different oscillating frequencies are studied. The best frequency can then be used for the blade pitch controller. The comparisons with the experimental results showed that the used CFD code can accurately predict the blade profile unsteady aerodynamic loads.

2012-01-01T23:59:59.000Z

51

CFD evaluation of pipeline gas stratification at low fluid flow due to temperature effects  

E-Print Network [OSTI]

variance in chord averaged velocities is apparent at these conditions. CFD analysis was performed. Low flow velocities of 0.1524 m/sec, 0.3048 m/sec and 0.6096 m/sec and temperature differences of 5.5 o K, 13.8 o K and 27.7 o K were considered. When... with gas velocity below 0.6096 m/sec. v DEDICATION To my family for their love and support. vi ACKNOWLEDGMENTS I would like to express my gratitude to Dr. Gerald Morrison for his valuable guidance and support. I...

Brar, Pardeep Singh

2005-02-17T23:59:59.000Z

52

A proposed framework for computational fluid dynamics code calibration/validation  

SciTech Connect (OSTI)

The paper reviews the terminology and methodology that have been introduced during the last several years for building confidence n the predictions from Computational Fluid Dynamics (CID) codes. Code validation terminology developed for nuclear reactor analyses and aerospace applications is reviewed and evaluated. Currently used terminology such as ``calibrated code,`` ``validated code,`` and a ``validation experiment`` is discussed along with the shortcomings and criticisms of these terms. A new framework is proposed for building confidence in CFD code predictions that overcomes some of the difficulties of past procedures and delineates the causes of uncertainty in CFD predictions. Building on previous work, new definitions of code verification and calibration are proposed. These definitions provide more specific requirements for the knowledge level of the flow physics involved and the solution accuracy of the given partial differential equations. As part of the proposed framework, categories are also proposed for flow physics research, flow modeling research, and the application of numerical predictions. The contributions of physical experiments, analytical solutions, and other numerical solutions are discussed, showing that each should be designed to achieve a distinctively separate purpose in building confidence in accuracy of CFD predictions. A number of examples are given for each approach to suggest methods for obtaining the highest value for CFD code quality assurance.

Oberkampf, W.L.

1993-12-31T23:59:59.000Z

53

Development and Validation of the 3-D Computational Fluid Dynamics Model for CANDU-6 Moderator Temperature Predictions  

SciTech Connect (OSTI)

A computational fluid dynamics (CFD) model for predicting the moderator circulation inside the Canada deuterium uranium (CANDU) reactor vessel has been developed to estimate the local subcooling of the moderator in the vicinity of the Calandria tubes. The buoyancy effect induced by internal heating is accounted for by Boussinesq approximation. The standard k-[curly epsilon] turbulence model associated with logarithmic wall treatment is applied to predict the turbulent jet flows from the inlet nozzles. The matrix of the Calandria tubes in the core region is simplified to porous media, in which anisotropic hydraulic impedance is modeled using an empirical correlation of the frictional pressure loss. The governing equations are solved by CFX-4.4, a commercial CFD code developed by AEA Technology. The CFD model has been successfully verified and validated against experimental data obtained at Stern Laboratories Inc. in Hamilton, Ontario, Canada.

Yoon, Churl; Rhee, Bo Wook; Min, Byung-Joo [Korea Atomic Energy Research Institute (Korea, Republic of)

2004-12-15T23:59:59.000Z

54

Investigation of Swirling Flow in Rod Bundle Subchannels Using Computational Fluid Dynamics  

SciTech Connect (OSTI)

The fluid dynamics for turbulent flow through rod bundles representative of those used in pressurized water reactors is examined using computational fluid dynamics (CFD). The rod bundles of the pressurized water reactor examined in this study consist of a square array of parallel rods that are held on a constant pitch by support grids spaced axially along the rod bundle. Split-vane pair support grids are often used to create swirling flow in the rod bundle in an effort to improve the heat transfer characteristics for the rod bundle during both normal operating conditions and in accident condition scenarios. Computational fluid dynamics simulations for a two subchannel portion of the rod bundle were used to model the flow downstream of a split-vane pair support grid. A high quality computational mesh was used to investigate the choice of turbulence model appropriate for the complex swirling flow in the rod bundle subchannels. Results document a central swirling flow structure in each of the subchannels downstream of the split-vane pairs. Strong lateral flows along the surface of the rods, as well as impingement regions of lateral flow on the rods are documented. In addition, regions of lateral flow separation and low axial velocity are documented next to the rods. Results of the CFD are compared to experimental particle image velocimetry (PIV) measurements documenting the lateral flow structures downstream of the split-vane pairs. Good agreement is found between the computational simulation and experimental measurements for locations close to the support grid. (authors)

Holloway, Mary V. [United States Naval Academy, 117 Decatur Road, Annapolis, MD 21402-5018 (United States); Beasley, Donald E. [Clemson University, Clemson, S.C. 29634 (United States); Conner, Michael E. [Westinghouse Nuclear Fuel (United States)

2006-07-01T23:59:59.000Z

55

3D Computational Fluid Dynamics Simulation of Natural Coke Steam Gasification in General and Improved Fluidized Beds  

Science Journals Connector (OSTI)

The thermal characteristics of natural coke steam gasification in a fluidized bed were three-dimensionally (3D) simulated based on the computational fluid dynamics (CFD) method using Fluent code. ... However, this technology seems difficult to carry out due to its abradability, hard ignition, hot burst, and so on. ... In short, all the results in this work have a significance to provide the theoretical basis for the design, operational optimization, and scale-up of the natural coke steam gasification process. ...

Ya-li Tang; Dai-jun Liu; Yu-hong Liu; Qian Luo

2010-09-30T23:59:59.000Z

56

Design strategy for a Chemical Looping Combustion system using process simulation and Computational Fluid Dynamics  

Science Journals Connector (OSTI)

A strategy for design and optimisation of chemical processes involving multiple fluidised bed reactors is presented through a combination of standard design calculations, process simulation and Computational Fluid Dynamics (CFD). The strategy is demonstrated in designing a Chemical Looping Combustion (CLC) process that generates 12.5 kW of heat in the air reactor. The resulting design strategy will allow for very economical investigations into various design and optimisation considerations. It also offers a platform from which to conduct virtual prototyping investigations for new process concepts, which will lead to significant economic benefits when compared with a traditional experimental process development strategy.

Schalk Cloete; Shahriar Amini

2012-01-01T23:59:59.000Z

57

Fluid dynamics kill Wyoming icicle  

SciTech Connect (OSTI)

Control of a blowout in which a portion of the drill collar string was extending through the rotary table and into the derrick was compounded by ice building up on the derrick and substructure. However, the momentum kill procedure proved successful. Topics considered in this paper include oil wells, natural gas wells, sleeves, rotary drills, drilling rigs, fluid mechanics, occupational safety, blowouts, drill pipes, rotary drilling, ice removal, and freezing.

Grace, R.D.

1987-04-01T23:59:59.000Z

58

Spinodal phase decomposition with dissipative fluid dynamics  

SciTech Connect (OSTI)

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

59

A proposed methodology for computational fluid dynamics code verification, calibration, and validation  

SciTech Connect (OSTI)

Verification, calibration, and validation (VCV) of Computational Fluid Dynamics (CFD) codes is an essential element of the code development process. The exact manner in which code VCV activities are planned and conducted, however, is critically important. It is suggested that the way in which code validation, in particular, is often conducted--by comparison to published experimental data obtained for other purposes--is in general difficult and unsatisfactory, and that a different approach is required. This paper describes a proposed methodology for CFD code VCV that meets the technical requirements and is philosophically consistent with code development needs. The proposed methodology stresses teamwork and cooperation between code developers and experimentalists throughout the VCV process, and takes advantage of certain synergisms between CFD and experiment. A novel approach to uncertainty analysis is described which can both distinguish between and quantify various types of experimental error, and whose attributes are used to help define an appropriate experimental design for code VCV experiments. The methodology is demonstrated with an example of laminar, hypersonic, near perfect gas, 3-dimensional flow over a sliced sphere/cone of varying geometrical complexity.

Aeschliman, D.P.; Oberkampf, W.L.; Blottner, F.G.

1995-07-01T23:59:59.000Z

60

Computational Fluid Dynamics (CFD) simulations of dilute fluid-particle flows in aerosol concentrators  

E-Print Network [OSTI]

's turbulent dispersion model. A detailed literature survey revealed the inherent technical deficiencies in the model, even for particle dispersion. Based on the results of this study, it was determined that while the code can be used for simulating aerosol...

Hari, Sridhar

2005-02-17T23:59:59.000Z

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

Geophysical Fluid Dynamics Laboratory Review May 20 May 22, 2014  

E-Print Network [OSTI]

in modeling fluid dynamics and heat transfer in large facilities is being applied to the analysis of new might use 25% less fuel than a conventional vehicle. Cool Designs for Hot Spaces Computational Fluid Computational Fluid Dynamics model. (Image Right) Image showing the geometry of a typical Computational Fluid

62

Development of a CFD Analysis Plan for the first VHTR Standard Problem  

SciTech Connect (OSTI)

Data from a scaled model of a portion of the lower plenum of the helium-cooled very high temperature reactor (VHTR) are under consideration for acceptance as a computational fluid dynamics (CFD) validation data set or standard problem. A CFD analysis will help determine if the scaled model is a suitable geometry for validation data. The present article describes the development of an analysis plan for the CFD model. The plan examines the boundary conditions that should be used, the extent of the computational domain that should be included and which turbulence models need not be examined against the data. Calculations are made for a closely related 2D geometry to address these issues. It was found that a CFD model that includes only the inside of the scaled model in its computational domain is adequate for CFD calculations. The realizable k~e model was found not to be suitable for this problem because it did not predict vortex-shedding.

Richard W. Johnson

2008-09-01T23:59:59.000Z

63

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

SciTech Connect (OSTI)

This paper assesses the accuracy of the simplified frame cavity conduction/convection and radiation models presented in ISO 15099 and used in software for rating and labeling window products. Temperatures and U-factors for typical horizontal window frames with internal cavities are compared; results from Computational Fluid Dynamics (CFD) simulations with detailed radiation modeling are used as a reference. Four different frames were studied. Two were made of polyvinyl chloride (PVC) and two of aluminum. For each frame, six different simulations were performed, two with a CFD code and four with a building-component thermal-simulation tool using the Finite Element Method (FEM). This FEM tool addresses convection using correlations from ISO 15099; it addressed radiation with either correlations from ISO 15099 or with a detailed, view-factor-based radiation model. Calculations were performed using the CFD code with and without fluid flow in the window frame cavities; the calculations without fluid flow were performed to verify that the CFD code and the building-component thermal-simulation tool produced consistent results. With the FEM-code, the practice of subdividing small frame cavities was examined, in some cases not subdividing, in some cases subdividing cavities with interconnections smaller than five millimeters (mm) (ISO 15099) and in some cases subdividing cavities with interconnections smaller than seven mm (a breakpoint that has been suggested in other studies). For the various frames, the calculated U-factors were found to be quite comparable (the maximum difference between the reference CFD simulation and the other simulations was found to be 13.2 percent). A maximum difference of 8.5 percent was found between the CFD simulation and the FEM simulation using ISO 15099 procedures. The ISO 15099 correlation works best for frames with high U-factors. For more efficient frames, the relative differences among various simulations are larger. Temperature was also compared, at selected locations on the frames. Small differences was found in the results from model to model. Finally, the effectiveness of the ISO cavity radiation algorithms was examined by comparing results from these algorithms to detailed radiation calculations (from both programs). Our results suggest that improvements in cavity heat transfer calculations can be obtained by using detailed radiation modeling (i.e. view-factor or ray-tracing models), and that incorporation of these strategies may be more important for improving the accuracy of results than the use of CFD modeling for horizontal cavities.

Gustavsen, Arlid; Kohler, Christian; Dalehaug, Arvid; Arasteh, Dariush

2008-12-01T23:59:59.000Z

64

Flow modeling of flat oval ductwork elbows using computational fluid dynamics  

SciTech Connect (OSTI)

Incompressible turbulent flow fields in heating, ventilating, and air-conditioning (HVAC) elbows were computed using an incompressible, three-dimensional computational fluid dynamics (CFD) solver implementing a {kappa}-{epsilon} turbulence model. Two different geometries were investigated, including 90-degree five-gore hard-bend and easy-bend flat oval elbows. The geometries represent a subset of many configurations analyzed in ASHRAE RP-854, Determination of Duct Fitting Resistance by Numerical Analysis. For each configuration, the zero-length pressure loss coefficient was calculated. The flow was described through contours of velocity and plots of static pressure. The Reynolds number for these flows was held constant at 100,000 based on duct diameter and mean fluid velocity.

Mahank, T.A.; Mumma, S.A. [Pennsylvania State Univ., University Park, PA (United States)

1997-12-31T23:59:59.000Z

65

Mech 521 Fluid Mechanics Project December 6, 2012 Introduction  

E-Print Network [OSTI]

the open source computational fluid dynamics (CFD) package OpenFOAM to computationally examine supersonic and a bow-shock wave is formed in front of the airfoil. Software and Computer Lab: OpenFOAM is an open source CFD package that is freely available and can be downloaded from its web page www.openfoam

Muradoglu, Metin

66

Computational Fluid Dynamics Analysis of Very High Temperature Gas-Cooled Reactor Cavity Cooling System  

SciTech Connect (OSTI)

The design of passive heat removal systems is one of the main concerns for the modular very high temperature gas-cooled reactors (VHTR) vessel cavity. The reactor cavity cooling system (RCCS) is a key heat removal system during normal and off-normal conditions. The design and validation of the RCCS is necessary to demonstrate that VHTRs can survive to the postulated accidents. The computational fluid dynamics (CFD) STAR-CCM+/V3.06.006 code was used for three-dimensional system modeling and analysis of the RCCS. A CFD model was developed to analyze heat exchange in the RCCS. The model incorporates a 180-deg section resembling the VHTR RCCS experimentally reproduced in a laboratory-scale test facility at Texas A&M University. All the key features of the experimental facility were taken into account during the numerical simulations. The objective of the present work was to benchmark CFD tools against experimental data addressing the behavior of the RCCS following accident conditions. Two cooling fluids (i.e., water and air) were considered to test the capability of maintaining the RCCS concrete walls' temperature below design limits. Different temperature profiles at the reactor pressure vessel (RPV) wall obtained from the experimental facility were used as boundary conditions in the numerical analyses to simulate VHTR transient evolution during accident scenarios. Mesh convergence was achieved with an intensive parametric study of the two different cooling configurations and selected boundary conditions. To test the effect of turbulence modeling on the RCCS heat exchange, predictions using several different turbulence models and near-wall treatments were evaluated and compared. The comparison among the different turbulence models analyzed showed satisfactory agreement for the temperature distribution inside the RCCS cavity medium and at the standpipes walls. For such a complicated geometry and flow conditions, the tested turbulence models demonstrated that the realizable k-epsilon model with two-layer all y+ wall treatment performs better than the other k-epsilon and k-omega turbulence models when compared to the experimental results and the Reynolds stress transport turbulence model results. A scaling analysis was developed to address the distortions introduced by the CFD model in simulating the physical phenomena inside the RCCS system with respect to the full plant configuration. The scaling analysis demonstrated that both the experimental facility and the CFD model achieve a satisfactory resemblance of the main flow characteristics inside the RCCS cavity region, and convection and radiation heat exchange phenomena are properly scaled from the actual plant.

Angelo Frisani; Yassin A. Hassan; Victor M. Ugaz

2010-11-02T23:59:59.000Z

67

Computational battery dynamics (CBD)--electrochemical/thermal coupled modeling and multi-scale modeling  

E-Print Network [OSTI]

Computational battery dynamics (CBD)--electrochemical/thermal coupled modeling and multi the development of first-principles based mathematical models for batteries developed on a framework parallel to computation fluid dynamics (CFD), herein termed computational battery dynamics (CBD). This general

68

Lattice Boltzmann scheme for fluids with dynamic heterogeneities  

Science Journals Connector (OSTI)

We introduce and discuss a three-dimensional mesoscopic lattice Boltzmann model for the numerical simulation of strongly-interacting fluids with dynamic inhomogeneities. The model is based on an extension of the standard lattice Boltzmann dynamics in which streaming between neighboring lattice sites is constrained by the value of the nonlocal density of the surrounding fluid. The resulting dynamics exhibits typical features of dynamically heterogeneous fluids, such as long-time relaxation, non-Gaussian density distributions and dynamic heterogeneities. Due to its intrinsically parallel dynamics and absence of statistical noise, the method is expected to compute significantly faster than molecular dynamics, Monte Carlo, and lattice glass models.

A. Lamura and S. Succi

2006-06-28T23:59:59.000Z

69

The MAX facility for CFD code validation  

SciTech Connect (OSTI)

ANL has recently completed construction of a fluid dynamics test facility devised to provide validation data for CFD simulation tools used to evaluate various aspects of nuclear power plant design and safety. Experiments with the facility involve mixing air jets within a 1x1x1.7m long glass tank at atmospheric pressure. A particle image velocimetry system measures flow velocity and turbulence quantities within the tank while a high-speed infrared camera records temperatures across the tank lid. The tandem of high fidelity thermal and turbulence data is particularly useful for benchmarking transient heat transfer phenomena such as thermal striping. This paper describes the MAX facility, preliminary data obtained during shakedown tests, and the results of companion CFD calculations employing RANS-based Star-CCM+ and large eddy simulations with Nek 5000. (authors)

Lomperski, S.; Merzari, E.; Obabko, A.; Pointer, W. D.; Fischer, P. [Argonne National Laboratory, Bldg. 206, 9700 S. Cass Ave, Argonne, IL 60439 (United States)

2012-07-01T23:59:59.000Z

70

Distributed computational fluid dynamics Karl Jenkins  

E-Print Network [OSTI]

of large and complex datasets. Thus, remote access to this information is an integral part of the CFD turbulent combustion pro- cesses is a strong coupling between turbulence, chemical kinetics and heat release provides a route around the departmental firewalls. The clusters run Globus and Condor for remote job

de Gispert, Adrià

71

Utilization of computational fluid dynamics technique in low NOx burner/furnace retrofits  

SciTech Connect (OSTI)

A computational fluid dynamics (CFD) technique has been utilized to provide design guidance for retrofitting low NOx combustion systems and incorporating associated furnace modifications into existing utility boilers. The CFD program utilized is FW-FIRES (Fossil fuel, Water-walled Furnace Integrated Reaction and Emission Simulation) which simulates furnace combustion, heat transfer and pollutant formation based on fundamental principals of mass, momentum and energy conservations. The program models the gas flow field as a three-dimensional turbulent reacting continuum and the particle flow as a series of discrete particle trajectories through the gas continuum. Chemical reaction, heat transfer, and pollutant formation mechanisms are incorporated in the program. FW-FIRES furnace simulation of low NOx combustion system retrofits has been performed for various furnace configurations including front wall-fired, front and real wall-fired, and tangentially-fired furnaces, to determine the effects of burner/furnace modifications on the NOx emission, furnace exit gas temperature, furnace heat absorption, unburned carbon, and furnace wall corrosion. For front wall-fired, and front and real wall-fired furnaces, the NOx emission requirement is met by the use of Foster Wheeler lox NOx burners and overfire air (OFA) staging. Studies of burner and OFA quantify and spacing are conducted to limit NOx emission and unburned carbon to acceptable levels. A major concern in once-through supercritical units with OFA is furnace wall corrosion which is caused by high furnace wall metal temperature and corrosive hydrogen sulfide (H{sub 2}S) created in a reducing atmosphere from part of coal sulfur. The FW-FIRES code is used to minimize this corrosion potential by selecting the proper location and quantity of boundary air. A simulation of tangentially-fired unit, which has been retrofitted with low NOx burners, is used to study the effect of the burner tilt on the furnace exit gas temperature. This paper details the basis and results of several CFD analyses conducted for potential retrofit programs.

Cho, S.M.; Seltzer, A.H.; Ma, J.; Steitz, T.H.; Grusha, J.; Cole, R.W.

1999-07-01T23:59:59.000Z

72

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

SciTech Connect (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

73

CFD modeling of buoyancy driven cavities with internal heat source -Application to heated rooms  

E-Print Network [OSTI]

comparisons are given with regard to heat transfer to the walls as well as to heat source behavior and plume. Keywords: CFD - Computational Fluid Dynamics modeling; buoyancy driven cavity; heat source; thermal plume enclosure helps to accurately assess the heat transfer phenomena that take place across the building

74

On spurious behavior of CFD simulations  

SciTech Connect (OSTI)

Spurious behavior in underresolved grids and/or semi-implicit temporal discretizations for four computational fluid dynamics (CFD) simulations are studied. The numerical simulations consist of (a) a 1-D chemically relaxed nonequilibrium model, (b) the direct numerical simulation (DNS) of 2-D incompressible flow over a backward facing step, (c) a loosely-coupled approach for a 2-D fluid-structure interaction, and (d) a 3-D compressible unsteady flow simulation of vortex breakdown in delta wings. Using knowledge from dynamical systems theory, various types of spurious behaviors that are numerical artifacts were systematically identified. These studies revealed the various possible dangers of misinterpreting numerical simulation of realistic complex flows that are constrained by the available computing power. In large scale computations underresolved grids, semi-implicit procedures, loosely-coupled implicit procedures, and insufficiently long time integration in DNS are most often unavoidable. Consequently, care must be taken in both computation and in interpretation of the numerical data. The results presented confirm the important role that dynamical systems theory can play in the understanding of the nonlinear behavior of numerical algorithms and in aiding the identification of the sources of numerical uncertainties in CFD.

Yee, H.C. [National Aeronautics and Space Administration, Moffett Field, CA (United States). Ames Research Center; Torczynski, J.R. [Sandia National Labs., Albuquerque, NM (United States); Morton, S.A.; Visbal, M.R. [Wright Lab., Wright-Patterson AFB, OH (United States); Sweby, P.K. [Univ. of Reading (United Kingdom)

1997-05-01T23:59:59.000Z

75

CFD analysis for solar chimney power plants  

Science Journals Connector (OSTI)

Abstract Solar chimney power plants are investigated numerically using ANSYS Fluent and an in-house developed Computational Fluid Dynamics (CFD) code. Analytical scaling laws are verified by considering a large range of scales with tower heights between 1m (sub-scale laboratory model) and 1000m (largest envisioned plant). A model with approximately 6m tower height is currently under construction at the University of Arizona. Detailed time-dependent high-resolution simulations of the flow in the collector and chimney of the model provide detailed insight into the fluid dynamics and heat transfer mechanisms. Both transversal and longitudinal convection rolls are identified in the collector, indicating the presence of a RayleighBnardPoiseuille instability. Local separation is observed near the chimney inflow. The flow inside the chimney is fully turbulent.

Hermann F. Fasel; Fanlong Meng; Ehsan Shams; Andreas Gross

2013-01-01T23:59:59.000Z

76

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

E-Print Network [OSTI]

and G. Aguilar. Fluid and heat transfer dynamics of cryogen108 5.4.3 Fluid and Heat Transfer Dynamics duringpractice. 5.4.3 Fluid and Heat Transfer Dynamics during CSC

Vu, Henry

2010-01-01T23:59:59.000Z

77

Reducing Toxic Exposure In Buildings: Application of Computational Fluid  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

78

Dynamics of Absolute Vorticity in the Boussinesq Fluid  

Science Journals Connector (OSTI)

The dynamics of absolute vorticity in the Boussinesq fluid is examined. It is shown that the Boussinesq approximation only captures one of the horizontal ... component of the solenoidal term neglected by the Boussinesq

Zuohao Cao

1999-01-01T23:59:59.000Z

79

Computational fluid dynamics simulation of hydrodynamics and chemical reaction in a CFB downer  

Science Journals Connector (OSTI)

Abstract A computational fluid dynamics (CFD) model for simulating the chemical reaction process in a gasparticle circulating fluidized bed (CFB) downer is introduced by combining the two-fluid model (TFM) for the gasparticle turbulent flows and the c 2 ? ? c model for the turbulent mass transfer. With the proposed model, the species concentration and solid volume fraction as well as the velocity distributions along the CFB downer are able to be predicted. In mathematical expression of the proposed model, the recently developed formulations of c 2 ? ? c is adopted to close the turbulent mass transfer equations so that the turbulent mass diffusivity can be determined without relying on empirical methods. As for the gassolid two phase turbulent momentum transfer equations, the methodology of kg??g?kp??p?? is used for their closures. To validate the proposed model, simulation is carried out for the catalytic ozone decomposition in a gassolid CFB downer. The simulation results are compared with the experimental data and satisfactory agreement is found between them in both axial/radial distributions of concentration and solid volume fraction. Furthermore, the simulations reveal that the turbulent mass diffusivity varies along axial and radial directions, and the turbulent Schmidt number is not a constant throughout the CFB downer.

Wenbin Li; Kuotsung Yu; Botan Liu; Xigang Yuan

2015-01-01T23:59:59.000Z

80

Computational fluid dynamics (CFD) study of co-firing of coal and pretreated biomass.  

E-Print Network [OSTI]

?? This master thesis describes the co-firing concept, benefits and opportunities of pretreated biomass in pulverized coal boilers for industrial use. Burning fossil fuels, i.e. (more)

Hye, A S M Abdul

2014-01-01T23:59:59.000Z

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.


81

Computational Fluid Dynamics (cfd) Modeling of a Laboratory Scale Coal Gasifier.  

E-Print Network [OSTI]

?? Furthering gasification technology is an essential part of advancing clean coal technologies. In order to seek insight into the appropriate operations for the formation (more)

Schultheiss, Kiel S

2013-01-01T23:59:59.000Z

82

American Institute of Aeronautics and Astronautics Coupled Flight Dynamics and CFD Analysis of Pilot  

E-Print Network [OSTI]

of the ship airwake on the rotorcraft as well as the effect of the rotorcraft on the ship airwake can of Pilot Workload in Ship Airwakes Derek O. Bridges,1 Joseph F. Horn,2 Emre Alpman,3 and Lyle N. Long4 of the helicopter/ship dynamic interface, in which pilot workload is examined using a novel coupling of flight

83

Predicting aerodynamic characteristic of typical wind turbine airfoils using CFD  

SciTech Connect (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

84

Gasification CFD Modeling for Advanced Power Plant Simulations  

SciTech Connect (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 NETLs 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

85

The legacy and future of CFD at Los Alamos  

SciTech Connect (OSTI)

The early history is presented of the prolific development of CFD methods in the Fluid Dynamics Group (T-3) at Los Alamos National Laboratory in the years from 1958 to the late 1960`s. Many of the currently used numerical methods--PIC, MAC, vorticity-stream-function, ICE, ALE methods and the {kappa}-{var_epsilon} method for turbulence--originated during this time. The rest of the paper summarizes the current research in T-3 for CFD, turbulence and solids modeling. The research areas include reactive flows, multimaterial flows, multiphase flows and flows with spatial discontinuities. Also summarized are modern particle methods and techniques developed for large scale computing on massively parallel computing platforms and distributed processors.

Johnson, N.L. [Los Alamos National Lab., NM (United States). Theoretical Div.

1996-06-01T23:59:59.000Z

86

Enabling the environmentally clean air transportation of the future: a vision of computational fluid dynamics in 2030  

Science Journals Connector (OSTI)

...stall and surge, combustion dynamics, turbine cooling and engine noise assessment. Similar...industry of the future with reduced greenhouse gas emissions will require revolutionary advances...considered wherever possible. Funding statement Vision 2030 CFD study was performed under NASA...

2014-01-01T23:59:59.000Z

87

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

SciTech Connect (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

88

Green Algae as Model Organisms for Biological Fluid Dynamics  

E-Print Network [OSTI]

In the past decade the volvocine green algae, spanning from the unicellular $Chlamydomonas$ to multicellular $Volvox$, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 $\\mu$m to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these remarkable organisms.

Raymond E. Goldstein

2014-09-08T23:59:59.000Z

89

Green Algae as Model Organisms for Biological Fluid Dynamics  

E-Print Network [OSTI]

In the past decade the volvocine green algae, spanning from the unicellular $Chlamydomonas$ to multicellular $Volvox$, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 $\\mu$m to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these re...

Goldstein, Raymond E

2014-01-01T23:59:59.000Z

90

Overall Efficiency Abstract-Computational fluid dynamics (C  

E-Print Network [OSTI]

to characterize the ef turbines. Efficiency is taken as the ratio of powe useful electricity) to total power lostOverall Efficiency Dept. of Abstract-Computational fluid dynamics (C have been completed from the u flow energy. Many tidal turbine developers ducted designs which accelerate the flow thro

Pedersen, Tom

91

Fluids as Dynamic Templates for Cytoskeletal Proteins in Plant Cells  

E-Print Network [OSTI]

The Dynamic Template model of biological cell membranes and the cytoplasm as spatially organised fluid layers is extended to plant cells, and is shown to offer a feasible shear driven mechanism for the co-alignment of internal and external fibres observed during growth and tropic responses

J. T. Lofthouse

2008-07-12T23:59:59.000Z

92

COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELLS  

E-Print Network [OSTI]

COMPUTATIONAL FLUID DYNAMICS MODELING OF SOLID OXIDE FUEL CELLS Ugur Pasaogullari and Chao-dimensional model has been developed to simulate solid oxide fuel cells (SOFC). The model fully couples current density operation. INTRODUCTION Solid oxide fuel cells (SOFC) are among possible candidates

93

3D Tomography from Few Projections in Experimental Fluid Dynamics  

E-Print Network [OSTI]

3D Tomography from Few Projections in Experimental Fluid Dynamics Stefania Petra, Andreas Schr projections due to both limited optical access to wind and water tunnels and cost S. Petra, C. Schn projection data. The latter are the pixel entries in the recorded 2D images that represent the integration

Schnörr, Christoph

94

CFD analysis of laminar oscillating flows  

SciTech Connect (OSTI)

This paper describes a numerical simulations of oscillating flow in a constricted duct and compares the results with experimental and theoretical data. The numerical simulations were performed using the computational fluid dynamics (CFD) code CFX4.2. The numerical model simulates an experimental oscillating flow facility that was designed to test the properties and characteristics of oscillating flow in tapered ducts, also known as jet pumps. Jet pumps are useful devices in thermoacoustic machinery because they produce a secondary pressure that can counteract an unwanted effect called streaming, and significantly enhance engine efficiency. The simulations revealed that CFX could accurately model velocity, shear stress and pressure variations in laminar oscillating flow. The numerical results were compared to experimental data and theoretical predictions with varying success. The least accurate numerical results were obtained when laminar flow approached transition to turbulent flow.

Booten, C. W. Charles W.); Konecni, S. (Snezana); Smith, B. L. (Barton L.); Martin, R. A. (Richard A.)

2001-01-01T23:59:59.000Z

95

TANK48 CFD MODELING ANALYSIS  

SciTech Connect (OSTI)

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

96

Fluid Dynamics in Bioreactor Design: Considerations for the Theoretical and Practical Approach  

Science Journals Connector (OSTI)

The following chapter summarizes principles of fluid dynamics in bioreactor design with a focus on mammalian cell-culture systems.

B. Weyand; M. Israelowitz; H. P. von Schroeder

2009-01-01T23:59:59.000Z

97

CFD-based design load analysis of 5MW offshore wind turbine  

Science Journals Connector (OSTI)

The structure and aerodynamic loads acting on NREL 5MW reference wind turbine blade are calculated and analyzed based on advanced Computational Fluid Dynamics (CFD) and unsteady Blade Element Momentum (BEM). A detailed examination of the six force components has been carried out (three force components and three moment components). Structure load (gravity and inertia load) and aerodynamic load have been obtained by additional structural calculations (CFD or BEM respectively ). In CFD method the Reynolds Average Navier-Stokes approach was applied to solve the continuity equation of mass conservation and momentum balance so that the complex flow around wind turbines was modeled. Written in C programming language a User Defined Function (UDF) code which defines transient velocity profile according to the Extreme Operating Gust condition was compiled into commercial FLUENT package. Furthermore the unsteady BEM with 3D stall model has also adopted to investigate load components on wind turbine rotor. The present study introduces a comparison between advanced CFD and unsteady BEM for determining load on wind turbine rotor. Results indicate that there are good agreements between both present methods. It is importantly shown that six load components on wind turbine rotor is significant effect under Extreme Operating Gust (EOG) condition. Using advanced CFD and additional structural calculations this study has succeeded to construct accuracy numerical methodology to estimate total load of wind turbine that compose of aerodynamic load and structure load.

T. T. Tran; G. J. Ryu; Y. H. Kim; D. H. Kim

2012-01-01T23:59:59.000Z

98

AN OVERVIEW OF GEORGIA TECH STUDIES ON THE FLUID DYNAMICS ASPECTS  

E-Print Network [OSTI]

and numerical studies on the fluid dynamics and heat transfer aspects of liquid -protected fusion energyAN OVERVIEW OF GEORGIA TECH STUDIES ON THE FLUID DYNAMICS ASPECTS OF LIQUID PROTECTION SCHEMES the fluid dynamics aspects of liquid protection schemes for fusion energy reactors. The problems described

99

Nuclear Energy CFD Application Management System  

SciTech Connect (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

100

Computational fluid dynamics for turbomachinery internal air systems  

Science Journals Connector (OSTI)

...modelling developments are discussed...the main gas path, which...designers and turbine aerodynamicists...1996 CFD developments for turbine blade heat...Engines and Gas Turbines...compressor gas turbine internal...on future strategies towards understanding...

2007-01-01T23:59:59.000Z

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.


