中文摘要：

为了深入研究逆布雷顿空气制冷机的降温特性与制冷性能,论文首先采用CFX数值模拟方法,对透平膨胀机冷端通流部分的流动与热力学过程进行了数值模拟,进一步对整机的热力性能进行了分析;在此基础上探讨了制动功率对膨胀机降温特性影响;并改进了逆布雷顿空气制冷机综合实验台,采用风机回路闭式循环,进行了定制动压力和定特性比两种典型制动策略下制冷机降温性能的实验研究。结果表明：通过调节风机闭式循环制动压力来匹配膨胀机工况的变化方案可行,理论预测与实验结果吻合较好;透平膨胀机的绝热效率62%,在120 min内制冷机最低无负荷出口温度达到了-170℃;采用透平膨胀机的逆布雷顿空气制冷机具有优异的制冷性能。

英文摘要：

For the purpose of investigating the cooling down and refrigerating performance of a reverse Brayton air refrigerator,a simulation method using CFX was firstly adopted to research flow and thermodynamics process in the cold end of the turboexpander and then the thermal performance of the whole turboexpander was analyzed.The influence of brake power on cooling characteristics of expander was discussed on this basis.The test apparatus was improved with closed blower circuit and tests with fixed brake pressure and fixed characteristic ratio which were two typical braking strategies were carried out to study the cooling down performance of the refrigerator.The result indicated that it was feasible to match the variation of working condition of expander by adjusting brake pressure of the closed blower circuit,and theoretical predictions agreed well with experimental results.The efficiency of the turboexpander reached 62%,the lowest outlet temperature reached-170℃ within120 minutes,and the reverse Brayton air refrigerator with turboexpander had excellent refrigerating performance.