Pub Date : 2012-01-01DOI: 10.1615/COMPUTTHERMALSCIEN.2012006084
T. Walker, S. Xue, G. Barton
{"title":"A robust Monte Carlo based ray-tracing approach for the calculation of view factors in arbitrary three-dimensional geometries","authors":"T. Walker, S. Xue, G. Barton","doi":"10.1615/COMPUTTHERMALSCIEN.2012006084","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012006084","url":null,"abstract":"","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":"56 1","pages":"425-442"},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1615/COMPUTTHERMALSCIEN.2012006084","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67418964","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}
Pub Date : 2012-01-01DOI: 10.1615/COMPUTTHERMALSCIEN.2012005118
L. Soucasse, P. Riviere, S. Xin, P. Quéré, A. Soufiani
The coupling between natural convection and gas and wall radiation is studied numerically in a differentially heated cubical cavity filled with an air/CO2/H2O mixture. In order to solve coupled flow, heat transfer, and radiation equations, we develop a 3D radiative transfer model based on the deterministic ray tracing method, coupled with a pseudo-spectral Chebyshev method for natural convection under Boussinesq approximation. An absorption distribution function (ADF) model is used to describe gas radiative properties. Coupled simulations are performed at Ra = 105, 106, and 3 × 107, considering wall and/or gas radiation. Steady solutions were obtained except at the highest Rayleigh number in the case of radiating walls. Results show a strong influence of radiative transfer on temperature and velocity fields. The global homogenization of the temperature field induced by radiation leads to a decrease of the thermal stratification parameter. Two different mechanisms leading to this behavior, involving either wall/wall or gas radiative exchanges, are identified. In addition, we observe a thickening of the vertical boundary layers and an increase of the global circulation in the cavity. The influence of the Rayleigh number and 3D effects are also discussed.
{"title":"NUMERICAL STUDY OF COUPLED MOLECULAR GAS RADIATION AND NATURAL CONVECTION IN A DIFFERENTIALLY HEATED CUBICAL CAVITY","authors":"L. Soucasse, P. Riviere, S. Xin, P. Quéré, A. Soufiani","doi":"10.1615/COMPUTTHERMALSCIEN.2012005118","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012005118","url":null,"abstract":"The coupling between natural convection and gas and wall radiation is studied numerically in a differentially heated cubical cavity filled with an air/CO2/H2O mixture. In order to solve coupled flow, heat transfer, and radiation equations, we develop a 3D radiative transfer model based on the deterministic ray tracing method, coupled with a pseudo-spectral Chebyshev method for natural convection under Boussinesq approximation. An absorption distribution function (ADF) model is used to describe gas radiative properties. Coupled simulations are performed at Ra = 105, 106, and 3 × 107, considering wall and/or gas radiation. Steady solutions were obtained except at the highest Rayleigh number in the case of radiating walls. Results show a strong influence of radiative transfer on temperature and velocity fields. The global homogenization of the temperature field induced by radiation leads to a decrease of the thermal stratification parameter. Two different mechanisms leading to this behavior, involving either wall/wall or gas radiative exchanges, are identified. In addition, we observe a thickening of the vertical boundary layers and an increase of the global circulation in the cavity. The influence of the Rayleigh number and 3D effects are also discussed.","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":"4 1","pages":"335-350"},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67419172","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}
Pub Date : 2012-01-01DOI: 10.1615/COMPUTTHERMALSCIEN.2012006430
D. Spalding
{"title":"A ROLE FOR COMPUTATIONAL HEAT TRANSFER (CHT) IN ENGINEERING EDUCATION","authors":"D. Spalding","doi":"10.1615/COMPUTTHERMALSCIEN.2012006430","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012006430","url":null,"abstract":"","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":"4 1","pages":"477-484"},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1615/COMPUTTHERMALSCIEN.2012006430","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67419268","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}
Pub Date : 2012-01-01DOI: 10.1615/COMPUTTHERMALSCIEN.2013006073
J. R. Marati, M. Budakli, T. Gambaryan-Roisman, P. Stephan
The objective of the study is to investigate hydrodynamics and heat transfer in a shear-driven liquid film flow. This process is relevant to fuel flow inside lean pre-mixed pre-vaporization (LPP) chambers. A combined numerical and experimental study has been performed to determine the heat transfer in gas-driven thin liquid films on the outer surface of vertical heated tubes. Numerical simulations have been performed using the volume of fluid (VOF) method implemented in an open source computational fluid dynamics (CFD) code OpenFOAM for turbulent air/water flow conditions. The code has been extended for simulation of two-phase flows with heat transfer. The Reynolds averaged Navier-Stokes equations (RANS) with the k - textgreeke turbulence model for gas-liquid two-phase flows have been solved using the finite volume method. The results on wall temperature distribution and average film thickness have been compared with experimental data. A reasonable agreement between the simulations and experiment has been found. The results indicate that the heat transfer is enhanced with increasing gas Reynolds number due to the film thinning and intensification of convection.
