有限热源下斯特林制冷机的χ函数优化

Optimization of χ function for Stirling refrigerator under finite heat source

以节能减排为目的,以牛顿线性传热为基础,建立高温热源为无限热容、低温热源为有限热容的单一有限热源斯特林制冷循环模型.综合考虑热阻、不可逆因子及热漏等不可逆因素,运用有限时间热力学分析方法,将能使制冷率和性能系数达到平衡的χ准则作为优化目标函数.数值模拟的结果表明:当热漏取值较小、不可逆因子接近于1、而有限低温热源的温差ΔT取值较大时,χ函数关于性能系数和制冷率的极值就越大.对于在某一范围内给定的热漏、不可逆因子和温差,存在一个最佳的传热系数比,使得该函数关于性能系数和制冷率有极大值,从而为实际斯特林制冷机的发展与改进提供理论依据.

Based on Newton linear heat transfer,a single finite heat source Stirling refrigeration cycle model,which consists of high temperature heat source as infinite heat capacity and low temperature heat source as finite heat capacity,is established to save energy and reduce emission.We use the finite-time thermodynamic to analyze the model,which some irreversible factors such as thermal resistance,irreversible factor and heat leakage are considered synthetically.Theχcriterion which keeps a balance between the cooling rate and the coefficient of performance is employed as the optimization objective function.The numerical simulation results show that the maximum value of the function related to the coefficient of performance and the cooling rate is greater when the heat leakage value is small,the irreversible factor is close to 1,and the temperature difference of the finite low temperature heat source is large.There is an optimal heat transfer coefficient ratio,which makes the function related to the coefficient of performance and the refrigeration rate have a maximum value when the heat leak,irreversible factor and temperature difference are given within the range.Thus these results will provide theoretical basis for the developments of the actual Stirling refrigerator.