回热式气体压缩制冷系统性能整体优化

Global Optimization of Regenerative Gas Compression Refrigeration

本文以回热式气体压缩制冷系统为研究对象,结合(火积)耗散分析与热力学分析,建立了回路中各点温度与设计参数的数学关系,明确了各设计参数间的约束关系,从而将系统设计优化问题转化为条件极值问题并求得理论解,实现了系统内多参数的全局优化。通过对以换热器总热导最小为优化目标的算例进行计算分析,发现当制冷需求、功耗及压比给定时,增大压比或预冷工质热容量流有利于回热式制冷系统总热导的减小,而增大净功耗则使总热导先减小后增加,在净功耗临界值处总热导极小。

This works tudies the optimization of regenerative gas compression refrigeration systems, where the entransy dissipation analysis and thermodynamic analysis are made to establish the mathematical relation between the intermediate temperatures and the design parameters, as well as the constraints of each design parameter. These relations are used to construct the mathematical model of the optimization problem in terms of the conditional extremum method, and the solution gives the optimal values of design parameters simultaneously. Taking the overall thermal conductance minimization of a regenerative refrigerator as an example, the results show that the minimum overall thermal conductance exists for fixed cooling requirements, running cost, and pressure ratio. Furthermore, the minimum overall thermal conductance decreases for the increase of themass flow rate of the hot-end fluidor the pressure ratio, whereas first decreases and then increases for the increase of the net power consumption.