有压气体做功能力热力学分析  

Thermodynamic Analysis for the Power Capability of Pressurized Gas

作　　者：吴腾马 柳建华[1] 徐小进[2] 刘旗[1] WU Teng-ma;LIU Jian-hua;XU Xiao-jin;LIU Qi(College of Power Engineering,University of Shanghai for Science Technology,Shanghai,China,Post Code 200093;NO.704 Research Institute,CSIC,Shanghai,China,Post Code 200031)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093 [2]中国船舶重工集团公司第七〇四研究所,上海200031

出　　处：《热能动力工程》2018年第8期15-19,98,共6页Journal of Engineering for Thermal Energy and Power

基　　金：上海市部分地方院校能力建设专项计划(16060502600);上海市教育委员会重点学科资助项目(J50502);上海市科委建设项目(13DZ2260900)~~

摘　　要：针对工质选择对热力循环系统效率有着重要影响等卡诺定理不能做出合理解释的问题,将工质吸热后的热力学能（火用）进一步划分为等熵膨胀（火用）与等压换热（火用）,指出可被动力设备直接利用的（火用）只有工质的等熵膨胀（火用）。理论推导表明：在等熵膨胀过程中,压缩气体的膨胀功并不能全部转化为有用功（火用）,气体膨胀功转化为有用功的效率取决于气体工质的内部压强和气体所处外部环境的压强。气体的内部压强越大、外部环境压强越小,气体膨胀功转化为有用功（火用）的效率越高。The selection of working fluid can influence the system efficiency of thermodynamic cycle, while the second law of thermodynamics falls short of directly providing a reasonable explanation to this phenomenon. In this paper, the exergy of gas after isochoric heat absorption process is divided into exergy in isentropic expansion and exergy in isobaric heat exchange. And it is pointed out that the exergy that can be used directly by power equipment is the exergy in isentropic expansion. By analyzing the thermodynam- ic cycle with air as working fluid, the results show that the expansion work in the pressurized gas cannot be converted to exergy entirely. The efficiency of the conversion depends on the air pressure and the ambient pressure. The higher air pressure and the lower ambient pressure, the higher conversion efficiency of the expansion work to exergy.

关 键 词：有压气体 热力学分析 等熵膨胀(火用) 等压换热[火用] 

分 类 号：TK123[动力工程及工程热物理—工程热物理]