Thermodynamic Analysis and Preliminary Test of a JT Cryogenic System Operating at Liquid Helium Temperature Zone Precooled by Two Independent PTRs

Mechanical refrigeration of liquid helium temperature zone in space is one of the key technologies in deep space exploration and quantum navigation.According to the JT cycle with two-stage precooling,the thermodynamic analysis was carried out to calculate the precooling requirement and the power consumption of a JT cryocooler.The influence of high pressure on the primary and secondary precooling capacity required by a JT refrigerator and the available maximum refrigerating capacity at the liquid helium temperature zone under different secondary precooling temperatures(18~22 K)were analyzed.The preliminary experiment results show that the system could provide a maximum cooling power 24 mW at 4.70 K or 12 mW at 4.18 K under different operating conditions.