101

ITP Chemicals: Technology Roadmap for Computational Fluid Dynamics, January 1999  

Broader source: Energy.gov [DOE]

As the 21st century approaches, the chemical industry faces considerable economic, environmental and societal challenges. CFD can assist the design and optimization of new and existing processes and products.

102

Nek5000: Computational Fluid Dynamics Code | Argonne National Laboratory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

103

Introduction to finite-difference methods for numerical fluid dynamics  

SciTech Connect (OSTI)

This work is intended to be a beginner`s exercise book for the study of basic finite-difference techniques in computational fluid dynamics. It is written for a student level ranging from high-school senior to university senior. Equations are derived from basic principles using algebra. Some discussion of partial-differential equations is included, but knowledge of calculus is not essential. The student is expected, however, to have some familiarity with the FORTRAN computer language, as the syntax of the computer codes themselves is not discussed. Topics examined in this work include: one-dimensional heat flow, one-dimensional compressible fluid flow, two-dimensional compressible fluid flow, and two-dimensional incompressible fluid flow with additions of the equations of heat flow and the {Kappa}-{epsilon} model for turbulence transport. Emphasis is placed on numerical instabilities and methods by which they can be avoided, techniques that can be used to evaluate the accuracy of finite-difference approximations, and the writing of the finite-difference codes themselves. Concepts introduced in this work include: flux and conservation, implicit and explicit methods, Lagrangian and Eulerian methods, shocks and rarefactions, donor-cell and cell-centered advective fluxes, compressible and incompressible fluids, the Boussinesq approximation for heat flow, Cartesian tensor notation, the Boussinesq approximation for the Reynolds stress tensor, and the modeling of transport equations. A glossary is provided which defines these and other terms.

Scannapieco, E.; Harlow, F.H.

1995-09-01T23:59:59.000Z

104

Geophysical Fluid Dynamics Laboratory Portal | Data.gov  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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}

105

Experimental and CFD Analysis of Advanced Convective Cooling Systems  

SciTech Connect (OSTI)

The objective of this project is to study the fundamental physical phenomena in the reactor cavity cooling system (RCCS) of very high-temperature reactors (VHTRs). One of the primary design objectives is to assure that RCCS acts as an ultimate heat sink capable of maintaining thermal integrity of the fuel, vessel, and equipment within the reactor cavity for the entire spectrum of postulated accident scenarios. Since construction of full-scale experimental test facilities to study these phenomena is impractical, it is logical to expect that computational fluid dynamics (CFD) simulations will play a key role in the RCCS design process. An important question then arises: To what extent are conventional CFD codes able to accurately capture the most important flow phenomena, and how can they be modified to improve their quantitative predictions? Researchers are working to tackle this problem in two ways. First, in the experimental phase, the research team plans to design and construct an innovative platform that will provide a standard test setting for validating CFD codes proposed for the RCCS design. This capability will significantly advance the state of knowledge in both liquid-cooled and gas-cooled (e.g., sodium fast reactor) reactor technology. This work will also extend flow measurements to micro-scale levels not obtainable in large-scale test facilities, thereby revealing previously undetectable phenomena that will complement the existing infrastructure. Second, in the computational phase of this work, numerical simulation of the flow and temperature profiles will be performed using advanced turbulence models to simulate the complex conditions of flows in critical zones of the cavity. These models will be validated and verified so that they can be implemented into commercially available CFD codes. Ultimately, the results of these validation studies can then be used to enable a more accurate design and safety evaluation of systems in actual nuclear power applications (both during normal operation and accident scenarios).

Yassin A. Hassan; Victor M. Ugaz

2012-06-27T23:59:59.000Z

106

CFD simulation of leak in residential HVAC ducts  

Science Journals Connector (OSTI)

A three-dimensional computational fluid dynamics model was used to simulate fluid flow in a duct and its simulated leaks with six different air leak geometries placed respectively on its periphery. The k? turbulence model for high Reynolds numbers flows was used for that purpose and the Reynolds numbers were varied to simulate a variety of flow conditions between 27,000 and 82,000. The computer code was used to produce pressure drop data and leak flow rates across the holes necessary to compute the pressure loss coefficients, as well as to produce flow field and static pressure plots that offer insight into the physics of the flow field. The flow coefficient and pressure exponent (C and n) were found for different leak geometries by curve fitting the pressure and leak flow data derived from CFD simulations and were compared to available data in the literature.

Samir Moujaes; Radhika Gundavelli

2012-01-01T23:59:59.000Z

107

Computational fluid dynamics study of wind turbine blade profiles at low Reynolds numbers for various angles of attack  

Science Journals Connector (OSTI)

Airfoil data are rarely available for Angles Of Attack (AOA) over the entire range of 180. This is unfortunate for the wind turbine designers because wind turbine airfoils do operate over this entire range. In this paper an attempt is made to study the lift and drag forces on a wind turbine blade at various sections and the effect of angle of attack on these forces. Aerodynamic simulations of the steady flow past two-dimensional wind-turbine blade-profiles developed by the National Renewable Energy Laboratory (NREL) at low Reynolds number will be performed. The aerodynamic simulation will be performed using Computational Fluid Dynamics (CFD) techniques. The governing equations used in the simulations are the Reynolds-Average-Navier-Stokes (RANS) equations. The simulations at different wind speeds will be performed on the S809 and the S826 blade profiles. The S826 blade profile is considered in this study because it is the most suitable blade profile for the wind conditions in Egypt in the site of Gulf El-Zayt on the red sea. Lift and drag forces along with the angle of attack are the important parameters in a wind turbine system. These parameters determine the efficiency of the wind turbine. The lift and drag forces are computed over the entire range of AOA of 180 at low Reynolds numbers. The results of the analysis showed that the AOA between 3 and 8 have high Lift/Drag ratio regardless of the wind speed and the blade profile. The numerical results are compared with wind tunnel measurements at the available limited range of the angle of attack. In addition the numerical results are compared with the results obtained from the equations developed by Viterna and Janetzke for deep stall. The comparisons showed that the used CFD code can accurately predict the aerodynamic loads on the wind-turbine blades.

2012-01-01T23:59:59.000Z

108

Coupling Lattice Boltzmann and Molecular Dynamics models for dense fluids  

E-Print Network [OSTI]

We propose a hybrid model, coupling Lattice Boltzmann and Molecular Dynamics models, for the simulation of dense fluids. Time and length scales are decoupled by using an iterative Schwarz domain decomposition algorithm. The MD and LB formulations communicate via the exchange of velocities and velocity gradients at the interface. We validate the present LB-MD model in simulations of flows of liquid argon past and through a carbon nanotube. Comparisons with existing hybrid algorithms and with reference MD solutions demonstrate the validity of the present approach.

A. Dupuis; E. M. Kotsalis; P. Koumoutsakos

2006-10-27T23:59:59.000Z

109

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

SciTech Connect (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

110

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

DOE Patents [OSTI]

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 the mold space through the openings, the fluid experiencing a dynamic fluid front while filling the mold space with the fluid; and characterizing temporal-spatial properties of the dynamic fluid front by monitoring a temperature 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 the mold 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. (Oak Ridge, TN)

2007-12-25T23:59:59.000Z

111

CFD Analysis of Core Bypass Phenomena  

SciTech Connect (OSTI)

The U.S. Department of Energy is exploring the potential for the VHTR which will be either of a prismatic or a pebble-bed type. One important design consideration for the reactor core of a prismatic VHTR is coolant bypass flow which occurs in the interstitial regions between fuel blocks. Such gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The existence of the gaps induces a flow bias in the fuel blocks and results in unexpected increase of maximum fuel temperature. Traditionally, simplified methods such as flow network calculations employing experimental correlations are used to estimate flow and temperature distributions in the core design. However, the distribution of temperature in the fuel pins and graphite blocks as well as coolant outlet temperatures are strongly coupled with the local heat generation rate within fuel blocks which is not uniformly distributed in the core. Hence, it is crucial to establish mechanistic based methods which can be applied to the reactor core thermal hydraulic design and safety analysis. Computational Fluid Dynamics (CFD) codes, which have a capability of local physics based simulation, are widely used in various industrial fields. This study investigates core bypass flow phenomena with the assistance of commercial CFD codes and establishes a baseline for evaluation methods. A one-twelfth sector of the hexagonal block surface is modeled and extruded down to whole core length of 10.704m. The computational domain is divided vertically with an upper reflector, a fuel section and a lower reflector. Each side of the sector grid can be set as a symmetry boundary

Richard W. Johnson; Hiroyuki Sato; Richard R. Schultz

2010-03-01T23:59:59.000Z

112

CFD Analysis of Core Bypass Phenomena  

SciTech Connect (OSTI)

The U.S. Department of Energy is exploring the potential for the VHTR which will be either of a prismatic or a pebble-bed type. One important design consideration for the reactor core of a prismatic VHTR is coolant bypass flow which occurs in the interstitial regions between fuel blocks. Such gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The existence of the gaps induces a flow bias in the fuel blocks and results in unexpected increase of maximum fuel temperature. Traditionally, simplified methods such as flow network calculations employing experimental correlations are used to estimate flow and temperature distributions in the core design. However, the distribution of temperature in the fuel pins and graphite blocks as well as coolant outlet temperatures are strongly coupled with the local heat generation rate within fuel blocks which is not uniformly distributed in the core. Hence, it is crucial to establish mechanistic based methods which can be applied to the reactor core thermal hydraulic design and safety analysis. Computational Fluid Dynamics (CFD) codes, which have a capability of local physics based simulation, are widely used in various industrial fields. This study investigates core bypass flow phenomena with the assistance of commercial CFD codes and establishes a baseline for evaluation methods. A one-twelfth sector of the hexagonal block surface is modeled and extruded down to whole core length of 10.704m. The computational domain is divided vertically with an upper reflector, a fuel section and a lower reflector. Each side of the one-twelfth grid can be set as a symmetry boundary

Richard W. Johnson; Hiroyuki Sato; Richard R. Schultz

2009-11-01T23:59:59.000Z

113

Bonneville Project: CFD of the Spillway Tailrace  

SciTech Connect (OSTI)

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

114

Development of a Computational Fluid Dynamics Model for Combustion of Fast Pyrolysis Liquid (Bio-oil).  

E-Print Network [OSTI]

??A study was carried out into the computational fluid dynamic simulation of bio-oil combustion. Measurements were taken in an empirical burner to obtain information regarding (more)

McGrath, Arran Thomas

2011-01-01T23:59:59.000Z

115

Multi-phase CFD modeling of solid sorbent carbon capture system  

SciTech Connect (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 EulerianEulerian and EulerianLagrangian 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 EulerianLagrangian simulations (DDPM) are unstable for the given reactor design; while the BARRACUDA EulerianLagrangian model is able to simulate the system given appropriate simplifying assumptions. FLUENT EulerianEulerian simulations also provide a stable solution for the carbon capture reactor given the appropriate simplifying assumptions.

Ryan, E. M.; DeCroix, D.; Breault, Ronald W. [U.S. DOE; Xu, W.; Huckaby, E. David [U.S. DOE

2013-01-01T23:59:59.000Z

116

Multi-Phase CFD Modeling of Solid Sorbent Carbon Capture System  

SciTech Connect (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

117

Comparison of a semi-analytic and a CFD model uranium combustion to experimental data.  

SciTech Connect (OSTI)

Two numerical models were developed and compared for the analysis of uranium combustion and ignition in a furnace. Both a semi-analytical solution and a computational fluid dynamics (CFD) numerical solution were obtained. Prediction of uranium oxidation rates is important for fuel storage applications, fuel processing, and the development of spent fuel metal waste forms. The semi-analytical model was based on heat transfer correlations, a semi-analytical model of flow over a flat surface, and simple radiative heat transfer from the material surface. The CFD model numerically determined the flowfield over the object of interest, calculated the heat and mass transfer to the material of interest, and calculated the radiative heat exchange of the material with the furnace. The semi-analytical model is much less detailed than the CFD model, but yields reasonable results and assists in understanding the physical process. Short computation times allowed the analyst to study numerous scenarios. The CFD model had significantly longer run times, was found to have some physical limitations that were not easily modified, but was better able to yield details of the heat and mass transfer and flow field once code limitations were overcome.

Clarksean, R.

1998-04-01T23:59:59.000Z

118

CFD INVESTIGATION OF EXPERIMENTAL DATA PROPOSED TO BE A VALIDATION DATA SET  

SciTech Connect (OSTI)

The U. S. Department of Energy (DOE) is currently supporting the development of a next generation nuclear plant (NGNP). The NGNP is based on the very high temperature reactor (VHTR), which is a Gen. IV gas-cooled reactor concept that will use helium as the coolant. Computational fluid dynamics (CFD) calculations are to be employed to estimate the details of the flow and heat transfer in the lower plenum where the heated coolant empties before exiting the reactor vessel. While it is expected that CFD will be able to provide detailed information about the flow, it must be validated using experimental data. Detailed experimental data have been taken in the INLs matched index of refraction (MIR) facility of a scaled model of a section of the prismatic VHTR lower plenum. The present article examines the data that were taken to determine the suitability of such data to be a validation data set for CFD calculations. CFD calculations were made to compare with the experimental data to explore potential issues and make recommendations regarding the MIR data.

Richard W. Johnson

2009-07-01T23:59:59.000Z

119

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

SciTech Connect (OSTI)

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

120

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

SciTech Connect (OSTI)

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

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121

Petascale, Adaptive CFD | Argonne Leadership Computing Facility  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

122

Identification of an average temperature and a dynamical pressure in a multitemperature mixture of fluids  

E-Print Network [OSTI]

Identification of an average temperature and a dynamical pressure in a multitemperature mixture pressure even if the fluids have a zero bulk viscosity. The nonequilib- rium dynamical pressure can

Boyer, Edmond

123

CFD Modeling of a CFB Riser Using Improved Inlet Boundary Conditions  

Science Journals Connector (OSTI)

A computational fluid dynamics (CFD) model based on Eulerian?Eulerian approach coupled with granular kinetics theory was adopted to investigate the hydrodynamics and flow structures in a circulating fluidized bed (CFB) riser column. A new approach to specify the inlet boundary conditions was proposed in this study to simulate gas?solids flow in CFB risers more accurately. Simulation results were compared with the experimental data and good agreement between the numerical results and experimental data was observed under different operating conditions which indicates the effectiveness and accuracy of the CFD model with the proposed inlet boundary conditions. The results also illustrate a clear core annulus structure in the CFB riser under all operating conditions both experimentally and numerically.

B. T. Peng; C. Zhang; J. X. Zhu; X. B. Qi

2010-01-01T23:59:59.000Z

124

A two-component heavy fuel oil evaporation model for CFD studies in marine Diesel engines  

Science Journals Connector (OSTI)

Abstract The paper presents an evaporation model for Heavy Fuel Oil (HFO) combustion studies. In the present work, HFO is considered as a mixture of a heavy and a light fuel component, with the thermophysical properties of the heavy component calculated from the recently introduced model of Kyriakides et al. (2009) [1]. The model proposes a proper treatment of convective heat transfer to the evaporating fuel droplets. Computational Fluid Dynamics (CFD) simulations of HFO spray combustion in constant volume chambers are performed, utilizing a modified characteristic time combustion model. The results are in good agreement with literature experimental data. Computational results for a two-stroke marine Diesel engine also compare favorably against experiments. The present development yields a basis for detailed CFD studies of HFO combustion in large marine Diesel engines.

Nikolaos Stamoudis; Christos Chryssakis; Lambros Kaiktsis

2014-01-01T23:59:59.000Z

125

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

SciTech Connect (OSTI)

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

126

Computational fluid dynamics modeling of chemical looping combustion process with calcium sulphate oxygen carrier - article no. A19  

SciTech Connect (OSTI)

To concentrate CO{sub 2} in combustion processes by efficient and energy-saving ways is a first and very important step for its sequestration. Chemical looping combustion (CLC) could easily achieve this goal. A chemical-looping combustion system consists of a fuel reactor and an air reactor. Two reactors in the form of interconnected fluidized beds are used in the process: (1) a fuel reactor where the oxygen carrier is reduced by reaction with the fuel, and (2) an air reactor where the reduced oxygen carrier from the fuel reactor is oxidized with air. The outlet gas from the fuel reactor consists of CO{sub 2} and H{sub 2}O, while the outlet gas stream from the air reactor contains only N{sub 2} and some unused O{sub 2}. The water in combustion products can be easily removed by condensation and pure carbon dioxide is obtained without any loss of energy for separation. Until now, there is little literature about mathematical modeling of chemical-looping combustion using the computational fluid dynamics (CFD) approach. In this work, the reaction kinetic model of the fuel reactor (CaSO{sub 4}+ H{sub 2}) is developed by means of the commercial code FLUENT and the effects of partial pressure of H{sub 2} (concentration of H{sub 2}) on chemical looping combustion performance are also studied. The results show that the concentration of H{sub 2} could enhance the CLC performance.

Baosheng Jin; Rui Xiao; Zhongyi Deng; Qilei Song [Southeast University (China). Key Laboratory of Clean Coal Power Generation and Combustion Technology of Ministry of Education

2009-07-01T23:59:59.000Z

127

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]

1980. Numerical heat transfer and fluid flow. Washington,of heat transfer by natural convection across vertical fluidFluid Dynamics and Conduction Simulations of Heat Transfer

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

2003-01-01T23:59:59.000Z

128

On the dynamics of magnetic fluids in magnetic resonance imaging  

E-Print Network [OSTI]

The hydrodynamics of magnetic fluids, often termed ferrofluids, has been an active area of research since the mid 1960s. However, it is only in the past twenty years that these fluids have begun to be used in magnetic ...

Cantillon-Murphy, Pdraig J

2008-01-01T23:59:59.000Z

129

Fan-shape optimisation using CFD and genetic algorithms for increasing the efficiency of electric motors  

Science Journals Connector (OSTI)

The electric motor efficiency represents the effectiveness with which the motor converts electrical energy into mechanical energy. As the energy losses are converted into heat, which is dissipated by the motor frame aided by internal and external fans, a better cooling system adds up to better efficiency. In recent years, improvements in motor efficiency have been achieved but at higher costs. By using Genetic Algorithms (GAs), changes are introduced to the fan shape looking for a better aerodynamic performance. The evaluation of the achieved fan efficiency with the modified shapes is performed with Computational Fluid Dynamics (CFD) simulation software.

Noel Leon-Rovira; Eduardo Uresti; Waldo Arcos

2007-01-01T23:59:59.000Z

130

CFD Simulation of Brine-Seawater Mixing in a Rotary Energy Recovery Device  

Science Journals Connector (OSTI)

CFD Simulation of Brine-Seawater Mixing in a Rotary Energy Recovery Device ... The effects of operational conditions on the mixing behavior of rotary energy recovery device have been systematically investigated through the combined methods of computational fluid dynamics and validating experiments in this paper. ... The obtained formulas between mixing and dimensionless flow length provide a simple way to calculate and predict the mixing of device, which will be beneficial to design and operate the rotary energy recovery device in a lower mixing level. ...

Enle Xu; Yue Wang; Liming Wu; Shichang Xu; Yuxin Wang; Shichang Wang

2014-11-05T23:59:59.000Z

131

Stratified Rotating Boussinesq Equations in Geophysical Fluid Dynamics: Dynamic Bifurcation and Periodic Solutions  

E-Print Network [OSTI]

The main objective of this article is to study the dynamics of the stratified rotating Boussinesq equations, which are a basic model in geophysical fluid dynamics. First, for the case where the Prandtl number is greater than one, a complete stability and bifurcation analysis near the first critical Rayleigh number is carried out. Second, for the case where the Prandtl number is smaller than one, the onset of the Hopf bifurcation near the first critical Rayleigh number is established, leading to the existence of nontrivial periodic solutions. The analysis is based on a newly developed bifurcation and stability theory for nonlinear dynamical systems (both finite and infinite dimensional) by two of the authors [16].

Chun-Hsiung Hsia; Tian Ma; Shouhong Wang

2006-10-31T23:59:59.000Z

132

Generalized dynamical density functional theory for classical fluids and the significance of inertia and hydrodynamic interactions  

E-Print Network [OSTI]

We study the dynamics of a colloidal fluid including inertia and hydrodynamic interactions, two effects which strongly influence the non-equilibrium properties of the system. We derive a general dynamical density functional theory (DDFT) which shows very good agreement with full Langevin dynamics. In suitable limits, we recover existing DDFTs and a Navier-Stokes-like equation with additional non-local terms.

Benjamin D. Goddard; Andreas Nold; Nikos Savva; Grigorios A. Pavliotis; Serafim Kalliadasis

2012-08-08T23:59:59.000Z

133

The Lattice Boltzmann Method For Computational Fluid Dynamics Applications.  

E-Print Network [OSTI]

??Dennis, Brian An analysis of lattice Boltzmann method is presented in this thesis. This analysis contrast with the traditional lattice Boltzmann work, where complex fluids (more)

Adhvaryu, Chinmay

2008-01-01T23:59:59.000Z

134

DRILL-STRING NONLINEAR DYNAMICS ACCOUNTING FOR DRILLING FLUID T. G. Ritto  

E-Print Network [OSTI]

;1. INTRODUCTION A drill-string is a slender structure used in oil wells to penetrate the soil in search of oilDRILL-STRING NONLINEAR DYNAMICS ACCOUNTING FOR DRILLING FLUID T. G. Ritto R. Sampaio thiagoritto Descartes, 77454 Marne-la-Vallée, France Abstract. The influence of the drilling fluid (or mud) on the drill

Boyer, Edmond

135

Phase transitions in high energy heavy ion collisions within fluid dynamics  

E-Print Network [OSTI]

Recent advances in Fluid Dynamical modeling of heavy ion collisions are presented, with particular attention to mesoscopic systems, QGP formation in the pre FD regime and QGP hadronization coinciding with the final freeze-out.

L. P. Csernai; Cs. Anderlik; V. Magas

2000-10-06T23:59:59.000Z

136

Parallel Simulation of Subsonic Fluid Dynamics on a Cluster of Workstations  

E-Print Network [OSTI]

An effective approach of simulating fluid dynamics on a cluster of non- dedicated workstations is presented. The approach uses local interaction algorithms, small communication capacity, and automatic migration of parallel ...

Skordos, Panayotis A.

1995-12-01T23:59:59.000Z

137

Investigation into the discrepancies between computational fluid dynamics lift predictions and experimental results  

E-Print Network [OSTI]

An analysis of current computational fluid dynamics capabilities in predicting mean lift forces for two dimensional foils is conducted. It is shown that both integral boundary layer theory and Reynolds Averaged Navier ...

Fairman, Randall S. (Randall Scott), 1967-

2002-01-01T23:59:59.000Z

138

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

Open Energy Info (EERE)

Mechanical Fluid-Dynamical Model For Ground Movements At Campi Flegrei Caldera Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: A Mechanical...

139

Nonequilibrium molecular dynamics simulations of confined fluids in contact with the bulk  

E-Print Network [OSTI]

Nonequilibrium molecular dynamics simulations of confined fluids in contact with the bulk Luzheng Zhang, Ramkumar Balasundaram,a) and Stevin H. Gehrke Department of Chemical Engineering, Kansas State University, Manhattan, Kansas 66506 Shaoyi Jiangb) Department of Chemical Engineering, University

Zhang, Luzheng

140

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

Open Energy Info (EERE)

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

Note: This page contains sample records for the topic "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.


141

Ex-Core CFD Analysis Results for the Prometheus Gas Reactor  

SciTech Connect (OSTI)

This paper presents the initial nozzle-to-nozzle (N2N) reactor vessel model scoping studies using computational fluid dynamics (CFD) analysis methods. The N2N model has been solved under a variety of different boundary conditions. This paper presents some of the basic hydraulic results from the N2N CFD analysis effort. It also demonstrates how designers were going to apply the analysis results to modify a number of the design features. The initial goals for developing a preliminary CFD N2N model were to establish baseline expectations for pressure drops and flow fields around the reactor core. Analysis results indicated that the averaged reactor vessel pressure drop for all analyzed cases was 46.9 kPa ({approx}6.8 psid). In addition, mass flow distributions to the three core fuel channel regions exhibited a nearly inverted profile to those specified for the in-core thermal/hydraulic design. During subsequent design iterations, the goal would have been to modify or add design features that would have minimized reactor vessel pressure drop and improved flow distribution to the inlet of the core.

Lorentz, Donald G. [Space Engineering, Bechtel Bettis, Inc. West Mifflin, PA 15122 (United States)

2007-01-30T23:59:59.000Z

142

Parcel EulerianLagrangian fluid dynamics of rotating geophysical flows  

Science Journals Connector (OSTI)

...J. 1981 Hamiltonian field description of two-dimensional vortex fluids and guiding center plasmas. Plasma Physics Laboratory report, Princeton University. PPPL-1793, p. 20. Morrison, P.J 1998Hamiltonian description of the ideal...

2006-01-01T23:59:59.000Z

143

Integrating multi-objective optimization with computational fluid dynamics to optimize boiler combustion process of a coal fired power plant  

Science Journals Connector (OSTI)

Abstract The dominant role of electricity generation and environment consideration have placed strong requirements on coal fired power plants, requiring them to improve boiler combustion efficiency and decrease carbon emission. Although neural network based optimization strategies are often applied to improve the coal fired power plant boiler efficiency, they are limited by some combustion related problems such as slagging. Slagging can seriously influence heat transfer rate and decrease the boiler efficiency. In addition, it is difficult to measure slag build-up. The lack of measurement for slagging can restrict conventional neural network based coal fired boiler optimization, because no data can be used to train the neural network. This paper proposes a novel method of integrating non-dominated sorting genetic algorithm (NSGA II) based multi-objective optimization with computational fluid dynamics (CFD) to decrease or even avoid slagging inside a coal fired boiler furnace and improve boiler combustion efficiency. Compared with conventional neural network based boiler optimization methods, the method developed in the work can control and optimize the fields of flue gas properties such as temperature field inside a boiler by adjusting the temperature and velocity of primary and secondary air in coal fired power plant boiler control systems. The temperature in the vicinity of water wall tubes of a boiler can be maintained within the ash melting temperature limit. The incoming ash particles cannot melt and bond to surface of heat transfer equipment of a boiler. So the trend of slagging inside furnace is controlled. Furthermore, the optimized boiler combustion can keep higher heat transfer efficiency than that of the non-optimized boiler combustion. The software is developed to realize the proposed method and obtain the encouraging results through combining ANSYS 14.5, ANSYS Fluent 14.5 and CORBA C++.

Xingrang Liu; R.C. Bansal

2014-01-01T23:59:59.000Z

144

Standard Problems for CFD Validation for NGNP - Status Report  

SciTech Connect (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 250C to perhaps 1000C. 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 INLs 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

145

Petrov type I Condition and Dual Fluid Dynamics  

E-Print Network [OSTI]

Recently Lysov and Strominger [arXiv:1104.5502] showed that imposing Petrov type I condition on a $(p+1)$-dimensional timelike hypersurface embedded in a $(p+2)$-dimensional vacuum Einstein gravity reduces the degrees of freedom in the extrinsic curvature of the hypersurface to that of a fluid on the hypersurface, and that the leading-order Einstein constraint equations in terms of the mean curvature of the embedding give the incompressible Navier-Stokes equations of the dual fluid. In this paper we show that the non-relativistic fluid dual to vacuum Einstein gravity does not satisfy the Petrov type I condition at next order, unless additional constraint such as the irrotational condition is added. In addition, we show that this procedure can be inversed to derive the non-relativistic hydrodynamics with higher order corrections through imposing the Petrov type I condition, and that some second order transport coefficients can be extracted, but the dual "Petrov type I fluid" does not match the dual fluid constructed from the geometry of vacuum Einstein gravity in the non-relativistic limit. We discuss the procedure both on the finite cutoff surface via the non-relativistic hydrodynamic expansion and on the highly accelerated surface via the near horizon expansion.

Rong-Gen Cai; Li Li; Qing Yang; Yun-Long Zhang

2014-03-17T23:59:59.000Z

146

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

SciTech Connect (OSTI)

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

147

CFD modeling of commercial-scale entrained-flow coal gasifiers  

SciTech Connect (OSTI)

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

148

Introduction to Computational Fluid Dynamics 424512 E #2Introduction to Computational Fluid Dynamics 424512 E #2 --rzrz IntroductionIntroduction toto ComputationalComputational Fluid DynamicsFluid DynamicsIntroductionIntroduction toto ComputationalComputa  

E-Print Network [OSTI]

transferExample: stationary heat transfer Stationary heat transfer, 2-D (Laplace eq'n): with a grid fluid flow (and heat,(and heat, massmass transfer)transfer) ((lecturelecture 4 of 5)4 of 5) Ron #2 -- rzrz Example: stationary heat transferExample: stationary heat transferExample: stationary heat

Zevenhoven, Ron

149

Numerical implication of Riemann problem theory for fluid dynamics  

SciTech Connect (OSTI)

The Riemann problem plays an important role in understanding the wave structure of fluid flow. It is also crucial step in some numerical algorithms for accurately and efficiently computing fluid flow; Godunov method, random choice method, and from tracking method. The standard wave structure consists of shock and rarefaction waves. Due to physical effects such as phase transitions, which often are indistinguishable from numerical errors in an equation of state, anomalkous waves may occur, ''rarefaction shocks'', split waves, and composites. The anomalous waves may appear in numerical calculations as waves smeared out by either too much artificial viscosity or insufficient resolution. In addition, the equation of state may lead to instabilities of fluid flow. Since these anomalous effects due to the equation of state occur for the continuum equations, they can be expected to occur for all computational algorithms. The equation of state may be characterized by three dimensionless variables: the adiabatic exponent ..gamma.., the Grueneisen coefficient GAMMA, and the fundamental derivative G. The fluid flow anomalies occur when inequalities relating these variables are violated. 18 refs.

Menikoff, R.

1988-01-01T23:59:59.000Z

150

CFD analysis of bubble hydrodynamics in a fuel reactor for a hydrogen-fueled chemical looping combustion system  

Science Journals Connector (OSTI)

Abstract This study investigates the temporal development of bubble hydrodynamics in the fuel reactor of a hydrogen-fueled chemical looping combustion (CLC) system by using a computational model. The model also investigates the molar fraction of products in gas and solid phases. The study assists in developing a better understanding of the CLC process, which has many advantages such as being a potentially promising candidate for an efficient carbon dioxide capture technology. The study employs the kinetic theory of granular flow. The reactive fluid dynamic system of the fuel reactor is customized by incorporating the kinetics of an oxygen carrier reduction into a commercial computational fluid dynamics (CFD) code. An Eulerian multiphase treatment is used to describe the continuum two-fluid model for both gas and solid phases. CaSO4 and H2 are used as an oxygen carrier and a fuel, respectively. The computational results are validated with the experimental and numerical results available in the open literature. The CFD simulations are found to capture the features of the bubble formation, rise and burst in unsteady and quasi-steady states very well. The results show a significant increase in the conversion rate with higher dense bed height, lower bed width, higher free board height and smaller oxygen carrier particles which upsurge an overall performance of the CLC plant.

Atal Bihari Harichandan; Tariq Shamim

2014-01-01T23:59:59.000Z

151

The GK Batchelor Laboratory of Fluid Dynamics Dr. S.B. Dalziel, Director of the Fluid Dynamics Laboratory,  

E-Print Network [OSTI]

to questions that either helps us construct appropriate mathematical models, and provide the data to validate of pollutants from our city streets? What governs the crystallisation of magma, or the progress of a pyroclastic of a suspended second phase? Is mix- ing sensitive to how we put the energy into the system? How do fluids

Cambridge, University of

152

CFD Calculation of Internal Natural Convection in the Annulus between Horizontal Concentric Cylinders  

SciTech Connect (OSTI)

The objective of this heat transfer and fluid flow study is to assess the ability of a computational fluid dynamics (CFD) code to reproduce the experimental results, numerical simulation results, and heat transfer correlation equations developed in the literature for natural convection heat transfer within the annulus of horizontal concentric cylinders. In the literature, a variety of heat transfer expressions have been developed to compute average equivalent thermal conductivities. However, the expressions have been primarily developed for very small inner and outer cylinder radii and gap-widths. In this comparative study, interest is primarily focused on large gap widths (on the order of half meter or greater) and large radius ratios. From the steady-state CFD analysis it is found that the concentric cylinder models for the larger geometries compare favorably to the results of the Kuehn and Goldstein correlations in the Rayleigh number range of about 10{sup 5} to 10{sup 8} (a range that encompasses the laminar to turbulent transition). For Rayleigh numbers greater than 10{sup 8}, both numerical simulations and experimental data (from the literature) are consistent and result in slightly lower equivalent thermal conductivities than those obtained from the Kuehn and Goldstein correlations.

N.D. Francis, Jr; M.T. Itamura; S.W. Webb; D.L. James

2002-10-01T23:59:59.000Z

153

Fluid Dynamic and Performance Behavior of Multiphase Progressive Cavity Pumps  

E-Print Network [OSTI]

on a night when I was back from the TurboLab. viii NOMENCLATURE g1827g3045g3042g3047g3042g3045 = Cross-sectional area of rotor g1827g3046g3047g3028g3047g3042g3045 = Cross-sectional area of stator g1827g3033 = Fluid flow area g1827... g3036= Acceleration in the direction of the co-ordinate i (r, ?, z) b= Pressure drop co-efficient g2010 = Thermal expansion coefficient ?g3049 = Volumetric efficiency e= Eccentricity of rotor f= Friction co-efficient Gr...

