强化对流换热中的热量加权温差分析与应用  

Analysis on the performance of convective heat transfer using temperature difference weighted with heat transfer capacity

作　　者：梁鑫 胡院林 王文[1] 陈熹挺 

机构地区：[1]上海交通大学制冷与低温研究所,上海200240

出　　处：《科学通报》2017年第25期2977-2987,共11页Chinese Science Bulletin

摘　　要：以电子器件对流散热为背景,提出热量加权温差综合评价传热量一定的多热源的平均温度和传热系统的传热效率.通过分析对流传热中控制体内"(火积)"的构成,结合变分原理推导了对流换热中的热量加权温差,讨论了温差均匀性、传热效率以及热量加权温差三者的关系,即热量加权温差越小,传热系统温差均匀程度越高;另外,从热量加权温差减小的方向来优化传热,设计一种开缝与翻折相结合的散热翅片,计算开缝和多翻折翅片与常规直翅片的热量加权温差大小,并用热量加权温差分析两种传热系统的多热源平均温度大小和温差均匀程度高低的原因,结果表明:传热系统的热量加权温差越小,冷却多热源物体平均温度效果越好.即对流换热总传热量一定时,热量加权温差可评价对流换热的传热效率和温差均匀性.For electronic systems cooling analysis,it is incomprehensive to evaluate heat transfer performance only by one parameter,such as heat transfer coefficient,heat transfer area,heat transfer temperature difference and so on,especially for the multidimensional heat transfer problems.The parameter,temperature difference weighted with heat transfer capacity（TDW）,is proposed to evaluate the heat transfer performance and the mean junction temperature of cooling systems with multiple heat source under the fixed heat flux.The weighted residual approach is employed to analyze the heat potential capacity transfer process in control volume of convection,then the variational principle is used as well to deduce the TDW,which could be used to optimize heat transfer performance in electronic systems cooling and reveal the relationship between temperature difference uniformity and heat transfer performance.Moreover,heat transfer performance could be improved by decreasing the TDW or improving the uniformity of temperature difference in cooling multiple heat sources.According to the theoretical analysis,the lower the TDW,which means the lower the thermal resistance,that is,the convection heat transfer is enhanced and heat transfer efficiency is improved.In order to validate the proposed theory,a new heat sink with slotted and folded fins is presented for the sake of obtaining lower value of the TDW.CFD simulations was conducted to validate the theory with the new heat sink.Simulation results indicate that both the mean junction temperature of heat sources and the TDW of the new designed heat sink with slotted and folded fins are lower than those of conventional heat sinks,so a lower TDW can be used to represent to the higher uniformity of temperature differences.Combined with theoretical calculation and CFD simulation,it could be concluded that for the fixed heat flux,if the TDW is low,uniformity of temperature differences will be high,and the mean junction temperature of heat source will be low as well,the efficiency of heat

关 键 词：对流换热 (火积) 热量加权温差 传热优化 

分 类 号：TK124[动力工程及工程热物理—工程热物理]