Role of entropy generation minimization in thermal optimization  

作　　者：程雪涛 梁新刚 

机构地区：[1]Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, School of Aerospace, Tsinghua University, Beijing 100084, China [2]The Administrative Committee of the Modern Industrial Park, New District of Zhengpu Port, Maanshan 238261, China

出　　处：《Chinese Physics B》2017年第12期160-166,共7页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.51376101);the National Natural Science Fund for Creative Research Groups,China(Grant No.51621062)

摘　　要：Thermal optimization is very important for improving the performances of thermal systems. In engineering, the entropy generation minimization （EGM） has been widely used to optimize and evaluate the performances of thermal systems. However, the consistency between the EGM and the optimization objective should be specified when the EGM is used. In this paper, we discuss the view angle of irreversibility of entropy generation, and show that entropy generation directly reflects the exergy destruction or the ability loss of doing work. As the design objective in a thermal system is not often consistent with the view angle of irreversibility of entropy generation, the EGM may not lead to the optimal value of the design objective. In heat transfer and heat-work conversion, the inconsistence between the design objectives and the EGM is shown with some examples, and the applicability of the EGM is found to be conditional. The “entropy generation paradox” in heat exchanger analyses is also discussed, and it is shown that there is no direct monotonic relation between the minimum entropy generation rate and the best heat transfer performance of heat exchangers.Thermal optimization is very important for improving the performances of thermal systems. In engineering, the entropy generation minimization （EGM） has been widely used to optimize and evaluate the performances of thermal systems. However, the consistency between the EGM and the optimization objective should be specified when the EGM is used. In this paper, we discuss the view angle of irreversibility of entropy generation, and show that entropy generation directly reflects the exergy destruction or the ability loss of doing work. As the design objective in a thermal system is not often consistent with the view angle of irreversibility of entropy generation, the EGM may not lead to the optimal value of the design objective. In heat transfer and heat-work conversion, the inconsistence between the design objectives and the EGM is shown with some examples, and the applicability of the EGM is found to be conditional. The “entropy generation paradox” in heat exchanger analyses is also discussed, and it is shown that there is no direct monotonic relation between the minimum entropy generation rate and the best heat transfer performance of heat exchangers.

关 键 词：entropy generation thermal analysis heat transfer heat-work conversion 

分 类 号：O414.1[理学—理论物理]