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Artykuły w czasopismach na temat "Industrial Standard Computational Fluid Dynamics Software Development"
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Halas, Dragan, Oskar Bera, Radovan Omorjan, Aleksandar Rajic i Danijela Jasin. "Analysis of new forms of orifice plates using computational fluid dynamics". Chemical Industry 73, nr 5 (2019): 311–23. http://dx.doi.org/10.2298/hemind190722030h.
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In many technologies, such as process industry or water supply, there is a need to measure fluid flowrates. Orifice plates are the most common instruments for measuring the fluid flowrate through pipelines due to their many advantages. On the other side, their use increases operating costs of industrial plants and pipelines. In this work, three new forms of orifice plates were designed and tested. These new forms and one standard, which served as a reference, were designed by using the SolidWorks software package. The aim of the new designs was energy savings, and consequently reduction of operating costs. Energy savings can be achieved by such a design, which decreases the orifice plate resistance an element of the pipeline. This was achieved by increasing the open part of the orifice plate permitting the fluid flow. CAD models of orifice plates were transferred to STL files that were further used for CFD simulation as well as 3D printing of experimental replicas. According to the proposed algorithm, the new designs were tested by CFD simulation performed in the COMSOL Multiphysics software package, by using a finite-difference method. Equations used were based on the Reynolds form of Navier-Stokes equations (RANS, Reynolds-averaged Navier-Stokes), and the continuity equation for incompressible fluids. Next, as we have proposed in our algorithm of development of new orifice plate designs, experimental orifice plates were made by using 3D printing technology and FDM (Fused Deposition Modeling) procedure and tested at laboratory conditions. The results of laboratory tests were compared with the results of CFD simulation. A considerable amount of energy saving was indicated, which was achieved already by the first of the three new orifice plate forms (V1) as compared to the reference (V0). For the other two proposed forms, the effect of energy savings was considerably lower. By using CFD simulation, data can be obtained based on which a decision can be made whether the new shape of the measuring device should be corrected or is appropriate for further laboratory tests. Based on the presented results it can be concluded that the proposed testing algorithm proved useful in designing new forms of orifice plates.
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Oberkampf, William L., Timothy G. Trucano i Charles Hirsch. "Verification, validation, and predictive capability in computational engineering and physics". Applied Mechanics Reviews 57, nr 5 (1.09.2004): 345–84. http://dx.doi.org/10.1115/1.1767847.
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Developers of computer codes, analysts who use the codes, and decision makers who rely on the results of the analyses face a critical question: How should confidence in modeling and simulation be critically assessed? Verification and validation (V&V) of computational simulations are the primary methods for building and quantifying this confidence. Briefly, verification is the assessment of the accuracy of the solution to a computational model. Validation is the assessment of the accuracy of a computational simulation by comparison with experimental data. In verification, the relationship of the simulation to the real world is not an issue. In validation, the relationship between computation and the real world, ie, experimental data, is the issue. This paper presents our viewpoint of the state of the art in V&V in computational physics. (In this paper we refer to all fields of computational engineering and physics, eg, computational fluid dynamics, computational solid mechanics, structural dynamics, shock wave physics, computational chemistry, etc, as computational physics.) We describe our view of the framework in which predictive capability relies on V&V, as well as other factors that affect predictive capability. Our opinions about the research needs and management issues in V&V are very practical: What methods and techniques need to be developed and what changes in the views of management need to occur to increase the usefulness, reliability, and impact of computational physics for decision making about engineering systems? We review the state of the art in V&V over a wide range of topics, for example, prioritization of V&V activities using the Phenomena Identification and Ranking Table (PIRT), code verification, software quality assurance (SQA), numerical error estimation, hierarchical experiments for validation, characteristics of validation experiments, the need to perform nondeterministic computational simulations in comparisons with experimental data, and validation metrics. We then provide an extensive discussion of V&V research and implementation issues that we believe must be addressed for V&V to be more effective in improving confidence in computational predictive capability. Some of the research topics addressed are development of improved procedures for the use of the PIRT for prioritizing V&V activities, the method of manufactured solutions for code verification, development and use of hierarchical validation diagrams, and the construction and use of validation metrics incorporating statistical measures. Some of the implementation topics addressed are the needed management initiatives to better align and team computationalists and experimentalists in conducting validation activities, the perspective of commercial software companies, the key role of analysts and decision makers as code customers, obstacles to the improved effectiveness of V&V, effects of cost and schedule constraints on practical applications in industrial settings, and the role of engineering standards committees in documenting best practices for V&V. There are 207 references cited in this review article.
