Pub Date : 2012-09-26DOI: 10.1615/COMPUTTHERMALSCIEN.2012004748
Jia Feng, C. Tseng, Chiun-Hsun Chen
{"title":"A numerical analysis of power efficiency of wind rotor systems in a parallel matrix","authors":"Jia Feng, C. Tseng, Chiun-Hsun Chen","doi":"10.1615/COMPUTTHERMALSCIEN.2012004748","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012004748","url":null,"abstract":"","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2012-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67418802","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 : 2012-07-03DOI: 10.1615/COMPUTTHERMALSCIEN.2012005093
K. Horikiri, Yufeng Yao, J. Yao
Numerical simulation of airflow in an indoor environment has been carried out for forced, natural, and mixed convection modes, respectively, by using the computational fluid dynamics (CFD) approach of solving the Reynolds-averaged Navier−Stokes equations. Three empty model rooms in two-dimensional configuration were studied first; focusing on the effects of grid refinement, mesh topology, and turbulence model. It was found that structured mesh results were in better agreement with available experimental measurements for all three convection scenarios, while the renormalized group (RNG) к − e turbulence model produced better results for both forced and mixed convections and the shear stress transport (SST) turbulence model for the natural convection prediction. Further studies of air velocity and temperature distributions in a three-dimensional cubic model room with and without an obstacle have shown reasonably good agreement with available test data at the measuring points. CFD results exhibited some unsteady flow phenomena that have not yet been observed or reported in previous experimental studies for the same problem. After analyzing the time history of velocity and temperature data using fast Fourier transformation (FFT), it was found that both air velocity and temperature field oscillated at low frequencies up to 0.4 Hz and the most significant velocity oscillations occurred at a vertical height of an ankle level (0.1 m) from the floor, where temperature oscillation was insignificant. The reasons for this flow unsteadiness were possibly a higher Grashof number, estimated at 0.5 × 106 based inflow conditions, and thus strong buoyancy driven effects caused the oscillations in the flow field. The appearance of an obstacle in the room induced flow separation at its sharp edges and this would further enhance the oscillations due to the unsteady nature of detached shear-layer flow.
{"title":"NUMERICAL STUDY OF UNSTEADY AIRFLOW PHENOMENA IN A VENTILATED ROOM","authors":"K. Horikiri, Yufeng Yao, J. Yao","doi":"10.1615/COMPUTTHERMALSCIEN.2012005093","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012005093","url":null,"abstract":"Numerical simulation of airflow in an indoor environment has been carried out for forced, natural, and mixed convection modes, respectively, by using the computational fluid dynamics (CFD) approach of solving the Reynolds-averaged Navier−Stokes equations. Three empty model rooms in two-dimensional configuration were studied first; focusing on the effects of grid refinement, mesh topology, and turbulence model. It was found that structured mesh results were in better agreement with available experimental measurements for all three convection scenarios, while the renormalized group (RNG) к − e turbulence model produced better results for both forced and mixed convections and the shear stress transport (SST) turbulence model for the natural convection prediction. Further studies of air velocity and temperature distributions in a three-dimensional cubic model room with and without an obstacle have shown reasonably good agreement with available test data at the measuring points. CFD results exhibited some unsteady flow phenomena that have not yet been observed or reported in previous experimental studies for the same problem. After analyzing the time history of velocity and temperature data using fast Fourier transformation (FFT), it was found that both air velocity and temperature field oscillated at low frequencies up to 0.4 Hz and the most significant velocity oscillations occurred at a vertical height of an ankle level (0.1 m) from the floor, where temperature oscillation was insignificant. The reasons for this flow unsteadiness were possibly a higher Grashof number, estimated at 0.5 × 106 based inflow conditions, and thus strong buoyancy driven effects caused the oscillations in the flow field. The appearance of an obstacle in the room induced flow separation at its sharp edges and this would further enhance the oscillations due to the unsteady nature of detached shear-layer flow.","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2012-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67418893","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 : 2012-06-20DOI: 10.1615/COMPUTTHERMALSCIEN.2012003941
T. Fiedler, I. Belova, A. Öchsner, G. Murch
The current paper aims to simulate combined mass diffusion and chemical reaction. Two solid reactants are brought into contact and the product is formed at the interface. Chemical reaction is assumed to occur instantaneously, thus the reaction rate is limited only by the interdiffusion of the two solid constituents. First, parametric studies for a range of constant diffusivities are performed and simple relations for the growth of the product phase are obtained. It is found that the thickness of the product layer increases proportionally to the square root of the product of diffusivity and time. In the second part of the analyses the formation of NiAl by interdiffusion of nickel and aluminum is simulated. This self-propagating exothermic reaction is of great interest for joining temperature-sensitive components. Within the limits of these calculations, the concentration dependence of the diffusion coefficients of nickel and aluminum is considered in order to improve the accuracy of the simulation.