Narayanan, Shankar Bhaskaran

2012-10-19T23:59:59.000Z

154

Geophysical Fluid Dynamics I P.B. Rhines Notes on the Boussinesq Approximation -I. 27 ii 2004  

E-Print Network [OSTI]

Geophysical Fluid Dynamics ­ I P.B. Rhines Notes on the Boussinesq Approximation - I. 27 ii 2004 compare with the full equations for a compressible fluid in Gill section 6.4. The Boussinesq approximation to the depth of the fluid layer. The Boussinesq equations most often used in the literature are accurate only

155

2.13 HEAT TRANSFER & FLUID FLOW IN MICROCHANNELS 2.13.7-1 Molecular dynamics methods in  

E-Print Network [OSTI]

2.13 HEAT TRANSFER & FLUID FLOW IN MICROCHANNELS 2.13.7-1 2.13.7 Molecular dynamics methods in microscale heat transfer Shigeo Maruyama A. Introduction In normal heat transfer and fluid flow calculations of molecules. This situation is approached in microscale heat transfer and fluid flow. Molecular level

Maruyama, Shigeo

156

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

157

Accuracy characteristics of traditional finite volume discretizations for unsteady computational fluid dynamics  

SciTech Connect (OSTI)

Recently Manson et al. demonstrated the shortcoming of traditional finite volume approaches, typified by Patankar`s SIMPLE algorithm, for discretizing the equations of fluid flow, heat transfer, and associated transport processes. They were able to show for one severe test case-low spatial resolution and zero diffusion that traditional finite volume approaches are ineffective for unsteady state problems with significant convective effects. They are ineffective because there exists a time step limitation, even for implicit methods, which is imposed by accuracy constraints rather than stability constraints. The objective of the present paper is to show that the poor performance of these methods in that paper was not simply due to the severity of the test case. This paper will demonstrate the same inadequacy prevails for a range of spatial resolutions and non-zero diffusion cases. This knowledge is already documented but its significance still seems to elude the CFD community who persist with traditional discretizations for unsteady advection. 7 refs., 5 figs.

Manson, J.R. [Bucknell Univ., Lewisburg, PA (United States)] [Bucknell Univ., Lewisburg, PA (United States); Wallis, S.G. [Heriot-Watt Univ., Edinburgh (United Kingdom)] [Heriot-Watt Univ., Edinburgh (United Kingdom)

1997-03-15T23:59:59.000Z

158

Computational Fluid Dynamics Simulation of Open-Channel Flows Over Bridge-Decks Under Various Flooding Conditions  

E-Print Network [OSTI]

. This study simulates limited scaled experimental data conducted elsewhere for bridge flooding in open channel simulation, Computational fluid dynamics, Flooding flows, Turbulence modeling, VOF modeling. 1. IntroductionComputational Fluid Dynamics Simulation of Open-Channel Flows Over Bridge-Decks Under Various

Kostic, Milivoje M.

159

Dynamics of a confined dusty fluid in a sheared ion flow  

SciTech Connect (OSTI)

Dynamics of an isothermally driven dust fluid is analyzed which is confined in an azimuthally symmetric cylindrical setup by an effective potential and is in equilibrium with an unconfined sheared flow of a streaming plasma. Cases are analyzed where the confining potential constitutes a barrier for the driven fluid, limiting its spatial extension and boundary velocity. The boundary effects entering the formulation are characterized by applying the appropriate boundary conditions and a range of solutions exhibiting single and multiple vortex are obtained. The equilibrium solutions considered in the cylindrical setup feature a transition from single to multiple vortex state of the driven flow. Effects of (i) the variation in dust viscosity, (ii) coupling between the driving and the driven fluid, and (iii) a friction determining the equilibrium dynamics of the driven system are characterized.

Laishram, Modhuchandra; Sharma, Devendra; Kaw, Predhiman K. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2014-07-15T23:59:59.000Z

160

Charles A. Stock Research Oceanographer, NOAA/Geophysical Fluid Dynamics Laboratory  

E-Print Network [OSTI]

Change Impacts on Living Marine Resources", 2012 Ocean Sciences Meeting, Salt Lake City 2012-13 MemberCharles A. Stock Research Oceanographer, NOAA/Geophysical Fluid Dynamics Laboratory Princeton-mail: Charles.Stock@noaa.gov Education 2005 Ph.D., Woods Hole Oceanographic Institution/MIT Joint Program Civil

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.


161

PREDICTION OF CUTTINGS BED HEIGHT WITH COMPUTATIONAL FLUID DYNAMICS IN DRILLING HORIZONTAL AND HIGHLY DEVIATED WELLS  

E-Print Network [OSTI]

Louisiana State University Abstract In oil well drilling, the efficient transport of drilled cuttings from pipe and excessive frictional pressure losses while drilling directional and horizontal oil wellsPREDICTION OF CUTTINGS BED HEIGHT WITH COMPUTATIONAL FLUID DYNAMICS IN DRILLING HORIZONTAL

Ullmer, Brygg

162

THERMO FLUID DYNAMICS AND CHAMBER AEROSOL BEHAVIOR FOR THIN LIQUID WALL UNDER IFE  

E-Print Network [OSTI]

thermal and injection control. Experimental and numerical studies have been con- ducted to examine beam propagation and focusing requirements, as well as the target thermal integrity and injection the fluid dynamic aspects of thin-liquid- film protection systems with either radial injection through

163

AN INVESTIGATION OF THE FLUID DYNAMICS ASPECTS OF THIN LIQUID FILM PROTECTION  

E-Print Network [OSTI]

a conservative "design window" for film detachment. Initial observations of film flow around cy- lindricalAN INVESTIGATION OF THE FLUID DYNAMICS ASPECTS OF THIN LIQUID FILM PROTECTION SCHEMES FOR INERTIAL liquid film wall protection systems have been conducted in support of the ARIES-IFE study. Both

California at San Diego, University of

164

Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer in Window Frames  

E-Print Network [OSTI]

1 Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer Arasteh and Dragan Curcija ABSTRACT Accurately analyzing heat transfer in window frame cavities radiation heat-transfer effects.) We examine three representative complex cavity cross-section profiles

165

FLUID DYNAMICAL AND MODELING ISSUES OF CHEMICAL FLOODING FOR ENHANCED OIL RECOVERY  

E-Print Network [OSTI]

FLUID DYNAMICAL AND MODELING ISSUES OF CHEMICAL FLOODING FOR ENHANCED OIL RECOVERY Prabir Daripa. Relevance of this HS model based result to EOR is established by performing direct numerical simulations of fully developed tertiary displacement in porous media. Results of direct numer- ical simulation

Daripa, Prabir

166

On the Dynamics of Magnetic Fluids in Magnetic Resonance Padraig J. Cantillon-Murphy  

E-Print Network [OSTI]

On the Dynamics of Magnetic Fluids in Magnetic Resonance Imaging by Padraig J. Cantillon-Murphy Submitted to the Department of Electrical Engineering and Computer Science in partial fulfillment of Electric'algngineering and Computer Science May 22nd, 2008. Certified

167

Experimental Validation of a Computational Fluid Dynamics Model for IAQ applications in Ice Rink Arenas  

E-Print Network [OSTI]

1 Experimental Validation of a Computational Fluid Dynamics Model for IAQ applications in Ice Rink, USA, Fax: 617-432-4122, Abstract Many ice rink arenas have ice resurfacing equipment that uses fossil temperature distributions in ice rinks. The numerical results agree reasonably with the corresponding

Chen, Qingyan "Yan"

168

CFD modelling of thermal distribution in industrial server centres for configuration optimisation and energy efficiency  

Science Journals Connector (OSTI)

The use of servers for computational and communication control tasks is becoming more and more frequent in industries and institutions. Ever increasing computational power and data storage combined with reduction in chipsets size resulted in the increased heat density and need for proper configurations of the server racks to enhance cooling and energy efficiency. While different methods can be used to model and design new server centres and optimise their configuration, there is no clear guideline in the literature on the best way to design them and how to increase energy efficiency of existing server centres. This paper presents a simplified yet reliable computational fluid dynamics (CFD) model used to qualitatively evaluate different cooling solutions of a data centre and proposes guidelines to improve its energy efficiency. The influence of different parameters and configurations on the cooling load of the server room is then analysed.

Pierre-Luc Paradis; Drishtysingh Ramdenee; Adrian Ilinca; Hussein Ibrahim

2014-01-01T23:59:59.000Z

169

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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,

170

A transient study on the dynamic coupling of a fluid-tank system  

E-Print Network [OSTI]

A TRANSIENT STUDY ON THE DYNAMIC COUPLING OF A FLUID-TANK SYSTEM A Thesis by PUI CHUN LUI Approved as to style and content by: ( airman of Ccrmittee) (Head of Department) (Member) (Member) August 1980 ABSTBACT A Transient Study... liquid-tank system are of great concern. This dl annie coupling problem is studied analy- tically for a t?o-dimensional, rectangular, rigid tank with no baffles. The governing equations of the liquid motion are derived with reference to a moving...

Lui, Pui Chun

1980-01-01T23:59:59.000Z

171

Computational fluid dynamics combustion modelling--A comparison of secondary air system designs  

SciTech Connect (OSTI)

A newly developed computer simulation of the combustion process in a kraft recovery furnace uses computational fluid dynamics to model the processes of mass, momentum, and energy transport. This paper describes two models and a presentation of the flow fields obtained. The results predict a dramatic improvement in combustion behavior using a refined secondary air system with reduction in particulate carryover, enhanced operating temperatures, more uniform gas flow, and less carbon monoxide at the furnace exit.

Jones, A.K. (ABB Combustion Engineering Systems, Ottawa, Ontario (Canada)); Chapman, P.J. (ABB Combustion Engineering Systems, Windsor, CT (United States))

1993-07-01T23:59:59.000Z

172

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

SciTech Connect (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 Laboratorys (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

173

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

SciTech Connect (OSTI)

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

174

CFD Model Of A Planar Solid Oxide Electrolysis Cell For Hydrogen Production From Nuclear Energy  

SciTech Connect (OSTI)

A three-dimensional computational fluid dynamics (CFD) model has been created to model hightemperature steam electrolysis in a planar solid oxide electrolysis cell (SOEC). The model represents a single cell as it would exist in an electrolysis stack. Details of the model geometry are specific to a stack that was fabricated by Ceramatec2, Inc. and tested at the Idaho National Laboratory. 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 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, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean model results are shown to compare favorably with experimental results obtained from an actual ten-cell stack tested at INL.

Grant L. Hawkes; James E. O'Brien; Carl M. Stoots; J. Stephen Herring

2005-10-01T23:59:59.000Z

175

EVALUATION OF AN EXPERIMENTAL DATA SET TO BE VALIDATION DATA FOR CFD FOR A VHTR  

SciTech Connect (OSTI)

The very high temperature reactor (VHTR) has been chosen as the concept for the next generation nuclear plant (NGNP), supported by the U. S. Department of Energy. There are two basic designs for the VHTR: a prismatic design and a pebble-bed design. In the prismatic design, the coolant (helium) exits the core into a lower plenum as jets. The helium then turns 90 and flows toward the exit duct around cylindrical support posts. Safety analysis by computational fluid dynamics (CFD) is desired to determine the level of mixing of the jets and check for hot spots. Experimental data were taken in a scaled model of a slice of the lower plenum of a prismatic VHTR. Numerical investigations have been made using CFD to determine if the data are suitable for validation. This paper provides the findings of the investigations including results for a modified version of the flow field. The investigations include a determination of the extent of the computational domain needed, the best outlet boundary condition to use, the accuracy of the inlet data, application of several turbulence models and the search for the cause of an instability that causes large random excursions of flow variables. It is found that the inlet data measured by PIV are not sufficiently accurate and that the instability is apparently caused by the presence of the first inlet jet which impinges on a recirculation zone.

Richard W. Johnson

2010-09-01T23:59:59.000Z

176

Molecular-dynamics simulation of compressible fluid flow in two-dimensional channels  

Science Journals Connector (OSTI)

We study compressible fluid flow in narrow two-dimensional channels using a molecular-dynamics simulation method. In the simulation area, an upstream source is maintained at constant density and temperature while a downstream reservoir is kept at vacuum. The channel is sufficiently long in the direction of the flow that the finite length has little effect on the properties of the fluid in the central region. The simulated system is represented by an efficient data structure, whose internal elements are created and manipulated dynamically in a layered fashion. Consequently the computer code is highly efficient and manifests completely linear performance in simulations of large systems. We obtain the steady-state velocity, temperature, and density distributions in the system. The velocity distribution across the channel is very nearly a quadratic function of the distance from the center of the channel and reveals velocity slip at the boundaries; the temperature distribution is only approximately a quartic function of this distance from the center to the channel. The density distribution across the channel is nonuniform. We attribute this nonuniformity to the relatively high Mach number, approximately 0.5, in the fluid flow. An equation for the density distribution based on simple compressibility arguments is proposed; its predictions agree well with the simulation results. The validity of the concept of local dynamic temperature and the variation of the temperature along the channel are discussed.

M. Sun and C. Ebner

1992-10-15T23:59:59.000Z

177

CFD validation in OECD/NEA t-junction benchmark.  

SciTech Connect (OSTI)

When streams of rapidly moving flow merge in a T-junction, the potential arises for large oscillations at the scale of the diameter, D, with a period scaling as O(D/U), where U is the characteristic flow velocity. If the streams are of different temperatures, the oscillations result in experimental fluctuations (thermal striping) at the pipe wall in the outlet branch that can accelerate thermal-mechanical fatigue and ultimately cause pipe failure. The importance of this phenomenon has prompted the nuclear energy modeling and simulation community to establish a benchmark to test the ability of computational fluid dynamics (CFD) codes to predict thermal striping. The benchmark is based on thermal and velocity data measured in an experiment designed specifically for this purpose. Thermal striping is intrinsically unsteady and hence not accessible to steady state simulation approaches such as steady state Reynolds-averaged Navier-Stokes (RANS) models.1 Consequently, one must consider either unsteady RANS or large eddy simulation (LES). This report compares the results for three LES codes: Nek5000, developed at Argonne National Laboratory (USA), and Cabaret and Conv3D, developed at the Moscow Institute of Nuclear Energy Safety at (IBRAE) in Russia. Nek5000 is based on the spectral element method (SEM), which is a high-order weighted residual technique that combines the geometric flexibility of the finite element method (FEM) with the tensor-product efficiencies of spectral methods. Cabaret is a 'compact accurately boundary-adjusting high-resolution technique' for fluid dynamics simulation. The method is second-order accurate on nonuniform grids in space and time, and has a small dispersion error and computational stencil defined within one space-time cell. The scheme is equipped with a conservative nonlinear correction procedure based on the maximum principle. CONV3D is based on the immersed boundary method and is validated on a wide set of the experimental and benchmark data. The numerical scheme has a very small scheme diffusion and is the second and the first order accurate in space and time, correspondingly. We compare and contrast simulation results for three computational fluid dynamics codes CABARET, Conv3D, and Nek5000 for the T-junction thermal striping problem that was the focus of a recent OECD/NEA blind benchmark. The corresponding codes utilize finite-difference implicit large eddy simulation (ILES), finite-volume LES on fully staggered grids, and an LES spectral element method (SEM), respectively. The simulations results are in a good agreement with experimenatl data. We present results from a study of sensitivity to computational mesh and time integration interval, and discuss the next steps in the simulation of this problem.

Obabko, A. V.; Fischer, P. F.; Tautges, T. J.; Karabasov, S.; Goloviznin, V. M.; Zaytsev, M. A.; Chudanov, V. V.; Pervichko, V. A.; Aksenova, A. E. (Mathematics and Computer Science); (Cambridge Univ.); (Moscow Institute of Nuclar Energy Safety)

2011-08-23T23:59:59.000Z

178

Approved Module Information for ME4501, 2014/5 Module Title/Name: Computational Fluid Dynamics and  

E-Print Network [OSTI]

-requisites: Thermodynamics and Fluids (ME3011). Engineering Mathematics 2 (AM21EM). Co-requisites: None Specified ModuleApproved Module Information for ME4501, 2014/5 Module Title/Name: Computational Fluid Dynamics and Applications Module Code: ME4501 School: Engineering and Applied Science Module Type: Standard Module New

Neirotti, Juan Pablo

179

Comparison of Homogeneous and Heterogeneous CFD Fuel Models for Phase I of the IAEA CRP on HTR Uncertainties Benchmark  

SciTech Connect (OSTI)

Computational Fluid Dynamics (CFD) evaluation of homogeneous and heterogeneous fuel models was performed as part of the Phase I calculations of the International Atomic Energy Agency (IAEA) Coordinate Research Program (CRP) on High Temperature Reactor (HTR) Uncertainties in Modeling (UAM). This study was focused on the nominal localized stand-alone fuel thermal response, as defined in Ex. I-3 and I-4 of the HTR UAM. The aim of the stand-alone thermal unit-cell simulation is to isolate the effect of material and boundary input uncertainties on a very simplified problem, before propagation of these uncertainties are performed in subsequent coupled neutronics/thermal fluids phases on the benchmark. In many of the previous studies for high temperature gas cooled reactors, the volume-averaged homogeneous mixture model of a single fuel compact has been applied. In the homogeneous model, the Tristructural Isotropic (TRISO) fuel particles in the fuel compact were not modeled directly and an effective thermal conductivity was employed for the thermo-physical properties of the fuel compact. On the contrary, in the heterogeneous model, the uranium carbide (UCO), inner and outer pyrolytic carbon (IPyC/OPyC) and silicon carbide (SiC) layers of the TRISO fuel particles are explicitly modeled. The fuel compact is modeled as a heterogeneous mixture of TRISO fuel kernels embedded in H-451 matrix graphite. In this study, a steady-state and transient CFD simulations were performed with both homogeneous and heterogeneous models to compare the thermal characteristics. The nominal values of the input parameters are used for this CFD analysis. In a future study, the effects of input uncertainties in the material properties and boundary parameters will be investigated and reported.

Gerhard Strydom; Su-Jong Yoon

2014-04-01T23:59:59.000Z

180

Bonneville Powerhouse 2 Fish Guidance Efficiency Studies: CFD Model of the Forebay  

SciTech Connect (OSTI)

In ongoing work, U.S. Army Corps of Engineers, Portland District (CENWP) is seeking to better understand and improve the conditions within the Bonneville Powerhouse 2 (B2) turbine intakes to improve survival of downstream migrant salmonid smolt. In this study, the existing B2 forebay computational fluid dynamics (CFD) model was modified to include a more detailed representation of all B2 turbine intakes. The modified model was validated to existing field-measured forebay ADCP velocities. The initial CFD model scenarios tested a single project operation and the impact of adding the Behavior Guidance System (BGS) or Corner Collector. These structures had impacts on forebay flows. Most notable was that the addition of the BGS and Corner Collector reduced the lateral extent of the recirculation areas on the Washington shore and Cascade Island and reduced the flow velocity parallel to the powerhouse in front of Units 11 and 12. For these same cases, at the turbine intakes across the powerhouse, there was very little difference in the flow volume into the gatewell for the clean forebay, and the forebay with the BGS in place and/or the Corner Collector operating. The largest differences were at Units 11 to 13. The CFD model cases testing the impact of the gatewell slot fillers showed no impact to the forebay flows, but large differences within the gatewells. With the slot fillers, the flow above the standard traveling screen and into the gatewell increased (about 100 cfs at each turbine intake) and the gap flow decreased across the powerhouse for all cases. The increased flow up the gatewell was further enhanced with only half the units operating. The flow into the gatewell slot was increased about 35 cfs for each bay of each intake across the powerhouse; this change was uniform across the powerhouse. The flows in the gatewell of Unit 12, the most impacted unit for the scenarios, was evaluated. In front of the vertical barrier screen, the CFD model with slot fillers showed reduced the maximum velocities (in spite of the increased the flow into the gatewell), and decreased the area of recirculation. The area near the VBS exceeding the normal velocity criteria of 1 ft/s was reduced and the flows were more balanced.

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

2012-07-01T23:59:59.000Z

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181

J. Non-Newtonian Fluid Mech. 130 (2005) 128 The dynamics of single-molecule DNA in flow  

E-Print Network [OSTI]

J. Non-Newtonian Fluid Mech. 130 (2005) 1­28 Review The dynamics of single-molecule DNA in flow Abstract Within the last decade, fluorescence microscopy of single molecules of DNA in a plethora of flow of the microscopy, employing a spectrum of possible DNA molecules, fragments, and concatemers with dynamic

Shaqfeh, Eric

182

Computational Fluid Dynamics of a Semi Batch Reactor for Heavy Oil Hydroconversion  

Science Journals Connector (OSTI)

This work presents the numerical results of the computational fluid dynamics of a semi batch reactor used for hydroconversion of heavy oil. The reactor is a multicomponent system and it is modeled as a pseudo two phase system ( gas + slurry ). The equations used are the continuity equations the momentum equation (Navier?Stokes) and the k?? for turbulence. The numerical method used to solve the mathematical method was the finite volume where the problem was divided in two domains in order to account for the moving part of the impeller. The numerical results indicated convergence of the procedure for the velocity profiles.

T. S. Yamada; R. Guirardello

2009-01-01T23:59:59.000Z

183

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

SciTech Connect (OSTI)

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

184

Computational Fluid Dynamics-Based Design of a Microfabricated Cell Capture Device  

Science Journals Connector (OSTI)

......physical characteristics as water at 293.15 K with constant...CFD-based MCCD design, where water was applied as flowing...Outlet boundary was set to atmospheric pressure using the pressure...DWL 66fs laser pattern generator (Heidelberg Inst...rehydrated in double deionized water resulting in 5 million......

Gabor Jarvas; Marton Szigeti; Laszlo Hajba; Peter Furjes; Andras Guttman

2014-09-01T23:59:59.000Z

185

Predicting the Three Dimensional Distribution of Gas Pollutants for Industrial-type Geometries in the South Pars Gas Complex Using Computational Fluid Dynamics  

Science Journals Connector (OSTI)

In the present investigation, a comprehensive map of the studied region, which includes several gas refinery phases, was prepared. ... The Reynolds averaged NavierStokes equations for continuity and momentum are defined as follows:(24, 25, 30, 31)(2)(3)where ? and ?t are molecular viscosity and turbulent viscosity, respectively, ? is density of the main fluid, V is mean velocity vector, P is static pressure, g is the gravitational acceleration, and Sm is the mass added to the continuous phase from other sources. ... Comparison between the CFD Calculated Concentration of the Pollutants in Two Different Input Wind Velocities of 2.5 and 3.5 (m/s) ...

Hessamodin Nourbakhsh; Dariush Mowla; Feridun Esmaeilzadeh

2013-04-02T23:59:59.000Z

186

Dynamic compression of materials: metallization of fluid hydrogen at high pressures  

Science Journals Connector (OSTI)

Dynamic high pressure is 1?GPa (10?kbar) or greater with a rise time and a duration ranging from 1?ps (10?12?s) to 1?s (10?6?s). Today it is possible in a laboratory to achieve pressures dynamically up to ~500?GPa (5?Mbar) and greater, compressions as much as ~15-fold greater than initial density in the case of hydrogen and temperatures from ~0.1 up to several electronvolts (11?600?K). At these conditions materials are extremely condensed semiconductors or degenerate metals. Temperature can be tuned independently of pressure by a combination of shock and isentropic compression. As a result, new opportunities are now available in condensed matter physics at extreme conditions. The basic physics of the dynamic process, experimental methods of generating and diagnosing matter at these extreme conditions and a technique to recover metastable materials intact from ~100?GPa shock pressures are discussed.Results include (i) generation of pressure standards at static pressures up to ~200?GPa (2?Mbar) at 300?K, (ii) single-shock compression of small-molecular fluids, including resolution of the recent controversy over the correct shock-compression curve of liquid D2 at 100?GPa pressures, (iii) the first observations of metallization of fluid hydrogen, nitrogen and oxygen compressed quasi-isentropically at 100?GPa pressures, (iv) implications for the interiors of giant planets within our solar system, extrasolar giant planets and brown dwarfs discovered recently and the equation of state of deuteriumtritium in inertial confinement fusion (ICF) and (v) prospects of recovering novel materials from extreme conditions, such as metastable solid metallic hydrogen. Future research is suggested.

W J Nellis

2006-01-01T23:59:59.000Z

187

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]

turbulence models. These models expressed in differential and or algebraic form with the Navier-Stokes and continuity equations make a closed set. The turbulence models simulate the averaged character of the real turbulence. In 1877, Boussinesq proposed... (15) The Reynolds stress tensor based on the Boussinesq assumption is then given by (pp SUJET 2 c~x zsxi (16) where Ps is the Kronecker delta and rc is the kinetic energy of turbulence. In equation 16, o?. . = 1 for i = j and o, = 0 for i w j...

D'Sousa, Cedric Benedict

2012-06-07T23:59:59.000Z

188

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

189

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

190

Transient Temperature Modeling For Wellbore Fluid Under Static and Dynamic Conditions  

E-Print Network [OSTI]

for geothermal wells and prediction of injection fluid temperatures. In this thesis, development and usage of three models for transient fluid temperature are presented. Two models predict transient temperature of flowing fluid under separate flow configurations...

Ali, Muhammad

2014-04-22T23:59:59.000Z

191

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

E-Print Network [OSTI]

Journal Series B-Fluids and Thermal Engineering, 1994. 37(Journal Series B-Fluids and Thermal Engineering, 1994. 37 (Journal Series B-Fluids and Thermal Engineering, 1994. 37(

Vu, Henry

2010-01-01T23:59:59.000Z

192

MecE 630 Fluid Dynamics (Fall 2013) Course objectives: To explore the essential dynamics of flowing fluids by expanding upon ma-  

E-Print Network [OSTI]

and vortex tubes. · Fluid kinematics and vector calculus ­ Summation notation, ­ Normal vs. shear strain- ing novel research projects. Course topics: · Review of basic concepts ­ Definition of a fluid is Incompressible Flow (fourth edition) by R.L. Panton. Problem sets: Roughly one per course topic. Problem sets

Flynn, Morris R.

193

MecE 630 Fluid Dynamics (Fall 2014) Course objectives: To explore the essential dynamics of flowing fluids by expanding upon ma-  

E-Print Network [OSTI]

and vortex tubes. · Fluid kinematics and vector calculus ­ Summation notation, ­ Normal vs. shear strain- ing novel research projects. Course topics: · Review of basic concepts ­ Definition of a fluid. Problem sets: Roughly one per course topic. Problem sets will be due 1-2 weeks after their initial

Flynn, Morris R.

194

Net-baryon number variance and kurtosis within nonequilibrium chiral fluid dynamics  

E-Print Network [OSTI]

We study the variance and kurtosis of the net-baryon number in a fluid dynamical model for heavy-ion collisions. It is based on an effective chiral model with dilatons for the strong coupling regime of QCD. Taking into account spinodal instabilities, we demonstrate that this model exhibits a diverging quark number susceptibility and kurtosis all along the spinodal lines of the first-order phase transition, with a change of universality class at the critical end point. During the (3+1) dimensional expansion of a hot and dense fireball, instabilities are created by fluctuations in the explicitly propagated chiral and dilaton field. We find a clear enhancement of event-by-event fluctuations of the baryon number at the critical point and first-order phase transition in comparison with an evolution through the crossover region.

Herold, Christoph; Yan, Yupeng; Kobdaj, Chinorat

2014-01-01T23:59:59.000Z

195

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

SciTech Connect (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

196

Sandia National Laboratories environmental fluid dynamics code : sediment transport user manual.  

SciTech Connect (OSTI)

This document describes the sediment transport subroutines and input files for the Sandia National Laboratories Environmental Fluid Dynamics Code (SNL-EFDC). Detailed descriptions of the input files containing data from Sediment Erosion at Depth flume (SEDflume) measurements are provided along with the description of the source code implementing sediment transport. Both the theoretical description of sediment transport employed in SNL-EFDC and the source code are described. This user manual is meant to be used in conjunction with the EFDC manual (Hamrick 1996) because there will be no reference to the hydrodynamics in EFDC. Through this document, the authors aim to provide the necessary information for new users who wish to implement sediment transport in EFDC and obtain a clear understanding of the source code.

Grace, Matthew D.; Thanh, Phi Hung X.; James, Scott Carlton

2008-09-01T23:59:59.000Z

197

THIESEL 2010 Conference on Thermo-and Fluid Dynamic Processes in Diesel Engines Influence of Nozzle Geometry on Spray Shape, Particle Size, Spray  

E-Print Network [OSTI]

THIESEL 2010 Conference on Thermo- and Fluid Dynamic Processes in Diesel Engines Influence Abstract. Air/fuel mixing process in the combustion chamber of Diesel engines plays an important role on Thermo- and Fluid Dynamic Processes in Diesel Engines, Valencia : Spain (2010)" #12;388 C. Hespel, J. B

Paris-Sud XI, Université de

198

Notes 10. A thermohydrodynamic bulk-flow model for fluid film bearings  

E-Print Network [OSTI]

The complete set of bulk-flow equations for the analysis of turbulent flow fluid film bearings. Importance of thermal effects in process fluid applications. A CFD method for solution of the bulk-flow equations....

San Andres, Luis

2009-01-01T23:59:59.000Z

199

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

SciTech Connect (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

200

3D CFD Model of High Temperature H2O/CO2 Co-electrolysis  

SciTech Connect (OSTI)

3D CFD Model of High Temperature H2O/CO2 Co-Electrolysis Grant Hawkes1, James OBrien1, Carl Stoots1, Stephen Herring1 Joe Hartvigsen2 1 Idaho National Laboratory, Idaho Falls, Idaho, grant.hawkes@inl.gov 2 Ceramatec Inc, Salt Lake City, Utah INTRODUCTION 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) using solid oxide fuel cell technology. 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. This paper presents CFD results of this model compared with experimental results. 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 produce syngas by simultaneously electrolyzing at high-temperature steam and carbon dioxide (CO2) using solid oxide fuel cell technology. A strong interest exists in the large-scale production of syn-gas from CO2 and steam to be reformed into a usable transportation fuel. If biomass is used as the carbon source, the overall process is climate neutral. Consequently, there is a high level of interest in production of syn-gas from CO2 and steam electrolysis. With the price of oil currently around $60 / 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. 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, using high-temperature nuclear process heat and electricity. 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 55%.

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

2007-06-01T23:59:59.000Z

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.


201

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

SciTech Connect (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 Resources?? 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

202

Technology of Computational Fluid Dynamics in space engines and solar-gravity draught power plants  

Science Journals Connector (OSTI)

Non-isentropic discontinuous, unsteady flows with energy addition or extraction, during ignition of solid propellant rocket motors or tall solar towers heating transients are approached through a wave front method, initially developed by Zannetti for isentropic flows in aerodynamics. Its application in discontinuous flows with zones of different behaviour and energy extraction proves highly efficient. Computational efficiency is demonstrated by Computational Fluid Dynamics simulation of the starting transients in ADDA Solid Rocket Engines (SRE) and in the SEATTLER solar mirror tower. The code is exclusively directed to unsteady flow simulations in slender channels. The wave front model scheme covers the dual behaviour of fully non-isentropic flow with mass addition and mixing in the thrust chamber or blunt heat addition in a heater and fully isentropic through the exhaust nozzle or gravity draught in a tall tower. Along the tower of the solar-gravity draught power plants, small perturbation discontinuous flows are covered. Code robustness is demonstrated during runs on the PC. The 1D numerical scheme is based on the resolution of gasdynamic discontinuities within the enhanced method of Zannetti.

Radu Dan Rugescu

2008-01-01T23:59:59.000Z

203

Transport properties of dense fluid mixtures using nonequilibrium molecular dynamics. Final report, September 15, 1987--March 14, 1997  

SciTech Connect (OSTI)

Computer Simulation Studies were carried out using the method of equilibrium and nonequilibrium molecular dynamics (NEMD) to examine a wide range of transport processes in both fluids and fluid mixtures. This included testing a wide range of mixing rules for thermal conductivity and viscosity. In addition a method was developed to calculate the internal rotational contributions to thermal conductivity and the accuracy of current methods for predicting these contributions were examined. These comparisons were then used to suggest possible ways of improving these theories. The method of NEMD was also used to examine the critical enhancements of thermal conductivity. Finally, molecular simulations were carried out to study the various transport coefficients of fluids confined by membranes, as well as important transport processes such as osmosis, and reverse osmosis.

Murad, S.

1997-05-01T23:59:59.000Z

204

Interfacial roughening in non-ideal fluids: Dynamic scaling in the weak- and strong-damping regime  

E-Print Network [OSTI]

Interfacial roughening denotes the nonequilibrium process by which an initially flat interface reaches its equilibrium state, characterized by the presence of thermally excited capillary waves. Roughening of fluid interfaces has been first analyzed by Flekkoy and Rothman [Phys. Rev. Lett. 75, 260 (1995)], where the dynamic scaling exponents in the weakly damped case in two dimensions were found to agree with the Kardar-Parisi-Zhang universality class. We extend this work by taking into account also the strong-damping regime and perform extensive fluctuating hydrodynamics simulations in two dimensions using the Lattice Boltzmann method. We show that the dynamic scaling behavior is different in the weakly and strongly damped case.

