Quasilinear irreversible thermodynamics of a low-temperature-differential kinematic Stirling heat engine
Quasilinear irreversible thermodynamics of a low-temperature-differential kinematic Stirling heat engine
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低温差运动斯特林热机的准线性不可逆热力学
DOI：
10.1103/physreve.102.012142
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发表时间：
2020-07-21
影响因子：
2.4
通讯作者：
Izumida, Yuki
中科院分区：
文献类型：
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作者：
Izumida, Yuki
低温差斯特林热机（low-temperature -differential Stirling heat engine，简称low-temperature - difference，简称low-temperature - difference）能够在我们日常生活中存在的低温热源之间以很小的温差运行，因此被认为是一种重要的可持续能源技术。作者最近提出了一个有限运动学斯特林热机的非线性动力学模型，以研究发动机的旋转机理[Y]。Izumida Europhys。科学通报，2012,(5)[j]。本文介绍了该发动机模型的非平衡热力学分析，其中引入了发动机做功的负载扭矩。我们证明了发动机的旋转状态是在一个准线性响应区，其中热力学通量显示线性依赖于热力学力。重要的是，发现拟线性关系的响应系数是对称的，这类似于线性不可逆热力学中的Onsager对称。基于这些关系，我们推导出了发动机的最大效率。我们还阐明了拟线性响应系数的对称性，通过反映在平衡状态附近为发动机松弛动力学确定的Onsager动力学系数的（反）互易性而出现。我们期望本研究将为发展作为非线性动力系统的自主热机的非平衡热力学铺平道路。
Low-temperature-differential (LTD) Stirling heat engines are able to operate with a small temperature difference between low-temperature heat reservoirs that exist in our daily lives, and thus they are considered to be an important sustainable energy technology. The author recently proposed a nonlinear dynamics model of an LTD kinematic Stirling heat engine to study the rotational mechanism of the engine [Y. Izumida, Europhys. Lett. 121 , 50004 (2018)]. This paper presents our study of the nonequilibrium thermodynamics analysis of this engine model, where a load torque against which the engine does work is introduced. We demonstrate that the engine's rotational state is in a quasilinear response regime where the thermodynamic fluxes show a linear dependence on the thermodynamic forces. Significantly, it is found that the response coefficients of the quasilinear relations are symmetric, which is similar to Onsager symmetry in linear irreversible thermodynamics. Based on these relations, we formulate the maximum efficiency of the engine. We also elucidate that the symmetry of the quasilinear response coefficients emerges by reflecting the (anti-)reciprocity of the Onsager kinetic coefficients identified for the relaxation dynamics of the engine in the vicinity of an equilibrium state. We expect that the present study will pave the way for developing nonequilibrium thermodynamics of autonomous heat engines described as a nonlinear dynamical system.