能造出功率和效率都高的热机吗?——有限时间热力学的发展与展望

Can we build a heat engine with both high power and high efficiency?——The development and prospects of finite-time thermodynamics

在热力学中,功率和效率是衡量热机性能的两个主要参数。根据经典热力学,可逆热机效率的上限是卡诺效率,但相应的功率为零。这是因为卡诺效率的实现依赖于时间无穷长的准静态假设。因此,如何根据实际需求,在保证热机功率前提下提高热机效率成为热力学一个重要的科学挑战问题。在20世纪上半叶应运而生的有限时间热力学,今天得到了蓬勃发展,为应对这个挑战提供了必要的科学支撑。文章主要介绍有限时间热力学的发展及现状,特别是最近对于有限时间热机功率效率约束关系及其优化问题上的研究。针对有限时间热力学循环功率—效率约束与不可逆性的关系,文章还简介最近作者关于有限时间等温过程中不可逆熵产生的理论和实验研究工作。最后展望未来有限时间热力学及有限系统非平衡物理的可能发展与应用。

Efficiency and power are the two main parameters to evaluate the performance of heat engines.The Carnot efficiency is the upper limit in the efficiency of a reversible heat engine.Due to the requirement of infinite operation time in quasi-static processes,the output power of a reversible heat engine approaches zero,with no practical value.Therefore,how to improve the efficiency of a heat engine while maintaining its power for practical purposes is an important scientific challenge in thermodynamics.Finite time thermodynamics,born in the first half of the last century,is developing rapidly to provide the necessary scientific support for this challenge.This paper sketches the early development and present status of finite-time thermodynamics,focusing on current investigations on the power—efficiency trade-off relation for finite-time heat engines.To explore the relation between this trade-off and the irreversibility of finite-time thermodynamic cycles,we introduce our recent theoretical and experimental studies on the irreversible entropy generation in finite-time isothermal processes.Possible future trends and applications of finite-time thermodynamics and the non-equilibrium physics of finite systems are also previewed.