Markus Gross; Fathollah Varnik

2013-01-18T23:59:59.000Z

205

Interfacial roughening in non-ideal fluids: Dynamic scaling in the weak- and strong-damping regime  

E-Print Network [OSTI]

Interfacial roughening denotes the nonequilibrium process by which an initially flat interface reaches its equilibrium state, characterized by the presence of thermally excited capillary waves. Roughening of fluid interfaces has been first analyzed by Flekkoy and Rothman [Phys. Rev. Lett. 75, 260 (1995)], where the dynamic scaling exponents in the weakly damped case in two dimensions were found to agree with the Kardar-Parisi-Zhang universality class. We extend this work by taking into account also the strong-damping regime and perform extensive fluctuating hydrodynamics simulations in two dimensions using the Lattice Boltzmann method. We find that the dynamic scaling behavior is different in the weakly and strongly damped case.

Gross, Markus

2013-01-01T23:59:59.000Z

206

Massively parallel computational fluid dynamics calculations for aerodynamics and aerothermodynamics applications  

SciTech Connect (OSTI)

Massively parallel computers have enabled the analyst to solve complicated flow fields (turbulent, chemically reacting) that were previously intractable. Calculations are presented using a massively parallel CFD code called SACCARA (Sandia Advanced Code for Compressible Aerothermodynamics Research and Analysis) currently under development at Sandia National Laboratories as part of the Department of Energy (DOE) Accelerated Strategic Computing Initiative (ASCI). Computations were made on a generic reentry vehicle in a hypersonic flowfield utilizing three different distributed parallel computers to assess the parallel efficiency of the code with increasing numbers of processors. The parallel efficiencies for the SACCARA code will be presented for cases using 1, 150, 100 and 500 processors. Computations were also made on a subsonic/transonic vehicle using both 236 and 521 processors on a grid containing approximately 14.7 million grid points. Ongoing and future plans to implement a parallel overset grid capability and couple SACCARA with other mechanics codes in a massively parallel environment are discussed.

Payne, J.L.; Hassan, B.

1998-09-01T23:59:59.000Z

207

Numerical schemes for dynamically orthogonal equations of stochastic fluid and ocean flows  

SciTech Connect (OSTI)

The quantification of uncertainties is critical when systems are nonlinear and have uncertain terms in their governing equations or are constrained by limited knowledge of initial and boundary conditions. Such situations are common in multiscale, intermittent and non-homogeneous fluid and ocean flows. The dynamically orthogonal (DO) field equations provide an adaptive methodology to predict the probability density functions of such flows. The present work derives efficient computational schemes for the DO methodology applied to unsteady stochastic Navier-Stokes and Boussinesq equations, and illustrates and studies the numerical aspects of these schemes. Semi-implicit projection methods are developed for the mean and for the DO modes, and time-marching schemes of first to fourth order are used for the stochastic coefficients. Conservative second-order finite-volumes are employed in physical space with new advection schemes based on total variation diminishing methods. Other results include: (i) the definition of pseudo-stochastic pressures to obtain a number of pressure equations that is linear in the subspace size instead of quadratic; (ii) symmetric advection schemes for the stochastic velocities; (iii) the use of generalized inversion to deal with singular subspace covariances or deterministic modes; and (iv) schemes to maintain orthonormal modes at the numerical level. To verify our implementation and study the properties of our schemes and their variations, a set of stochastic flow benchmarks are defined including asymmetric Dirac and symmetric lock-exchange flows, lid-driven cavity flows, and flows past objects in a confined channel. Different Reynolds number and Grashof number regimes are employed to illustrate robustness. Optimal convergence under both time and space refinements is shown as well as the convergence of the probability density functions with the number of stochastic realizations.

Ueckermann, M.P., E-mail: mpuecker@mit.edu [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Mass. Avenue, Cambridge, MA 02139 (United States); Lermusiaux, P.F.J., E-mail: pierrel@mit.edu [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Mass. Avenue, Cambridge, MA 02139 (United States)] [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Mass. Avenue, Cambridge, MA 02139 (United States); Sapsis, T.P., E-mail: sapsis@mit.edu [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Mass. Avenue, Cambridge, MA 02139 (United States)

2013-01-15T23:59:59.000Z

208

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

209

CFD calculations of S809 aerodynamic characteristics  

SciTech Connect (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

210

Pre-test CFD Calculations for a Bypass Flow Standard Problem  

SciTech Connect (OSTI)

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

211

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

SciTech Connect (OSTI)

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] [ORNL; Jain, Prashant K [ORNL] [ORNL; Freels, James D [ORNL] [ORNL

2012-01-01T23:59:59.000Z

212

CFD analysis of the effects of the flow distribution and heat losses on the steam reforming of methanol in catalytic (Pd/ZnO) microreactors  

Science Journals Connector (OSTI)

Abstract A three-dimensional computational fluid dynamics (CFD) simulation study of the effects of the flow distribution and the heat losses on the performance of microchannels and microslits reactors for the steam reforming of methanol (SRM) over Pd/ZnO is presented. Several flow distributing headers covering a wide range of the flow diffuser expansion angle (?) have been considered. Large values of ? lead to flow maldistribution characterized by jet flow resulting in negative effects on the SRM conversion and hydrogen yield, especially for the microslits at high reaction temperatures and space velocities. Simulations have also evidenced that heat losses constitute a critical issue for microreactors operation, particularly at low space velocities. Heat losses may reach very high values, above 8090% of the energy supplied to the microreactor, with the consequence that it may be necessary to provide up to 9times the heat of the SRM reaction to achieve high methanol conversions.

I. Uriz; G. Arzamendi; P.M. Diguez; F.J. Echave; O. Sanz; M. Montes; L.M. Ganda

2014-01-01T23:59:59.000Z

213

Multidimensional CFD simulation of syngas combustion in a micro-pilot-ignited dual-fuel engine using a constructed chemical kinetics mechanism  

Science Journals Connector (OSTI)

A multidimensional computational fluid dynamics (CFD) simulation of a constructed syngas chemical kinetic mechanism was performed to evaluate the combustion of syngas in a supercharged dual-fuel engine for various syngas initial compositions under lean conditions. The modelled results were validated by comparing predictions against corresponding experimental data for a supercharged dual-fuel engine. The predicted and measured in-cylinder pressure, temperature, and rate of heat release (ROHR) data were in good agreement. The effect of the hydrogen peroxide chain-propagation reaction on the progress of combustion under supercharged conditions was examined for different types of syngas using various initial H2 concentrations. The effect of the main syngas kinetic mechanism reactions on the combustion progress was analysed in terms of their contribution to the total heat of the reaction. The best results compared with experimental data were obtained in the range of equivalence ratios below about 0.8 for all types of syngas considered in this paper. As the equivalence ratio increased above 0.8, the results deviated from the experiment data. The spatial distribution of the in-cylinder temperature and OH? within this equivalence-ratio range showed the completeness of the combustion. The present CFD model captured the overall combustion process well and could be further developed into a useful tool for syngas-engine combustion simulations.

Ulugbek Azimov; Masahiro Okuno; Kazuya Tsuboi; Nobuyuki Kawahara; Eiji Tomita

2011-01-01T23:59:59.000Z

214

Development of a %22Solar Patch%22 calculator to evaluate heliostat-field irradiance as a boundary condition in CFD models.  

SciTech Connect (OSTI)

A rigorous computational fluid dynamics (CFD) approach to calculating temperature distributions, radiative and convective losses, and flow fields in a cavity receiver irradiated by a heliostat field is typically limited to the receiver domain alone for computational reasons. A CFD simulation cannot realistically yield a precise solution that includes the details within the vast domain of an entire heliostat field in addition to the detailed processes and features within a cavity receiver. Instead, the incoming field irradiance can be represented as a boundary condition on the receiver domain. This paper describes a program, the Solar Patch Calculator, written in Microsoft Excel VBA to characterize multiple beams emanating from a 'solar patch' located at the aperture of a cavity receiver, in order to represent the incoming irradiance from any field of heliostats as a boundary condition on the receiver domain. This program accounts for cosine losses; receiver location; heliostat reflectivity, areas and locations; field location; time of day and day of year. This paper also describes the implementation of the boundary conditions calculated by this program into a Discrete Ordinates radiation model using Ansys{reg_sign} FLUENT (www.fluent.com), and compares the results to experimental data and to results generated by the code DELSOL.

Khalsa, Siri Sahib S. (Sandia Staffing Alliance); Ho, Clifford Kuofei

2010-05-01T23:59:59.000Z

215

Development of a %22solar patch%22 calculator to evaluate heliostat-field irradiance as a boundary condition in CFD models.  

SciTech Connect (OSTI)

A rigorous computational fluid dynamics (CFD) approach to calculating temperature distributions, radiative and convective losses, and flow fields in a cavity receiver irradiated by a heliostat field is typically limited to the receiver domain alone for computational reasons. A CFD simulation cannot realistically yield a precise solution that includes the details within the vast domain of an entire heliostat field in addition to the detailed processes and features within a cavity receiver. Instead, the incoming field irradiance can be represented as a boundary condition on the receiver domain. This paper describes a program, the Solar Patch Calculator, written in Microsoft Excel VBA to characterize multiple beams emanating from a 'solar patch' located at the aperture of a cavity receiver, in order to represent the incoming irradiance from any field of heliostats as a boundary condition on the receiver domain. This program accounts for cosine losses; receiver location; heliostat reflectivity, areas and locations; field location; time of day and day of year. This paper also describes the implementation of the boundary conditions calculated by this program into a Discrete Ordinates radiation model using Ansys{reg_sign} FLUENT (www.fluent.com), and compares the results to experimental data and to results generated by the code DELSOL.

Khalsa, Siri Sahib; Ho, Clifford Kuofei

2010-04-01T23:59:59.000Z

216

Experimental study and CFD approach for scroll type expander used in low-temperature organic Rankine cycle  

Science Journals Connector (OSTI)

Abstract This study focuses on experimental test of scroll type expanders in low-temperature organic Rankine cycle (ORC) system. In this circuit, lubricant has been mixed with \\{R245fa\\} as working fluid. In this experiment, two scroll expanders with different built-in volume ratio have been experimentally tested. Main test parameters considered are the pressure difference and the rotational speed of the expanders. It is found that the expander performance could be significantly improved when bigger built-in volume ratio is used. However the internal leakage and friction loss are vital factors to influence expander performance. The maximum shaft power output by expander of 1.77kW and deliver electricity by generator of 1.375kW. A Computational Fluid Dynamics approach (CFD) has been employed for preliminary investigation on the thermal-hydraulic behavior of the scroll type expanders. The simulation result shows that unbalance pressure distribution were occurred in the expander by means of top scroll wrap has been modified.

Jen-Chieh Chang; Chao-Wei Chang; Tzu-Chen Hung; Jaw-Ren Lin; Kuo-Chen Huang

2014-01-01T23:59:59.000Z

217

High-performance computing in computational fluid dynamics: progress and challenges  

Science Journals Connector (OSTI)

...Issue New science from high-performance computing organized by Richard Catlow...Tildesley and Maggie Wilson High-performance computing in computational fluid...far the largest user of high-performance computing (HPC) in engineering...

2002-01-01T23:59:59.000Z

218

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

E-Print Network [OSTI]

. 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...

Yango, Takwe

2011-10-21T23:59:59.000Z

219

Two-fluid magnetic island dynamics in slab geometry: I -Isolated islands  

E-Print Network [OSTI]

that there be zero net electromagnetic force acting on the island. Finally, the ion polarization current correction determination of the island phase-velocity, and the calculation of the ion and electron fluid flow profiles

Fitzpatrick, Richard

220

Two-fluid magnetic island dynamics in slab geometry Richard Fitzpatrick  

E-Print Network [OSTI]

. Moreover, the island propaga- tion velocity is uniquely specified by the condition that there be zero net determination of the island propagation velocity, and the calculation of the ion and electron fluid flow

Fitzpatrick, Richard

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.


221

Rotational dynamics of a superhelix towed in a Stokes fluid Sunghwan Jung  

E-Print Network [OSTI]

shaped bacteria that screw through viscous fluids due to the action of internal periplasmic flagella , we affected by a simple helical flagellum attached to and extruded from the cell body.3,6 Recently, there have

Fauci, Lisa

222

Optimization of a high-efficiency jet ejector by computational fluid dynamic software  

E-Print Network [OSTI]

large nozzle diameter ratio. Dimensionless group analysis reveals that the research results are valid for any fluid, operating pressure, and geometric scale for a given motive-stream Mach number and Reynolds ratio between the motive and propelled streams...

Watanawanavet, Somsak

2005-08-29T23:59:59.000Z

223

validation and Enhancement of Computational Fluid Dynamics and Heat Transfer Predictive Capabilities for Generation IV Reactor Systems  

SciTech Connect (OSTI)

Nationwide, the demand for electricity due to population and industrial growth is on the rise. However, climate change and air quality issues raise serious questions about the wisdom of addressing these shortages through the construction of additional fossil fueled power plants. In 1997, the President's Committee of Advisors on Science and Technology Energy Research and Development Panel determined that restoring a viable nuclear energy option was essential and that the DOE should implement a R&D effort to address principal obstacles to achieving this option. This work has addressed the need for improved thermal/fluid analysis capabilities, through the use of computational fluid dynamics, which are necessary to support the design of generation IV gas-cooled and supercritical water reactors.

Robert E. Spall; Barton Smith; Thomas Hauser

2008-12-08T23:59:59.000Z

224

Development of a Prototype Lattice Boltzmann Code for CFD of Fusion Systems.  

SciTech Connect (OSTI)

Designs of proposed fusion reactors, such as the ITER project, typically involve the use of liquid metals as coolants in components such as heat exchangers, which are generally subjected to strong magnetic fields. These fields induce electric currents in the fluids, resulting in magnetohydrodynamic (MHD) forces which have important effects on the flow. The objective of this SBIR project was to develop computational techniques based on recently developed lattice Boltzmann techniques for the simulation of these MHD flows and implement them in a computational fluid dynamics (CFD) code for the study of fluid flow systems encountered in fusion engineering. The code developed during this project, solves the lattice Boltzmann equation, which is a kinetic equation whose behaviour represents fluid motion. This is in contrast to most CFD codes which are based on finite difference/finite volume based solvers. The lattice Boltzmann method (LBM) is a relatively new approach which has a number of advantages compared with more conventional methods such as the SIMPLE or projection method algorithms that involve direct solution of the Navier-Stokes equations. These are that the LBM is very well suited to parallel processing, with almost linear scaling even for very large numbers of processors. Unlike other methods, the LBM does not require solution of a Poisson pressure equation leading to a relatively fast execution time. A particularly attractive property of the LBM is that it can handle flows in complex geometries very easily. It can use simple rectangular grids throughout the computational domain -- generation of a body-fitted grid is not required. A recent advance in the LBM is the introduction of the multiple relaxation time (MRT) model; the implementation of this model greatly enhanced the numerical stability when used in lieu of the single relaxation time model, with only a small increase in computer time. Parallel processing was implemented using MPI and demonstrated the ability of the LBM to scale almost linearly. The equation for magnetic induction was also solved using a lattice Boltzmann method. This approach has the advantage that it fits in well to the framework used for the hydrodynamic equations, but more importantly that it preserves the ability of the code to run efficiently on parallel architectures. Since the LBM is a relatively recent model, a number of new developments were needed to solve the magnetic induction equation for practical problems. Existing methods were only suitable for cases where the fluid viscosity and the magnetic resistivity are of the same order, and a preconditioning method was used to allow the simulation of liquid metals, where these properties differ by several orders of magnitude. An extension of this method to the hydrodynamic equations allowed faster convergence to steady state. A new method of imposing boundary conditions using an extrapolation technique was derived, enabling the magnetic field at a boundary to be specified. Also, a technique by which the grid can be stretched was formulated to resolve thin layers at high imposed magnetic fields, allowing flows with Hartmann numbers of several thousand to be quickly and efficiently simulated. In addition, a module has been developed to calculate the temperature field and heat transfer. This uses a total variation diminishing scheme to solve the equations and is again very amenable to parallelisation. Although, the module was developed with thermal modelling in mind, it can also be applied to passive scalar transport. The code is fully three dimensional and has been applied to a wide variety of cases, including both laminar and turbulent flows. Validations against a series of canonical problems involving both MHD effects and turbulence have clearly demonstrated the ability of the LBM to properly model these types of flow. As well as applications to fusion engineering, the resulting code is flexible enough to be applied to a wide range of other flows, in particular those requiring parallel computations with many processors. For example, at

Pattison, Martin J; Premnath, Kannan N; Banerjee, Sanjoy; Dwivedi, Vinay

2007-02-26T23:59:59.000Z

225

The use of ducts to improve the control of supply air temperature rise in UFAD systems: CFD and lab study  

Science Journals Connector (OSTI)

Abstract Cool supply air flowing through the underfloor plenum is exposed to heat gain from both the concrete slab (conducted from the warm return air on the adjacent floor below the slab) and the raised floor panels (conducted from the warmer room above). The magnitude of this heat gain can be quite high, resulting in undesirable loss of control of the supply air temperature from the plenum into the occupied space. These warmer supply air temperatures can make it more difficult to maintain comfort in the occupied space (without increasing airflow rates), particularly in perimeter zones where cooling loads reach their highest levels. How to predict plenum thermal performance is one of the key design issues facing practicing engineers evidence from completed projects indicates that excessive temperature rise in the plenum can be a problem. One of the recommended strategies for addressing temperature rise in UFAD systems is the use of ductwork (flexible or rigid) within the underfloor plenum to deliver cool air preferentially to perimeter zones or other critical areas of high cooling demand. Several experiments were carried out in a full-scale underfloor plenum test facility, in order to characterize all the phenomena that take place in an underfloor plenum equipped with a fabric or metal duct. Experimental data were collected for validation of a computational fluid dynamics (CFD) model of the plenum. This paper describes the first part of a more comprehensive work, whose aim is to use the validated CFD plenum model to conduct simulations of a broader range of plenum design and operational parameters. This work proves that using ductwork within the underfloor plenum reduce the temperature rise in the plenum.

Wilmer Pasut; Fred Bauman; Michele De Carli

2014-01-01T23:59:59.000Z

226

Computational Fluid Dynamics Simulations of Raw Gas Composition from a Black Liquor GasifierComparison with Experiments  

Science Journals Connector (OSTI)

Computational Fluid Dynamics Simulations of Raw Gas Composition from a Black Liquor GasifierComparison with Experiments ... The black liquor spray was represented by 1003 discrete particles having a fitted Rosin Rammler distribution of power 2 and a characteristic size of 200 ?m. ... Additional PFR calculations were performed using different inlet gas compositions with similar results (not presented here), i.e. the Jones and Lindstedt model showed a significantly higher reformation rate of methane than GRI-Mech at gasification conditions in the medium temperature range (1150 < T < 1500 K). ...

Per Carlsson; Kristiina Iisa; Rikard Gebart

2011-07-05T23:59:59.000Z

227

Nuclear Fluid Dynamics versus Intranuclear CascadePossible Evidence for Collective Flow in Central High-Energy Nuclear Collisions  

Science Journals Connector (OSTI)

The predictions of a variety of current theoretical models of high-energy nuclear collisions are compared with recent experimental data for central collisions of Ne20 on U238 at Elab=393 MeV/u. The experimental observation of broad sideward maxima in the angular distributions of low- and medium-energy protons is reproduced by a nuclear fluid-dynamical calculation with final freezeout of the protons. In contrast, the current intranuclear-cascade and simplified collision models predict forward-peaked angular distributions.

H. Stcker; C. Riedel; Y. Yariv; L. P. Csernai; G. Buchwald; G. Graebner; J. A. Maruhn; W. Greiner; K. Frankel; M. Gyulassy; B. Schrmann; G. Westfall; J. D. Stevenson; J. R. Nix; D. Strottman

1981-12-21T23:59:59.000Z

228

Fluid inflation  

SciTech Connect (OSTI)

In this work we present an inflationary mechanism based on fluid dynamics. Starting with the action for a single barotropic perfect fluid, we outline the procedure to calculate the power spectrum and the bispectrum of the curvature perturbation. It is shown that a perfect barotropic fluid naturally gives rise to a non-attractor inflationary universe in which the curvature perturbation is not frozen on super-horizon scales. We show that a scale-invariant power spectrum can be obtained with the local non-Gaussianity parameter f{sub NL} = 5/2.

Chen, X. [Centre for Theoretical Cosmology, DAMTP, University of Cambridge, Cambridge CB3 0WA (United Kingdom); Firouzjahi, H. [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Namjoo, M.H. [School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Sasaki, M., E-mail: x.chen@damtp.cam.ac.uk, E-mail: firouz@ipm.ir, E-mail: mh.namjoo@ipm.ir, E-mail: misao@yukawa.kyoto-u.ac.jp [Yukawa Institute for theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

2013-09-01T23:59:59.000Z

229

Gasificaton Transport: A Multiphase CFD Approach & Measurements  

SciTech Connect (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

230

CFD modelling of air-fired and oxy-fuel combustion in a large-scale furnace at Loy Yang A brown coal power station  

Science Journals Connector (OSTI)

Oxy-fuel combustion technique is a viable option to reduce several types of greenhouse gases (GHGs) emissions from the pulverized coal (PC) combustion systems. In this paper, a computational fluid dynamics (CFD) modelling study has been developed in order to investigate the Victorian brown coal combustion in a 550MW utility boiler under the air-fired (reference case) and three oxy-fuel-fired scenarios. The reference firing case was modelled based on the operating conditions of Loy Yang A power plant located in the state of Victoria, Australia. While Chalmers oxy-fuel combustion approach was selected for the present oxy-fuel combustion simulations, which referred to as OF25 (25vol.% O2), OF27 (27vol.% O2), and OF29 (29vol.% O2). User-defined functions (UDFs) were written and incorporated into the CFD code to calculate the following mathematical models: the PC devolatilization, char burnout, multi-step chemical reactions, mass and heat transfer, carbon in fly-ash, and \\{NOx\\} formation/destruction. A level of confidence of the CFD model was achieved validating four different parameters of the conventional combustion case, as well as the previous preliminary CFD studies that conducted on a 100kW unit firing propane and lignite under oxy-fuel combustion environments. The numerical results of OF29 combustion condition were considerably similar to the reference firing results in terms of gas temperature levels and radiative heat transfer relative to the OF25 and OF27 combustion cases. This similarity was due to increasing the residence time of PC in the combustion zone and O2-enriched in feed oxidizer gases. A significant increase in the CO2 concentrations and a noticeable decrease in the \\{NOx\\} formation were observed under all oxy-fuel combustion scenarios. The combustion chemistry was adopted in these investigations in order to capture the effects of O2 concentrations and gas temperatures on the CO/CO2 production rate and equilibrium between H2 and H2O in the combustion zone. Also, the use of O2-enriched atmospheres during oxy-fuel-fired cases was slightly enhanced the carbon burnout rate. These predicted results were reasonably consistent with the experimental investigations and numerical modelling found in the literature. This study of Victorian brown coal oxy-fuel combustion in a large-scale tangentially-fired boiler is important prior to its implementation in real-life.

Audai Hussein Al-Abbas; Jamal Naser; David Dodds

2012-01-01T23:59:59.000Z

231

Enabling the environmentally clean air transportation of the future: a vision of computational fluid dynamics in 2030  

Science Journals Connector (OSTI)

...recommendations from a recent NASA-funded...emissions. A recent report [1...revolutionary advances in CFD capability...aerodynamics, aerospace engineering...and computer science were used to...computational science. At the same...traditional aerospace engineering...substantial advances in simulation...

2014-01-01T23:59:59.000Z

232

Accelerating Fast Fluid Dynamics with a Coarse-grid Projection Scheme Mingang Jin, Qingyan Chen*  

E-Print Network [OSTI]

applications, such as emergency management, fast design of sustainable buildings, and development of integrated for providing fast and informative building airflow simulations. Initially designed for visualizing fluid flow model that can provide fast and informative building airflow simulations. Although reasonably good

Chen, Qingyan "Yan"

233

Fluid-dynamical basis of the embryonic development of left-right asymmetry in vertebrates  

Science Journals Connector (OSTI)

...tracers (submicrometer-sized spherical particles) are introduced into the nodal fluid above...always laminar flow, and the complex particle paths observed in low-Reynolds-number...as Wolfgang Pauli famously put it, God is weakly left-handed (3). But...

Julyan H. E. Cartwright; Oreste Piro; Idan Tuval

2004-01-01T23:59:59.000Z

234

Thermo-fluid dynamics preliminary design of turbo-expanders for ORC cycles  

Science Journals Connector (OSTI)

Selecting the best design options for turbo-expanders to be used in Organic Rankine Power Cycle applications is a difficult task, with special reference to the low-temperature applications (Tturbo-expander efficiency. Referring to a radial-type turbo-expander, a comparison of different working fluids is presented and discussed.

Daniele Fiaschi; Giampaolo Manfrida; Francesco Maraschiello

2012-01-01T23:59:59.000Z

235

Under consideration for publication in J. Fluid Mech. 1 Dynamics of Bead Formation,  

E-Print Network [OSTI]

evolution it is possible to extract transient extensional viscosity information even for very low viscosity the instability and breakup of polymeric jets is important for a wide variety of applications including spraying- stable when compared to a Newtonian fluid of the same viscosity and inertia (Middleman (1965), Goldin et

236

Optimization of Computational Performance and Accuracy in 3?D Transient CFD Model for CFB Hydrodynamics Predictions  

Science Journals Connector (OSTI)

This work aims to present a pure 3?D CFD model accurate and efficient for the simulation of a pilot scale CFB hydrodynamics. The accuracy of the model was investigated as a function of the numerical parameters in order to derive an optimum model setup with respect to computational cost. The necessity of the in depth examination of hydrodynamics emerges by the trend to scale up CFBCs. This scale up brings forward numerous design problems and uncertainties which can be successfully elucidated by CFD techniques. Deriving guidelines for setting a computational efficient model is important as the scale of the CFBs grows fast while computational power is limited. However the optimum efficiency matter has not been investigated thoroughly in the literature as authors were more concerned for their models accuracy and validity. The objective of this work is to investigate the parameters that influence the efficiency and accuracy of CFB computational fluid dynamics models find the optimum set of these parameters and thus establish this technique as a competitive method for the simulation and design of industrial large scale beds where the computational cost is otherwise prohibitive. During the tests that were performed in this work the influence of turbulence modeling approach time and space density and discretization schemes were investigated on a 1.2 MWth CFB test rig. Using Fourier analysis dominant frequencies were extracted in order to estimate the adequate time period for the averaging of all instantaneous values. The compliance with the experimental measurements was very good. The basic differences between the predictions that arose from the various model setups were pointed out and analyzed. The results showed that a model with high order space discretization schemes when applied on a coarse grid and averaging of the instantaneous scalar values for a 20 sec period adequately described the transient hydrodynamic behaviour of a pilot CFB while the computational cost was kept low. Flow patterns inside the bed such as the core?annulus flow and the transportation of clusters were at least qualitatively captured.

I. Rampidis; A. Nikolopoulos; N. Koukouzas; P. Grammelis; E. Kakaras

2007-01-01T23:59:59.000Z

237

Real-time POD-CFD Wind-Load Calculator for PV Systems  

SciTech Connect (OSTI)

The primary objective of this project is to create an accurate web-based real-time wind-load calculator. This is of paramount importance for (1) the rapid and accurate assessments of the uplift and downforce loads on a PV mounting system, (2) identifying viable solutions from available mounting systems, and therefore helping reduce the cost of mounting hardware and installation. Wind loading calculations for structures are currently performed according to the American Society of Civil Engineers/ Structural Engineering Institute Standard ASCE/SEI 7; the values in this standard were calculated from simplified models that do not necessarily take into account relevant characteristics such as those from full 3D effects, end effects, turbulence generation and dissipation, as well as minor effects derived from shear forces on installation brackets and other accessories. This standard does not include provisions that address the special requirements of rooftop PV systems, and attempts to apply this standard may lead to significant design errors as wind loads are incorrectly estimated. Therefore, an accurate calculator would be of paramount importance for the preliminary assessments of the uplift and downforce loads on a PV mounting system, identifying viable solutions from available mounting systems, and therefore helping reduce the cost of the mounting system and installation. The challenge is that although a full-fledged three-dimensional computational fluid dynamics (CFD) analysis would properly and accurately capture the complete physical effects of air flow over PV systems, it would be impractical for this tool, which is intended to be a real-time web-based calculator. CFD routinely requires enormous computation times to arrive at solutions that can be deemed accurate and grid-independent even in powerful and massively parallel computer platforms. This work is expected not only to accelerate solar deployment nationwide, but also help reach the SunShot Initiative goals of reducing the total installed cost of solar energy systems by 75%. The largest percentage of the total installed cost of solar energy system is associated with balance of system cost, with up to 40% going to soft costs; which include customer acquisition, financing, contracting, permitting, interconnection, inspection, installation, performance, operations, and maintenance. The calculator that is being developed will provide wind loads in real-time for any solar system designs and suggest the proper installation configuration and hardware; and therefore, it is anticipated to reduce system design, installation and permitting costs.

Huayamave, Victor [Centecorp; Divo, Eduardo [Centecorp; Ceballos, Andres [Centecorp; Barriento, Carolina [Centecorp; Stephen, Barkaszi [FSEC; Hubert, Seigneur [FSEC

2014-03-21T23:59:59.000Z

238

CFD simulation of heat transfer enhancement of Al2O3/water and Al2O3/ethylene glycol nanofluids in a car radiator  

Science Journals Connector (OSTI)

Abstract The present numerical study simulated turbulent and laminar flow heat transfer in nanofluids (Al2O3 particles in water and ethylene glycol-based fluid) passing through a flat tube in 3D using computational fluid dynamics (CFD) for single and two-phase approaches. The advantages over pure base fluids were evaluated. Empirical correlations were used to calculate nanofluid viscosity and thermal conductivity as a function of the volumetric concentration of the nanoparticles. First, the Nusselt numbers of the pure water and pure ethylene glycol in flat tubes were compared with the experimental data. Next, the Nusselt numbers for both approaches were compared with those for experimental data at the same Reynolds number for different concentrations of nanoparticles. A small difference in the friction factors of the tube was observed between the two approaches and the Nusselt number for the two-phase model was markedly different from that for the single-phase model; however, the volumetric flow for the same heat transfer rate decreased and less pumping power was required for the nanofluids.

Vahid Delavari; Seyed Hassan Hashemabadi

2014-01-01T23:59:59.000Z

239

Femtosecond Raman induced polarization spectroscopy studies of coherent rotational dynamics in molecular fluids  

SciTech Connect (OSTI)

We develop a polarization-sensitive femtosecond pump probe technique, Raman induced polarization spectroscopy (RIPS), to study coherent rotation in molecular fluids. By observing the collisional dephasing of the coherently prepared rotational states, we are able to extract information concerning the effects of molecular interactions on the rotational motion. The technique is quite sensitive because of the zero background detection method, and is also versatile due to its nonresonant nature.

Morgen, M.M. [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; [Lawrence Berkeley National Lab., CA (United States)

1997-05-01T23:59:59.000Z

240

CFD-based Optimization for Automotive Aerodynamics  

E-Print Network [OSTI]

Chapter 1 CFD-based Optimization for Automotive Aerodynamics Laurent Dumas Abstract The car drag- ments. An overview of the main characteristics of automotive aerodynamics and a detailed presentation.dumas@upmc.fr) 1 #12;2 Laurent Dumas 1.1 Introducing Automotive Aerodynamics 1.1.1 A Major Concern for Car

Dumas, Laurent

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241

Dynamic analysis of tension leg platform for offshore wind turbine support as fluid-structure interaction  

Science Journals Connector (OSTI)

Tension leg platform (TLP) for offshore wind turbine support is a new type structure in wind energy utilization. The strong-interaction method is ... and the dynamic characteristics of the TLP for offshore wind turbine

Hu Huang ? ?; She-rong Zhang ???

2011-03-01T23:59:59.000Z

242

Relaxation dynamics in a transient network fluid with competing gel and glass phases  

E-Print Network [OSTI]

We use computer simulations to study the relaxation dynamics of a model for oil-in-water microemulsion droplets linked with telechelic polymers. This system exhibits both gel and glass phases and we show that the competition between these two arrest mechanisms can result in a complex, three-step decay of the time correlation functions, controlled by two different localization lengthscales. For certain combinations of the parameters, this competition gives rise to an anomalous logarithmic decay of the correlation functions and a subdiffusive particle motion, which can be understood as a simple crossover effect between the two relaxation processes. We establish a simple criterion for this logarithmic decay to be observed. We also find a further logarithmically slow relaxation related to the relaxation of floppy clusters of particles in a crowded environment, in agreement with recent findings in other models for dense chemical gels. Finally, we characterize how the competition of gel and glass arrest mechanisms affects the dynamical heterogeneities and show that for certain combination of parameters these heterogeneities can be unusually large. By measuring the four-point dynamical susceptibility, we probe the cooperativity of the motion and find that with increasing coupling this cooperativity shows a maximum before it decreases again, indicating the change in the nature of the relaxation dynamics. Our results suggest that compressing gels to large densities produces novel arrested phases that have a new and complex dynamics.

Pinaki Chaudhuri; Pablo I. Hurtado; Ludovic Berthier; Walter Kob

2015-02-01T23:59:59.000Z

243

Picosecond spectroscopy and solvation clusters. The dynamics of localizing electrons in polar fluids  

SciTech Connect (OSTI)

New spectroscopic evidence concerning the dynamics of electron-induced solvation clusters in polar liquids is presented and integrated with previous picosecond data, in order to outline the roles molecular dynamics and structure can play both in initiating electron localization at subpicosecond times and in governing the solvation dynamics to form e/sup -//sub s/ in the picosecond domain. Particulr emphasis is placed on the picosecond time-resolved absorption spectroscopy of electrons in a wide range of alcohols and alcohol-alkane systems at 300/sup 0/K as a framework for the cluster model of electron solvation. While the configurationally relaxed final quantum state of e/sup -//sub s/ appears identical for e/sup -//sub s/ generated by different techniques, it is possible that the time evolution of the solvation cluster and the dynamics of electron populations between localized and continuum states could be influenced by the initial state of the system. Selected examples are discussed for alcohols, amines, and water, and comparisons are made for picosecond observations from different visible and IR spectroscopic techniques, NMR, and complementary nanosecond electron mobility data to demonstrate the overall consistency of a model in which only the dynamical, microscopic properties of the liquid determine these solvation events.