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Schultz, Richard, Edwin Harvego i Ryan Crane. "Development of a Standard for Verification and Validation of Software Used to Calculate Nuclear System Thermal Fluids Behavior." Mechanical Engineering 132, nr 05 (1.05.2010): 56–57. http://dx.doi.org/10.1115/1.2010-may-6.
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This article focuses on the need for development of a standard for verification and validation (V&V) of software used to calculate nuclear system thermal fluids behavior. The V&V 30 Committee has been established to develop an ASME standard for verification and validation of computational fluid dynamics and system analysis software that will be used in the design and analysis of advanced nuclear reactor systems, with an initial focus on high-temperature gas-cooled reactors. The processes and procedures that will be addressed in the new standard will be used in the design and analysis of advanced reactor systems to be licensed in the United States. Recently, the V&V20 standard was released: Standard for Verification and Validation (V&V) in Computational Fluid Dynamics and Heat Transfer. Because of similarities in the standards being developed by the V&V20 and V&V30 Committees, it is important to define the relationship between the work embodied in the V&V20 Standard versus the work that will be forthcoming in the V&V30 Standard, as noted in the V&V20 Standard.
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Baburic, Mario, Alexandre Raulot i Neven Duic. "Implementation of discrete transfer radiation method into swift computational fluid dynamics code". Thermal Science 8, nr 1 (2004): 19–28. http://dx.doi.org/10.2298/tsci0401019b.
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The Computational Fluid Dynamics (CFD) has developed into a powerful tool widely used in science, technology and industrial design applications, when ever fluid flow, heat transfer, combustion, or other complicated physical processes, are involved. During decades of development of CFD codes scientists were writing their own codes, that had to include not only the model of processes that were of interest, but also a whole spectrum of necessary CFD procedures, numerical techniques, pre-processing and post-processing. That has arrested much of the scientist effort in work that has been copied many times over, and was not actually producing the added value. The arrival of commercial CFD codes brought relief to many engineers that could now use the user-function approach for mod el ling purposes, en trusting the application to do the rest of the work. This pa per shows the implementation of Discrete Transfer Radiation Method into AVL?s commercial CFD code SWIFT with the help of user defined functions. Few standard verification test cases were per formed first, and in order to check the implementation of the radiation method it self, where the comparisons with available analytic solution could be performed. After wards, the validation was done by simulating the combustion in the experimental furnace at IJmuiden (Netherlands), for which the experimental measurements were available. The importance of radiation prediction in such real-size furnaces is proved again to be substantial, where radiation itself takes the major fraction of over all heat transfer. The oil-combustion model used in simulations was the semi-empirical one that has been developed at the Power Engineering Department, and which is suit able for a wide range of typical oil flames.
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Liplenko, M. A., A. N. Borodenko i G. V. Mosolov. "The calculation of loads on buildings and structures caused by outdoor explosions of the fuel-air mixture". Pozharovzryvobezopasnost/Fire and Explosion Safety 31, nr 1 (17.03.2022): 88–98. http://dx.doi.org/10.22227/0869-7493.2022.31.01.88-98.
