论焓的物理意义

尽管焓在自然科学、工程热物理和热能工程中是使用十分广泛的物理参量,但其物理意义却是不够清楚的。本文首先评价了已有的一些关于焓的物理意义的论点,然后论述并发挥了作者以前论述过的焓中的pv是在压力场为定常时,流体微团在其迹线上的压力势能的观点。为此,需涉及到体系的势能与外力场对体系作功的关系,以及流体微元体在流场中运动时,流场对此微元体的作功关系的定量概念。通过以上论述,以期对探讨焓的物理意义有所帮助。

On the Physical Meaning of Enthalpy

Although the physical quantity of enthalpy is used frequently in natural sciences and technical sciences, its physical meaning is ambiguous for quite a long time. In this paper, the author treats of the mistakes concerning this concept in the thermodynamics texts and references and points out that the physical meaning of pv is the potential energy of pressure along the path lines in the flowfield when the field of pressure is steady(namely). Also, this physical meaning of enthalpy is suitable for closed system under the condition of quasi-static process with constant pressure.