Kenney-Wallace, G.A. (Univ. of Toronto, Ontario); Jonah, C.D.

1982-07-08T23:59:59.000Z

244

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

245

Development of one-dimensional computational fluid dynamics code 'GFLOW' for groundwater flow and contaminant transport analysis  

SciTech Connect (OSTI)

Prediction of groundwater movement and contaminant transport in soil is an important problem in many branches of science and engineering. This includes groundwater hydrology, environmental engineering, soil science, agricultural engineering and also nuclear engineering. Specifically, in nuclear engineering it is applicable in the design of spent fuel storage pools and waste management sites in the nuclear power plants. Ground water modeling involves the simulation of flow and contaminant transport by groundwater flow. In the context of contaminated soil and groundwater system, numerical simulations are typically used to demonstrate compliance with regulatory standard. A one-dimensional Computational Fluid Dynamics code GFLOW had been developed based on the Finite Difference Method for simulating groundwater flow and contaminant transport through saturated and unsaturated soil. The code is validated with the analytical model and the benchmarking cases available in the literature. (authors)

Rahatgaonkar, P. S.; Datta, D.; Malhotra, P. K.; Ghadge, S. G. [Nuclear Power Corporation of India Ltd., R-2, Ent. Block, Nabhikiya Urja Bhavan, Anushakti Nagar, Mumbai - 400 094 (India)

2012-07-01T23:59:59.000Z

246

Adapting SAFT-? perturbation theory to site-based molecular dynamics simulation. I. Homogeneous fluids  

SciTech Connect (OSTI)

In this work, we aim to develop a version of the Statistical Associating Fluid Theory (SAFT)-? equation of state (EOS) that is compatible with united-atom force fields, rather than experimental data. We rely on the accuracy of the force fields to provide the relation to experimental data. Although, our objective is a transferable theory of interfacial properties for soft and fused heteronuclear chains, we first clarify the details of the SAFT-? approach in terms of site-based simulations for homogeneous fluids. We show that a direct comparison of Helmholtz free energy to molecular simulation, in the framework of a third order Weeks-Chandler-Andersen perturbation theory, leads to an EOS that takes force field parameters as input and reproduces simulation results for Vapor-Liquid Equilibria (VLE) calculations. For example, saturated liquid density and vapor pressure of n-alkanes ranging from methane to dodecane deviate from those of the Transferable Potential for Phase Equilibria (TraPPE) force field by about 0.8% and 4%, respectively. Similar agreement between simulation and theory is obtained for critical properties and second virial coefficient. The EOS also reproduces simulation data of mixtures with about 5% deviation in bubble point pressure. Extension to inhomogeneous systems and united-atom site types beyond those used in description of n-alkanes will be addressed in succeeding papers.

Ghobadi, Ahmadreza F.; Elliott, J. Richard, E-mail: elliot1@uakron.edu [Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325 (United States)

2013-12-21T23:59:59.000Z

247

Heat transfer and friction factor analysis in a circular tube with Al2O3 nanofluid by using computational fluid dynamics  

Science Journals Connector (OSTI)

Turbulent fully developed flow heat transfer coefficient and friction factor of Al2O3 nanoparticles are dispersed in water and ethylene glycol in circular tube is discussed in this paper. In order to validate the heat transfer coefficient and friction factor of nanofluid in circular tube commercially available CFD software FLUENT 6.0 is used. To achieve the fully developed flow condition, the aspect ratio (L/D) of the test section is equal to 94. The thermo-physical properties of the Al2O3 nanofluid are estimated by using the equations available in literature. Thermo-physical properties of the nanofluid are considered for heat transfer coefficient and friction factor by assuming nanofluid is a single-phase fluid. Constant Wall Heat Flux (CWHF) boundary condition is incorporated for heat transfer analysis and adiabatic boundary condition is incorporated for friction factor analysis. The analysis is conducted in the volume concentration range from 0.1% to 4%. A maximum of 2.25 times heat transfer enhancement and 1.42 times of friction is obtained by using nanofluid as working medium.

L. Syam Sundar; K.V. Sharma; Shabana Parveen

2009-01-01T23:59:59.000Z

248

Multiphase CFD-based models for chemical looping combustion process: Fuel reactor modeling  

SciTech Connect (OSTI)

Chemical looping combustion (CLC) is a flameless two-step fuel combustion that produces a pure CO2 stream, ready for compression and sequestration. The process is composed of two interconnected fluidized bed reactors. The air reactor which is a conventional circulating fluidized bed and the fuel reactor which is a bubbling fluidized bed. The basic principle is to avoid the direct contact of air and fuel during the combustion by introducing a highly-reactive metal particle, referred to as oxygen carrier, to transport oxygen from the air to the fuel. In the process, the products from combustion are kept separated from the rest of the flue gases namely nitrogen and excess oxygen. This process eliminates the energy intensive step to separate the CO2 from nitrogen-rich flue gas that reduce the thermal efficiency. Fundamental knowledge of multiphase reactive fluid dynamic behavior of the gassolid flow is essential for the optimization and operation of a chemical looping combustor. Our recent thorough literature review shows that multiphase CFD-based models have not been adapted to chemical looping combustion processes in the open literature. In this study, we have developed the reaction kinetics model of the fuel reactor and implemented the kinetic model into a multiphase hydrodynamic model, MFIX, developed earlier at the National Energy Technology Laboratory. Simulated fuel reactor flows revealed high weight fraction of unburned methane fuel in the flue gas along with CO2 and H2O. This behavior implies high fuel loss at the exit of the reactor and indicates the necessity to increase the residence time, say by decreasing the fuel flow rate, or to recirculate the unburned methane after condensing and removing CO2.

Jung, Jonghwun (ANL); Gamwo, I.K.

2008-04-21T23:59:59.000Z

249

Bonneville Powerhouse 2 3D CFD for the Behavioral Guidance System  

SciTech Connect (OSTI)

In 2008 and 2009, a 700 ft long, 10-ft deep floating forebay guidance wall called a behavioral guidance structure (BGS) was deployed in the Bonneville Powerhouse 2 forebay. The US Army Corps of Engineers, Portland District (CENWP) contracted with the Pacific Northwest National Laboratory (PNNL) to develop computational tools to assess the impact of the BGS on forebay hydraulics (this study). The tools developed here to provide a characterization of forebay hydraulics to be integrated with acoustic telemetry studies designed to measure the impact on juvenile salmon guidance and survival through Bonneville Powerhouse 2. In previous work, PNNL performed computational fluid dynamics (CFD) studies for the Bonneville forebay for CENWP. In this study, the existing model was modified to include the BGS. The model included a bay-by-bay spillway, a truncated Powerhouse 1 forebay, Powerhouse 2 turbine intakes and corner collector, and the forebay bathymetry extending approximately 1.5km upstream from the tip of Cascade Island. Model validation outcomes were similar to that of past studies. Additional checks were included on the impact of the differencing scheme to flow solution. It was found that using upwind differencing was adequate and it was possible to use a truncated computational mesh of this model that included a BGS upstream of Powerhouse 2 and increased spatial resolution in the vicinity of the BGS. This model has been validated, run, and provided to CENWP to use for additional analysis of the Powerhouse 2 forebay hydraulics. The PNNL particle tracking software (PT6) was used to assess the impacts of mass and relative buoyancy on particle fate. The particle tracker was run for the Half Load case for the clean forebay and for the forebay with the BGS in place and the Corner Collector on. All tracker cases showed that the BGS moved the particles across the forebay increasing the number of particles exiting the model through the Corner Collector and (for streamlines and neutrally-buoyant particles) the lower numbered turbine units.

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

2010-02-01T23:59:59.000Z

250

The potential energy landscape and inherent dynamics of a hard-sphere fluid  

E-Print Network [OSTI]

Hard-sphere models exhibit many of the same kinds of supercooled-liquid behavior as more realistic models of liquids, but the highly non-analytic character of their potentials makes it a challenge to think of that behavior in potential-energy-landscape terms. We show here that it is possible to calculate an important topological property of hard-sphere landscapes, the geodesic pathways through those landscapes, and to do so without artificially coarse-graining or softening the potential. We show, moreover, that the rapid growth of the lengths of those pathways with increasing packing fraction quantitatively predicts the precipitous decline in diffusion constants in a glass-forming hard-sphere mixture model. The geodesic paths themselves can be considered as defining the intrinsic dynamics of hard spheres, so it is also revealing to find that they (and therefore the features of the underlying potential-energy landscape) correctly predict the occurrence of dynamic heterogeneity and non-zero values of the non-Gaussian parameter. The success of these landscape predictions for the dynamics of such a singular model emphasizes that there is more to potential energy landscapes than is revealed by looking at the minima and saddle points.

Qingqing Ma; Richard M. Stratt

2014-08-13T23:59:59.000Z

251

Advanced CFD Models for High Efficiency Compression Ignition Engines  

Broader source: Energy.gov [DOE]

Advanced CFD models for high efficiency compression-ignition engines can be used to show how turbulence-chemistry interactions influence autoignition and combustion.

252

CFD Combustion Modeling with Conditional Moment Closure using...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Combustion Modeling with Conditional Moment Closure using Tabulated Chemistry CFD Combustion Modeling with Conditional Moment Closure using Tabulated Chemistry A method is...

253

The Effects of Fluid Flow On Shear Localization and Frictional Strength From Dynamic Models Of Fault Gouge During Earthquakes  

E-Print Network [OSTI]

This thesis explores the effects of fluid flow on shear localization and frictional strength of fault gouge through the use of a coupled 2-phase (pore fluid-grain) Finite Difference-Discrete Element Numerical model. The model simulates slip...

Bianco, Ronald

2013-12-02T23:59:59.000Z

254

CFD simulating the transient thermalhydraulic characteristics in a 17נ17 bundle for a spent fuel pool under the loss of external cooling system accident  

Science Journals Connector (OSTI)

Abstract This paper develops a three-dimensional (3-D) transient computational fluid dynamics (CFD) model to simulate the thermalhydraulic characteristics in a fuel bundle located in a spent fuel pool (SFP) under the loss of external cooling system accident. The SFP located in the Maanshan nuclear power plant (NPP) is selected herein. Without adopting the porous media approach usually used in the previous CFD works, this model uses a real-geometry simulation of a 17נ17 fuel bundle, which can obtain the localized distributions of the flow and heat transfer during the accident. These distribution characteristics include several peaks in the axial distributions of flow, pressure, temperature, and Nusselt number (Nu) near the support grids, the non-uniform distribution of secondary flow, and the non-uniform temperature distribution due to flow mixing between rods, etc. According to the conditions adopted in the Procedure 597.1 (MNPP Plant Procedure 597.1, 2010) for the management of the loss-of-cooling event of the spent fuel pool in the Maanshan NPP, the temperature rising rate predicted by the present model can be equivalent to 1.26K/h, which is the same order as that of 3.5K/h in the this procedure. This result also confirms that the temperature rising rate used in the Procedure 597.1 for the Maanshan NPP is conservative. In addition, after the loss of external cooling system, there are about 44h for the operator to repair the malfunctioning system or provide the alternative water source for the pool inventory to avoid the occurrence of the local boiling in the SFP based on the present predicted temperature rising rate.

S.R. Chen; W.C. Lin; Y.M. Ferng; C.C. Chieng; B.S. Pei

2014-01-01T23:59:59.000Z

255

Some thoughts on exploiting CFD for turbomachinery design  

E-Print Network [OSTI]

Some thoughts on exploiting CFD for turbomachinery design M. B. Giles Oxford University Computing enormously and it is now used extensively by all turbomachinery companies in designing speci c components was presented at the IMeche Symposium on Exploiting CFD for Turbomachinery Design, on March 19th, 1998

Giles, Mike

256

CFD simulation of neutral ABL flows Xiaodong Zhang  

E-Print Network [OSTI]

Title: CFD simulation of neutral ABL flows Division: Aero-elastic Design ­ Wind Energy Division Risø flow field over different terrains employing Fluent 6.3 software. How accurate the simulation could.5 Comparison and conclusion 22 3.6 Closure 24 4 CFD Simulation of the Askervein Hill 24 4.1 Simulation

257

3457, Page, 1 Coupled CFD/Building Envelope Model  

E-Print Network [OSTI]

Performance Buildings Conference at Purdue, 2012 (Accepted) #12;3457, Page, 2 a standard model for a single3457, Page, 1 Coupled CFD/Building Envelope Model for the Purdue Living Lab Donghun KIM (kim1077 features. In the present case we develop a procedure for coupling a building envelope model to a CFD

Gugercin, Serkan

258

CFD study of mixing and segregation in CFB risers: Extension of EMMS drag model to binary gassolid flow  

Science Journals Connector (OSTI)

Abstract The Energy Minimization Multi-Scale (EMMS) drag model, using Sauter mean particle diameter to represent real particle size distribution, has proven to be effective in improving the accuracy of continuum modeling of gassolid flow. Nevertheless, mixing and segregation characteristics in circulating fluidized bed (CFB) risers are very important in many situations, which necessitates the explicit consideration of the effects of particle size distribution on the bed hydrodynamics. To this end, an attempt is made to extend the EMMS drag model to binary gassolid system, where four input parameters that can be obtained from computational fluid dynamics (CFD) simulation, including two slip velocities between gas and each particle phase and two particle concentrations of each phase, are used to solve the proposed EMMS drag model. Heterogeneous indexes, which are used to modify the drag correlation obtained from homogeneous fluidization, are then predicted and fed into multifluid model (MFM) to predict the dynamical behavior of mixing and segregation of binary gassolid flow in a CFB riser. The effects of different drag force models, kinetic theories and particleparticle drag force models are also systematically evaluated. It was shown that (i) MFM with the proposed EMMS drag model and the kinetic theory developed by Chao et al. (Chemical Engineering Science 2011, 66: 36053616) is able to correctly predict the mixing and segregation pattern in the studied riser, while MFM with homogenous drag forces and the simplified kinetic theory available in commercial software FLUENT completely fails; and (ii) with or without particleparticle drag force has a substantial influence upon the particle behavior.

Quan Zhou; Junwu Wang

2015-01-01T23:59:59.000Z

259

Multisoliton solutions in terms of double Wronskian determinant for a generalized variable-coefficient nonlinear Schroedinger equation from plasma physics, arterial mechanics, fluid dynamics and optical communications  

SciTech Connect (OSTI)

In this paper, the multisoliton solutions in terms of double Wronskian determinant are presented for a generalized variable-coefficient nonlinear Schroedinger equation, which appears in space and laboratory plasmas, arterial mechanics, fluid dynamics, optical communications and so on. By means of the particularly nice properties of Wronskian determinant, the solutions are testified through direct substitution into the bilinear equations. Furthermore, it can be proved that the bilinear Baecklund transformation transforms between (N - 1)- and N-soliton solutions.

Lue Xing [School of Science, P.O. Box 122, Beijing University of Posts and Telecommunications, Beijing 100876 (China)], E-mail: xinglv655@yahoo.com.cn; Zhu Hongwu; Yao Zhenzhi; Meng Xianghua; Zhang Cheng [School of Science, P.O. Box 122, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Zhang Chunyi [Ministry-of-Education Key Laboratory of Fluid Mechanics and National Laboratory for Computational Fluid Dynamics, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); Meteorology Center of Air Force Command Post, Changchun 130051 (China); Tian Bo [School of Science, P.O. Box 122, Beijing University of Posts and Telecommunications, Beijing 100876 (China); State Key Laboratory of Software Development Environment, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); Key Laboratory of Optical Communication and Lightwave Technologies, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing 100876 (China)], E-mail: gaoyt@public.bta.net.cn

2008-08-15T23:59:59.000Z

260

Fluid Flow Modeling in Fractures  

E-Print Network [OSTI]

In this paper we study fluid flow in fractures using numerical simulation and address the challenging issue of hydraulic property characterization in fractures. The methodology is based on Computational Fluid Dynamics, ...

Sarkar, Sudipta

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.


261

AIAA Fluid Dynamics Conference and Exhibit, Orlando, FL. 23-26 June 2003 AIAA Paper No. 2003-3441 CFD VALIDATION ISSUES FOR BOUNDARY-LAYER STABILITY AND TRANSITION  

E-Print Network [OSTI]

requirements for gas-turbine-engine blades and vanes, low-Reynolds-number vehicles, submarines and torpedoes application. REVIEW OF ROADMAP TO TRANSITION Motivation Transition location can be a significant source

262

Experimental study of dynamic barite sag in oil-based drilling fluids using a modified rotational viscometer and a flow loop  

Science Journals Connector (OSTI)

During drilling operations, control of the sub-surface pressure is of utmost importance. High density minerals, such as barite and hematite, are used to increase the density of drilling fluids and thereby control these pressures. However, contributing factors, such as the gravitational force, cause the weighting material particles to settle out of the suspension. This is designated as sag within the drilling industry and can lead to a variety of major drilling problems, including lost circulation, well control difficulties, poor cement jobs, and stuck pipes. The study of this phenomenon, including ways to mitigate its effects, has long been of interest. In this paper several methods for evaluating dynamic barite sag in oil-based drilling fluids are examined in a flow loop with the use of a rotational viscometer modified by the addition of a sag shoe (MRV). Tests using the MRV in the range of 0100RPM were conducted, and the effects of rotation speed on sag were correlated with flow loop tests performed by varying the inner pipe rotation speed. The combined effects of eccentricity and pipe rotation on dynamic barite sag in oil-based drilling fluids are also described in this paper. Flow loop test results indicate that pipe rotation has a greater impact on reducing sag when the pipe is eccentric rather than concentric. Additionally, results in the MRV indicate a strong correlation between the test RPM and the degree of measured sag.

Tan Nguyen; Stefan Miska; Mengjiao Yu; Nicholas Takach; Ramadan Ahmed; Arild Saasen; Tor Henry Omland; Jason Maxey

2011-01-01T23:59:59.000Z

263

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...

Haghshenas, Arash

2013-04-24T23:59:59.000Z

264

Analyzing Ventilation Effects of Different Apartment Styles by CFD  

E-Print Network [OSTI]

ICEBO2006, Shenzhen, China Renewable Renewable Energy Resources and a Greener Future Vol.VIII-3-5 Analyzing Ventilation Effects of Different Apartment Styles by CFD Xiaodong Li Lina Wang Zhixing Ye Associate Professor School...

Li, X.; Wang, L.; Ye, Z.

2006-01-01T23:59:59.000Z

265

CFD Simulation of the NREL Phase VI Rotor  

E-Print Network [OSTI]

The simulation of the turbulent and potentially separating flow around a rotating, twisted, and tapered airfoil is a challenging task for CFD simulations. This paper describes CFD simulations of the NREL Phase VI turbine that was experimentally characterized in the 24.4m x 36.6m NREL/NASA Ames wind tunnel (Hand et al., 2001). All computations in this article are performed on the experimental base configuration of 0o yaw angle, 3o tip pitch angle, and a rotation rate of 72 rpm. The significance of specific mesh resolution regions to the accuracy of the CFD prediction is discussed. The ability of CFD to capture bulk quantities, such as the shaft torque, and the detailed flow characteristics, such as the surface pressure distributions, are explored for different inlet wind speeds. Finally, the significant three-dimensionality of the boundary layer flow is demonstrated.

Song, Yang

2014-01-01T23:59:59.000Z

266

OPTIMIZATION OF FUEL-AIR MIXING FOR A SCRAMJET COMBUSTOR GEOMETRY USING CFD AND A GENETIC ALGORITHM .  

E-Print Network [OSTI]

??A new methodology for the optimization of fuel-air mixing in a scramjet combustor using integrated Genetic Algorithms and Computational Fluid Dynamics is presented. A typical (more)

Ahuja, Vivek

2008-01-01T23:59:59.000Z

267

Evaluation of a CFD-model for simulation of simplified flow conditioners  

SciTech Connect (OSTI)

Perforated plate flow conditioners are used to generate a fully developed turbulent flow profile upstream of an orifice meter. It is very time-consuming to measure the effect of a flow conditioner for different upstream flow profiles. Therefore a project is initiated to evaluate the performance of a computational fluid computer code for this purpose. If the code correctly predicts the flow characteristics downstream of more complex flow conditioners. In this study a k-{var_epsilon} CFD-model was used to predict the flow downstream of obstruction plates having one large or nine small holes. Both mean velocity, turbulent kinetic energy, k, and the dissipation rate of turbulent kinetic energy, {var_epsilon}, were calculated and compared against measured data. The results indicate that it is possible to predict the mean velocity well and that the accuracy of the predicted k and {var_epsilon} depends on the complexity of the flow.

Erdal, A. [Statoil/K-LAB, Haugesund (Norway); Torbergsen, L.E.; Rimestad, S.; Krogstad, P.A. [Norwegian Inst. of Technology, Trondheim (Norway)

1995-12-31T23:59:59.000Z

268

SciTech Connect: Development of CFD-Based Simulation Tools for...  

Office of Scientific and Technical Information (OSTI)

Development of CFD-Based Simulation Tools for In-Situ Thermal Processing of Oil ShaleSands Citation Details In-Document Search Title: Development of CFD-Based Simulation Tools for...

269

Aerodynamic Shape Design of Transonic Airfoils Using Hybrid Optimization Techniques and CFD  

E-Print Network [OSTI]

This paper will analyze the effects of using hybrid optimization methods for optimizing objective functions that are determined by computational fluid dynamics solvers for compressible viscous flow for optimal design of ...

Xing, X.Q.

270

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

Science Journals Connector (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

271

Stochastic Dynamic Programming and Stochastic Fluid-Flow Models in the Design and Analysis of Web-Server Farms  

E-Print Network [OSTI]

A Web-server farm is a specialized facility designed specifically for housing Web servers catering to one or more Internet facing Web sites. In this dissertation, stochastic dynamic programming technique is used to obtain the optimal admission...

Goel, Piyush

2010-10-12T23:59:59.000Z

272

Comparison of Hydrodynamic Load Predictions Between Engineering Models and Computational Fluid Dynamics for the OC4-DeepCwind Semi-Submersible: Preprint  

SciTech Connect (OSTI)

Hydrodynamic loads on the platforms of floating offshore wind turbines are often predicted with computer-aided engineering tools that employ Morison's equation and/or potential-flow theory. This work compares results from one such tool, FAST, NREL's wind turbine computer-aided engineering tool, and the computational fluid dynamics package, OpenFOAM, for the OC4-DeepCwind semi-submersible analyzed in the International Energy Agency Wind Task 30 project. Load predictions from HydroDyn, the offshore hydrodynamics module of FAST, are compared with high-fidelity results from OpenFOAM. HydroDyn uses a combination of Morison's equations and potential flow to predict the hydrodynamic forces on the structure. The implications of the assumptions in HydroDyn are evaluated based on this code-to-code comparison.

Benitz, M. A.; Schmidt, D. P.; Lackner, M. A.; Stewart, G. M.; Jonkman, J.; Robertson, A.

2014-09-01T23:59:59.000Z

273

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

SciTech Connect (OSTI)

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

DownloadedBy:[UniversityofCaliforniaLosAngeles]At:16:419December2007 Geophysical and Astrophysical Fluid Dynamics,  

E-Print Network [OSTI]

and convective heat transfer scalingy J. M. AURNOU* Department of Earth and Space Sciences, University shell to generate larger-scale zonal flows. Comparing quantitative results, heat transfer data at high heat transfer rates. Keywords: Core dynamics; Convection; Heat transfer; Planetary dynamos 1

275

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

SciTech Connect (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

276

Fluid Volumes: The Program FLUIDS  

Science Journals Connector (OSTI)

This chapter describes the program FLUIDS. The mathematical model underlying this program contains over 200 variables and describes control mechanisms of body fluid volumes and electrolytes as well as respirat...

Fredericus B. M. Min

1993-01-01T23:59:59.000Z

277

Metallization of fluid hydrogen  

Science Journals Connector (OSTI)

...P. Tunstall Metallization of fluid hydrogen W. J. Nellis 1 A. A. Louis 2 N...The electrical resistivity of liquid hydrogen has been measured at the high dynamic...which structural changes are paramount. hydrogen|metallization of hydrogen|liquid...

1998-01-01T23:59:59.000Z

278

GEOPHYSICAL FLUID DYNAMICS-I OC512/AS509 2011 P.Rhines LECTUREs 9-14 (weeks 4-5) verson 2.1, 2 March 2011 Stratified, rotating fluid: thermal  

E-Print Network [OSTI]

interacting with one another). Or, even the generation of non-geostrophic fronts and waves through flow March 2011 Stratified, rotating fluid: thermal wind and stratified geostrophic adjustment to geostrophic.7 and Bernoulli equation 4.8 Geostrophic adjustment in a 1-layer fluid with a free surface: notes The idealized

279

A Multiscale Analysis of Dynamic Wetting  

E-Print Network [OSTI]

Williams, B. C. (2008). Engineering Fluid Mechanics. Wiley,Thermo-Fluid Dynamics: In Materials Science and Engineering.Fluid Dynamics. McGraw-Hill Sci- ence/Engineering/Math, 1st

Minaki, Hiroyuki

2013-01-01T23:59:59.000Z

280

Low Energy Buildings: CFD Techniques for Natural Ventilation and Thermal  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

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.


281

Parallel processing with the Wind CFD code at Boeing  

Science Journals Connector (OSTI)

Wind is a general purpose CFD code capable of either Euler or NavierStokes analysis (R.H. Bush, A Three Dimensional Zonal NavierStokes Code for Subsonic through Hypersonic Propulsion Flowfields, AIAA 88-2380, 11 July 1998; R.H. Bush, G.D. Power, The Wind Production Flow Solver For the NPARC Alliance, AIAA 98-0935, 12 January 1998). The Wind code and its predecessor NASTD have been used for CFD applications, using its parallel mode, at Boeing since 1993. The Wind code is currently developed and distributed by the NPARC alliance. For more information see the NPARC web site at http://www.lerc.nasa.gov/www/winddocs/.

M.S Fisher; M Mani; D Stookesberry

2001-01-01T23:59:59.000Z

282

Microsoft Word - CFD MHD Post Grad Researcher.docx  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

283

CFD?Phenomenological Diesel Spray Analysis under Evaporative Conditions  

Science Journals Connector (OSTI)

CFD?Phenomenological Diesel Spray Analysis under Evaporative Conditions ... Despite their great uncertainties compared to the experimental studies, numerical simulations permit carrying out extensive parametric studies, isolating every single variable involved in the general process at any point in time and at any position in physical space. ... The thermodynamic codes assume that the cylinder charge is uniform in both composition and temperature, at all times during the cycle. ...

J. M. Desantes; X. Margot; J. M. Pastor; M. Chavez; A. Pinzello

2009-07-13T23:59:59.000Z

284

Introduction Fluid/Jeans  

E-Print Network [OSTI]

Introduction Fluid/DMSC Fluid/Jeans Comments Fluid/Kinetic Hybrid Modeling of the Thermosphere;Introduction Fluid/DMSC Fluid/Jeans Comments Outline 1 Fluid/DMSC 2 Fluid/Jeans 3 Comments Justin Erwin Fluid/Kinetic Hybrid Modeling of the Thermosphere of Pluto #12;Introduction Fluid/DMSC Fluid/Jeans Comments Motivation

Johnson, Robert E.

285

Effective perfect fluids in cosmology  

SciTech Connect (OSTI)

We describe the cosmological dynamics of perfect fluids within the framework of effective field theories. The effective action is a derivative expansion whose terms are selected by the symmetry requirements on the relevant long-distance degrees of freedom, which are identified with comoving coordinates. The perfect fluid is defined by requiring invariance of the action under internal volume-preserving diffeomorphisms and general covariance. At lowest order in derivatives, the dynamics is encoded in a single function of the entropy density that characterizes the properties of the fluid, such as the equation of state and the speed of sound. This framework allows a neat simultaneous description of fluid and metric perturbations. Longitudinal fluid perturbations are closely related to the adiabatic modes, while the transverse modes mix with vector metric perturbations as a consequence of vorticity conservation. This formalism features a large flexibility which can be of practical use for higher order perturbation theory and cosmological parameter estimation.

Ballesteros, Guillermo [Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Piazza del Viminale 1, I-00184 Rome (Italy); Bellazzini, Brando, E-mail: guillermo.ballesteros@unige.ch, E-mail: brando.bellazzini@pd.infn.it [Dipartimento di Fisica, Universit di Padova and INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy)

2013-04-01T23:59:59.000Z

286

Dusts resuspension Test in the STARDUST Facility: Experimental and CFD Analysis.  

E-Print Network [OSTI]

??This thesis is related to the application of the CFD FLUENT code to the dust resuspension tests performed inside the STARDUST (Small Tank for Aerosol (more)

FREDIANI, FRANCESCO

2009-01-01T23:59:59.000Z

287

E-Print Network 3.0 - advanced cfd codes Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laboratory Collection: Engineering 13 Solution characters of iterative coupling between energy simulation and CFD programs Summary: 1 Solution characters of iterative coupling...

288

E-Print Network 3.0 - air contamination due Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Experimental Validation of a Computational Fluid Dynamics Model for IAQ applications in Ice Rink Arenas Summary: dynamics (CFD) model has been used to predict the contaminant...

289

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

Science Journals Connector (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 Lundstrm

2012-01-01T23:59:59.000Z

290

Modeling and CFD Simulation of Water Desalination Using Nanoporous Membrane Contactors  

Science Journals Connector (OSTI)

Modeling and CFD Simulation of Water Desalination Using Nanoporous Membrane Contactors ... It also avoids common problems encountered in conventional contactors such as flooding, foaming, and entraining. ... A series of CFD simulations have been carried out for single-fiber modules using simplified 2D heat-transfer models. ...

Mehdi Ghadiri; Safoora Fakhri; Saeed Shirazian

2013-02-07T23:59:59.000Z

291

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

E-Print Network [OSTI]

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...

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

2010-01-01T23:59:59.000Z

292

COMPUTATIONAL FLUID DYNAMICS INCOMPRESSIBLE FLOW  

E-Print Network [OSTI]

to numerically solve the Euler equations in order to predict effects of bomb blast waves following WW II­71, and was published the following year [1]. Computing power at that time was still grossly inadequate for what we.S., in Europe (especially France, Great Britain and Sweden) and in the (former) Soviet Union. Today

McDonough, James M.

293

Surface pressure measurements for CFD code validation in hypersonic flow  

SciTech Connect (OSTI)

Extensive surface pressure measurements were obtained on a hypersonic vehicle configuration at Mach 8. All of the experimental results were obtained in the Sandia National Laboratories Mach 8 hypersonic wind tunnel for laminar boundary layer conditions. The basic vehicle configuration is a spherically blunted 10{degrees} half-angle cone with a slice parallel with the axis of the vehicle. The bluntness ratio of the geometry is 10% and the slice begins at 70% of the length of the vehicle. Surface pressure measurements were obtained for angles of attack from {minus}10 to + 18{degrees}, for various roll angles, at 96 locations on the body surface. A new and innovative uncertainty analysis was devised to estimate the contributors to surface pressure measurement uncertainty. Quantitative estimates were computed for the uncertainty contributions due to the complete instrumentation system, nonuniformity of flow in the test section of the wind tunnel, and variations in the wind tunnel model. This extensive set of high-quality surface pressure measurements is recommended for use in the calibration and validation of computational fluid dynamics codes for hypersonic flow conditions.

Oberkampf, W.L.; Aeschliman, D.P.; Henfling, J.F.; Larson, D.E.

1995-07-01T23:59:59.000Z

294

Relativistic viscoelastic fluid mechanics  

SciTech Connect (OSTI)

A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.

Fukuma, Masafumi; Sakatani, Yuho [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)

2011-08-15T23:59:59.000Z

295

Combustion process in a biomass grate fired industry furnace: a CFD study  

Science Journals Connector (OSTI)

This paper presents a CFD investigation of the combustion process in a 50 MW grate fired furnace. The CFD results were compared with available experimental data at the furnace outlet to validate the models for the volatile oxidation and NOx formation. The models were then used to predict the effect of an 'ECO' tube system on NOx emissions. It was shown that with an improved flow structure and air distribution, 30% NOx reduction can be obtained. CFD results revealed the impact of load and fuel moisture on the flow structure, the temperature distribution and the flow residence time.

T. Klason; X.S. Bai

2006-01-01T23:59:59.000Z

296

Comparative Study: CFD ?P Versus Measured ?P for 30% Flexible Ducts  

E-Print Network [OSTI]

foot-long circular ducts placed on both ends. A CFD model was built and simulations were run under different volumetric air flows. The static pressure drop for those conditions were analyzed and displayed. The final CFD model is tuned until...) computer model. Fluent 6.2.16 CFD software package was used to simulate the static pressure drop inside the flexible duct. 3-D computer model of 6 diameter flexible duct was generated for 30% compression in 5 ft. long. The laboratory data...

Ugursal, A.; Culp, C.

