Single-stage G-m Type Pulse Tube Refrigerator Performance Study

Pulse tube was a new type cryocooler first introduced in 1960s' of last century. It has higher reliability, lower vibration and electromagnetic noise than normal regenerative cryocoolers. Pulse tube shows strong competitiveness with its gradually increase of performance. Its potential application includes space, military, cryoelectronics, cryobiology, gas liquefaction, etc.This paper targets on lowering cooling temperature and increasing cooling power and efficiency from 20K to 40K of a single-stage G-M type pulse tube through experimental and theoretical research. With numerical simulation of REGEN3.2 and thermodynamic analysis, our work focus on improving regenerator, the key element of a cryocooler, which including: comparing Pb spheres of different hydra-diameter, adding magnetic material Er₃Ni, using stainless steel screens to replace original phosphor bronze screens, using 300# stainless steel screens to replace 250# ones. The experimental outcome reaches 11.1 K from 13.8K which is the best record ever been reported over the world. Meanwhile, it can have cooling power of 17.8W, 40.7W, 64.4W at 20K, 30K, 40K respectively. Its application is greatly widened by this achievement, indicates that our cryocooler can be used from 20K to 40K which originally is the field of G-M type cryocoolers. Besides, we run several tests on repeatability which also gives optimistic results that the cryocooler is completely fit for practical usage.