{"title":"HEAT TRANSFER IN SHEAR-DRIVEN THIN LIQUID FILM FLOWS","authors":"J. R. Marati, M. Budakli, T. Gambaryan-Roisman, P. Stephan","doi":"10.1615/COMPUTTHERMALSCIEN.2013006073","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2013006073","url":null,"abstract":"The objective of the study is to investigate hydrodynamics and heat transfer in a shear-driven liquid film flow. This process is relevant to fuel flow inside lean pre-mixed pre-vaporization (LPP) chambers. A combined numerical and experimental study has been performed to determine the heat transfer in gas-driven thin liquid films on the outer surface of vertical heated tubes. Numerical simulations have been performed using the volume of fluid (VOF) method implemented in an open source computational fluid dynamics (CFD) code OpenFOAM for turbulent air/water flow conditions. The code has been extended for simulation of two-phase flows with heat transfer. The Reynolds averaged Navier-Stokes equations (RANS) with the k - textgreeke turbulence model for gas-liquid two-phase flows have been solved using the finite volume method. The results on wall temperature distribution and average film thickness have been compared with experimental data. A reasonable agreement between the simulations and experiment has been found. The results indicate that the heat transfer is enhanced with increasing gas Reynolds number due to the film thinning and intensification of convection.","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":"5 1","pages":"303-315"},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67419380","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}
Pub Date : 2012-01-01DOI: 10.1615/COMPUTTHERMALSCIEN.2012003930
D. Chatterjee, B. Mondal
{"title":"ON THE VORTEX SHEDDING MECHANISM BEHIND A CIRCULAR CYLINDER SUBJECTED TO CROSS BUOYANCY AT LOW REYNOLDS NUMBERS","authors":"D. Chatterjee, B. Mondal","doi":"10.1615/COMPUTTHERMALSCIEN.2012003930","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012003930","url":null,"abstract":"","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":"4 1","pages":"23-38"},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67418457","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}
Pub Date : 2012-01-01DOI: 10.1615/COMPUTTHERMALSCIEN.2013006954
I. Egorov, N. Palchekovskaya, V. V. Shvedchenko
{"title":"INFLUENCE OF THREE-DIMENSIONAL PERTURBATIONS ON HEAT TRANSFER IN HYPERSONIC FLOW","authors":"I. Egorov, N. Palchekovskaya, V. V. Shvedchenko","doi":"10.1615/COMPUTTHERMALSCIEN.2013006954","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2013006954","url":null,"abstract":"","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":"5 1","pages":"83-95"},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67419576","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}
Pub Date : 2012-01-01DOI: 10.1615/COMPUTTHERMALSCIEN.2012003938
R. L. Corral-Bustamante, Aarón Raúl Rodríguez-Corral, T.J Amador-Parra, Eva Martinez-Loera, G. Irigoyen-Chávez
{"title":"MODELING OF VIRTUAL PARTICLES OF THE BIG BANG","authors":"R. L. Corral-Bustamante, Aarón Raúl Rodríguez-Corral, T.J Amador-Parra, Eva Martinez-Loera, G. Irigoyen-Chávez","doi":"10.1615/COMPUTTHERMALSCIEN.2012003938","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012003938","url":null,"abstract":"","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":"4 1","pages":"169-181"},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67418468","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}
Pub Date : 2012-01-01DOI: 10.1615/COMPUTTHERMALSCIEN.2012004010
Paulo Brito, L. Durães, A. Portugal
and composition dependency for all system properties during propagation. Therefore, an adaptive numerical algorithm that conjugates a method of lines (MOL) strategy based on finite differences space discretizations, with a collocation scheme based on increasing level dyadic grids is applied for the solution of the problem. The particular integration method proves to cope satisfactorily with the steep traveling thermal wave in 1D and 2D spatial domains, either for trivial uniform mixing conditions, as in complex examples developed to feature more sophisticated circumstances, such as nonhomogeneous reactant mixing, which realistically replicate the observed experimental conditions.
