基于(火积)守恒方程的可逆热力循环(火积)分析及其应用  

Entransy analysis of reversible thermodynamic cycles based on the conservation of entransy equation and its application

作　　者：过增元[1] 赵甜[1] 薛提微 Zengyuan Guo;Tian Zhao;Tiwei Xue(Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Engineering Mechanics,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学工程力学系热科学与动力工程教育部重点实验室,北京100084

出　　处：《科学通报》2019年第11期1200-1210,共11页Chinese Science Bulletin

基　　金：国家自然科学基金变革性重大项目(51356001);国家自然科学基金创新研究群体科学基金(51621062)资助

摘　　要：将(火积)分析应用于热力循环性能的分析和优化中.首先在可逆热力过程和热力循环的分析中提出了热(火积)流和功热(火积)流的概念,并建立了相应的(火积)守恒方程.其次通过对可逆热机热泵联合循环中(火积)守恒的分析表明,与通常的热泵循环不同,热机-热泵联合循环的功能类似于电学中的变压器(电压变换器),因此可把此类联合循环称之为变温器或温度变换器.此外,取决于联合循环热源的温度,在某些条件下联合循环必须向环境输出功热(火积)流,从而降低联合循环的性能;而在另外一些条件下则可以从环境吸收功热(火积)流,从而提高联合循环的性能.最后,基于热质理论指出了热(火积)实际上是热质能的简化表达式,因而热(火积)流和功热(火积)流则分别是热质能流和功热质能流的简化表达式,它们实际上都是相对性能量.因此,类似于电压变换器中电能与磁能满足能量守恒定律,热机热泵联合循环中不仅热量和功量满足能量守恒定律,热(火积)流和功热(火积)流还满足相对性能量守恒定律,从而(火积)分析方法可用于分析可逆热力循环的性能,而熵分析及?分析方法则无法分析可逆热力循环的性能.最后,本文以两种典型的热机-热泵联合循环为例分析了联合循环的性能评价方法.Entropy analyses and entropy generation analyses have been widely used to analyze and optimize thermal processes. For instance, the entropy generation minimization principle has been used to optimize heat transfer processes, heat transfer systems and thermodynamic cycles. However, some studies have reported that the entropy generation minimization principle cannot derive the optimal results for pure heat transfer processes and heat transfer systems without heat-work conversion processes. The concept of entransy and the principle of the least entransy dissipation-based thermal resistance were proposed for these problems, and they have been widely applied to optimize pure heat transfer processes and systems. Besides, the concept of work entransy was developed for irreversible thermodynamic cycles involving heat-work conversion processes, and it is defined as the product of the work and the temperature. This concept was then used as the entransy analysis approach to optimize thermodynamic cycles. However, previous studies applying the work entransy concept mainly focused on(1) the relation between the work entransy loss and the endoreversible thermodynamic cycle efficiency, and(2) the optimization of practical thermodynamic cycles involving irreversible processes. There have been few such studies of reversible thermodynamic cycles or combined cycles. This article analyzes reversible thermodynamic cycles and combined thermodynamic cycles using the entransy analysis method with a derivation of the conservation of entransy equation. First, the entransy conservation equation for a reversible thermodynamic process is derived, which introduces the concept of heat entransy and heat-work entransy flow. They are both process dependent physical quantities. The corresponding entransy conservation equation is then derived for a reversible thermodynamic cycle. The equation shows that there are two different conservation equations for reversible thermodynamic cycles, i.e. the energy conservation equation(1 st law of thermodynamic

关 键 词：热力循环 [火积]分析 热机-热泵联合循环 热质理论 

分 类 号：TK123[动力工程及工程热物理—工程热物理]