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Introduction. An important engineering task, to be solved in the process of designing buildings and structures for hazardous industrial facilities, is to determine values of loads caused by outdoor explosions of the fuel-air mixture. Nowadays software packages, that use the computational fluid dynamics (CFD) approach, are widely applied in the design practice to assess various effects on building structures. In this regard, it is necessary to develop a load calculation method, that employs numerical simulation, and verify it in comparison with the experimental data.Goals and objectives. The purpose of this work is to use the method of computational fluid dynamics to analyze external sympathetic detonation loads on various types of buildings and structures.The body of the article. The article addresses the “compressed balloon” method used to analyze loads, caused by outdoor explosions of gas. Dependencies, proposed in the article, are needed to set the input data and make numerical calculations using the computational fluid dynamics (CFD) technique. The numerical modeling of various experiments in the ANSYS Fluent software package was conducted. The authors compared the results of numerical modeling and standard engineering methods with various experiments to assess the accuracy of the “compressed balloon” method used to analyze an outdoor detonation explosion.Conclusions. The authors have proven the qualitative and quantitative convergence of the numerical model of blast wave propagation and the experimental data. This calculation method allows to accurately apply the pressure profile to any surface of a building or structure in the course of an outdoor detonation explosion and estimate the bearing capacity of building structures. The proposed method can be used in the design of buildings or structures that feature various configurations.
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Bao, Hai Tao. "Transient Numerical of Piston Wind in Subway Station". Applied Mechanics and Materials 644-650 (wrzesień 2014): 467–70. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.467.
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Computational Fluid Dynamics (CFD) is used for the investigation of the piston wind. The Navier-Stokes (N-S) equations and standard turbulence model were applied to set up the model. The train transient aerodynamic characteristic has been research during the crossing process. The simulation results are trustworthy and numerical simulation of piston wind is feasible using dynamic grid in CFD software, which provides the basis for the virtual design of piston wind. It is significant importance for further studying the structure of train, shorten its development and guiding significance for practical application.
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Ramanath, H. S., i C. K. Chua. "Application of rapid prototyping and computational fluid dynamics in the development of water flow regulating valves". International Journal of Advanced Manufacturing Technology 30, nr 9-10 (8.12.2005): 828–35. http://dx.doi.org/10.1007/s00170-005-0119-5.
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Okafor, Chinedum Vincent, U. John Ezeokonkwo, Dominic Anosike Obodoh i Peter Ogunoh. "Atmospheric Boundary Layer Simulation Using Wall Function Approach in OpenFoam CFD Software". European Journal of Engineering Research and Science 3, nr 2 (6.02.2018): 1. http://dx.doi.org/10.24018/ejers.2018.3.2.597.
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The significant development in computer resources in the past years has increased the awareness of computational fluid dynamics as an alternative tool to the costly wind tunnel testing. The paper presented the application of CFD technique for a case study in simulating an existing site together with a proposed building and the local landscape. Finally, the limitations of the code analytical methods to the CFD method for wind around building analysis were discussed. From the result obtained, it was observed that the British standard (BS6399-2:1997) procedures are based on general assumptions and are not always conservative and do not provide accurate wind load results due to complex geometrical shapes, aerodynamic interaction, torsion, and load combinations as discussed in section VII.
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Okafor, Chinedum Vincent, U. John Ezeokonkwo, Dominic Anosike Obodoh i Peter Ogunoh. "Atmospheric Boundary Layer Simulation Using Wall Function Approach in OpenFoam CFD Software". European Journal of Engineering and Technology Research 3, nr 2 (6.02.2018): 1–6. http://dx.doi.org/10.24018/ejeng.2018.3.2.597.
Pełny tekst źródłaStreszczenie:
The significant development in computer resources in the past years has increased the awareness of computational fluid dynamics as an alternative tool to the costly wind tunnel testing. The paper presented the application of CFD technique for a case study in simulating an existing site together with a proposed building and the local landscape. Finally, the limitations of the code analytical methods to the CFD method for wind around building analysis were discussed. From the result obtained, it was observed that the British standard (BS6399-2:1997) procedures are based on general assumptions and are not always conservative and do not provide accurate wind load results due to complex geometrical shapes, aerodynamic interaction, torsion, and load combinations as discussed in section VII.
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Salakhov, Rishat, Andrey Ermakov i Elvira Gabdulkhakova. "Numerical and Experimental Study of the Impeller of a Liquid Pump of a Truck Cooling System and the Development of a New Open-Type Impeller". Tehnički glasnik 14, nr 2 (11.06.2020): 135–42. http://dx.doi.org/10.31803/tg-20200309115417.