2006-01-01T23:59:59.000Z

297

CFD Numerical Simulation of Vortex-Induced Vibration of a Stay Cable under a Wind Profile  

Science Journals Connector (OSTI)

VIV (Vortex-induced vibration) of a stay cable subjected to a wind profile is numerically simulated through combining CFD ... numerical model. Under a profile of mean wind speed, unsteady aerodynamic lift coeffic...

Wenli Chen; Hui Li

2009-01-01T23:59:59.000Z

298

A Multi-Model Approach for Uncertainty Propagation and Model Calibration in CFD Applications  

E-Print Network [OSTI]

Proper quantification and propagation of uncertainties in computational simulations are of critical importance. This issue is especially challenging for CFD applications. A particular obstacle for uncertainty quantifications in CFD problems is the large model discrepancies associated with the CFD models used for uncertainty propagation. Neglecting or improperly representing the model discrepancies leads to inaccurate and distorted uncertainty distribution for the Quantities of Interest. High-fidelity models, being accurate yet expensive, can accommodate only a small ensemble of simulations and thus lead to large interpolation errors and/or sampling errors; low-fidelity models can propagate a large ensemble, but can introduce large modeling errors. In this work, we propose a multi-model strategy to account for the influences of model discrepancies in uncertainty propagation and to reduce their impact on the predictions. Specifically, we take advantage of CFD models of multiple fidelities to estimate the model ...

Wang, Jian-xun; Xiao, Heng

2015-01-01T23:59:59.000Z

299

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

SciTech Connect (OSTI)

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

300

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...

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

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).
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

General Purpose Steam Table Library: CASL L3:THM.CFD.P7.04 Milestone...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

General Purpose Steam Table Library: CASL L3:THM.CFD.P7.04 Milestone Report John H. Carpenter, Noel Belcourt, Robert Nourgalieu SNLINL Completed: August 30, 2013 CASL-...

302

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

303

Lab-scale Experimentation and CFD Modeling of a Small Particle Heat Exchange Receiver  

Science Journals Connector (OSTI)

Abstract Concentrating solar power currently relies on high temperature central receivers that utilize liquid cooling and operate in power steam cycles. However, highly efficient central receivers are being designed to operate at higher temperatures in a gas turbine power cycle. To address this, San Diego State University's (SDSU) Combustion and Solar Energy Laboratory is experimenting with a lab-scale Small Particle Heat Exchange Receiver (SPHER) in order to understand performance and develop experience for designing and operating a full-scale 5 MW design. The full-scale design will be tested at the National Solar Thermal Test Facility at Sandia National Laboratories as part of the Department of Energy SunShot Initiative grant. The SPHER relies on carbon nanoparticles as an absorption medium and air as a working fluid. The carbon particles are generated onsite by the Carbon Particle Generator (CPG) and are mixed with dilution air prior to entering the SPHER. Lab scale on-sun testing is carried out with a 15kWe solar simulator. The lab scale experimental goal is to achieve an outlet flow of 650C at 5bar absolute operating pressure. To model the performance of the SPHER, CFD analysis is being used for comparison to lab scale testing. The lab scale SPHER is being modeled in ANSYS Fluent with coupled codes for oxidation and radiation input. In this paper, we present results of testing the lab-scale receiver and compare the measured outlet temperatures to predictions from the computer model. Finally, correlations are drawn for future experimenation and feasibility.

L. Frederickson; M. Dordevich; F. Miller

2014-01-01T23:59:59.000Z

304

From: Numerical Grid Generation in Computational Fluid Dynamics and Related Fields, ed. B. K. Soni, J. F. Thompson, H. Hausser and P. R.  

E-Print Network [OSTI]

. GEOMESH is a modeling tool developed for automating finite element grid generation. This tool maintains represent an important boundary condition in reservoir simulations. Rapid changes and large pressure for Finite Element Grids Terry A. Cherry1 Carl W. Gable1 Harold Trease2 ABSTRACT Modeling fluid, vapor

Gable, Carl W.

305

E-Print Network 3.0 - artery flow velocity Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Artery by Proper Orthogonal Decomposition Summary: employ computational fluid dynamics (CFD) to investigate blood flow in a carotid artery, which has... to turbulence is expected...

306

Mobile Ice Nucleus Spectrometer  

SciTech Connect (OSTI)

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

307

E-Print Network 3.0 - aneurysm repair reflect Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

47 The University of Western Ontario DEPARTMENT OF PHYSICS AND ASTRONOMY Summary: "Validation and application of Computational Fluid Dynamics (CFD) to cerebral aneurysms"...

308

E-Print Network 3.0 - aortoiliac aneurysm repair Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

40 The University of Western Ontario DEPARTMENT OF PHYSICS AND ASTRONOMY Summary: "Validation and application of Computational Fluid Dynamics (CFD) to cerebral aneurysms"...

309

Modelling microscale fuel cells.  

E-Print Network [OSTI]

??The focus of this work is to investigate transport phenomena in recently developed microscale fuel cell designs using computational fluid dynamics (CFD). Two microscale fuel (more)

Bazylak, Aimy Ming Jii

2009-01-01T23:59:59.000Z

310

Modeling and simulation for a PEM fuel cell with catalyst layers in finite thickness.  

E-Print Network [OSTI]

??A detailed non-isothermal computational fluid dynamics (CFD) model for proton electrolyte membrane (PEM) fuel cells is developed in this thesis. This model consists of the (more)

Yin, Jianghui (Author)

2007-01-01T23:59:59.000Z

311

E-Print Network 3.0 - artery spatial distribution Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Engineering, Duke University Collection: Biology and Medicine 5 Abstract Computed tomography (CT) slices are combined with computational fluid dynamics (CFD) to Summary:...

312

E-Print Network 3.0 - atherosclerotic human coronary Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

for: atherosclerotic human coronary Page: << < 1 2 3 4 5 > >> 1 Abstract Computed tomography (CT) slices are combined with computational fluid dynamics (CFD) to Summary: ) to...

313

E-Print Network 3.0 - atherosclerotic proximal coronary Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

for: atherosclerotic proximal coronary Page: << < 1 2 3 4 5 > >> 1 Abstract Computed tomography (CT) slices are combined with computational fluid dynamics (CFD) to Summary: ) to...

314

Dynamics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

315

Dual-level parallelism for high-order CFD methods  

E-Print Network [OSTI]

Division of Applied Mathematics, Center for Fluid Mechanics, Brown University, Box ..... The MPI calls are handled by only one thread within each process. ..... from George Loriot and Samuel Fulcomer at the Technology Center for Advanced

2004-01-02T23:59:59.000Z

316

Euler's fluid equations: Optimal Control vs Optimization  

E-Print Network [OSTI]

An optimization method used in image-processing (metamorphosis) is found to imply Euler's equations for incompressible flow of an inviscid fluid, without requiring that the Lagrangian particle labels exactly follow the flow lines of the Eulerian velocity vector field. Thus, an optimal control problem and an optimization problem for incompressible ideal fluid flow both yield the \\emph {same} Euler fluid equations, although their Lagrangian parcel dynamics are \\emph{different}. This is a result of the \\emph{gauge freedom} in the definition of the fluid pressure for an incompressible flow, in combination with the symmetry of fluid dynamics under relabeling of their Lagrangian coordinates. Similar ideas are also illustrated for SO(N) rigid body motion.

Darryl D. Holm

2009-09-28T23:59:59.000Z

317

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...

Carlisle, Bruce Scott

2012-06-07T23:59:59.000Z

318

Attractor local dimensionality, nonlinear energy transfers and finite-time instabilities in unstable dynamical systems with applications to two-dimensional fluid flows  

Science Journals Connector (OSTI)

...Attractor local dimensionality, nonlinear energy transfers and finite-time instabilities...relate its nonlinear dimensionality to energy exchanges between dynamical components...the attractor with the circulation of energy: (i) from the mean flow to the unstable...

2013-01-01T23:59:59.000Z

319

Viscosity of a nucleonic fluid  

E-Print Network [OSTI]

The viscosity of nucleonic matter is studied both classically and in a quantum mechanical description. The collisions between particles are modeled as hard sphere scattering as a baseline for comparison and as scattering from an attractive square well potential. Properties associated with the unitary limit are developed which are shown to be approximately realized for a system of neutrons. The issue of near perfect fluid behavior of neutron matter is remarked on. Using some results from hard sphere molecular dynamics studies near perfect fluid behavior is discussed further.

Aram Z. Mekjian

2012-03-21T23:59:59.000Z

320

INVESTIGATION OF A DYNAMIC POWER LINE RATING CONCEPT FOR IMPROVED WIND ENERGY INTEGRATION OVER COMPLEX TERRAIN  

SciTech Connect (OSTI)

Dynamic Line Rating (DLR) is a smart grid technology that allows the rating of power line to be based on real-time conductor temperature dependent on local weather conditions. In current practice overhead power lines are generally given a conservative rating based on worst case weather conditions. Using historical weather data collected over a test bed area, we demonstrate there is often additional transmission capacity not being utilized with the current static rating practice. We investigate a new dynamic line rating methodology using computational fluid dynamics (CFD) to determine wind conditions along transmission lines at dense intervals. Simulated results are used to determine conductor temperature by calculating the transient thermal response of the conductor under variable environmental conditions. In calculating the conductor temperature, we use both a calculation with steady-state assumption and a transient calculation. Under low wind conditions, steady-state assumption predicts higher conductor temperatures that could lead to curtailments, whereas transient calculations produce conductor temperatures that are significantly lower, implying the availability of additional transmission capacity.

Jake P. Gentle; Kurt S Myers; Tyler B Phillips; Inanc Senocak; Phil Anderson

2014-08-01T23:59:59.000Z

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321

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS Int. J. Numer. Meth. Fluids (2012)  

E-Print Network [OSTI]

are still within reasonable range. Nevertheless, for test case two, which has higher density and viscosity, emulsification, spraying and so on. The kinematics and dynamics of the fluid interfaces play an important role

Frey, Pascal

322

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

SciTech Connect (OSTI)

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

323

Fluid Inclusion Gas Analysis  

SciTech Connect (OSTI)

Fluid inclusion gas analysis for wells in various geothermal areas. Analyses used in developing fluid inclusion stratigraphy for wells and defining fluids across the geothermal fields. Each sample has mass spectrum counts for 180 chemical species.

Dilley, Lorie

2013-01-01T23:59:59.000Z

324

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"

325

Accurate Predictions of Fuel Effects on Combustion and Emissions in Engines Using CFD Simulations With Detailed Fuel Chemistry  

Broader source: Energy.gov [DOE]

Accurate fuel models with hundreds of species in advanced CFD with reasonable simulation times. Reaction workbench used for surrogate blend formulation and model reduction. FORTE CFD used for HCCI and LTC diesel engine and validated for PRF-ethanol and diesel

326

CFD simulations of enhanced condensational growth (ECG) applied to respiratory drug delivery with comparisons to in vitro data  

E-Print Network [OSTI]

CFD simulations of enhanced condensational growth (ECG) applied to respiratory drug delivery t Enhanced condensational growth (ECG) is a newly proposed concept for respiratory drug delivery in which and evaluate a CFD model of ECG in a simple tubular geometry with direct comparisons to in vitro results

Frey, Pascal

327

CFD analyses of natural circulation in the air-cooled reactor cavity cooling system  

SciTech Connect (OSTI)

The Natural Convection Shutdown Heat Removal Test Facility (NSTF) is currently being built at Argonne National Laboratory, to evaluate the feasibility of the passive Reactor Cavity Cooling System (RCCS) for Next Generation Nuclear Plant (NGNP). CFD simulations have been applied to evaluate the NSTF and NGNP RCCS designs. However, previous simulations found that convergence was very difficult to achieve in simulating the complex natural circulation. To resolve the convergence issue and increase the confidence of the CFD simulation results, additional CFD simulations were conducted using a more detailed mesh and a different solution scheme. It is found that, with the use of coupled flow and coupled energy models, the convergence can be greatly improved. Furthermore, the effects of convection in the cavity and the effects of the uncertainty in solid surface emissivity are also investigated. (authors)

Hu, R. [Nuclear Engineering Division, Argonne National Laboratory, Argonne IL (United States); Pointer, W. D. [Reactor and Nuclear Systems Division, Oak Ridge National Laboratory, Oak Ridge TN (United States)

2013-07-01T23:59:59.000Z

328

Friction-Induced Fluid Heating in Nanoscale Helium Flows  

SciTech Connect (OSTI)

We investigate the mechanism of friction-induced fluid heating in nanoconfinements. Molecular dynamics simulations are used to study the temperature variations of liquid helium in nanoscale Poiseuille flows. It is found that the fluid heating is dominated by different sources of friction as the external driving force is changed. For small external force, the fluid heating is mainly caused by the internal viscous friction in the fluid. When the external force is large and causes fluid slip at the surfaces of channel walls, the friction at the fluid-solid interface dominates over the internal friction in the fluid and is the major contribution to fluid heating. An asymmetric temperature gradient in the fluid is developed in the case of nonidentical walls and the general temperature gradient may change sign as the dominant heating factor changes from internal to interfacial friction with increasing external force.

Li Zhigang [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

2010-05-21T23:59:59.000Z

329

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

SciTech Connect (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

330

Modelling suspended sediment in environmental turbulent fluids  

E-Print Network [OSTI]

Modelling sediment transport in environmental turbulent fluids is a challenge. This article develops a sound model of the lateral transport of suspended sediment in environmental fluid flows such as floods and tsunamis. The model is systematically derived from a 3D turbulence model based on the Smagorinski large eddy closure. Embedding the physical dynamics into a family of problems and analysing linear dynamics of the system, centre manifold theory indicates the existence of slow manifold parametrised by macroscale variables. Computer algebra then constructs the slow manifold in terms of fluid depth, depth-averaged lateral velocities, and suspended sediment concentration. The model includes the effects of sediment erosion, advection, dispersion, and also the interactions between the sediment and turbulent fluid flow. Vertical distributions of the velocity and concentration in steady flow agree with the established experimental data. Numerical simulations of the suspended sediment under large waves show that ...

Cao, Meng

2014-01-01T23:59:59.000Z

331

Transport and dynamics in toroidal fusion systems. Report of second year progress, 1993--1994  

SciTech Connect (OSTI)

In this document the author describes an extension of the spatial gridding techniques to an MHD model suitable for the description of the dynamics of toroidal fusion devices. Since the dominant MHD modes in these devices have relatively long toroidal wavelength, the toroidal coordinate is approximated with finite Fourier series. The unstructured, triangular mesh is used to describe the details of the poloidal geometry. With some exceptions, the hydrodynamic variables are treated in a manner analogous to that used in CFD. These quantities (mass, energy, and momentum) are volume based densities that satisfy scalar or vector conservation laws. The electromagnetic variables (the magnetic flux density B and the electric current density J) are area based densities that satisfy pseudo-vector conservation laws, and have no counterpart in fluid dynamics. These variables are also constrained to remain solenoidal. These quantities are represented on the triangular mesh in a new manner that is an extension of that used on rectangular, structured meshes. In this work the author has chosen to solve the primitive MHD equations in order to make the resulting codes and techniques more generally applicable to problems beyond the narrow scope of tokamak plasmas. The temporal stiffness problems inherent in this description of tokamak dynamics that motivate the reduced MHD model are addressed here with the semi-implicit method of time integration. Finally, the author remarks that, while the present work deals strictly with the MHD equations, other volume based fluid descriptions, such as diffusive transport could easily be adapted to these techniques and coupled with the description of the electromagnetic field presented here.

Schnack, D.D. [Science Applications International Corp., San Diego, CA (United States). Applied Plasma Physics and Technology Div.

1994-05-09T23:59:59.000Z

332

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

333

Validation of a CFD Analysis Model for Predicting CANDU-6 Moderator Temperature Against SPEL Experiments  

SciTech Connect (OSTI)

A validation of a 3D CFD model for predicting local subcooling of the moderator in the vicinity of calandria tubes in a CANDU-6 reactor is performed. The small scale moderator experiments performed at Sheridan Park Experimental Laboratory (SPEL) in Ontario, Canada[1] is used for the validation. Also a comparison is made between previous CFD analyses based on 2DMOTH and PHOENICS, and the current analysis for the same SPEL experiment. For the current model, a set of grid structures for the same geometry as the experimental test section is generated and the momentum, heat and continuity equations are solved by CFX-4.3, a CFD code developed by AEA technology. The matrix of calandria tubes is simplified by the porous media approach. The standard k-{epsilon} turbulence model associated with logarithmic wall treatment and SIMPLEC algorithm on the body fitted grid are used. Buoyancy effects are accounted for by the Boussinesq approximation. For the test conditions simulated in this study, the flow pattern identified is the buoyancy-dominated flow, which is generated by the interaction between the dominant buoyancy force by heating and inertial momentum forces by the inlet jets. As a result, the current CFD moderator analysis model predicts the moderator temperature reasonably, and the maximum error against the experimental data is kept at less than 2.0 deg. C over the whole domain. The simulated velocity field matches with the visualization of SPEL experiments quite well. (authors)

Churl Yoon; Bo Wook Rhee; 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

Performance of Coupled Building Energy and CFD Simulations Zhiqiang (John) Zhai  

E-Print Network [OSTI]

and CFD. This investigation implemented these concepts and developed an integrated building design tool, E, West Lafayette, IN 47907-2088, USA Abstract The integration of building energy simulation (ES of the integrated building simulation over the separated energy simulation and computational

Chen, Qingyan "Yan"

335

Biologically-Inspired Adaptive Pectoral-Like Fin Control System For CFD Parameterized AUV  

E-Print Network [OSTI]

on the normalized gradient scheme. In the closed-loop system, time-varying yaw an- gle reference trajectoriesBiologically-Inspired Adaptive Pectoral-Like Fin Control System For CFD Parameterized AUV Mugdha S fin control, Adaptive control, Yaw plane control. Abstract- This paper treats the question of adaptive

Mittal, Rajat

336

CFD Analysis of Nuclear Fuel Bundles and Spacer Grids for PWR Reactors  

E-Print Network [OSTI]

4.3 The Numerical Approach ......................................................... 95 viii 4.4 Implementation in CFD Codes ................................................. 99 4... Total standard error refinement 3 ................................................................... 56 xii Figure 62 Experimental results plane B1 axial velocity (a), KER 138M mesh constant inlet (b), SST138M mesh periodic inlet (c...

Capone, Luigi

2012-10-19T23:59:59.000Z

337

CFD Investigations of a Transonic Swept-Wing Laminar Flow Control Flight Experiment  

E-Print Network [OSTI]

wing glove was identified. Next, a full CFD analysis of the aircraft was performed to determine any adverse effects on the wing flow-field from the aircraft engines. This required an accurate CAD model of the selected aircraft. Proper modeling...

Neale, Tyler P.

2011-08-08T23:59:59.000Z

338

CFD Simulation of Open Channel Flooding Flows and Scouring Around Bridge Structures  

E-Print Network [OSTI]

CFD Simulation of Open Channel Flooding Flows and Scouring Around Bridge Structures B. D. ADHIKARYKalb, IL 60115 U.S.A. Email: kostic@niu.edu; Web: http://www.kostic.niu.edu Abstract: - Simulation of scour caused by flooding and pressure flow conditions, is of significant interest nowadays to computational

Kostic, Milivoje M.

339

Development of CFD Simulation for 3-D Flooding Flow and Scouring Around a Bridge Structure  

E-Print Network [OSTI]

Development of CFD Simulation for 3-D Flooding Flow and Scouring Around a Bridge Structure B of bridge failure during storms and floods. Simulation of scour-hole formation under the bridge deck and around the bridge piers, due to sediment entrainment and transport caused by flooding flow conditions

Kostic, Milivoje M.

340

Application of CFD to Predict and Control Chemical and Biological Agent Dispersion in Buildings  

E-Print Network [OSTI]

1 Application of CFD to Predict and Control Chemical and Biological Agent Dispersion in Buildings Z, West Lafayette, IN 47907 Abstract Terrorist attack in buildings by chemical and biological agents (CBAs in an office building in order to find the best locations for CBA sensors and to develop effective ventilation

Chen, Qingyan "Yan"

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

Numerical Simulation of Heat Transfer and Fluid Flow Characteristics of Server Rack in Datacenter  

Science Journals Connector (OSTI)

This chapter is studying the fluid mechanics and heat transfer of single server rack using the computational fluid dynamics software. The ... effect of the different structure parameters of server rack in datacen...

Jianfei Zhang; Donghao Liu; Xiping Qiao

2014-01-01T23:59:59.000Z

342

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

343

Standardization of Thermo-Fluid Modeling in Modelica.Fluid  

E-Print Network [OSTI]

Thermo-Fluid Systems, Modelica 2003 Conference, Linkping,H. Tummescheit: The Modelica Fluid and Media Library forThermo-Fluid Pipe Networks, Modelica 2006 Conference, Vi-

Franke, Rudiger

2010-01-01T23:59:59.000Z

344

Accurate equations of state for CF4, CF4Ar, and CF4CH4 fluids using two-body and three-body intermolecular potentials from molecular dynamics simulation  

Science Journals Connector (OSTI)

Abstract Molecular dynamics simulations have been performed to obtain pressures and equations of state of CF4, CF4Ar, and CF4CH4 fluids using different inversion and ab initio pair-potentials. To take many-body forces into account, the three-body potentials of Hauschild and Prausnitz, Mol. Simul. 11 (1993) 177185, Wang and Sadus, J. Chem. Phys. 125 (2006) 144509144513, and Guzman et al., Mol. Phys. 109 (2011) 955967 have been used with the pair-potentials. The significance of this work is that the many-body potential of Hauschild and Prausnitz is extended as a function of density, temperature, and molar fraction and is used with the HFD-like pair-potentials of CF4, CF4Ar, and CF4CH4 systems to improve the prediction of the pressure values without requiring an expensive three-body calculation. We have also simulated the self-diffusion coefficient of CF4 in good agreement with experimental data.

Mohsen Abbaspour; Maryam Sheykh

2014-01-01T23:59:59.000Z

345

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

SciTech Connect (OSTI)

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 (~850C). 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

346

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

347

HEAT TRANSFER FLUIDS  

E-Print Network [OSTI]

The choice of heat transfer fluids has significant effects on the performance, cost, and reliability of solar thermal systems. In this chapter, we evaluate existing heat transfer fluids such as oils and molten salts based ...

Lenert, Andrej

2012-01-01T23:59:59.000Z

348

CFD model for the simulation of chemical looping combustion  

Science Journals Connector (OSTI)

Abstract A chemical looping combustion (CLC) system uses a metal oxide solid carrier to combust a source of fuel in isolation from the source of oxygen which produces an exhaust gas of primarily carbon dioxide and water. In this work, a full three-dimensional model of a chemical looping combustion system was developed to simulate the particlefluid hydrodynamics, thermal characteristics, and reaction efficiency of the CLC system using coal particles as a fuel source. Multiple heterogeneous and homogenous reactions are considered in the CLC model including the oxidation and reduction reactions of the metal oxide carrier and gasification reactions. Within each coal particle, the temperature-dependent devolatilization, moisture release, and particle swelling effects are included. Modeling results showing fluidization regimes, circulation rate, reactor efficiencies, and temperature profiles are presented to demonstrate the utility of the model.

James M. Parker

2014-01-01T23:59:59.000Z

349

Fluid force transducer  

DOE Patents [OSTI]

An electrical fluid force transducer for measuring the magnitude and direction of fluid forces caused by lateral fluid flow, includes a movable sleeve which is deflectable in response to the movement of fluid, and a rod fixed to the sleeve to translate forces applied to the sleeve to strain gauges attached to the rod, the strain gauges being connected in a bridge circuit arrangement enabling generation of a signal output indicative of the magnitude and direction of the force applied to the sleeve.

Jendrzejczyk, Joseph A. (Warrenville, IL)

1982-01-01T23:59:59.000Z

350

E-Print Network 3.0 - arbitrarily shaped particles Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

+41 71 282 31 30; www.fisba.ch & www.fh-aargau.ch Optimization of Fluid Jet Polishing CNC tool design Summary: Computational Fluid Dynamics (CFD). To verify these simulations,...

351

EXPERIMENTING WITH FLUIDS OC-569a Winter 2010 GFD lab: Ocean Sciences Bldg. Rm 107; teaching lab: Ocean Teaching Building Rm 206  

E-Print Network [OSTI]

or basic Stirling engines. There are so few fluid dynamics labs in the world that meaningful and unique

352

Carbon-bearing fluids at nanoscale interfaces  

SciTech Connect (OSTI)

The behaviour of fluids at mineral surfaces or in confined geometries (pores, fractures) typically differs from their bulk behaviour in many ways due to the effects of large internal surfaces and geometrical confinement. We summarize research performed on C-O-H fluids at nanoscale interfaces in materials of interest to the earth and material sciences (e.g., silica, alumina, zeolites, clays, rocks, etc.), emphasizing those techniques that assess microstructural modification and/or dynamical behaviour such as gravimetric analysis, small-angle (SANS) neutron scattering, and nuclear magnetic resonance (NMR). Molecular dynamics (MD) simulations will be described that provide atomistic characterization of interfacial and confined fluid behaviour as well as aid in the interpretation of the neutron scattering results.

Cole, David [Ohio State University; Ok, Salim [Ohio State University, Columbus; Phan, A [Ohio State University, Columbus; Rother, Gernot [ORNL; Striolo, Alberto [Oklahoma University; Vlcek, Lukas [ORNL

2013-01-01T23:59:59.000Z

353

Cryogenic Fluid Flow Heat Transfer in a Porous Heat Exchanger  

Science Journals Connector (OSTI)

The recent utilization of porous heat exchangers in various key industries has aroused considerable interest in the heat transfer and fluid dynamics processes in channel flows involving suction...1], suction with...

L. L. Vasiliev; G. I. Bobrova; S. K. Vinokurov

1978-01-01T23:59:59.000Z

354

A numerical study on the effects of 2d structured sinusoidal elements on fluid flow and heat transfer at microscale  

E-Print Network [OSTI]

Computational fluid dynamics Microchannel Minichannel Surface roughness Roughness elements Heat transfer Fluid to achieve enhancement in heat transfer with relatively low cooling fluid flow rate [1]. In spite of havingA numerical study on the effects of 2d structured sinusoidal elements on fluid flow and heat

Kandlikar, Satish

355

A decoupled approach for NOxN2O 3-D CFD modeling in CFB plants  

Science Journals Connector (OSTI)

Abstract In this study, a 3D CFD model for the formation of \\{NOx\\} and N2O in a lignite fired 1.2MWth CFB pilot plant is developed. The decoupled approach (decoupled from combustion simulation) is tested for the minimization of computational cost. As combustion simulation is prerequired, this was achieved through a simplified 3-D CFD combustion model. The developed model is then applied to the pilot-scale 1.2MWth CFB plant and validated against experimental data. As concerns the NOxN2O model, an extensive literature review is also carried out for the incorporation of the appropriate reactions network and respective reaction rates expressions. Results show that homogenous reactions are favoured on the lower section of the bed, due to the abundance of fuel devolatilization products. On the other hand, on the upper section, heterogeneous reactions govern nitric oxide formation/reduction. It is found that for the lignite examined in this work, HCN is released in negligible amounts during char combustion. The proposed and validated CFD model for \\{NOx\\} and N2O, is capable of examining the effect of different operational parameters and coal properties on the overall nitric oxides emissions from a CFB combustor, with low computational cost and without the additional expenses for pilot-scale experiments.

A. Nikolopoulos; I. Malgarinos; N. Nikolopoulos; P. Grammelis; S. Karrelas; E. Kakaras

2014-01-01T23:59:59.000Z

356

Vehicle Technologies Office Merit Review 2014: CFD Simulations and Experiments to Determine the Feasibility of Various Alternate Fuels for Compression Ignition Engine Applications  

Broader source: Energy.gov [DOE]

Presentation given by Argonne National Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about CFD simulations...

357

Fiber optic fluid detector  

DOE Patents [OSTI]

Particular gases or liquids are detected with a fiber optic element having a cladding or coating of a material which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses. 10 figs.

Angel, S.M.

1987-02-27T23:59:59.000Z

358

Lattice-Boltzmann model for interacting amphiphilic fluids  

Science Journals Connector (OSTI)

We develop our recently proposed lattice-Boltzmann method for the nonequilibrium dynamics of amphiphilic fluids [H. Chen, B. M. Boghosian, P. V. Coveney, and M. Nekovee, Proc. R. Soc. London, Ser. A 456, 2043 (2000)]. Our method maintains an orientational degree of freedom for the amphiphilic species and models fluid interactions at a microscopic level by introducing self-consistent mean-field forces between the particles into the lattice-Boltzmann dynamics, in a way that is consistent with kinetic theory. We present the results of extensive simulations in two dimensions which demonstrate the ability of our model to capture the correct phenomenology of binary and ternary amphiphilic fluids.

Maziar Nekovee; Peter V. Coveney; Hudong Chen; Bruce M. Boghosian

2000-12-01T23:59:59.000Z

359

Modeling quantum fluid dynamics at nonzero temperatures  

Science Journals Connector (OSTI)

...1073/pnas.1312549111 Natalia G. Berloff Marc Brachet Nick P. Proukakis aDepartment of Applied Mathematics and Theoretical...field. A discussion of contrasting viewpoints relating the merits of "c-field" vs. "ZNG-type" approaches for ultracold...

Natalia G. Berloff; Marc Brachet; Nick P. Proukakis

2014-01-01T23:59:59.000Z

360

Numerical Simulation of Flow Field Inside a Squeeze Film Damper and the Study of the Effect of Cavitation on the Pressure Distribution  

E-Print Network [OSTI]

of SFDs can be expensive and time consuming. The current work simulates the flow field inside the dynamically deforming annular gap of a SFD using the commercial computational fluid dynamics (CFD) code Fluent and compares the results to the experimental...

Khandare, Milind Nandkumar

2012-02-14T23:59:59.000Z

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.


361

Numerical modeling of in-flight characteristics of inconel 625 particles during high-velocity oxy-fuel thermal spraying  

Science Journals Connector (OSTI)

A computational fluid dynamics (CFD) model is developed to predict particle dynamic behavior in a high-velocity oxyfuel (HVOF) thermal spray gun in which premixed oxygen and propylene are ... 20 to 40 m. At a pa...

S. Gu; D. G. McCartney; C. N. Eastwick; K. Simmons

2004-01-01T23:59:59.000Z

362

Thermodynamics and Fluids  

Science Journals Connector (OSTI)

... AN important section of the work of modern chemical engineers lies in the application of thermodynamics to problems of fluid systems. This volume, the fourth in the series, is ... properties of physical systems and to the transport properties of fluids. The first section on thermodynamics has been written by Dr. R. Strickland Constable of the Chemical Engineering Department at ...

J. M. COULSON

1958-09-27T23:59:59.000Z

363

A two-fluid model for relativistic heat conduction  

SciTech Connect (OSTI)

Three years ago it was presented in these proceedings the relativistic dynamics of a multi-fluid system together with various applications to a set of topical problems [1]. In this talk, I will start from such dynamics and present a covariant formulation of relativistic thermodynamics which provides us with a causal constitutive equation for the propagation of heat in a relativistic setting.

Lpez-Monsalvo, Csar S. [Instituto de Ciencias Nucleares, Universidad Nacional Autnoma de Mxico (Mexico)

2014-01-14T23:59:59.000Z

364

Thermodynamic properties of the Mie n-6 fluid: a comparison between Statistical Associating Fluid Theory  

E-Print Network [OSTI]

Theory of Variable Range (SAFT-VR) approach and Molecular Dynamics results. Guillaume Galliero1 test of the monomer-monomer interaction estimation of a recently derived SAFT-VR equation of state with this parameter in the SAFT-VR equation of state. In addition, is proposed a new empirical one-fluid approximation

Paris-Sud XI, Université de

365

To cite this document: Bechet, S. and Negulescu, C. and Chapin, Vincent and Simon, Frank Integration of CFD tools in aerodynamic design of contra-rotating  

E-Print Network [OSTI]

Integration of CFD tools in aerodynamic design of contra-rotating propellers blades. (2011) In: 3rd CEAS concerns. After a Integration of CFD Tools in Aerodynamic Design of Contra-Rotating Propeller Blades S. Béchet and C. A. Negulescu Airbus Operations S.A.S. - Aerodynamics Department, Toulouse, France V. Chapin

Mailhes, Corinne

366

L3:THM.CFD.P5.02 J.N. Shadid, T.M. Smith, R.P. Pawlowski, E....  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

2 J.N. Shadid, T.M. Smith, R.P. Pawlowski, E. C. Cyr, P.D. Weber SNL Completed: October 31, 2012 CASL-U-2012-0164-000 RANS CFD SIMULATIONS FOR CASL THM USING DREKAR::CFD J. N....

367

RESEARCH ARTICLE OPEN ACCESS CFD Studies on Multi Lead Rifled [MLR] Boiler Tubes  

E-Print Network [OSTI]

This paper reports the merits of multi lead rifled [MLR] tubes in vertical water tube boiler using CFD tool. Heat transfer enhancement of MLR tubes was mainly taken in to consideration. Performance of multi lead rifled tube was studied by varying its influencing geometrical parameter like number of rifling, height of rifling, length of pitch of rifling for a particular length. The heat transfer analysis was done at operating conditions of an actual coal fired water tube boiler situated at Apollo Tyres LTD, Chalakudy, India for saturated process steam production. The results showed that the heat transfer increased when compared with existing inner plane wall water tubes.

