R600a/R32用于自复叠低温冰箱的实验研究

Experimental Study on R600a/R32 Used in Self Stacking Cryogenic Refrigerator

设计搭建了一套小型低温冰箱自复叠制冷系统,实验对比分析了R600a/R32和R600a/R290两种制冷剂组合的系统循环性能,结果表明R600a/R32组合更符合-50℃低温冰箱的工况要求。通过实验进一步对比了R600a/R32在不同充注比例下的系统循环特性,得到R600a/R32最佳充注比例为0.61/0.39。此配比下,环境温度为25℃时,该系统冷冻室温度可以达到-51.8℃。由于小型制冷装置的空间限制,部分运行参数无法测得,对此提出一种制冷运行数据的分析模型,利用回热器换热平衡和气液分离器质量守恒计算出关键数据,并得到混合工质总运行浓度比例,以便进行系统性能的分析。

In this paper,a self-cascade refrigeration system for a small cryogenic refrigerator is designed and built.The cycle performance of R600a/R32 and R600a/R290 refrigerant combinations is compared and analyzed experimentally.The experimental results show that the R600a/R32 combination is more in line with the working conditions of-50℃cryogenic refrigerators.This paper further compares the system cycle characteristics of R600a/R32 under different charging ratios through experiments,and obtains that the optimal charging ratio of R600a/R32 is 0.61/0.39.Under this ratio,when the ambient temperature is 25℃,the freezing chamber temperature of the system can reach-51.8℃.Due to the space limitation of a small refrigeration unit,some operating parameters cannot be measured.In this paper,an analysis model of refrigeration operating data is proposed.Key data are calculated using the heat transfer balance of the regenerator and the mass conservation of the gas-liquid separator,and the ratio of the total operating concentration of the mixed working medium is obtained to analyze the system performance.