The geometry of a heat generating volume cooled by forced convection is optimized by applying the entransy dissipation extremum principle and constructal theory, while the optimal spacing between the adjacent tubes an...The geometry of a heat generating volume cooled by forced convection is optimized by applying the entransy dissipation extremum principle and constructal theory, while the optimal spacing between the adjacent tubes and the optimal diameter of each tube are obtained based on entransy dissipation rate minimization. The results of this work show that the optimal constructs based on entransy dissipation rate minimization and maximum temperature difference minimization, respectively, are clearly different. For the former, the porosity of the volume of channels allocated to the heat generating volume is 1/2; while for the latter, the larger the porosity is, the better the performance will be. The optimal construct of the former greatly decreases the mean thermal resistance and improves the global heat transfer performance of the system compared with the optimal construct of the latter. This is identical to the essential requirement of the entransy dissipation extremum principle that the required heat transfer temperature difference is minimal with the same heat transfer rate (the given amount of heat generated in the heat generating volume) based on the entransy dissipation extremum principle.展开更多
This paper investigates the heat transfer characteristics of a thermoelectric generator. The influence of heat dissipation intensity to the sub-thermal resistances distribution is experimentally studied. Based on the ...This paper investigates the heat transfer characteristics of a thermoelectric generator. The influence of heat dissipation intensity to the sub-thermal resistances distribution is experimentally studied. Based on the thermal network analysis and finite time thermodynamics, an analytical model including all thermal resistances (in both thermocouples and external heat exchangers) is developed to predict the performance of the generator. The results show that the computed values of output power agree well with the experimental values. The heat transfer enhancement on the generator cold side greatly reduces the cold side temperature and thermal resistance, and obviously improves the output power. Compare with air natural convection cooling, the main thermal resistance changes from the resistance between the fins and the ambient to the thermal contact resistances between the generator and the heat sink at the conditions of forced convection and water cooling. This study may be guide the optimization of generator structure.展开更多
We prove the convergence of an adaptive mixed finite element method(AMFEM) for(nonsymmetric) convection-diffusion-reaction equations. The convergence result holds for the cases where convection or reaction is not pres...We prove the convergence of an adaptive mixed finite element method(AMFEM) for(nonsymmetric) convection-diffusion-reaction equations. The convergence result holds for the cases where convection or reaction is not present in convection- or reaction-dominated problems. A novel technique of analysis is developed by using the superconvergence of the scalar displacement variable instead of the quasi-orthogonality for the stress and displacement variables, and without marking the oscillation dependent on discrete solutions and data. We show that AMFEM is a contraction of the error of the stress and displacement variables plus some quantity. Numerical experiments confirm the theoretical results.展开更多
TN242 2001053142表面对流冷却下非稳腔激光窗口温升分布的计算=Temperature increment distribution of laser unstable cavity window for convectivc cooling Systems[刊,中]/杜少军,陆启生,赵伊君,刘泽金(国防科技大学应用物理系.湖...TN242 2001053142表面对流冷却下非稳腔激光窗口温升分布的计算=Temperature increment distribution of laser unstable cavity window for convectivc cooling Systems[刊,中]/杜少军,陆启生,赵伊君,刘泽金(国防科技大学应用物理系.湖南,长沙(410073))//强激光与粒子束.—2000,12(1).—23-展开更多
基金supported by the National Natural Science Foundation of China (10905093)the Program for New Century Excellent Talents in University of China (NCET-04-1006)the Foundation for Authors of National Excellent Doctoral Dissertations of China (200136)
文摘The geometry of a heat generating volume cooled by forced convection is optimized by applying the entransy dissipation extremum principle and constructal theory, while the optimal spacing between the adjacent tubes and the optimal diameter of each tube are obtained based on entransy dissipation rate minimization. The results of this work show that the optimal constructs based on entransy dissipation rate minimization and maximum temperature difference minimization, respectively, are clearly different. For the former, the porosity of the volume of channels allocated to the heat generating volume is 1/2; while for the latter, the larger the porosity is, the better the performance will be. The optimal construct of the former greatly decreases the mean thermal resistance and improves the global heat transfer performance of the system compared with the optimal construct of the latter. This is identical to the essential requirement of the entransy dissipation extremum principle that the required heat transfer temperature difference is minimal with the same heat transfer rate (the given amount of heat generated in the heat generating volume) based on the entransy dissipation extremum principle.
基金supported by The Major Technology Special Program of Guangdong Province(Grant No.2008A080302002 and 2010A080405003)
文摘This paper investigates the heat transfer characteristics of a thermoelectric generator. The influence of heat dissipation intensity to the sub-thermal resistances distribution is experimentally studied. Based on the thermal network analysis and finite time thermodynamics, an analytical model including all thermal resistances (in both thermocouples and external heat exchangers) is developed to predict the performance of the generator. The results show that the computed values of output power agree well with the experimental values. The heat transfer enhancement on the generator cold side greatly reduces the cold side temperature and thermal resistance, and obviously improves the output power. Compare with air natural convection cooling, the main thermal resistance changes from the resistance between the fins and the ambient to the thermal contact resistances between the generator and the heat sink at the conditions of forced convection and water cooling. This study may be guide the optimization of generator structure.
基金supported by Education Science Foundation of Chongqing(Grant No.KJ120420)National Natural Science Foundation of China(Grant No.11171239)+1 种基金Major Research Plan of National Natural Science Foundation of China(Grant No.91430105)Open Fund of Key Laboratory of Mountain Hazards and Earth Surface Processes,Chinese Academy Sciences
文摘We prove the convergence of an adaptive mixed finite element method(AMFEM) for(nonsymmetric) convection-diffusion-reaction equations. The convergence result holds for the cases where convection or reaction is not present in convection- or reaction-dominated problems. A novel technique of analysis is developed by using the superconvergence of the scalar displacement variable instead of the quasi-orthogonality for the stress and displacement variables, and without marking the oscillation dependent on discrete solutions and data. We show that AMFEM is a contraction of the error of the stress and displacement variables plus some quantity. Numerical experiments confirm the theoretical results.
文摘TN242 2001053142表面对流冷却下非稳腔激光窗口温升分布的计算=Temperature increment distribution of laser unstable cavity window for convectivc cooling Systems[刊,中]/杜少军,陆启生,赵伊君,刘泽金(国防科技大学应用物理系.湖南,长沙(410073))//强激光与粒子束.—2000,12(1).—23-
