液氢温区直接节流JT制冷机降温实验

Cool-down Experiment of the Direct Throttling JT Cryocooler Working at Liquid Hydrogen Temperature

空间用大冷量低温制冷机是实现液氢长期在轨零蒸发贮存的关键技术之一。预冷型液氢温区直接节流JT制冷机无低温运动部件,结构简单,降温过程无需旁通,具备实现空间大冷量制冷的潜力,可单独实现冷量远距离传输。采用直接节流流程方案搭建了用GM制冷机预冷的液氢温区直接节流JT制冷机开式系统实验测试平台,阐述了制冷过程,分析了降温过程存在的问题,在20.8 K测得了10.19 W制冷量。

The cryocooler working at liquid hydrogen temperature with a large cooling capacity is one of key technologies for hydrogen zero boil-off storage in space.The precooled direct throttling JT cryocooler has advantages of absence of moving parts at low temperature and simplicity.With the potential to provide a large cooling capacity,it can realize longdistance transmission of cooling capacity separately.Meanwhile,the bypass structure is no longer required during the cooldown process.Based on the scheme of direct throttling JT cryocooler,an open-cycle experimental prototype of the direct throttling JT cryocooler working at liquid hydrogen temperature was built which was precooled by the GM cryocooler.Cool-down process was introduced.The cooling capacity of 10.19 W was measured at 20.8 K.