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Typically, closed-type impellers are more efficient than open-type impellers, but in the manufacture of closed-type impellers, cost of wheels is higher. This paper describes the development of cost-effective and simple impeller wheel for a fluid pump in the truck cooling system. To perform this task, the numerical computations of a standard impeller wheel were carried out, its characteristics were also obtained from a test bench, the standard impeller wheel model was verified. The open-type impeller wheel was developed according to the current dimensions of standard impeller wheel and then analyzed with the numerical computations by the software ANSYS CFX (Academic license) computational fluid dynamics. The developed open-type impeller wheel works very effectively in spite of performance degradation by 5% in comparison to the closed-type impeller wheel. When working as a part of engine, the pump efficiency is 0.552-0.579. The maximum value of the pump efficiency is 0.579, it can be achieved at the highest speed of the pump (4,548 rpm and 655 l/min).
Rozprawy doktorskie na temat "Industrial Standard Computational Fluid Dynamics Software Development"
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Yousuf, Mohamed Amali Uthuman. "Automated Meshless CFD Process using Cartesian Point Distribution". Thesis, 2020. https://etd.iisc.ac.in/handle/2005/4398.
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The thesis deals with the meshless methods based on generalized finite difference procedure operating on the mere distribution of points. The work per se focuses on maturing the meshless LSFD-U solver as a standard industrial tool for Aerospace CFD.
One of the purported advantages of this class of methods as opposed to finite- volume methods is that they can considerably ease the need for generating grids. This aspect has been truly exploited in this thesis by projecting the meshless LSFD-U solver as a Cartesian grid methodology. The point distribution required by the LSFD-U solver is obtained from Cartesian grids. The Cartesian grid with its immense potential for process automation and the LSFD-U method with its ability to discretize the conservation equations on any arbitrary point distribution, form a natural pair for solving complex engineering problems in an automated process. The thesis presents a number of complex configurations of industrial relevance where the point distribution for the meshless solver are obtained from Cartesian grids in short turn-around times and without any human intervention. The grid convergence of the 3D inviscid solver is also established on a sequence of Cartesian point distributions.
The automation capability is one of the key requirements for solving multi-body dynamics, moving body and optimization problems. The CFD process on such problems primarily involves repetitive grid generation. Any need for human intervention and expertise in the CFD process seriously hampers the overall performance and productivity. The meshless LSFD-U solver offers complete automation in the CFD process regardless of the complexity in the configurations. This aspect has been demonstrated in this thesis by predicting the store trajectory using quasi-steady simulations. In order to understand these results better, the work has also been extended to include the viscous effects in the trajectory prediction (although within a finite volume framework) and the sensitivities of the 6-DOF model integration. An automated CFD process to determine the optimal flap location has also been included in the demonstrations.
Mesh adaptivity is one of the important areas of focus in a CFD work-flow for obtaining high resolution CFD solutions. Adopting such methodology for the meshless LSFD-U solver is attempted in this thesis work. A residual-based grid adaptive strategy in which an estimate of the local truncation error is used to define length scales for adequately resolving the flow in a given region is developed in the context of the LSFD-U solver. An attempt has been made to evolve an automated termination of the grid adaptation, which establishes the efficacy of the proposed adaptive strategy. For the flows with discontinuities, a hybrid strategy is employed in which the smooth flow regions are adapted using the R-parameter and the limiter operational regions are adapted using the divergence of velocity based indicator.
A critical milestone for the success of the meshless methods is their ability to simulate turbulent flows by the way of solving RANS equations using highly anisotropic point distribution. The LSFD-U RANS solver makes use of a wall resolved hybrid Cartesian grid for the viscous turbulent flow computations. The Spalart-Allmaras turbulence model implementation within the meshless framework is discussed in detail. A combination of high aspect ratio grids (in a finite volume parlance) exhibiting grid folding, which is common in domains with wall slope discontinuity, results in loss in accuracy and robustness of the meshless solver. In order to handle such issues, we have proposed a point adaptive strategy which detects such regions with grid folding and improves the grid quality by introducing points along the rays exhibiting grid folding. The 2D LSFD-U RANS solver is validated for complex high lift cases. The work also includes some attempts towards achieving a successful 3D LSFD-U RANS solver.
