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NAFEMS International Journal of CFD Case Studies最新文献

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Simulation of Turbulent Swirling Flows: Gas Turbine Combustor Application and Validation 紊流旋流模拟:燃气轮机燃烧室的应用与验证
NAFEMS International Journal of CFD Case Studies Pub Date : 2008-08-01 DOI: 10.59972/drurpexw
A. Benim, P. Stopford, E. Buchanan, K. Syed
{"title":"Simulation of Turbulent Swirling Flows: Gas Turbine Combustor Application and Validation","authors":"A. Benim, P. Stopford, E. Buchanan, K. Syed","doi":"10.59972/drurpexw","DOIUrl":"https://doi.org/10.59972/drurpexw","url":null,"abstract":"In the first part of the paper, CFD analysis of the combusting flow within a high-swirl lean premixed gas turbine combustor and over the 1st row nozzle guide vanes is presented. In this analysis, the focus of the investigation is the fluid dynamics at the combustor/turbine interface and its impact on the turbine. The predictions show the existence of a highly-rotating vortex core in the combustor, which is in strong interaction with the turbine nozzle guide vanes. This has been observed to be in agreement with the temperature indicated by thermal paint observations. The results suggest that swirling flow vortex core transition phenomena play a very important role in gas turbine combustors with modern lean-premixed dry low emissions technology. As the predictability of vortex core transition phenomena has not yet sufficiently been investigated, a fundamental validation study has been initiated, with the aim of validating the predictive capability of currently-available modelling procedures for turbulent swirling flows near the sub/supercritical vortex core transition. In the second part of the paper, results are presented, which analyse such transitional turbulent swirling flows in a laboratory water test rig. It has been observed that turbulent swirling flows of interest are dominated by low-frequency transient motion of coherent structures, which can not be adequately simulated within the framework of steady-state RANS turbulence modelling approaches. It has been found that useful results can be obtained only by modelling strategies, which resolve the three-dimensional, transient motion of coherent structures, and do not assume a scalar turbulent viscosity at all scales. These models include RSM based URANS procedures as well as LES. To exploit the full potential of LES, however, additional attention needs to be paid to modelling issues such as achieving the necessary grid resolution as well as providing convenient inlet boundary conditions.","PeriodicalId":183819,"journal":{"name":"NAFEMS International Journal of CFD Case Studies","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128924304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Simulations of Viscoelastic Polymer Solution Flows 粘弹性聚合物溶液流动的模拟
NAFEMS International Journal of CFD Case Studies Pub Date : 2007-03-01 DOI: 10.59972/d8hd7bkp
D. Niedziela, A. Latz, O. Iliev
{"title":"Simulations of Viscoelastic Polymer Solution Flows","authors":"D. Niedziela, A. Latz, O. Iliev","doi":"10.59972/d8hd7bkp","DOIUrl":"https://doi.org/10.59972/d8hd7bkp","url":null,"abstract":"Many natural and synthetic fluids are viscoelastic materials i.e. the stress at a certain fluid particle depends upon the history of the deformation experienced by that particle. Polymer melts and most polymer solutions are examples of such liquids. Simulation of the flow of these fluids is therefore of great interest for the plastic industry. Viscoelastic fluids are examples of non - Newtonian fluids. While the Newtonian fluids are characterised by a constant viscosity (i.e., constant ratio between shear stress and the rate of strain), the non-Newtonian fluids require more complicated constitutive relations in order to close the governing system of equations...","PeriodicalId":183819,"journal":{"name":"NAFEMS International Journal of CFD Case Studies","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122564990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Simulation of Flows in Complex Geometries: New Meshing and Solution Methods 复杂几何流动的模拟:新的网格划分和求解方法
NAFEMS International Journal of CFD Case Studies Pub Date : 2007-03-01 DOI: 10.59972/utux3hbg
M. Peric
{"title":"Simulation of Flows in Complex Geometries: New Meshing and Solution Methods","authors":"M. Peric","doi":"10.59972/utux3hbg","DOIUrl":"https://doi.org/10.59972/utux3hbg","url":null,"abstract":"The use of CFD is spreading in all areas of engineering. The flow domains are usually very complicated, which places high demands on both meshing and solution methods. In this manuscript the newest developments in the handling of complex geometries in CFD are presented. The limitations with respect to the shape of control volumes that may appear in a numerical grid are lifted: cells of arbitrary polyhedral shape are allowed. CAD-integration of all CFD tools and automatic generation of polyhedral meshes, as well as a solution method that can use such meshes, are also presented and the advantages of the new technology are discussed. The emphasis is on CAD integration, automatic mesh generation, and optimisation of mesh quality. The aim of all of these measures is the shortening of analysis time in all phases of a CFD simulation and at the same time an improvement of solution quality.","PeriodicalId":183819,"journal":{"name":"NAFEMS International Journal of CFD Case Studies","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116886848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 7