Dr T C Mohankumar; Nice Thomachan

368

Thermal Fluid Multiphysics Optimization of Spherical Tokamak  

SciTech Connect (OSTI)

An experimental Fusion Nuclear Science Facility (FNSF) is required that will create the environment that simultaneously achieves high energy neutrons and high ion fluence necessary in order to bridge the gaps from ITER to the realization of a fusion nuclear power plant. One concept for achieving this is a high duty cycle spherical torus. This study will focus on thermal modeling of the spherical torus centerpost using computational fluid dynamics to effectively model the thermal transfer of the cooling fluid to the centerpost. The design of the fluid channels is optimized in order to minimize the temperature in the centerpost. Results indicate the feasibility of water cooling for a long-pulse spherical torus FNSF.

Lumsdaine, Arnold [ORNL; Tipton, Joseph B [ORNL; Peng, Yueng Kay Martin [ORNL

2012-01-01T23:59:59.000Z

369

Fluid sampling tool  

DOE Patents [OSTI]

A fluid sampling tool is described for sampling fluid from a container. The tool has a fluid collecting portion which is drilled into the container wall, thereby affixing it to the wall. The tool may have a fluid extracting section which withdraws fluid collected by the fluid collecting section. The fluid collecting section has a fluted shank with an end configured to drill a hole into a container wall. The shank has a threaded portion for tapping the borehole. The shank is threadably engaged to a cylindrical housing having an inner axial passageway sealed at one end by a septum. A flexible member having a cylindrical portion and a bulbous portion is provided. The housing can be slid into an inner axial passageway in the cylindrical portion and sealed to the flexible member. The bulbous portion has an outer lip defining an opening. The housing is clamped into the chuck of a drill, the lip of the bulbous section is pressed against a container wall until the shank touches the wall, and the user operates the drill. Wall shavings (kerf) are confined in a chamber formed in the bulbous section as it folds when the shank advances inside the container. After sufficient advancement of the shank, an o-ring makes a seal with the container wall. 6 figs.

Garcia, A.R.; Johnston, R.G.; Martinez, R.K.

1999-05-25T23:59:59.000Z

370

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

371

Multiphase fluid characterization system  

DOE Patents [OSTI]

A measurement system and method for permitting multiple independent measurements of several physical parameters of multiphase fluids flowing through pipes are described. Multiple acoustic transducers are placed in acoustic communication with or attached to the outside surface of a section of existing spool (metal pipe), typically less than 3 feet in length, for noninvasive measurements. Sound speed, sound attenuation, fluid density, fluid flow, container wall resonance characteristics, and Doppler measurements for gas volume fraction may be measured simultaneously by the system. Temperature measurements are made using a temperature sensor for oil-cut correction.

Sinha, Dipen N.

2014-09-02T23:59:59.000Z

372

Fluid pumping apparatus  

DOE Patents [OSTI]

A method and apparatus suitable for coupling seismic or other downhole sensors to a borehole wall in high temperature and pressure environments. In one embodiment, one or more metal bellows mounted to a sensor module are inflated to clamp the sensor module within the borehole and couple an associated seismic sensor to a borehole wall. Once the sensing operation is complete, the bellows are deflated and the sensor module is unclamped by deflation of the metal bellows. In a further embodiment, a magnetic drive pump in a pump module is used to supply fluid pressure for inflating the metal bellows using borehole fluid or fluid from a reservoir. The pump includes a magnetic drive motor configured with a rotor assembly to be exposed to borehole fluid pressure including a rotatable armature for driving an impeller and an associated coil under control of electronics isolated from borehole pressure.

West, Phillip B. (Idaho Falls, ID)

2006-01-17T23:59:59.000Z

373

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

374

Knots and dynamics tienne Ghys  

E-Print Network [OSTI]

was the starting point of the (now forgotten) theory of "vortex atoms", trying to explain elementary "atoms-hydrodynamics: the dynamics of electrically conducting fluids (like a plasma). If one assumes that the fluid is perfect and has no resistance (ideal MHD), the magnetic (divergence free) vector field is merely tran

Ghys, ?tienne

375

A CFD M&S PROCESS FOR FAST REACTOR FUEL ASSEMBLIES  

SciTech Connect (OSTI)

A CFD modeling and simulation process for large-scale problems using an arbitrary fast reactor fuel assembly design was evaluated. Three dimensional flow distributions of sodium for several fast reactor fuel assembly pin spacing configurations were simulated on high performance computers using commercial CFD software. This research focused on 19-pin fuel assembly benchmark geometry, similar in design to the Advanced Burner Test Reactor, where each pin is separated by helical wire-wrap spacers. Several two-equation turbulence models including the k-e and SST (Menter) k-? were evaluated. Considerable effort was taken to resolve the momentum boundary layer, so as to eliminate the need for wall functions and reduce computational uncertainty. High performance computers were required to generate the hybrid meshes needed to predict secondary flows created by the wire-wrap spacers; computational meshes ranging from 65 to 85 million elements were common. A general validation methodology was followed, including mesh refinement and comparison of numerical results with empirical correlations. Predictions for velocity, temperature, and pressure distribution are shown. The uncertainty of numerical models, importance of high fidelity experimental data, and the challenges associated with simulating and validating large production-type problems are presented.

Kurt D. Hamman; Ray A. Berry

2008-09-01T23:59:59.000Z

376

A CFD Model for High Pressure Liquid Poison Injection for CANDU-6 Shutdown System No. 2  

SciTech Connect (OSTI)

In CANDU reactor one of the two reactor shutdown systems is the liquid poison injection system which injects the highly pressurized liquid neutron poison into the moderator tank via small holes on the nozzle pipes. To ensure the safe shutdown of a reactor it is necessary for the poison curtains generated by jets provide quick, and enough negative reactivity to the reactor during the early stage of the accident. In order to produce the neutron cross section necessary to perform this work, the poison concentration distribution during the transient is necessary. In this study, a set of models for analyzing the transient poison concentration induced by this high pressure poison injection jet activated upon the reactor trip in a CANDU-6 reactor moderator tank has been developed and used to generate the poison concentration distribution of the poison curtains induced by the high pressure jets injected into the vacant region between the pressure tube banks. The poison injection rate through the jet holes drilled on the nozzle pipes is obtained by a 1-D transient hydrodynamic code called, ALITRIG, and this injection rate is used to provide the inlet boundary condition to a 3-D CFD model of the moderator tank based on CFX4.3, a CFD code, to simulate the formation of the poison jet curtain inside the moderator tank. For validation, an attempt was made to validate this model against a poison injection experiment performed at BARC. As conclusion this set of models is judged to be appropriate. (authors)

Bo Wook Rhee; Chang Jun Jeong [Korea Atomic Energy Research Institute, 150, Dukjin-Dong, Yusong-Gu, Taejon 305-353 (Korea, Republic of); Hye Jeong Yun; Dong Soon Jang [Choongnam National University, Daejeon 305-764 (Korea, Republic of)

2002-07-01T23:59:59.000Z

377

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

SciTech Connect (OSTI)

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

378

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

379

Diffusion Enhancement in Core-softened fluid confined in nanotubes  

E-Print Network [OSTI]

We study the effect of confinement in the dynamical behavior of a core-softened fluid. The fluid is modeled as a two length scales potential. This potential in the bulk reproduces the anomalous behavior observed in the density and in the diffusion of liquid water. A series of $NpT$ Molecular Dynamics simulations for this two length scales fluid confined in a nanotube were performed. We obtain that the diffusion coefficient increases with the increase of the nanotube radius for wide channels as expected for normal fluids. However, for narrow channels, the confinement shows an enhancement in the diffusion coefficient when the nanotube radius decreases. This behavior, observed for water, is explained in the framework of the two length scales potential.

Jos R. Bordin; Alan B. de Oliveira; Alexandre Diehl; Marcia C. Barbosa

2012-08-05T23:59:59.000Z

380

2D Axisymmetric Coupled CFD-kinetics Modeling of a Nonthermal Arc Plasma Torch for Diesel Fuel  

E-Print Network [OSTI]

-assisted diesel fuel reformer developed for two different applications: (i) onboard H2 production for fuel cell been also developed for different reforming reactors: solid oxide fuel cell (SOFC)7 , membrane reformer1 2D Axisymmetric Coupled CFD-kinetics Modeling of a Nonthermal Arc Plasma Torch for Diesel Fuel

Boyer, Edmond

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

Fluid driven reciprocating apparatus  

DOE Patents [OSTI]

An apparatus is described comprising a pair of fluid driven pump assemblies in a back-to-back configuration to yield a bi-directional pump. Each of the pump assemblies includes a piston or diaphragm which divides a chamber therein to define a power section and a pumping section. An intake-exhaust valve is connected to each of the power sections of the pump chambers, and function to direct fluid, such as compressed air, into the power section and exhaust fluid therefrom. At least one of the pistons or diaphragms is connected by a rod assembly which is constructed to define a signal valve, whereby the intake-exhaust valve of one pump assembly is controlled by the position or location of the piston or diaphragm in the other pump assembly through the operation of the rod assembly signal valve. Each of the pumping sections of the pump assemblies are provided with intake and exhaust valves to enable filling of the pumping section with fluid and discharging fluid therefrom when a desired pressure has been reached. 13 figs.

Whitehead, J.C.

1997-04-01T23:59:59.000Z

382

Development of an analytical model for organic-fluid fouling  

SciTech Connect (OSTI)

The research goal of this project is to determine ways to effectively mitigate fouling in organic fluids: hydrocarbons and derived fluids. The fouling research focuses on the development of methodology for determining threshold conditions for fouling. Initially, fluid containing chemicals known to produce foulant is analyzed; subsequently, fouling of industrial fluids is investigated. The fouling model developed for determining the effects of physical parameters is the subject of this report. The fouling model is developed on the premise that the chemical reaction for generation of precursor can take place in the bulk fluid, in the thermal-boundary layer, or at the fluid/wall interface, depending upon the interactive effects of fluid dynamics, heat and mass transfer, and the controlling chemical reaction. In the analysis, the experimental data are examined for fouling deposition of polyperoxide produced by autoxidation of indene in kerosene. The effects of fluid and wall temperatures for two flow geometries are analyzed. The results show that the relative effects of physical parameters on the fouling rate differ for the three fouling mechanisms. Therefore, to apply the closed-flow-loop data to industrial conditions, the controlling mechanism must be identified.

Panchal, C.B.; Watkinson, A.P.

1994-10-01T23:59:59.000Z

383

Visually simulating realistic fluid motion  

E-Print Network [OSTI]

where 0 stands for obstacle cell, S surface cell, F full cell, I inlet cell, U outlet cell and the cells not marked are empty cells . . . . . . 34 12 Area weighting interpolation scheme for determining local fluid velocity for a marker k [9] . . 35... in the fluid. It is measured as the force on the face of a unit cube, inserted into the fluid. If the pressure varies in the fluid, the fluid will move due to the acceleration generated by the pressure force. The pressure at a point is isotropic in a fluid...

Naithani, Priyanka

2012-06-07T23:59:59.000Z

384

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 OpenEI Reference LibraryAdd to library Conference Proceedings:...

385

An enhanced parallel version of kiva3v, coupled with a 1d CFD code, and its use in general purpose engine applications  

Science Journals Connector (OSTI)

Numerical simulations of reactive flows are among the most computational demanding applications in the scientific computing world. KIVA-3V, a widely used computer program for CFD, specifically tailored to engine applications, had been deeply modified ...

Gino Bella; Fabio Bozza; Alessandro De Maio; Francesco Del Citto; Salvatore Filippone

2006-09-01T23:59:59.000Z

386

The influence of fluid properties on the success of hydraulic fracturing operations  

SciTech Connect (OSTI)

Hydroxypropylguar based fluids are the most commonly used fluids for hydraulic fracturing. Through the addition of borate ions the polymer present in the fluid can crosslink to form a high viscosity gel. Prior to placement in the fracture the fluid is required to have a low viscosity to minimize friction losses in the tubular goods. A high viscosity fluid is required in the fracture for several reasons, primarily to suspend the proppant and to minimize fluid loss into the formation. This paper describes a new method which can be used to model the gelation reaction of crosslinking fluids. By modeling the dynamic properties of the fluid it is possible to predict the physical state of the fluid at any time during a fracturing treatment. Small amplitude oscillatory measurements are applied to fluid samples in a cone-and-plate geometry. The change in the dynamic properties with time can be fitted to a simple model which can then be used to determine the gel time for the fluid. Methods used to distinguish between the liquid and gel state are also discussed.

Power, D.J.; Boger, D.V. [Univ. of Melbourne, Victoria (Australia); Paterson, L.

1994-12-31T23:59:59.000Z

387

Massively-parallel Spectral Element Algorithm Development for High Speed Flows  

E-Print Network [OSTI]

Fluid Dynamics in the Design Cycle . . . . . . . . . . 3 1.2.1 Nature of the Flow Equations and Turbulence . . . . . . . . . 3 1.2.2 Industrial CFD Use . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2.3 Massive-parallelism and CFD... . . . . . . . . . . . . . . . . . . 7 1.2.4 Towards Improving Design Cycle Analysis . . . . . . . . . . . 7 1.3 Keys for Effective High-Fidelity CFD . . . . . . . . . . . . . . . . . . 9 1.3.1 Need for High Order . . . . . . . . . . . . . . . . . . . . . . . 9 1.3.2 Need for High...

Camp, Joshua Lane

2013-10-07T23:59:59.000Z

388

Magnetically stimulated fluid flow patterns  

ScienceCinema (OSTI)

Sandia National Laboratories' Jim Martin and Kyle Solis explain research on the effects of magnetic fields on fluid flows and how they stimulate vigorous flows. Fluid flow is a necessary phenomenon in everything from reactors to cooling engines in cars.

Martin, Jim; Solis, Kyle

2014-08-06T23:59:59.000Z

389

Evaluation of mixing in three duct configurations and development of a Generic Tee Plenum System (GTPS) for application to single point aerosol sampling  

E-Print Network [OSTI]

considered when using different types of elbows upstream of the stack. Numerical studies for velocity profile in the GTPS were conducted with a commercial computational fluid dynamics (CFD) software, FLUENT. Good agreement was found between the experimental...

Han, Tae Won

2012-06-07T23:59:59.000Z

390

A study on the effect of inlet turbulence on gas mixing for single point aerosol sampling  

E-Print Network [OSTI]

not be effective for achieving a uniform velocity profile. Numerical computations are performed with commercially available computational fluid dynamics (CFD) software (FLUENT[], Version 5.4), and the performance of the turbulence and particle tracking models...

Mohan, Anand

2012-06-07T23:59:59.000Z

391

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

Science Journals Connector (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

392

Measurement of Nucleate Pool Boiling with Synchronized Particle Imaging Velocimetry and Infrared Thermometry  

E-Print Network [OSTI]

Nucleate boiling is important in many energy systems including light water reactors. Currently significant efforts are underway to develop mechanisticmodels for nucleate boiling based on computational fluid dynamics (CFD). ...

Duan, X.

393

Stochastic Modeling for Uncertainty Analysis and Multiobjective Optimization of IGCC System with Single-Stage Coal Gasification  

Science Journals Connector (OSTI)

The work initially focuses on developing a computational fluid dynamics (CFD) model for the single-stage coal gasifier, which is a part of the IGCC system. ... Medium pressure (MP) steam is produced from the heat liberated from this reaction. ...

Yogendra Shastri; Urmila Diwekar

2010-11-22T23:59:59.000Z

394

Bright minds shine in Los Angeles: The 2014 ISEF  

Science Journals Connector (OSTI)

...a model of a neighborhood in Hoboken, New Jersey, using the Google Earth Pro and Autodesk Inventor Fusion software, and simulated wind flows using the Autodesk Simulation CFD computational fluid dynamics software. Ross found that buildings concentrated...

Richard Nolen-Hoeksema

395

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

396

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

397

A simplex cut-cell adaptive method for high-order discretizations of the compressible Navier-Stokes equations  

E-Print Network [OSTI]

While an indispensable tool in analysis and design applications, Computational Fluid Dynamics (CFD) is still plagued by insufficient automation and robustness in the geometry-to-solution process. This thesis presents two ...

Fidkowski, Krzysztof J., 1981-

2007-01-01T23:59:59.000Z

398

Simulation results of an inductively-coupled rf plasma torch in two and three dimensions for producing a metal matrix composite for nuclear fuel cladding  

E-Print Network [OSTI]

. In this work, a magnetohydrodynamic (MHD) model is used along with a computational fluid dynamic (CFD) software package called FLUENT to simulate an ICPT. To solve the electromagnetic equations and incorporate forces and resistive heating, several userdefined...

Holik III, Eddie Frank (Trey)

2009-05-15T23:59:59.000Z

399

Scale-out of Microreactor Stacks for Portable and Distributed Processing: Coupling of Exothermic and Endothermic Processes for Syngas Production  

Science Journals Connector (OSTI)

Computational fluid dynamics (CFD) simulations are used to simulate stacks of different sizes, to understand nonlinear effects that arise in scaleout of microchemical systems. As an example process, syngas production from methane is studied using a ...

Matthew S. Mettler; Georgios D. Stefanidis; Dionisios G. Vlachos

2010-06-11T23:59:59.000Z

400

Review of fluid flow and convective heat transfer within rotating disk cavities with impinging jet  

E-Print Network [OSTI]

Fluid flow and convective heat transfer in rotor-stator configurations, which are of great importance in different engineering applications, are treated in details in this review. The review focuses on convective heat transfer in predominantly outward air flow in the rotor-stator geometries with and without impinging jets and incorporates two main parts, namely, experimental/theoretical methodologies and geometries/results. Experimental methodologies include naphthalene sublimation techniques, steady state (thin layer) and transient (thermochromic liquid crystals) thermal measurements, thermocouples and infra-red cameras, hot-wire anemometry, laser Doppler and particle image velocimetry, laser plane and smoke generator. Theoretical approaches incorporate modern CFD computational tools (DNS, LES, RANS etc). Geometries and results part being mentioned starting from simple to complex elucidates cases of a free rotating disk, a single disk in the crossflow, single jets impinging onto stationary and rotating disk,...

Harmand, Souad; Poncet, Sbastien; Shevchuk, Igor V; 10.1016/j.ijthermalsci.2012.11.009

2013-01-01T23:59:59.000Z

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.


401

The effects of obstacle geometry on jet mixing in releases of silane  

E-Print Network [OSTI]

Releases of silane into air and the effects of obstacles were modeled with the Computational Fluid Dynamics (CFD) code, FLUENT. First the CFD code simulated the release of a free turbulent jet of silane into air to assure that the code agreed...

Sposato, Christina F

2012-06-07T23:59:59.000Z

402

Ris-R-1543(EN) Aerodynamic investigation of Winglets on  

E-Print Network [OSTI]

Risø-R-1543(EN) Aerodynamic investigation of Winglets on Wind Turbine Blades using CFD Jeppe Johansen and Niels N. Sørensen Title: Aerodynamic investigation of Winglets on Wind Turbine Blades using of the aerodynamics around a wind turbine blade with a winglet using Computational Fluid Dynamics, CFD. Five winglets

403

Short communication Study of pollution dispersion in urban areas using  

E-Print Network [OSTI]

of the Reynolds numbers covers the laminar, transitional and part of the turbulent regimes of the flow (CFD) and Geographic Information System (GIS) A.K.M. Chua , R.C.W. Kwokb , K.N. Yua, * a Department rights reserved. Keywords: Street canyons; Computational Fluid Dynamics; CFD; CFX; Geographic Information

Yu, K.N.

404

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

405

A multi-scale framework for CFD modelling of multi-phase complex systems based on the EMMS approach  

Science Journals Connector (OSTI)

The averaged conservative equations in CFD modelling are inadequate to achieve a complete description of the multi-scale structures in multiphase complex systems. By considering the relationship between meso-scale structures and meso-scale energy consumption, stability conditions mathematically expressed as a mutually constrained extremum are proposed in the Energy-Minimization Multi-Scale (EMMS) approach and indispensable to reflect the compromise of different dominant mechanisms for various multiphase systems. The approach is first applied to global systems to predict and physically interpret the macro-scale structure evolution, i.e., regime transition. Then when applied to computational cells, it corrects interphase momentum transfer and greatly improves the accuracy of coarse-grid CFD simulation.

Ning Yang

2012-01-01T23:59:59.000Z

406

Oscillating fluid power generator  

SciTech Connect (OSTI)

A system and method for harvesting the kinetic energy of a fluid flow for power generation with a vertically oriented, aerodynamic wing structure comprising one or more airfoil elements pivotably attached to a mast. When activated by the moving fluid stream, the wing structure oscillates back and forth, generating lift first in one direction then in the opposite direction. This oscillating movement is converted to unidirectional rotational movement in order to provide motive power to an electricity generator. Unlike other oscillating devices, this device is designed to harvest the maximum aerodynamic lift forces available for a given oscillation cycle. Because the system is not subjected to the same intense forces and stresses as turbine systems, it can be constructed less expensively, reducing the cost of electricity generation. The system can be grouped in more compact clusters, be less evident in the landscape, and present reduced risk to avian species.

Morris, David C

2014-02-25T23:59:59.000Z

407

Downhole Fluid Analyzer Development  

SciTech Connect (OSTI)

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

408

Why are Fluid Densities So Low in Carbon Nanotubes?  

E-Print Network [OSTI]

The equilibrium density of fluids under nanoconfinement can differ substantially from their bulk density. Using a mean-field approach to describe the energetic landscape near the carbon nanotube (CNT) wall, we obtain analytical results describing the lengthscales associated with the layering observed at the fluid-CNT interface. When combined with molecular simulation results for the fluid density in the layered region, this approach allows us to derive a closed-form prediction for the overall equilibrium fluid density as a function of the CNT radius that is in excellent agreement with molecular dynamics simulations. We also show how aspects of this theory can be extended to describe water confined within CNTs and find good agreement with results from the literature.

Wang, Gerald J

2014-01-01T23:59:59.000Z

409

Why are Fluid Densities So Low in Carbon Nanotubes?  

E-Print Network [OSTI]

The equilibrium density of fluids under nanoconfinement can differ substantially from their bulk density. Using a mean-field approach to describe the energetic landscape near the carbon nanotube (CNT) wall, we obtain analytical results describing the lengthscales associated with the layering observed at the fluid-CNT interface. When combined with molecular simulation results for the fluid density in the layered region, this approach allows us to derive a closed-form prediction for the overall equilibrium fluid density as a function of the CNT radius that is in excellent agreement with molecular dynamics simulations. We also show how aspects of this theory can be extended to describe water confined within CNTs and find good agreement with results from the literature.

Gerald J. Wang; Nicolas G. Hadjiconstantinou

2014-09-27T23:59:59.000Z

410

Coalescence of bubbles and drops in an outer fluid  

E-Print Network [OSTI]

When two liquid drops touch, a microscopic connecting liquid bridge forms and rapidly grows as the two drops merge into one. Whereas coalescence has been thoroughly studied when drops coalesce in vacuum or air, many important situations involve coalescence in a dense surrounding fluid, such as oil coalescence in brine. Here we study the merging of gas bubbles and liquid drops in an external fluid. Our data indicate that the flows occur over much larger length scales in the outer fluid than inside the drops themselves. Thus we find that the asymptotic early regime is always dominated by the viscosity of the drops, independent of the external fluid. A phase diagram showing the crossovers into the different possible late-time dynamics identifies a dimensionless number that signifies when the external viscosity can be important.

Joseph D. Paulsen; Rmi Carmigniani; Anerudh Kannan; Justin C. Burton; Sidney R. Nagel

2014-07-24T23:59:59.000Z

411

Proceedings of FEDSM'03: ASME/JSME Joint Fluids Engineering Conference  

E-Print Network [OSTI]

Proceedings of FEDSM'03: 4th ASME/JSME Joint Fluids Engineering Conference Honolulu, Hawaii, USA Reni Raju and Subrata Roy Computational Plasma Dynamics Laboratory Department of Mechanical Engineering is no longer valid as the mean free path of the fluid becomes comparable to the dimension of the system

Roy, Subrata

412

Acoustic concentration of particles in fluid flow  

SciTech Connect (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

413

Phenotypic plasticity in juvenile jellyfish medusae facilitates effective animalfluid interaction  

Science Journals Connector (OSTI)

...switching to tissue-dominated propulsion at higher temperatures where...visualization and assays of propulsion efficiency. phenotypic plasticity|propulsion|fluid dynamics|ontogeny...and feeding performance of marine animals depends on the interaction...

2010-01-01T23:59:59.000Z

414

FLUID MECHANICS AND HEAT TRANSFER OF ELECTRON FLOW IN SEMICONDUCTORS  

E-Print Network [OSTI]

= heat, f = LO-mode, g = LO, h = LA-mode, i = negligible, j = remote heat sink 7/ 70 #12;Heat conductionFLUID MECHANICS AND HEAT TRANSFER OF ELECTRON FLOW IN SEMICONDUCTORS Mihir Sen Department · Shallow water analogy · Vorticity dynamics · Linear stability analysis · Numerical simulations of heat

Sen, Mihir

415

Fluid-driven deformation of a soft granular material  

E-Print Network [OSTI]

Compressing a porous, fluid-filled material will drive the interstitial fluid out of the pore space, as when squeezing water out of a kitchen sponge. Inversely, injecting fluid into a porous material can deform the solid structure, as when fracturing a shale for natural gas recovery. These poromechanical interactions play an important role in geological and biological systems across a wide range of scales, from the propagation of magma through the Earth's mantle to the transport of fluid through living cells and tissues. The theory of poroelasticity has been largely successful in modeling poromechanical behavior in relatively simple systems, but this continuum theory is fundamentally limited by our understanding of the pore-scale interactions between the fluid and the solid. In growing, melting, granular, and fibrous materials, these interactions can be extremely complex. Here, we present a high-resolution measurement of poromechanical deformation driven by fluid injection. We inject fluid into a dense, confined monolayer of soft particles and use particle tracking to reveal the dynamics of the multi-scale deformation field. While a continuum model based on a modification of conventional poroelastic theory captures certain macroscopic features of the deformation, the particle-scale deformation field exhibits dramatic departures from smooth, continuum behavior. We observe novel grain-scale plasticity and hysteresis, as well as petal-like mesoscale structures that are connected to material failure through spiral shear banding.

Christopher W. MacMinn; Eric R. Dufresne; John S. Wettlaufer

2014-05-28T23:59:59.000Z

416

Annu. Rev. Fluid Mech. 2005. 37:183210 doi: 10.1146/annurev.fluid.36.050802.121940  

E-Print Network [OSTI]

, lift, drag, efficiency Abstract "What force does an insect wing generate?" Finding answers but difficult to catch. From a fluid dynamics point of view, their diverse and stunning aerial acrobatics milligrams to grams. To deduce the force on a single wing, all four (or two) wings are presumed to behave

Wang, Z. Jane

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

Influence of turbulencechemical interaction on CFD pulverized coal MILD combustion modeling  

Science Journals Connector (OSTI)

MILD (Moderate and Intensive Low oxygen Dilution) combustion is a novel approach to reducing \\{NOx\\} emissions and improving combustion efficiency in fossil fuels power plants. It is characterized by elevated temperature and high dilution of reactants and strong recirculation inside the combustion chamber which produce a low temperature increase, thus reducing \\{NOx\\} formation. The main differences with conventional combustion concern the chemical reactions that take place in almost the entire volume of the combustion chamber and the uniformity of both temperature and the chemical species concentration. For this reason advanced turbulence-chemistry interaction models with detailed kinetic mechanisms are required to accurately simulate MILD by means of CFD calculations. The main aim of this work is to deepen the influence of turbulence-chemistry interaction on pulverized coal MILD combustion and to understand which models are more accurate and suitable to reproduce the process. In particular, two turbulence-chemistry interaction models are analyzed. On one hand, a conventional model based on infinitely fast chemistry Eddy Dissipation Model with a two-step global kinetic mechanism is considered. On the other hand, an advanced model based on finite rate chemistry Eddy Dissipation Concept is considered and used with both a global and detailed kinetic mechanisms. The results are finally compared with an experimental test-case. From the comparison, advanced turbulence-chemistry models used with complex kinetic mechanisms give, as expected, the best agreement with numerical results, despite the higher computational resources required.

M. Vascellari; G. Cau

2012-01-01T23:59:59.000Z

419

CO{sub 2} adsorption: Experimental investigation with kinetics verification and CFD reactor model validation  

SciTech Connect (OSTI)

The National Energy Technology Laboratory is investigating a new process for CO{sub 2} capture from large sources such as utility power generation facilities as an alternative to liquid amine based absorption processes. Many, but not all of these advanced dry processes are based upon sorbents composed of supported polyamines. In this analysis, experiments have been conducted in a small facility at different temperatures and compared to CFD reactor predictions using kinetics obtained from TGA tests. This particular investigation compares the predicted performance and the experimental performance of one of these new class of sorbents in a fluidized bed reactor. In the experiment, the sorbent absorbs CO{sub 2} from simulated flue gas in a riser reactor, separates the carbonated particles from the de-carbonated flue gas in a cyclone and then regenerates the sorbent, creating a concentrated stream of pure CO{sub 2} for sequestration. In this work, experimental measurements of adsorption are compared to predictions from a 3-dimensional non-isothermal reacting multiphase flow model. The effects of the gas flow rate and reactor temperature are explored. It is shown that the time duration for CO{sub 2} adsorption decreased for an increase in the gas flow. The details of the experimental facility and the model as well as the comparative analysis between the data and the simulation results are discussed.

Breault, Ronald W, [U.S. DOE; Huckaby, Ernest D. [U.S. DOE; Shadle, Lawrence J [U.S. DOE; Spenik, James L. [REM Engineering PLLC

2013-01-01T23:59:59.000Z

420

CFD investigation of effects of wind tunnel walls on flow properties over S809 airfoil  

Science Journals Connector (OSTI)

This article researches CFD simulations of the subsonic wind tunnel at Xi'an Jiaotong University's Laboratory of Thermal Turbo-machines. The wind tunnel cross section measures 800600 mm2 and the simulations are conducted on a wind tunnel with a 375 mm chord S809 airfoil at the Reynolds number of one million. The angles of attack for the 2D airfoil range from 0 to 22 degrees. In another set of 2D simulations a 750 mm chord airfoil is calculated in open-air with no walls restricting airflow. The pressure fields flow patterns and lift and drag coefficients are compared with each other to show the blockage effects in the wind tunnel. As the results show the wind tunnel walls directly cause the flow to stream faster and increase the lift and drag values. Another consequence of this channeled flow is that the separated area expands. Moreover the commencement of the separation also occurs at a smaller angle of attack.

2013-01-01T23:59:59.000Z

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

An Integrated Experimental and Computational Investigation into the Dynamic Loads and Free-surface Wave-Field Perturbations Induced by Head-Sea Regular Waves on a 1/8.25 Scale-Model of the R/V ATHENA  

E-Print Network [OSTI]

A 1/8.25 scale-model of the U.S. Navy Research Vessel ATHENA was tested in regular head-sea waves to obtain data for validation of computational fluid dynamics (CFD) predictive tools. The experiments were performed in the David Taylor Model Basin at the Naval Surface Warfare Center (NSWC). With the model towed fixed in head-seas, horizontal and vertical loads on the model were obtained at two Froude numbers, $F_r=0.25$ and $F_r=0.43$. The model was run at two conditions of head-sea wavelengths corresponding to $\\lambda=2L_o$ and $\\lambda=1/2L_o$ with $H/\\lambda=0.03$, where $L_o$ is the length of the model and $H=2 a$ is the wave height. The wave field perturbations induced by the head-sea waves were quantified from free-surface images generated by a laser light sheet. Predictions of the horizontal and vertical loads on the model in regular head sea waves were made with the Numerical Flow Analysis (NFA) code. Numerical predictions of the wave-field perturbations were compared with the experimental data and th...

Ratcliffe, Toby; O'Shea, Thomas T; Fu, Thomas; Russell, Lauren; Dommermuth, Douglas G

2014-01-01T23:59:59.000Z

422

Notes 09. Fluid inertia and turbulence in fluid film bearings  

E-Print Network [OSTI]

When fluid inertia effects are important. Bulk-flow model for inertial flows. Turbulence and inertia in short length journal bearings and open end dampers....

San Andres, Luis

2009-01-01T23:59:59.000Z

423

Thermodynamic Model for Fluid-Fluid Interfacial Areas in Porous...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

areas are important in controlling the rate of mass and energy transfer between fluid phases in porous media. We present a modified thermodynamically based model (TBM) to...

424

Self-regulation in Self-Propelled Nematic Fluids  

E-Print Network [OSTI]

We consider the hydrodynamic theory of an active fluid of self-propelled particles with nematic aligning interactions. This class of materials has polar symmetry at the microscopic level, but forms macrostates of nematic symmetry. We highlight three key features of the dynamics. First, as in polar active fluids, the control parameter for the order-disorder transition, namely the density, is dynamically convected by active currents, resulting in a generic, model independent dynamical self-regulation that destabilizes the uniform nematic state near the mean-field transition. Secondly, curvature driven currents render the system unstable deep in the nematic state, as found previously. Finally, and unique to self-propelled nematics, nematic order induces local polar order that in turn leads to the growth of density fluctuations. We propose this as a possible mechanism for the smectic order of polar clusters seen in numerical simulations.

Aparna Baskaran; M. Cristina Marchetti

2012-04-15T23:59:59.000Z

425

CSE IGERTCOMPUTATIONAL SCIENCE AND ENGINEERING IGERT QUARTERLy NEwSLETTER Simulations of a two-component fluid (left) using a phase field  

E-Print Network [OSTI]

CSE IGERTCOMPUTATIONAL SCIENCE AND ENGINEERING IGERT QUARTERLy NEwSLETTER Simulations of a two-component fluid (left) using a phase field model with dynamic adaptive mesh refinement (right). Hector Ceniceros patterns when a less viscous fluid (dyed water in the image) is injected into a more viscous fluid (clear

Bigelow, Stephen

426

Techniques for Enhancing Wind Energy Generation - A CFD Based Multibody Dynamics Approach in Horizontal Axis Wind Turbines.  

