积与积减原理

文章分析了重力势能、引力势能、电荷势能、化学势能、热量势能、质量积、动量积等多种势能,发现它们均可表达为一种守恒广延量和对应的强度量的乘积,因此可将其统一定义为"积".基于积这一概念,文章得到了孤立系统内守恒广延量传递过程的积减原理,即孤立系统内进行的守恒广延量传递过程中系统的积总是减小的.进一步,文章还基于积的概念发展了孤立系统和封闭系统的势平衡判据,发现孤立系统达到势平衡状态时,系统的积达到最小值(最小积原理);当封闭系统达到势平衡状态时,系统的准自由积达到最小值(最小准自由积原理).上述结论应用于传热学中即可得到热量传递过程的(火积)减原理及相应的热平衡判据.与热力学中的核心概念熵相对应,由于物理量(火积)可以描述传热过程的不可逆性,作为传热过程的优化准则,度量系统的无序度,并给出系统的热平衡判据,因此(火积)是传热学中的核心概念. 关键词： 势能 积 积减原理 平衡判据

Potential entransy and potential entransy decrease principle

In this paper, we analyze some kinds of potential energies, such as the geopotential energy, the electrostatic potential energy, the chemical potential energy, the mass entransy and so on. It is found that they all can be expressed as the product of a conservative extensive quantity and an intensity quantity. This kind of potential energy is named potential entransy. Based on the concept of potential entransy, the potential entransy decrease principle is developed. It is found that the potential entransy of an isolated system always decreases when the extensive quantity is transferred in the system. Furthermore, the criteria of equilibrium state for an isolated system and a common closed system are derived on the basis of the concept of potential entransy. It is found that when an isolated system reaches its equilibrium state, its potential entransy is a minimum value. When a common closed system reaches its equilibrium state, its quasi-free potential entransy is also a minimum value. In addition, when a closed system with prescribed potential is in its equilibrium state, its free potential entransy is also a minimum value. When the principles above are used in heat transfer, the entransy decrease principle for heat transfer and the thermal equilibrium criteria can be developed. We think that the new physical quantity, entransy in heat transfer, is the core concept of the subject, because it can be used to describe the irreversibility of heat transfer, optimize heat transfer processes, measure the disorder degree of one system, and set up the thermal equilibrium criteria.