基于耗散功的角度对热力学第二定律的教学探讨

Discussion on the Teaching of the Second Law of Thermodynamics fromthe Perspective of Dissipated Work

热力学第二定律的本质是自然界中自发实现的与热现象相关的过程都是不可逆的,而不可逆过程总伴随着能量“质”的下降。文章通过引入耗散功来描述一般封闭体系的热力学第二定律,这是从能量的角度而不是像通常那样基于熵的视角去描述热力学第二定律。作者推导了耗散功所满足的关系,再通过三个简单的例子来说明对于非准静态等温过程其耗散功大于零。这些结论将有助于学生更好地掌握热力学第二定律。

The essence of the second law of thermodynamics is that spontaneous processes related to thermal phenomena in nature are irreversible,and irreversible processes are always accompanied by a decrease in energy and quality.The article describes the second law of thermodynamics in general closed systems by introducing dissipated work,which is fromthe perspective of energy rather than entropy as usual.The author derived the relationship satisfied by the dissipated work,and then used three simple examples to illustrate that the dissipated work is greater than zero for non quasi-static isothermal processes.These conclusions will help students better grasp the second law of thermodynamics.