Części książek na temat "Industrial Standard Computational Fluid Dynamics Software Development"
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Fiorini, Cesare, Hélder D. Craveiro, Aldina Santiago, Luís Laim i Luís Simões da Silva. "Microscale fire modelling at the Wildland-Urban Interface". W Advances in Forest Fire Research 2022, 689–94. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_105.
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The direct and indirect impacts of Wildland-Urban Interface fires on infrastructures and communities have become more severe in the last few decades, mainly due to the disproportionate growth of urban areas lacking planning and management, the abandonment of rural areas and activities, and climate changes. Many regions of the southern Mediterranean, the United States, Australia, and South America have been severely affected with catastrophic losses. Building codes addressing the problem of WUI fires in the vicinity of the built environment are still scarce, but already with a few good examples, namely the Australian Standard AS 3959-2009, Construction of Buildings in Bushfire Prone Areas. But with the increasing risks, nowadays mainly driven by climate change, it is necessary to develop new approaches and codes for existing and new buildings effectively contributing to enhance the resilience of the built environment and communities in the WUI. Moreover, taking advantage of new and ever-evolving computational tools, the use of a performance-based approach, replacing or complementing prescriptive codes, shows great potential to enable a deeper understanding of the complex fire spread mechanisms from forest fires to urban fires, namely radiant heat, direct flame contact and firebrands. Physics-based modelling enables a better understanding of such phenomena, bearing in mind that up to date no accurate and reliable models for firebrands can be found. In this investigation, a performance-based approach is considered, exploring the capabilities of computational fluid dynamics and the software Fire Dynamics Simulation (FDS) to investigate and quantify WUI fire exposures. This was achieved by considering available experimental data on vegetation burning and developing and calibrating the numerical models using FDS. A Particle Method, based on Lagrangian particles was selected for this investigation, since this model is particularly suitable to simulate surface and raised vegetation fire spread. With this strategy all thermo-physical properties of the fuels must be used as input, ensuring that the fire spread can be computed by the model. Based on the calibrated models for a single tree, a new case study scenario was created (structure exposed to wildfire) and investigated aiming to assess in detail WUI fire exposures under different conditions by varying several parameters, such as wind speed and direction, distance to the structure and elevation of the terrain. Since a performance-based approach was selected and considering the basic principles associated with Fire Safety Engineering (FSE), 3 basic components must be assessed, namely the fire modelling, the thermal analysis in the structure and finally the structural analysis considering temperature increase and degradation of mechanical properties of materials. From the fire modelling investigated in this paper, some attention was devoted to assessing Adiabatic Surface Temperatures in the structure and consequently defining in a simple way to couple CFD field models to Finite Element Models (FEM) that will enable the understanding and development of ignition resistant structures in the WUI.
Streszczenia konferencji na temat "Industrial Standard Computational Fluid Dynamics Software Development"
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Diwakar, Philip, Vibhor Mehrotra, Rimon Vallavanatt i Thomas McLean. "Challenges in Modeling Ground Flares Using Computational Fluid Dynamics". W ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-3121.
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Industrial application of Computational Fluid Dynamics (CFD) are varied and many. However CFD requires the solution of complex fluid-flow problems in conjunction with equipment design, process and product development and optimization. The solution of such complex problems is possible through the coordination between industrial CFD engineers, software developers, consultants and academic scientists. In the petrochemical industry, CFD may be used for a variety of purposes such as air recirculation studies in LNG plants, burners in coker furnaces, multiphase studies in heat exchangers to name just a few. In particular combustion, flames, flares and chemical reaction are of interest because of the physics and the complex nature of the process. The topic selected for this presentation is the study of wet ground flares during a large-scale propane release and the effect of the radiation release on the environment and surrounding buildings and vegetation. The flare characteristics and radiation on the surrounding terrain form an integral part of the information required by the National standard for “Control of Major Hazard Facilities”. The study of individual flames from each burner with nozzles of the order of 1mm and the effect of 180 burners in a large area and surrounding terrain with length scales of several hundred meters make up a very intriguing problem of varying length scales. The results of this analysis are presented concentrating on the effects during the large scale conflagration event on the surrounding buildings, vegetation, aircraft, hills and mangroves.