{"title":"1D AND 2D MODELING AND SIMULATION OF RADIAL COMBUSTION PROPAGATION ON Fe2O3/Al THERMITE SYSTEMS","authors":"Paulo Brito, L. Durães, A. Portugal","doi":"10.1615/COMPUTTHERMALSCIEN.2012004010","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012004010","url":null,"abstract":"and composition dependency for all system properties during propagation. Therefore, an adaptive numerical algorithm that conjugates a method of lines (MOL) strategy based on finite differences space discretizations, with a collocation scheme based on increasing level dyadic grids is applied for the solution of the problem. The particular integration method proves to cope satisfactorily with the steep traveling thermal wave in 1D and 2D spatial domains, either for trivial uniform mixing conditions, as in complex examples developed to feature more sophisticated circumstances, such as nonhomogeneous reactant mixing, which realistically replicate the observed experimental conditions.","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":"4 1","pages":"137-149"},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67418491","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}
Pub Date : 2012-01-01DOI: 10.1615/COMPUTTHERMALSCIEN.2012005125
L. Rocha, M. V. Real, A. Correia, J. Vaz, E. D. Santos, L. Isoldi
Preface Special Issue on Fluid Flow: Analysis and Numerics 10.1615/ComputThermalScien.2012005125 DOI: Article price $35.00 GEOMETRIC OPTIMIZATION BASED ON THE CONSTRUCTAL DESIGN OF PERFORATED THIN PLATES SUBJECT TO BUCKLING Luiz Alberto O. Rocha Departamento de Engenharia Mecânica, Luiz Alberto Oliveira Rocha, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 425, CEO 90050-170, Porto Alegre, Rio Grande do Sul, Brazil M. V. Real Programa de Pos-Graduacão em Engenharia Oceânica (PPGEO), Escola de Engenharia (EE), Universidade Federal do Rio Grande (FURG), Rio Grande do Sul, Brazil A. L. G. Correia Programa de Pos-Graduacão em Engenharia Oceânica (PPGEO), Escola de Engenharia (EE), Universidade Federal do Rio Grande (FURG), Rio Grande do Sul, Brazil J. Vaz Programa de Pos-Graduacão em Engenharia Oceânica (PPGEO), Escola de Engenharia (EE), Universidade Federal do Rio Grande (FURG), Rio Grande do Sul, Brazil E. D. dos Santos Programa de Pos-Graduacão em Engenharia Oceânica (PPGEO), Escola de Engenharia (EE), Universidade Federal do Rio Grande (FURG), Rio Grande do Sul, Brazil L. A. Isoldi Programa de Pos-Graduacão em Engenharia Oceânica (PPGEO), Escola de Engenharia (EE), Universidade Federal do Rio Grande (FURG), Rio Grande do Sul, Brazil ABSTRACT Elastic buckling is an instability phenomenon that can occur if a slender and thin-walled plate is subjected to axial compressive load. It is well known that the presence of holes in structural plate elements is almost inevitable in inspection, maintenance, and service purposes, or to reduce the structural weight. In this paper constructal design was employed to optimize the geometry of thin perforated plates submitted to elastic buckling. Simply supported rectangular perforated plates were analyzedElastic buckling is an instability phenomenon that can occur if a slender and thin-walled plate is subjected to axial compressive load. It is well known that the presence of holes in structural plate elements is almost inevitable in inspection, maintenance, and service purposes, or to reduce the structural weight. In this paper constructal design was employed to optimize the geometry of thin perforated plates submitted to elastic buckling. Simply supported rectangular perforated plates were analyzed with three different shapes of centered holes: elliptical, rectangular, and diamond. The purpose was to obtain the optimal geometry that maximizes the critical buckling load. The ratio between the height and length of the plate was kept constant, while the ratio between the characteristic dimensions of the holes was optimized for several hole volume fractions (φ). A finiteelement model was used to assess the plate buckling load, and the Lanczos method was applied to the solution of the corresponding eigenvalue problem. When φ ≤ 0.20 the optimum geometry is the diamond hole, reaching maximum buckling loads around 80.0,21.5, and 17.4% higher than a plate without perforation and plates with ellipti