{"title":"A LATTICE MONTE CARLO ANALYSIS ON CHEMICAL REACTION WITH MOVING BOUNDARY","authors":"T. Fiedler, I. Belova, A. Öchsner, G. Murch","doi":"10.1615/COMPUTTHERMALSCIEN.2012003941","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012003941","url":null,"abstract":"The current paper aims to simulate combined mass diffusion and chemical reaction. Two solid reactants are brought into contact and the product is formed at the interface. Chemical reaction is assumed to occur instantaneously, thus the reaction rate is limited only by the interdiffusion of the two solid constituents. First, parametric studies for a range of constant diffusivities are performed and simple relations for the growth of the product phase are obtained. It is found that the thickness of the product layer increases proportionally to the square root of the product of diffusivity and time. In the second part of the analyses the formation of NiAl by interdiffusion of nickel and aluminum is simulated. This self-propagating exothermic reaction is of great interest for joining temperature-sensitive components. Within the limits of these calculations, the concentration dependence of the diffusion coefficients of nickel and aluminum is considered in order to improve the accuracy of the simulation.","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2012-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67418480","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.2012004715
M. Yamakawa, Daiki Takekawa, K. Matsuno, S. Asao
{"title":"NUMERICAL SIMULATION FOR A FLOW AROUND BODY EJECTION USING AN AXISYMMETRIC UNSTRUCTURED MOVING GRID METHOD","authors":"M. Yamakawa, Daiki Takekawa, K. Matsuno, S. Asao","doi":"10.1615/COMPUTTHERMALSCIEN.2012004715","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012004715","url":null,"abstract":"","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1615/COMPUTTHERMALSCIEN.2012004715","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67418692","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.2012006423
Dean Vijay K. Dhir, G. Warrier, Eduardo Aktinol
{"title":"BUBBLE DYNAMICS DURING POOL BOILING UNDER MICROGRAVITY CONDITIONS","authors":"Dean Vijay K. Dhir, G. Warrier, Eduardo Aktinol","doi":"10.1615/COMPUTTHERMALSCIEN.2012006423","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012006423","url":null,"abstract":"","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67419255","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.2012005345
F. Al-Malki
{"title":"NUMERICAL STUDY OF THE EFFECT OF HEAT LOSS ON TRIPLE FLAME PROPAGATION IN A POROUS WALLS CHANNEL","authors":"F. Al-Malki","doi":"10.1615/COMPUTTHERMALSCIEN.2012005345","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012005345","url":null,"abstract":"","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67419348","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.2012005792
K. Suga, M. Shibahara
This special section consists of selected papers from the third Asian Symposium on Computational Heat Transfer and Fluid Flow (ASCHT-11) chaired by Prof. Hiroshi Kawamura of Tokyo University of Science, Suwa, held from 22 to 26 September, 2011 in Kyoto, Japan. As the two preceding symposia in Xi’an, China (2007) and Jeju, Korea (2009), the ASCHT-11 successfully attracted 169 delegates from a wide variety of countries: China, India, Iraq, Japan, Korea, Russia, Taiwan and UK (in alphabetical order). The ASCHT-11 was mainly operated by Heat Transfer Society of Japan, as one of her 50th anniversary events, and was held in cooperation with the International
{"title":"PREFACE: ASIAN SYMPOSIUM ON COMPUTATIONAL HEAT TRANSFER AND FLUID FLOW-2011 (ASCHT-11)","authors":"K. Suga, M. Shibahara","doi":"10.1615/COMPUTTHERMALSCIEN.2012005792","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012005792","url":null,"abstract":"This special section consists of selected papers from the third Asian Symposium on Computational Heat Transfer and Fluid Flow (ASCHT-11) chaired by Prof. Hiroshi Kawamura of Tokyo University of Science, Suwa, held from 22 to 26 September, 2011 in Kyoto, Japan. As the two preceding symposia in Xi’an, China (2007) and Jeju, Korea (2009), the ASCHT-11 successfully attracted 169 delegates from a wide variety of countries: China, India, Iraq, Japan, Korea, Russia, Taiwan and UK (in alphabetical order). The ASCHT-11 was mainly operated by Heat Transfer Society of Japan, as one of her 50th anniversary events, and was held in cooperation with the International","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1615/COMPUTTHERMALSCIEN.2012005792","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67419410","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.2012004213
A. Rout, A. Satapathy
{"title":"COMPUTATIONAL AND EXPERIMENTAL INVESTIGATION ON THERMAL INSULATION CAPABILITIES OF RICE-HUSK FILLED EPOXY COMPOSITES","authors":"A. Rout, A. Satapathy","doi":"10.1615/COMPUTTHERMALSCIEN.2012004213","DOIUrl":"https://doi.org/10.1615/COMPUTTHERMALSCIEN.2012004213","url":null,"abstract":"","PeriodicalId":45052,"journal":{"name":"Computational Thermal Sciences","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1615/COMPUTTHERMALSCIEN.2012004213","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67418596","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.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":null,"pages":null},"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}
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