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Mehrotra, Vibhor, Philip Diwakar i Rimon Vallavanatt. "Troubleshooting Furnace Operations Using Computational Fluid Dynamics (CFD)". W ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-3127.
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Industrial application of Computational Fluid Dynamics (CFD) requires the solution of complex fluid-flow problems in conjunction with equipment design, process and product development and optimization. For the successful solution of these problems, a high degree of coordination between industrial CFD engineers, software developers, consultants and academic scientists is necessary. In a refinery, CFD may be applied to a variety of problems. In particular, combustion, flames, flares and chemical reaction are of interest because of the physics and the complex nature of the process. Two applications are presented in this paper to demonstrate the use of CFD modeling for improving furnace operations. The first concerns improvements in reboiler operation by changing burner arrangement. A three-burner arrangement has resulted in tube burnout in the past. CFD modeling suggested a four-burner arrangement is better. The recommendation was accepted and implemented by the refinery in 2002. Feedback from the refinery suggests a much cooler furnace operation is observed in the field. The second application concerns predicting Coker furnace operation of as yet uninstalled heater. The Coker radiant section is modeled with 4 burners. Predicting the impact of burner-burner interaction on the radiant heat flux helps in determining the time period for decoke. Several mitigation steps are suggested to increase the run length between decoking intervals. Further recommendation to create a balanced heat flux profile is provided.
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Harvego, Edwin A., Richard R. Schultz i Ryan L. Crane. "Development of a Standard for Verification and Validation of Software Used to Calculate Nuclear System Thermal Fluids Behavior". W 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-30243.
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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.
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Thomson, Allan, i David A. Anderton. "Development in Gas Turbine Repairs". W ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22239.
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The need for repair rather than replace of gas turbine components is becoming increasingly important to operators in today’s economic climate. The use of commercially available numerical analysis software, computational fluid dynamics (CFD) and finite element (FE) have become well established within Wood Group Light Industrial Turbines Ltd. They have allowed the business to be extremely competitive by being able to rapidly respond to a customers request for a repair which may involve a fluid structure interaction and/or conjugate heat transfer analysis. The software has also been used to study critical design limitations and to rapidly enhance reverse engineered parts. Two such cases are presented here: the repair of a compressor rotor blade airfoil and the changes made to an existing design of a cooling passage in a high pressure turbine rotor blade. Each analysis was completed in a very competitive time span.
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Sorokes, James M., i Bradley R. Hutchinson. "The Practical Application of CFD in the Design of Industrial Centrifugal Compressors". W ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1670.
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Abstract In the development of industrial turbomachinery, the aerodynamic designer is faced with many complex fluid flow problems. In the mid to late 1980’s, Computational Fluid Dynamics (CFD) software was developed to assist in the solution of these flow fields. Initially applied only by high end gas turbine or jet engine designers, these sophisticated tools eventually found their way to engineers at industrial turbomachinery manufacturers. However, it has only been in the last five to ten years that industrial users have begun to make more widespread use of CFD. There are a variety of reasons for this slow adoption.
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Talukder, Shoab Ahmed, i B. Phuoc Huynh. "Effects of Number of Stator Blades on the Performance of a Torque Converter". W ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-65078.
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Torque converter (TC) is a totally enclosed hydrodynamic turbomachine, used most often in automobiles for the smooth transfer of power and speed change from the engine to the transmission, and torque magnification. A typical TC has 3 major components: a pump that is attached directly to the TC cover and connected to the engine shaft, a turbine connected to the transmission shaft, and a stator connected to the transmission housing via a one-way clutch and providing guidance for the fluid flow. In this work, effects of the number of stator blades on the performance of a TC are investigated numerically, using a commercial Computational Fluid Dynamics (CFD) software package. The standard k-epsilon turbulence model was used. A Newtonian fluid whose properties correspond to industrial oil was used for the working fluid. The range of speed ratio (between turbine’s speed and pump’s) of 0.2–0.8 was considered. It was found that as the stator blades’ number increases (here from 13 to 19), the TC’s efficiency and torque ratio vary significantly, passing through minimum and generally also reaching a maximum.