{"title":"Geometric optimization based on the constructal design of perforated thin plates subject to buckling","authors":"L. Rocha, M. V. Real, A. Correia, J. Vaz, E. D. Santos, L. Isoldi","doi":"10.1615/COMPUTTHERMALSCIEN.2012005125","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012005125","url":null,"abstract":"Preface Special Issue on Fluid Flow: Analysis and Numerics 10.1615/ComputThermalScien.2012005125 DOI: Article price $35.00 GEOMETRIC OPTIMIZATION BASED ON THE CONSTRUCTAL DESIGN OF PERFORATED THIN PLATES SUBJECT TO BUCKLING Luiz Alberto O. Rocha Departamento de Engenharia Mecânica, Luiz Alberto Oliveira Rocha, Universidade Federal do Rio Grande do Sul (UFRGS), Rua Sarmento Leite, 425, CEO 90050-170, Porto Alegre, Rio Grande do Sul, Brazil M. V. Real Programa de Pos-Graduacão em Engenharia Oceânica (PPGEO), Escola de Engenharia (EE), Universidade Federal do Rio Grande (FURG), Rio Grande do Sul, Brazil A. L. G. Correia Programa de Pos-Graduacão em Engenharia Oceânica (PPGEO), Escola de Engenharia (EE), Universidade Federal do Rio Grande (FURG), Rio Grande do Sul, Brazil J. Vaz Programa de Pos-Graduacão em Engenharia Oceânica (PPGEO), Escola de Engenharia (EE), Universidade Federal do Rio Grande (FURG), Rio Grande do Sul, Brazil E. D. dos Santos Programa de Pos-Graduacão em Engenharia Oceânica (PPGEO), Escola de Engenharia (EE), Universidade Federal do Rio Grande (FURG), Rio Grande do Sul, Brazil L. A. Isoldi Programa de Pos-Graduacão em Engenharia Oceânica (PPGEO), Escola de Engenharia (EE), Universidade Federal do Rio Grande (FURG), Rio Grande do Sul, Brazil ABSTRACT Elastic buckling is an instability phenomenon that can occur if a slender and thin-walled plate is subjected to axial compressive load. It is well known that the presence of holes in structural plate elements is almost inevitable in inspection, maintenance, and service purposes, or to reduce the structural weight. In this paper constructal design was employed to optimize the geometry of thin perforated plates submitted to elastic buckling. Simply supported rectangular perforated plates were analyzedElastic buckling is an instability phenomenon that can occur if a slender and thin-walled plate is subjected to axial compressive load. It is well known that the presence of holes in structural plate elements is almost inevitable in inspection, maintenance, and service purposes, or to reduce the structural weight. In this paper constructal design was employed to optimize the geometry of thin perforated plates submitted to elastic buckling. Simply supported rectangular perforated plates were analyzed with three different shapes of centered holes: elliptical, rectangular, and diamond. The purpose was to obtain the optimal geometry that maximizes the critical buckling load. The ratio between the height and length of the plate was kept constant, while the ratio between the characteristic dimensions of the holes was optimized for several hole volume fractions (φ). A finiteelement model was used to assess the plate buckling load, and the Lanczos method was applied to the solution of the corresponding eigenvalue problem. When φ ≤ 0.20 the optimum geometry is the diamond hole, reaching maximum buckling loads around 80.0,21.5, and 17.4% higher than a plate without perforation and plates with ellipti","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":"52 1","pages":"119-129"},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1615/COMPUTTHERMALSCIEN.2012005125","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67419216","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}
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