Coal Combustion - Partial Validation of a Complex Problem 煤燃烧——一个复杂问题的部分验证
NAFEMS International Journal of CFD Case Studies Pub Date : 2007-03-01 DOI: 10.59972/k0tghmrx
P. Stephenson
{"title":"Coal Combustion - Partial Validation of a Complex Problem","authors":"P. Stephenson","doi":"10.59972/k0tghmrx","DOIUrl":"https://doi.org/10.59972/k0tghmrx","url":null,"abstract":"This paper summarises efforts made over a number of years to apply CFD to coal combustion in the Combustion Test Facility (CTF) currently owned and operated by RWE npower. It formed a key part of a strategy to develop a CFD capability in this area. The first two applications (to a drop tube furnace and to the CTF fitted with one type of burner) were successful. However, a subsequent application (the CTF with a completely different burner) had only limited success. The precise reasons for this limited success apply solely to this particular application. However, the work raised two questions that are relevant to any industrial application of a commercial CFD code. Therefore the aim of this paper is to provide an overview of this work and to use the experience gained to discuss two questions...","PeriodicalId":183819,"journal":{"name":"NAFEMS International Journal of CFD Case Studies","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122658678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
IMPNS Computations of the X-15 Flight Vehicle: A Validation and Verification X-15飞行器的IMPNS计算:验证与验证
NAFEMS International Journal of CFD Case Studies Pub Date : 2007-03-01 DOI: 10.59972/0sjv74yh
S. Shaw, M. Mifsud, B. Wagner, A. Moureaux, J. Bennett
{"title":"IMPNS Computations of the X-15 Flight Vehicle: A Validation and Verification","authors":"S. Shaw, M. Mifsud, B. Wagner, A. Moureaux, J. Bennett","doi":"10.59972/0sjv74yh","DOIUrl":"https://doi.org/10.59972/0sjv74yh","url":null,"abstract":"A verification and validation study of the IMPNS space-marching flow solver has been undertaken for a complete hypersonic air-vehicle configuration. A hierarchical approach was adopted in which the vehicle aerodynamics was decomposed and related flow phenomenon studied. Using this hierarchy benchmark solutions and laboratory experiments were identified that provide the basis of the verification and validation exercises. Detailed comparisons of iterative and grid converged IMPNS computations with benchmark solutions and wind tunnel measurements are presented. Computations of the X-15 wind tunnel and flight experiments are described and comparison is made with measured surface and off-surface pressure measurements and wind tunnel flow visualization observations that demonstrate the reliability and capability of the IMPNS flow solver for complex configurations.","PeriodicalId":183819,"journal":{"name":"NAFEMS International Journal of CFD Case Studies","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128833112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Simulation of Turbulent Swirling Flows: Gas Turbine Combustor Application and Validation 紊流旋流模拟:燃气轮机燃烧室的应用与验证
NAFEMS International Journal of CFD Case Studies Pub Date : 2007-03-01 DOI: 10.59972/1mh6ehmz
U. Göhner, A. Haufe
{"title":"Simulation of Turbulent Swirling Flows: Gas Turbine Combustor Application and Validation","authors":"U. Göhner, A. Haufe","doi":"10.59972/1mh6ehmz","DOIUrl":"https://doi.org/10.59972/1mh6ehmz","url":null,"abstract":"Many accidents with children or small adults, where the ignition of the airbag leads to dangerous and even fatal injuries for the passengers, have led to a number of efforts to analyse this so-called “Out-of- Position” load case more deeply within the development process of an airbag system. In the framework of simulation systems the fluid-structure interaction between the inflating gas and the airbag fabric has not been taken into account in the past. Recent developments in the LS-DYNA software package allow a fully coupled arbitrary Lagrange-Euler formulation and thus a more exact representation of the airbag deployment process within the simulation system. In the present contribution we will describe the standard procedure, based on the assumption of a uniform pressure distribution in the airbag and the recently achieved advances in LS-DYNA with respect to fluid-structure interaction of the expanding gas and the inflating airbag fabric.","PeriodicalId":183819,"journal":{"name":"NAFEMS International Journal of CFD Case Studies","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114566333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Numerical Simulation of Coolant Mixing at the ROCOM Test Facility with CFX-4 and CFX-5 based on Complex Meshes 基于复杂网格的CFX-4和CFX-5 ROCOM试验场冷却剂混合数值模拟
NAFEMS International Journal of CFD Case Studies Pub Date : 2006-04-01 DOI: 10.59972/mg4zu1sr
T. Höhne
