微膨胀型低温热开关研究

Experimental research on a practical cryogenic heat switch

低温热开关是空间制冷中多机并联的关键技术之一，主要用于耦合备用制冷机以减少非运转机上的寄生热载。在比较了各种空间用低温热开关的性能的基础上，详细介绍了中国科学院理化技术研究所研制的被动型热开关的设计及实验情况。其工作原理是根据不同材料的热胀冷缩性能不同进行的，结构总长度在20～40mm之间，仅由3部分组成。设计了长寿命实验的自动测试实验台，并进行1500次的开关循环实验，证明此装置的可靠性。实验结果表明，该热开关闭合热阻小于1．1K／w，断开热阻大于1400K／w。

The cryogenic heat switch （CHST）is mainly used as one of the key technologies for connecting several cryocoolers in parallel between couple redundant cryocoolers and cryogenic components to minimize the parasitic heat load from the off-cryocoolers. Based on the comparison of performances for some types of heat switches for space application, a passively operated heat switch devised by Technical Institute of Physics and Chemistry（TIPC） was presented . The cryogenic heat switch worked on the principle of different thermal expansions has only three parts and its total length is between 20 mm and 40 mm. The performance of switch gap varying from 0.15 mm to 0.40 mm was studied and an automatic test platform for long duration life time testing was designed. The experimental results show that the heat switch has an ＂ON＂ resistance of less than 1.1 K/W and an ＂OFF＂ resistance of more than 1 400 K/W.