中国物理B ›› 2017, Vol. 26 ›› Issue (12): 120505-120505.doi: 10.1088/1674-1056/26/12/120505

• GENERAL • 上一篇    下一篇

Role of entropy generation minimization in thermal optimization

Xue-Tao Cheng(程雪涛), Xin-Gang Liang(梁新刚)   

  1. 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
  • 收稿日期:2017-08-03 修回日期:2017-08-31 出版日期:2017-12-05 发布日期:2017-12-05
  • 通讯作者: Xue-Tao Cheng E-mail:chengxt02@gmail.com
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 51376101) and the National Natural Science Fund for Creative Research Groups, China (Grant No. 51621062).

Role of entropy generation minimization in thermal optimization

Xue-Tao Cheng(程雪涛)1,2, Xin-Gang Liang(梁新刚)1   

  1. 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
  • Received:2017-08-03 Revised:2017-08-31 Online:2017-12-05 Published:2017-12-05
  • Contact: Xue-Tao Cheng E-mail:chengxt02@gmail.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 51376101) and 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.

关键词: entropy generation, thermal analysis, heat transfer, heat-work conversion

Abstract: 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.

Key words: entropy generation, thermal analysis, heat transfer, heat-work conversion

中图分类号:  (Nonequilibrium and irreversible thermodynamics)

  • 05.70.Ln
44.05.+e (Analytical and numerical techniques)