液氮温区大冷量自由活塞斯特林制冷机实验及模拟研究

Experimental and Numerical Study on a Free-Piston Stirling Cooler With Large Cooling Capacity in the Liquid Nitrogen Temperature

自由活塞斯特林制冷机具有高可靠性、高效率、结构紧凑等优点,在高温强电超导和气体液化等领域有较广阔的应用前景。本文针对一台液氮温区大冷量自由活塞斯特林制冷机展开了实验和计算研究.实验中,输入声功2.35 kW时,制冷机在80 K获得了215 W制冷量,相对卡诺效率为24.9%。数值计算表明室温端换热器的性能不足对制冷机性能影响较大,此外,结构缺陷导致的回热器轴向孔隙率不均匀可能是制约制冷机性能的主要因素。针对上述问题优化系统有望显著提升制冷机性能。

The free-piston Stirling cooler possesses advantages of high reliability, high efficiency and compact structure, thus has great application potential in many fields such as high temperature superconductivity and gas liquefaction. In this paper, a free piston Stirling cooler with a large cooling capacity in the liquid nitrogen temperature was studied through both experiments and calculations. In the experiment, the cooler could provide a cooling power of 215 W at 80 K with the input electric power of 2.35 kW, corresponding to a relative Carnot efficiency of 24.9%. Numerical calculation showned that the heat transfer ability of the ambient heat exchanger has an obviously influence on the performance of the cooler. In addition, the inhomogeneity of the porosity along regenerator, which was caused by the structural defects of the cooler, might be the primary factor that deteriorated the performance of the cooler. Some measures will be taken to solve the problems above and a better performance of the cooler can be expected.