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Gan, Fujun, Libing Zhu, Jiazheng Liu, Yixiong Zheng i Xing Tong. "Development and Application of Single-Phase CFD Methodology for Estimating Flow Field in Rod Bundles". W 2013 21st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icone21-15198.
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Computational Fluid Dynamics (CFD) simulation has been increasingly used in Nuclear Reactor Safety (NRS) analysis to describe safety–relevant phenomena occurring in the reactor coolant system in greater detail. In this paper, the work about single-phase CFD simulation of rod bundles conducted in Shanghai Nuclear Engineering Research & Design Institute (SNERDI) is introduced. A single-phase methodology based on commercial software STAR-CCM+ is developed to simulate the flow field and temperature distribution in fuel rod bundles. Solid model is simply introduced at first. Mesh types, including tetrahedral, polyhedral and trimmer, are compared in order to select the most best one with both good accuracy and less cost. Several turbulence models available in STAR-CCM+, including standard k-epsilon model, realizable k-epsilon model (RKE), shear stress transport k-omega model (SST k-omega), and Reynolds stress model (RSM) are investigated. Trimmed mesh and RKE turbulence model with two-layer all y+ model are finally employed for following calculations. Vortex structures downstream of mixing vanes is qualitatively compared with Particle Image Velocity (PIV) results, and good agreement is achieved. The present method will be further refined in order to play significant role in future optimal design of fuel assembly (FA) grid.
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Biswas, Dipankar, Steven A. Lottes, Pradip Majumdar i Milivoje Kostic. "Development of an Analysis Methodology for Pressure Flow Scour Under Flooded Bridge Decks Using Commercial CFD Software". W ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-37198.
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Bridges are a significant component of the ground transportation infrastructure in the United States. With about sixty percent of bridge failures due to hydraulic causes, primarily scour, application of computational fluid dynamics (CFD) analysis techniques to the assessment of risk of bridge failure under flood conditions can provide increased accuracy in scour risk assessment at a relatively low cost. The analysis can be used to make optimum use of limited federal and state funds available to maintain and replace bridges and ensure public safety while traveling on the nation’s roads and highways during and after floods. Scour is the erosion of riverbed material during high flow conditions, such as floods. When scouring of the supporting soil around the piers and abutments of bridges takes place, risk of bridge failure increases. A simulation methodology to conservatively predict equilibrium shape and size of the scour hole under pressure flow conditions for flooded bridge decks using commercial CFD software was developed. The computational methodology has been developed using C++ to compute changes in the bed contour outside of the CFD software and generate a re-meshing script to change the bed boundary contour. STAR-CD was used to run the hydrodynamic analysis to obtain bed shear stress, and a BASH script was developed to automate cycling between computing bed shear stress with the CFD software and computing changes in the bed contour due to scour predicted using the computed shear stress for the current bed contour. A single-phase moving boundary formulation has been developed to compute the equilibrium scour hole contour that proceeds through a series of quasi-steady CFD computations. It is based on CFD analysis of the flow fields around the flooded bridge deck and shear stress computed at the bed modeled as a rough wall. A high Reynolds number k-ε turbulence model with standard wall functions, based on a Reynolds-Averaged Navier-Stokes (RANS) turbulence model, was used to compute bed shear stress. The scour sites on the bed were identified as those sites where the computed shear stress exceeded the critical shear stress computed from a published correlation for flat bed conditions. Comparison with experimental data obtained from the Turner-Fairbank Highway Research Center (TFHRC), McLean, VA, USA, revealed larger discrepancies than anticipated between the bridge inundation ratio and the scour hole depth. Although scour hole slopes were small for the cases tested, a correction to critical shear stress to account for bed slope was also tested. It did not significantly improve the correlation between CFD prediction and experimental observations. These results may be a consequence of using only excess shear stress above critical as a criteria for scour when other physical mechanisms also contribute to the initiation of scour. Prediction of scour depth using federal guidelines over predicts scour depth by as much as an order of magnitude in some cases. Over prediction is acceptable for purposes of ensuring bridge safety. CFD methods for scour prediction can be a significant improvement of current methods as long as under prediction of scour depth is avoided. Conservative scour prediction using CFD methods can be achieved by using conservative values of parameters such as critical shear stress and effective bed roughness.
