回冷式逆布雷顿空气制冷机的试验分析

Experimental analysis on the performance of a regenerative brayton refrigeration cycle

为对透平机械中的流动及传热问题进行研究,建立可靠的设计方法与修正模型,并为多目标非线性优化、人工神经网络和遗传算法等理论分析提供可靠、系统、详实的试验数据,对小型逆布雷顿循环空气制冷机系统及其关键部件-气体轴承透平膨胀机和高效紧凑换热器进行了热力性能试验,分析了各运行参数及几何结构的影响,考核了新型弹性支承动压气体轴承的机械性能,并进行了24.6×104r/min超速试验.试验结果表明:该空气制冷机膨胀机可在22×104r/min转速下长期稳定工作,出口温度和系统温降可达-101℃和122℃,效率达到60%,各部件运行参数匹配良好.

The thermodynamic performance of a small air refrigerator and its components was experimentally studied to provide reliable and detailed data for the research on the flow and heat transfer in turbomachinery, and for the design and optimization of air refrigerator. The effects of operation structural parameters on the overall performance of the air refrigerator and its key components （turbo-expander and compact heat exchanger） were presented. Moreover, mechanical characteristics of the compliant foil bearings were examined, and overspeed test was conducted at 24. 6× 10^4 r/min. Results show that the turbo-expander can work stably at 22 × 10^4 r/rain with the efficiency of 60%. The lowest temperature of - 101 ℃ is obtained at the outlet of the turbo-ex- pander, and the temperature difference between the system inlet and the turbo-expander outlet has reached 122 ℃.