非准静态过程体积功的定义及计算问题

Investigation of Volume Work for Non Quasi-static Process

体积功是热力学中的一个重要概念,是体系膨胀或被压缩时体系与环境之间能量交换的一种形式。对于非准静态过程体积功的计算方法有不同的观点。根据动能定律进行推导、分析,提出体系被压缩时,体系得到的体积功应以系统压力定义和计算,而对于膨胀过程,体积功应按外界压力定义和计算。

The definition of pressure-volume work in irreversible thermodynamic process remains a contentious topic. There were two approaches in use to define pressure-volume works w. One is ＂surroundings-based＂ definition, which defined work by using the pressure of surroundings, the other ＂system-based＂ definition, which define work by using pressure of System. Different from above, from the work-energy theorem, a conclusion from our analysis was that ＂system-based＂ definition should be taken for compression work in non quasi-static process, while ＂surroundings-based＂ definition for expansion work.