E-Print Network [OSTI]

??Wind energy has emerged as a major sustainable source of energy.The efficiency of wind power generation by wind mills has improved a lot during the (more)

Rajendran, C

2011-01-01T23:59:59.000Z

427

Fluid equations in the presence of electron cyclotron current drive  

SciTech Connect (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

428

Memory Effects and Transport Coefficients for Non-Newtonian Fluids  

E-Print Network [OSTI]

We discuss the roles of viscosity in relativistic fluid dynamics from the point of view of memory effects. Depending on the type of quantity to which the memory effect is applied, different terms appear in higher order corrections. We show that when the memory effect applies on the extensive quantities, the hydrodynamic equations of motion become non-singular. We further discuss the question of memory effect in the derivation of transport coefficients from a microscopic theory. We generalize the application of the Green-Kubo-Nakano (GKN) to calculate transport coefficients in the framework of projection operator formalism, and derive the general formula when the fluid is non-Newtonian.

T. Kodama; T. Koide

2008-12-22T23:59:59.000Z

429

Fracturing Fluid Characterization Facility  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

430

Fluid Inclusion Analysis At Raft River Geothermal Area (2011) | Open Energy  

Open Energy Info (EERE)

Fluid Inclusion Analysis At Raft River Geothermal Area (2011) Fluid Inclusion Analysis At Raft River Geothermal Area (2011) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Fluid Inclusion Analysis At Raft River Geothermal Area (2011) Exploration Activity Details Location Raft River Geothermal Area Exploration Technique Fluid Inclusion Analysis Activity Date 2011 Usefulness not indicated DOE-funding Unknown Notes Hydrogen isotope values of muscovite (δDMs ∼-100‰) and fluid inclusions in quartz (δDFluid ∼-85‰) indicate the presence of meteoric fluids during detachment dynamics. Recrystallized grain-shape fabrics and quartz c-axis fabric patterns reveal a large component of coaxial strain (pure shear), consistent with thinning of the detachment section. Therefore, the high thermal gradient preserved in the Raft River

431

Viscosity of Quantum Hall Fluids  

Science Journals Connector (OSTI)

The viscosity of quantum fluids with an energy gap at zero temperature is related to the adiabatic curvature on the space parametrizing flat background metrics. For quantum Hall fluids on two-dimensional tori, the quantum viscosity is computed. It turns out to be isotropic, constant, and proportional to the magnetic field strength.

J. E. Avron; R. Seiler; P. G. Zograf

1995-07-24T23:59:59.000Z

432

Fluid Mechanics and Homeland Security  

E-Print Network [OSTI]

Fluid Mechanics and Homeland Security Gary S. Settles Mechanical and Nuclear Engineering Department and sampling, explosive detection, microfluidics and labs-on-a-chip, chem- ical plume dispersal in urban security combines established fluids topics like plume dispersion with others that are new

Settles, Gary S.

433

Efficient simulation of press hardening process through integrated structural and CFD analyses  

SciTech Connect (OSTI)

Press hardened steel parts are being increasingly used in automotive structures for their higher strength to meet safety standards while reducing vehicle weight to improve fuel consumption. However, manufacturing of sheet metal parts by press hardening process to achieve desired properties is extremely challenging as it involves complex interaction of plastic deformation, metallurgical change, thermal distribution, and fluid flow. Numerical simulation is critical for successful design of the process and to understand the interaction among the numerous process parameters to control the press hardening process in order to consistently achieve desired part properties. Until now there has been no integrated commercial software solution that can efficiently model the complete process from forming of the blank, heat transfer between the blank and tool, microstructure evolution in the blank, heat loss from tool to the fluid that flows through water channels in the tools. In this study, a numerical solution based on Altair HyperWorks product suite involving RADIOSS, a non-linear finite element based structural analysis solver and AcuSolve, an incompressible fluid flow solver based on Galerkin Least Square Finite Element Method have been utilized to develop an efficient solution for complete press hardening process design and analysis. RADIOSS is used to handle the plastic deformation, heat transfer between the blank and tool, and microstructure evolution in the blank during cooling. While AcuSolve is used to efficiently model heat loss from tool to the fluid that flows through water channels in the tools. The approach is demonstrated through some case studies.

Palaniswamy, Hariharasudhan [Altair, 1820 East Big Beaver Road, Troy, MI 48083 (United States); Mondalek, Pamela; Wronski, Maciek [Altair Development France, Sophia Antipolis Cedex 06903 (France); Roy, Subir [Altair, 1820 East Big Beaver Road, Troy, MI 48083 (France)

2013-12-16T23:59:59.000Z

434

Tabular water properties interface for Hydra-TH : CASL THM.CFD.P6.03 milestone report.  

SciTech Connect (OSTI)

Completion of the CASL L3 milestone THM.CFD.P6.03 provides a tabular material properties capability to the Hydra code. A tabular interpolation package used in Sandia codes was modified to support the needs of multi-phase solvers in Hydra. Use of the interface is described. The package was released to Hydra under a government use license. A dummy physics was created in Hydra to prototype use of the interpolation routines. Finally, a test using the dummy physics verifies the correct behavior of the interpolation for a test water table. 3

Carpenter, John H.; Belcourt, Noel

2013-04-01T23:59:59.000Z

435

The modeling and the simulation of the fluid machines of synthetic biology  

Science Journals Connector (OSTI)

In the past century, several conceptual and technological breakthroughs produced the digital computers and open the digital information age. At the very same time, the Watson --- Crick model of the digital coding of the genetic information was developed. ... Keywords: (DS)2: dynamical systems with a dynamical structure, MGS, computer modeling, domain specific language (DSL), fluid machines, simulation, spatial computing, synthetic biology, topological rewriting

Jean-Louis Giavitto

2011-08-01T23:59:59.000Z

436

oil-emulsion (rotary) drilling fluid  

Science Journals Connector (OSTI)

oil-emulsion (rotary) drilling fluid, oil-emulsion fluid [Used where low fluid-loss, very thin cake, and good lubrication of the drill pipe are of primary importance, such as in directional drilling ...

2014-08-01T23:59:59.000Z

437

oil-base(d) (rotary) drilling fluid  

Science Journals Connector (OSTI)

oil-base(d) (rotary) drilling fluid, oil-base(d) fluid [Used primarily for drilling-in or recomputing wells in formations subject ... with low formation pressures. See remark under drilling fluid] ...

2014-08-01T23:59:59.000Z

438

Lattice Boltzmann simulations of complex fluids  

Science Journals Connector (OSTI)

......research-article Articles Lattice Boltzmann simulations of complex fluids...OX1 3NP, UK We discuss how lattice Boltzmann simulations can be used to model...binary and lamellar fluids. lattice Boltzmann|complex fluids|shear flow......

J. M. YEOMANS; ALEXANDER J. WAGNER

2000-10-01T23:59:59.000Z

439

Multipurpose Acoustic Sensor for Downhole Fluid Monitoring  

Broader source: Energy.gov [DOE]

Novel sensor design based on acoustics. Determine in real-timeand in a single sensor packagemultiple parameters: temperature, pressure, fluid flow; and fluid properties, such as density, viscosity, fluid composition.

440

Finite element simulation of electrorheological fluids  

E-Print Network [OSTI]

Electrorheological (ER) fluids change their flow properties dramatically when an electric field is applied. These fluids are usually composed of dispersions of polarizable particles in an insulating base fluid or composed ...

Rhyou, Chanryeol, 1973-

2005-01-01T23:59:59.000Z

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.


441

Fluid flow monitoring device  

DOE Patents [OSTI]

A flow meter and temperature measuring device are described comprising a tube with a body centered therein for restricting flow and a sleeve at the upper end of the tube to carry several channels formed longitudinally in the sleeve to the appropriate axial location where they penetrate the tube to allow pressure measurements and temperature measurements with thermocouples. The high pressure measurement is made using a channel penetrating the tube away from the body and the low pressure measurement is made at a location at the widest part of the body. An end plug seals the end of the device and holes at its upper end allow fluid to pass from the interior of the tube into a plenum. The channels are made by cutting grooves in the sleeve, the grooves widened at the surface of the sleeve and then a strip of sleeve material is welded to the grooves closing the channels. Preferably the sleeve is packed with powdered graphite before cutting the grooves and welding the strips. 7 figures.

McKay, M.D.; Sweeney, C.E.; Spangler, B.S. Jr.

1993-11-30T23:59:59.000Z

442

Fluid flow monitoring device  

DOE Patents [OSTI]

A flow meter and temperature measuring device comprising a tube with a body centered therein for restricting flow and a sleeve at the upper end of the tube to carry several channels formed longitudinally in the sleeve to the appropriate axial location where they penetrate the tube to allow pressure measurements and temperature measurements with thermocouples. The high pressure measurement is made using a channel penetrating the tube away from the body and the low pressure measurement is made at a location at the widest part of the body. An end plug seals the end of the device and holes at its upper end allow fluid to pass from the interior of the tube into a plenum. The channels are made by cutting grooves in the sleeve, the grooves widened at the surface of the sleeve and then a strip of sleeve material is welded to the grooves closing the channels. Preferably the sleeve is packed with powdered graphite before cutting the grooves and welding the strips.

McKay, Mark D. (1426 Socastee Dr., North Augusta, SC 29841); Sweeney, Chad E. (3600 Westhampton Dr., Martinez, GA 30907-3036); Spangler, Jr., B. Samuel (2715 Margate Dr., Augusta, GA 30909)

1993-01-01T23:59:59.000Z

443

Fluid sampling system  

DOE Patents [OSTI]

An fluid sampling system allows sampling of radioactive liquid without spillage. A feed tank is connected to a liquid transfer jet powered by a pumping chamber pressurized by compressed air. The liquid is pumped upwardly into a sampling jet of a venturi design having a lumen with an inlet, an outlet, a constricted middle portion, and a port located above the constricted middle portion. The liquid is passed under pressure through the constricted portion causing its velocity to increase and its pressure to be decreased, thereby preventing liquid from escaping. A septum sealing the port can be pierced by a two pointed hollow needle leading into a sample bottle also sealed by a pierceable septum affixed to one end. The bottle is evacuated by flow through the sample jet, cyclic variation in the sampler jet pressure periodically leaves the evacuated bottle with lower pressure than that of the port, thus causing solution to pass into the bottle. The remaining solution in the system is returned to the feed tank via a holding tank. 4 figs.

Houck, E.D.

1994-10-11T23:59:59.000Z

444

Tracing Geothermal Fluids  

SciTech Connect (OSTI)

Geothermal water must be injected back into the reservoir after it has been used for power production. Injection is critical in maximizing the power production and lifetime of the reservoir. To use injectate effectively the direction and velocity of the injected water must be known or inferred. This information can be obtained by using chemical tracers to track the subsurface flow paths of the injected fluid. Tracers are chemical compounds that are added to the water as it is injected back into the reservoir. The hot production water is monitored for the presence of this tracer using the most sensitive analytic methods that are economically feasible. The amount and concentration pattern of the tracer revealed by this monitoring can be used to evaluate how effective the injection strategy is. However, the tracers must have properties that suite the environment that they will be used in. This requires careful consideration and testing of the tracer properties. In previous and parallel investigations we have developed tracers that are suitable from tracing liquid water. In this investigation, we developed tracers that can be used for steam and mixed water/steam environments. This work will improve the efficiency of injection management in geothermal fields, lowering the cost of energy production and increasing the power output of these systems.

Michael C. Adams; Greg Nash

2004-03-01T23:59:59.000Z

445

Detachment Energies of Spheroidal Particles from Fluid-Fluid Interfaces  

E-Print Network [OSTI]

The energy required to detach a single particle from a fluid-fluid interface is an important parameter for designing certain soft materials, for example, emulsions stabilised by colloidal particles, colloidosomes designed for targeted drug delivery, and bio-sensors composed of magnetic particles adsorbed at interfaces. For a fixed particle volume, prolate and oblate spheroids attach more strongly to interfaces because they have larger particle-interface areas. Calculating the detachment energy of spheroids necessitates the difficult measurement of particle-liquid surface tensions, in contrast with spheres, where the contact angle suffices. We develop a simplified detachment energy model for spheroids which depends only on the particle aspect ratio and the height of the particle centre of mass above the fluid-fluid interface. We use lattice Boltzmann simulations to validate the model and provide quantitative evidence that the approach can be applied to simulate particle-stabilized emulsions, and highlight the experimental implications of this validation.

Gary B. Davies; Timm Krger; Peter V. Coveney; Jens Harting

2014-07-01T23:59:59.000Z

446

Downhole Fluid Sampling | Open Energy Information  

Open Energy Info (EERE)

Downhole Fluid Sampling Downhole Fluid Sampling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Downhole Fluid Sampling Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Downhole Techniques Exploration Sub Group: Well Testing Techniques Parent Exploration Technique: Well Testing Techniques Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Water composition and source of fluids. Gas composition and source of fluids. Thermal: Water temperature. Distinguish magmatic/mantle heat inputs. Can be used to estimate reservoir fluid temperatures. Dictionary.png Downhole Fluid Sampling: Downhole fluid sampling is done to characterize the chemical, thermal, or hydrological properties of a surface or subsurface aqueous system. Downhole

447

Isotopic Analysis- Fluid | Open Energy Information  

Open Energy Info (EERE)

Isotopic Analysis- Fluid Isotopic Analysis- Fluid Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Isotopic Analysis- Fluid Details Activities (61) Areas (32) Regions (6) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Fluid Lab Analysis Parent Exploration Technique: Fluid Lab Analysis Information Provided by Technique Lithology: Water rock interaction Stratigraphic/Structural: Hydrological: Origin of hydrothermal fluids; Mixing of hydrothermal fluids Thermal: Isotopic ratios can be used to characterize and locate subsurface thermal anomalies. Dictionary.png Isotopic Analysis- Fluid: Isotopes are atoms of the same element that have different numbers of neutrons. An isotopic analysis looks at a particular isotopic element(s) in

448

Gel Evolution in Oil Based Drilling Fluids.  

E-Print Network [OSTI]

?? Drilling fluids make up an essential part of the drilling operation. Successful drilling operations rely on adequate drilling fluid quality. With the development of (more)

Sandvold, Ida

2012-01-01T23:59:59.000Z

449

Shale Gas Development Challenges: Fracture Fluids | Department...  

Office of Environmental Management (EM)

Fluids Shale Gas Development Challenges: Fracture Fluids More Documents & Publications Natural Gas from Shale: Questions and Answers Shale Gas Glossary FracFocus 2.0 Task Force...

450

Chemically Reactive Working Fluids | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Chemically Reactive Working Fluids for the Capture and Transport of Concentrated Solar Thermal Energy for Power Generation Chemically Reactive Working Fluids SunShot CSP...

451

Acoustic Concentration Of Particles In Fluid Flow  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. Available for thumbnail of...

452

Fluid Gravity Engineering Rocket motor flow analysis  

E-Print Network [OSTI]

Fluid Gravity Engineering Capability · Rocket motor flow analysis -Internal (performance) -External young scientists/engineers Fluid Gravity Engineering Ltd #12;

Anand, Mahesh

453

Optimization of a simplified sub-model for NO emission prediction by CFD in large 4-stroke marine diesel engines  

Science Journals Connector (OSTI)

A simplified sub-model for NO emission prediction at pressurized conditions has been put forth at bo Akademi University [7,9] including NO formation via the thermal NO path (3 reactions) and via the nitrous oxide intermediate paths (2+5 reactions). CFD simulations carried out with the sub-model for marine and off-road diesel engines showed, however, that it significantly by an order of magnitude over-predicted NO emission as compared to measurements. The objective of this work was to find the reasons to the discrepancy and to suggest and incorporate improvements. By detailed investigations, a number of programming technical errors and chemical kinetic shortcomings were identified. The improved sub-model and its sub-parts were then tested for CFD simulation of a medium-speed, four-stroke, direct-injection marine diesel engine for different loads and fuels. The importance of NO reduction by soot and hydrocarbons was also investigated. All the sub-models correctly predicted the trend of increasing NO emission with increasing load. In absolute amounts, NO emission was over-predicted by a factor of 2 to 4, if no fitting of rate constants was allowed. Including NO reduction by soot and hydrocarbons, decreased NO emission by ca 425% for the cases studied.

Pia Kilpinen

2010-01-01T23:59:59.000Z

454

!"#%$'&(0)213546)708$'97)2@A$B)23 DCE$FHGPIQ92SR TU$B0$ VW0 Wim de Leeuw and Robert van Liere  

E-Print Network [OSTI]

. Fluid dynamics experts would like to obtain a detailed understanding of the transition from laminar's visualization sys- tems.X Computational fluid dynamics(CFD) simulations are capable of accurate simulation figure 5. The data is a slice of a 3D data set from a direct numerical simulation of turbulent flow

Liere, Robert van

455

Development of a consensus standard for verification and validation of nuclear system thermal-fluids software  

Science Journals Connector (OSTI)

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 thermalhydraulic 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. Although software verification will be an important and necessary part of the standard, much of the initial effort of the committee will be focused on the validation of existing software and new models that could be used in the licensing process. 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

2011-01-01T23:59:59.000Z

456

Modeling bubbles and droplets in magnetic fluids Mark S. Korlie, Arup Mukherjee, Bogdan G. Nita, John G.  

E-Print Network [OSTI]

and linear magnetic material are assumed and uniform imposed magnetic fields are considered, although of vertical fields, due to a combination of elongation along the field lines and the fluid dynamics. In both cases, #12;Modeling bubbles and droplets in magnetic fluids 2 an imposed magnetic field, even

Yecko, Philip

457

Nanoparticle Assembly at Fluid Interfaces: Structure and Yao Lin, Alexander Boker, Habib Skaff, David Cookson, A. D. Dinsmore,*,  

E-Print Network [OSTI]

Nanoparticle Assembly at Fluid Interfaces: Structure and Dynamics Yao Lin, Alexander Bo¨ker, Habib-assembly of nanoparticles at fluid interfaces, driven by the reduction in interfacial energy, was investigated. With spherical, tri-n-octyl-phosphine-oxide covered cadium selenide (CdSe) nanoparticles (1-8 nm), thermal

Dinsmore, Tony

458

Fluid Imaging | Open Energy Information  

Open Energy Info (EERE)

Page Page Edit History Facebook icon Twitter icon » Fluid Imaging Jump to: navigation, search Contents 1 Geothermal Lab Call Projects for Fluid Imaging 2 Geothermal ARRA Funded Projects for Fluid Imaging Geothermal Lab Call Projects for Fluid Imaging Loading map... {"format":"googlemaps3","type":"ROADMAP","types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"limit":200,"offset":0,"link":"all","sort":[""],"order":[],"headers":"show","mainlabel":"","intro":"","outro":"","searchlabel":"\u2026 further results","default":"","geoservice":"google","zoom":14,"width":"600px","height":"350px","centre":false,"layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","icon":"","visitedicon":"","forceshow":true,"showtitle":true,"hidenamespace":false,"template":false,"title":"","label":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"locations":[{"text":"

459

Bio-inspired fluid locomotion  

E-Print Network [OSTI]

We have developed several novel methods of locomotion at low Reynolds number, for both Newtonian and non-Newtonian fluids: Robosnails 1 and 2, which operate on a lubrication layer, and the three-link swimmer which moves ...

Chan, Brian, 1980-

2009-01-01T23:59:59.000Z

460

Self-similar perfect fluids  

E-Print Network [OSTI]

Space-times admitting an $r$-parameter Lie group of homotheties are studied for $r > 2$ devoting a special attention to those representing perfect fluid solutions to Einstein's field equations.

J. Carot; A. M. Sintes

2000-05-16T23:59:59.000Z

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.


461

Biocatalytic transformations of hydrothermal fluids  

Science Journals Connector (OSTI)

...emission into oxygenated ambient seawater. The large metabolic and physiological...emission into oxygenated ambient seawater. The large metabolic and physiological...DNA (the reproducing genetic storage for each species), individual...where entrained oxygenated seawater mixes with hydrothermal fluid...

1997-01-01T23:59:59.000Z

462

Atomistic methods in fluid simulation  

Science Journals Connector (OSTI)

...easily describable by traditional methods, as ICF involves a complex coupling between fluid instabilities and combustion processes at very small length and times scales. One contribution of 13 to a Theme Issue Turbulent mixing and beyond . Figure...

2010-01-01T23:59:59.000Z

463

Transparent fluids for 157-nm immersion lithography  

E-Print Network [OSTI]

- gineers. [DOI: 10.1117/1.1637366] Subject terms: 157-nm lithography; immersion fluid; perfluoropolyether

Rollins, Andrew M.

464

Pitch-catch only ultrasonic fluid densitometer  

DOE Patents [OSTI]

The present invention is an ultrasonic fluid densitometer that uses a material wedge and pitch-catch only ultrasonic transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface.

Greenwood, Margaret S. (Richland, WA); Harris, Robert V. (Pasco, WA)

1999-01-01T23:59:59.000Z

465

Pitch-catch only ultrasonic fluid densitometer  

DOE Patents [OSTI]

The present invention is an ultrasonic fluid densitometer that uses a material wedge and pitch-catch only ultrasonic transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface. 6 figs.

Greenwood, M.S.; Harris, R.V.

1999-03-23T23:59:59.000Z

466

Fluid Mechanics IB Lecturer: Dr Natalia Berloff  

E-Print Network [OSTI]

-efficient aircraft design, hydroelectric power, chemical processing, jet-driven cutting tools · our fluid environment

467

Computing the dynamics of biomembranes by combining conservative level set and adaptive finite element methods  

Science Journals Connector (OSTI)

The numerical simulation of the deformation of vesicle membranes under simple shear external fluid flow is considered in this paper. A saddle-point approach is proposed for the imposition of the fluid incompressibility and the membrane inextensibility ... Keywords: Adaptive finite element method, Fluid mechanics, Helfrich energy, Level set method, Mass conservation, Vesicle dynamics

Aymen Laadhari, Pierre Saramito, Chaouqi Misbah

2014-04-01T23:59:59.000Z

468

Heterogeneous perturbation of fluid density and solid elastic strain in consolidating porous media  

E-Print Network [OSTI]

The occurrence of heterogeneous perturbations of fluid mass density and solid elastic strain of a porous continuum, as a consequence of its undrained response is a very important topic in theoretical and applied poromechanics. The classical Mandel--Cryer effect provides an explanation of fluid overpressure in the central region of a porous sample, immediately after the application of the loading. However this effect fades away when the fluid leaks out of the porous network. Here this problem is studied within the framework of a second gradient theory and a thorough description of the static and the dynamics of the phenomenon is given.

P. Artale Harris; E. N. M. Cirillo; G. Sciarra

2014-07-20T23:59:59.000Z

469

Dark energy from cosmological fluids obeying a Shan-Chen non-ideal equation of state  

E-Print Network [OSTI]

We consider a Friedmann-Robertson-Walker universe with a fluid source obeying a non-ideal equation of state with "asymptotic freedom," namely ideal gas behavior (pressure changes directly proportional to density changes) both at low and high density regimes, following a fluid dynamical model due to Shan and Chen. It is shown that, starting from an ordinary energy density component, such fluids naturally evolve towards a universe with a substantial "dark energy" component at the present time, with no need of invoking any cosmological constant. Moreover, we introduce a quantitative indicator of darkness abundance, which provides a consistent picture of the actual matter-energy content of the universe.

Bini, Donato; Gregoris, Daniele; Succi, Sauro

2014-01-01T23:59:59.000Z

470

Dark energy from cosmological fluids obeying a Shan-Chen non-ideal equation of state  

E-Print Network [OSTI]

We consider a Friedmann-Robertson-Walker universe with a fluid source obeying a non-ideal equation of state with "asymptotic freedom," namely ideal gas behavior (pressure changes directly proportional to density changes) both at low and high density regimes, following a fluid dynamical model due to Shan and Chen. It is shown that, starting from an ordinary energy density component, such fluids naturally evolve towards a universe with a substantial "dark energy" component at the present time, with no need of invoking any cosmological constant. Moreover, we introduce a quantitative indicator of darkness abundance, which provides a consistent picture of the actual matter-energy content of the universe.

Donato Bini; Andrea Geralico; Daniele Gregoris; Sauro Succi

2014-08-23T23:59:59.000Z

471

Dynamic shape factors for hydox-generated plutonium dioxide-type non-sperical objects  

E-Print Network [OSTI]

. . . . . . . . . 1X NOMENCLATURE INTRODUCTION. BACKGROUND. THEORY. METHOD. . 14 Dynamic Shape Factors of a Hedron Characterized as a Single Variable, x. . Dynamic Shape Factors of a Hedron Characterized as Two Variables, x and y. Dynamic Shape Factors of a..., and this thesis to evaluates effects of the density and dynamic shape factors on the settling velocities of plutonium dioxide. THEORY Assume a particle in motion in a viscous fluid with velocity v. The fluid exerts a drag force on the particle defined as Fn...

Lohaus, James Harold

2012-06-07T23:59:59.000Z

472

DEVELOPMENT OF NEW DRILLING FLUIDS  

SciTech Connect (OSTI)

The goal of the project has been to develop new types of drill-in fluids (DIFs) and completion fluids (CFs) for use in natural gas reservoirs. Phase 1 of the project was a 24-month study to develop the concept of advanced type of fluids usable in well completions. Phase 1 tested this concept and created a kinetic mathematical model to accurately track the fluid's behavior under downhole conditions. Phase 2 includes tests of the new materials and practices. Work includes the preparation of new materials and the deployment of the new fluids and new practices to the field. The project addresses the special problem of formation damage issues related to the use of CFs and DIFs in open hole horizontal well completions. The concept of a ''removable filtercake'' has, as its basis, a mechanism to initiate or trigger the removal process. Our approach to developing such a mechanism is to identify the components of the filtercake and measure the change in the characteristics of these components when certain cleanup (filtercake removal) techniques are employed.

David B. Burnett

2003-08-01T23:59:59.000Z

473

Effect of Char Combustion Product Distribution Coefficient on the CFD Modeling of Biomass Gasification in a Circulating Fluidized Bed  

Science Journals Connector (OSTI)

The predicted temperature profile can be used to select the refractory linings or bricks of the gasifier, and the predicted gas composition distribution may help to determine the size and shape of the gasifier. ... The enthalpy source from thermal radiation is computed by the P-1 model:(20, 26)(13)(14)where a, ?s, C, and n are the absorption coefficient, the scattering coefficient, the linear-anisotropic phase function coefficient, and the refractive index of the medium, respectively. ... A 3D unsteady-state CFD model is built in ANSYS Fluent 14.0, and the simulation results will be compared and validated with experimental data by Garca-Ibaez, et al.(18) Figure 1 shows the schematic diagram of the gasifier for the current studies, which sizes are the same as those of the gasifier used in the experiment. ...

Hui Liu; Ali Elkamel; Ali Lohi; Mazda Biglari

2014-03-12T23:59:59.000Z

474

CFD modeling of two-stage ignition in a rapid compression machine: Assessment of zero-dimensional approach  

SciTech Connect (OSTI)

In modeling rapid compression machine (RCM) experiments, zero-dimensional approach is commonly used along with an associated heat loss model. The adequacy of such approach has not been validated for hydrocarbon fuels. The existence of multi-dimensional effects inside an RCM due to the boundary layer, roll-up vortex, non-uniform heat release, and piston crevice could result in deviation from the zero-dimensional assumption, particularly for hydrocarbons exhibiting two-stage ignition and strong thermokinetic interactions. The objective of this investigation is to assess the adequacy of zero-dimensional approach in modeling RCM experiments under conditions of two-stage ignition and negative temperature coefficient (NTC) response. Computational fluid dynamics simulations are conducted for n-heptane ignition in an RCM and the validity of zero-dimensional approach is assessed through comparisons over the entire NTC region. Results show that the zero-dimensional model based on the approach of 'adiabatic volume expansion' performs very well in adequately predicting the first-stage ignition delays, although quantitative discrepancy for the prediction of the total ignition delays and pressure rise in the first-stage ignition is noted even when the roll-up vortex is suppressed and a well-defined homogeneous core is retained within an RCM. Furthermore, the discrepancy is pressure dependent and decreases as compressed pressure is increased. Also, as ignition response becomes single-stage at higher compressed temperatures, discrepancy from the zero-dimensional simulations reduces. Despite of some quantitative discrepancy, the zero-dimensional modeling approach is deemed satisfactory from the viewpoint of the ignition delay simulation. (author)

Mittal, Gaurav [Department of Mechanical Engineering, The University of Akron, Akron, OH 44325 (United States); Raju, Mandhapati P. [General Motor R and D Tech Center, Warren, MI 48090 (United States); Sung, Chih-Jen [Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269 (United States)

2010-07-15T23:59:59.000Z

475

Visco-elastic fluid simulations of coherent structures in strongly coupled dusty plasma medium  

SciTech Connect (OSTI)

A generalized hydrodynamic model depicting the behaviour of visco-elastic fluids has often been invoked to explore the behaviour of a strongly coupled dusty plasma medium below their crystallization limit. The model has been successful in describing the collective normal modes of the strongly coupled dusty plasma medium observed experimentally. The paper focuses on the study of nonlinear dynamical characteristic features of this model. Specifically, the evolution of coherent vorticity patches is being investigated here within the framework of this model. A comparison with Newtonian fluids and molecular dynamics simulations treating the dust species interacting through the Yukawa potential has also been presented.

Singh Dharodi, Vikram; Kumar Tiwari, Sanat; Das, Amita, E-mail: amita@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2014-07-15T23:59:59.000Z

476

Visco-elastic fluid simulations of coherent structures in strongly coupled dusty plasma medium  

E-Print Network [OSTI]

A generalized hydrodynamic (GHD) model depicting the behaviour of visco-elastic fluids has often been invoked to explore the behaviour of a strongly coupled dusty plasma medium below their crystallization limit. The model has been successful in describing the collective normal modes of the strongly coupled dusty plasma medium observed experimentally. The paper focuses on the study of nonlinear dynamical characteristic features of this model. Specifically, the evolution of coherent vorticity patches are being investigated here within the framework of this model. A comparison with Newtonian fluids and Molecular Dynamics (MD) simulations treating the dust species interacting through the Yukawa potential has also been presented.

Dharodi, Vikram Singh; Das, Amita

2014-01-01T23:59:59.000Z

477

Fluid structure interaction modelling for the vibration of tube bundles, part I: analysis of the fluid flow in a tube bundle  

SciTech Connect (OSTI)

It is well known that a fluid may strongly influence the dynamic behaviour of a structure. Many different physical phenomena may take place, depending on the conditions: fluid flow, fluid at rest, little or high displacements of the structure. Inertial effects can take place, with lower vibration frequencies, dissipative effects also, with damping, instabilities due to the fluid flow (Fluid Induced Vibration). In this last case the structure is excited by the fluid. Tube bundles structures are very common in the nuclear industry. The reactor cores and the steam generators are both structures immersed in a fluid which may be submitted to a seismic excitation or an impact. In this case the structure moves under an external excitation, and the movement is influence by the fluid. The main point in such system is that the geometry is complex, and could lead to very huge sizes for a numerical analysis. Homogenization models have been developed based on the Euler equations for the fluid. Only inertial effects are taken into account. A next step in the modelling is to build models based on the homogenization of the Navier-Stokes equations. The papers presents results on an important step in the development of such model: the analysis of the fluid flow in a oscillating tube bundle. The analysis are made from the results of simulations based on the Navier-Stokes equations for the fluid. Comparisons are made with the case of the oscillations of a single tube, for which a lot of results are available in the literature. Different fluid flow pattern may be found, depending in the Reynolds number (related to the velocity of the bundle) and the Keulegan Carpenter number (related to the displacement of the bundle). A special attention is paid to the quantification of the inertial and dissipative effects, and to the forces exchanges between the bundle and the fluid. The results of such analysis will be used in the building of models based on the homogenization of the Navier-Stokes equations for the fluid. (authors)

Desbonnets, Quentin; Broc, Daniel [CEA, Lab Etudes Mecan Sism, DEN, SEMT, DM2S, F-91191 Gif Sur Yvette, (France)

2012-07-01T23:59:59.000Z

478

Parallel Transient Dynamics Simulations: Algorithms for Contact Detection  

E-Print Network [OSTI]

February 5, 1998 Abstract Transient dynamics simulations are commonly used to model phenomena such as car and deform with the objects as they undergo stress. Fluids (gasoline, water) or fluid­ like materials (soil is a natural candidate for the power of parallel computers. Unfortunately, these kinds of simulations have

Plimpton, Steve

479

Compressor bleed cooling fluid feed system  

DOE Patents [OSTI]

A compressor bleed cooling fluid feed system for a turbine engine for directing cooling fluids from a compressor to a turbine airfoil cooling system to supply cooling fluids to one or more airfoils of a rotor assembly is disclosed. The compressor bleed cooling fluid feed system may enable cooling fluids to be exhausted from a compressor exhaust plenum through a downstream compressor bleed collection chamber and into the turbine airfoil cooling system. As such, the suction created in the compressor exhaust plenum mitigates boundary layer growth along the inner surface while providing flow of cooling fluids to the turbine airfoils.

Donahoo, Eric E; Ross, Christopher W

2014-11-25T23:59:59.000Z

480