{"title":"Numerical Simulation of Coolant Mixing at the ROCOM Test Facility with CFX-4 and CFX-5 based on Complex Meshes","authors":"T. Höhne","doi":"10.59972/mg4zu1sr","DOIUrl":"https://doi.org/10.59972/mg4zu1sr","url":null,"abstract":"The work was aimed at the numerical simulation of coolant mixing in the downcomer and the lower plenum of the Rossendorf test facility ROCOM. ROCOM is a 1:5 scale Plexiglas model of a German pressurised water reactor allowing conductivity measurements by wire mesh sensors and velocity measurements by LDA technique. The CFD calculations were carried out with the CFD-codes CFX-4 and CFX-5. In the case of stationary mixing, the maximum value of the averaged mixing scalar at the core inlet was found in the sector below the inlet nozzle, where the tracer was injected. The comparison of a very detailed mesh (CFX-5) and a mesh with simplifications and additional physical models (CFX-4) showed that, in the referred case, the use of these models is allowed. For turbulent flows CFX-4 and CFX-5 were validated in accordance with the Best Practice Guidelines and can be used in the reactor safety analysis. A better description of the mixing processes inside the RPV is the basis of a more realistic safety assessment.","PeriodicalId":183819,"journal":{"name":"NAFEMS International Journal of CFD Case Studies","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116665695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
CµFD: Simulation of Microfluidic Systems CµFD:微流体系统仿真
NAFEMS International Journal of CFD Case Studies Pub Date : 2006-04-01 DOI: 10.59972/5f1ncmu3
F. Schönfeld, K. Drese, S. Hardt
{"title":"CµFD: Simulation of Microfluidic Systems","authors":"F. Schönfeld, K. Drese, S. Hardt","doi":"10.59972/5f1ncmu3","DOIUrl":"https://doi.org/10.59972/5f1ncmu3","url":null,"abstract":"We discuss the applicability of standard CFD techniques in µ-fluidics, highlight challenges and introduce methods which allow for corresponding extensions. The focus is especially on problems of major practical importance, namely liquid mixing in micro mixers and free-surface micro flows. With respect to the former two approaches are presented allowing eliminating the problems due to numerical discretisation errors for specific cases of miscible liquids. In the case of emulsion formation of immiscible liquids the RayleighPlateau decay is identified to be the driving mechanism for droplet formation under certain process conditions. Furthermore we investigate capillary filling of a narrow slit, where a special focus is put on the effects induced by a dynamic variation of the contact angle. The test case shows that on practically manageable grids the dynamic behaviour of the contact angle cannot be sufficiently reproduced. A result of the studies performed is the possibility to incorporate the correct contact-angle dynamics even on comparatively coarse grids by introducing a macroscopic slip range at the 3-phase contact line. By virtue of such an “artificial slip method”, correct results for free-surface micro flows can be obtained on grids with a moderate number of computational cells, without the need to resolve the contact line very accurately. Finally, a micro fluidic application involving both mixing of miscible liquids and free-surface flows is exemplarily outlined as one of the future challenges.","PeriodicalId":183819,"journal":{"name":"NAFEMS International Journal of CFD Case Studies","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127350437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Turbulence Modelling for Technical Flows 技术流的湍流模型
NAFEMS International Journal of CFD Case Studies Pub Date : 2006-04-01 DOI: 10.59972/zy8s6eve
F. Menter
{"title":"Turbulence Modelling for Technical Flows","authors":"F. Menter","doi":"10.59972/zy8s6eve","DOIUrl":"https://doi.org/10.59972/zy8s6eve","url":null,"abstract":"The paper describes the need for turbulence modelling in industrial flow simulations. It will describe the general problem in the simulation of turbulent flows and the required averaging procedures to arrive at a manageable equation system. The principal concepts behind turbulence models will be described and some current model formulations will be described briefly. Simulations will be shown for generic testcases and industrial applications.","PeriodicalId":183819,"journal":{"name":"NAFEMS International Journal of CFD Case Studies","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123021568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Simulation of a Plasma Enhanced µ-jet-CVD Process 等离子体增强微射流- cvd过程的模拟
NAFEMS International Journal of CFD Case Studies Pub Date : 2006-04-01 DOI: 10.59972/8ptzprew
C. Dehning, A. Holländer, A. Leventi-Peetz, K. Silmy
{"title":"Simulation of a Plasma Enhanced µ-jet-CVD Process","authors":"C. Dehning, A. Holländer, A. Leventi-Peetz, K. Silmy","doi":"10.59972/8ptzprew","DOIUrl":"https://doi.org/10.59972/8ptzprew","url":null,"abstract":"We present results of a coupled calculation to simulate the combined movement and plasma excitation of a process gas, accelerated in the form of a fine beam, known as micro-jet (µ-jet-CVD), between the RF electrodes of a CVD-plasma-reactor, before it reaches the deposition surface. The form and geometry of the deposition, as well as its chemical and physical properties, depend on the chemical properties of the gas, the externally supplied electrical energy as well as the gas-dynamical characteristics of the flow [1]. Previous open jet numerical simulations have examined the possibility of an existing direct analogy of the deposition form to the form of jet lines-geometry for corresponding pressure values in the reactor device. The present preliminary study shows the feasibility of flow coupled to plasma-excitation simulation calculations. The process simulated here is most probably well away from the equilibrium state.","PeriodicalId":183819,"journal":{"name":"NAFEMS International Journal of CFD Case Studies","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131076763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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