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Kunick, Matthias, Hans-Joachim Kretzschmar, Francesca di Mare i Uwe Gampe. "CFD Analysis of Steam Turbines With the IAPWS Standard on the Spline-Based Table Look-Up Method (SBTL) for the Fast Calculation of Real Fluid Properties". W ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-43984.
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Accurate simulations of non-stationary processes in steam turbines by means of Computational Fluid Dynamics (CFD) require precise and extremely fast algorithms for computing real fluid properties. To fulfill these requirements, the International Association for the Properties of Water and Steam (IAPWS) issues the “Guideline on the Fast Calculation of Steam and Water Properties with the Spline-Based Table Look-Up Method (SBTL)” as an international standard. Through the use of this method, spline functions for the independent variables specific volume and specific internal energy (v,u) are generated for water and steam based on the industrial formulation IAPWS-IF97. With these spline functions, thermodynamic and transport properties can be computed. The desired backward functions of the variables pressure and specific volume (p,v), and specific internal energy and specific entropy (u,s) are numerically consistent with the spline functions from (v,u). The properties calculated from these SBTL functions are in agreement with those of IAPWS-IF97 within a maximum relative deviation of 10 to 100 ppm depending on the property and the range of thermodynamic states spanned under the given conditions (range of state). Consequently, the differences between the results of process simulations using the SBTL method and those obtained through the use of IAPWS-IF97 are negligible. Moreover, the computations from the (v,u) spline functions are more than 200 times faster than the iterative calculations with IAPWS-IF97. In order to demonstrate the efficiency and applicability of the SBTL method, the SBTL functions have been implemented into the CFD software TRACE, developed by the German Aerospace Center (DLR). As a result, the computing times required for the simulations of steam flow in a turbine cascade considering real fluid behavior are reduced by a factor of 6–10 in comparison to the calculations based on IAPWS-IF97. Furthermore, computing times are increased by a factor of 1.4 only with respect to CFD calculations where steam is considered to be an ideal gas, through the use of the SBTL method.
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Amano, R. S., Takahiko Hasegawa i Shaohua Shen. "A Study of the Development of an Analytical Wall Function for LES". W ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21191.
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In order to invent a new near-wall treatment for turbulence in Computational Fluid Dynamics (CFD) simulation, an Analytical Wall Function (AWF) has been studied and shown that it is possible to work accurately with Reynolds Averaged Navier-Stokes (RANS) Simulation even for complicated geometry such as impinging jet flow or separation and reattachment flow. One of the most common wall functions is the Standard Wall Function (SWF) which assumes log-law inside the boundary layer. However, there is a problem that SWF has been used for industrial applications even though it is difficult to analyze the turbulence phenomenon in a complicated geometry accurately because log-law is not applicable in that geometry. On the other hand, since AWF derives the boundary condition on the wall by integrating analytically the boundary layer equation in wall adjacent cells, it can analyze the turbulence accurately even in complicated geometry. AWF has an advantage over SWF from this point of view. In this study, AWF was improved and optimized for Large Eddy Simulation (LES) by changing the way of modeling of eddy viscosity inside the boundary layer for steady state simulation to that for unsteady state simulation. This is because RANS is a steady state simulation; on the other hand, LES is unsteady state simulation, which is one of the largest differences between them. The accuracy of the new AWF for LES (LES-AWF) was validated by both of experimental results and CFD simulation results. Both of the experiment and CFD simulation are conducted in the wind tunnel.