液氦温区节流制冷机流程分析及实验验证（英文）

Process analysis and experimental verification of compact J-T cryocooler in liquid helium temperature region

设计研制了采用两级GM预冷的小型节流制冷机,GM制冷机在两级将氦气分别预冷至91 K和14 K。开展了开式和闭式两种形式的实验,闭式中采用带有单项阀的压缩机为循环提供高压气源。实验给出了节流降温曲线并测量了制冷量,开式和闭式实验中最低无负载温度分别为3.4 K和4.27 K,4.5 K时制冷量分别为30 m W和5 m W。

A compact 4 He Joule-Thomson （J-T）cryocooler using two-stage GM cooler as pre-cooling sta- ges has been successfully designed and developed. The GM refrigerator cools the incoming helium gas to 91 K at the first stage and 14K at the second stage. The J-T system consists of three tube-in-tube heat ex- changers（HEX） , two spiral heat exchangers and one J-T orifice. Experiments with open loop and closed cycle were carried out respectively. A new J-T compressor with single cylinder and check valves is used in the closed cycle to provide high pressure gas. The curves of throttling are given and the cooling power is measured. In open loop the no-load temperature of 3.4 K and the cooling power of 30 mW@ 4.5 K are ob- tained, while in closed cycle 4.27 K and 5 mW@ 4.5 K are obtained respectively.