氦液化循环中透平流量的优化及影响因素热力学分析

Turbine mass flow optimization in helium liquefiers and thermodynamic analysis of factors for affecting optimal turbine mass flow

为了在氦液化循环中获得最大的液化率,采用MATLAB编程实现流程中的热力学计算,针对带液氮预冷的Collins循环中的透平流量(me_1、me_2)进行优化分析。首先根据前人已得到的结论验证了模型的正确性,在此基础上进行深入研究。结果显示,当固定流程中的高低压力、换热器有效度以及透平的等熵效率时,透平的分流量为压缩机入口总流量的74%并且两台透平均分时系统可获得最大的液化率,且这一最优流量并不随透平的等熵效率和换热器的有效度改变。

A program was developed by MATLAB to realize the thermodynamic simulation of the Collins helium liquefier with nitrogen precooling. The turbine mass flow was optimized to get the maximum liquid helium. The accuracy of the model was certified based on the existing conclusions drawn by previous researches. It turns out that when the high pressure, low pressure, effectiveness of all the heat exchangers and the isentropic efficiency of turbines are fixed and the optimal turbine mass flow is 74% of the compressor mass flow,liguefier has the maximum liquefaction rate. Furthermore,the optimal turbine mass flow doesn＇ t vary with the variation of isentropie efficiency of turbines and effectiveness of heat exchangers.