脉管制冷机液氦温区高频特性

High Frequency Characteristics of Pulse Tube Cryocooler at Liquid Helium Temperature

从主动制冷的角度,探索冷端无运动部件的低温制冷机-脉管制冷机高频下达到液氦温区的条件,在前期理论设计的基础上,研制了一台预冷型的单级高频脉管制冷机,采用低温惯性管和低温气库为调相方式,开展了频率、平均充气压力、预冷温度以及输入功率等对制冷机性能影响的实验研究。实验结果表明:当采用氦-4为工质,预冷温度为4.54 K,工作压力为0.775 MPa,工作频率为40 Hz时,该制冷机最低无负荷制冷温度达4.23 K。

A precooled single-stage Stirling type pulse tube cryocooler （PTC） is designed to investigate the high frequency characteristics of PTC to reach liquid helium temperature and the performance of the cryocooler at liquid helium temperature. The cold inertance tube and the cold reservoir are used as the phase shifter for this stifling type PTC. Experiments on the influence of operating frequency, average pressure, precooling temperature, and input power on the performance of the Stifling type PTC are carr- ied out. Results show that under conditions of the precooling temperature of 4. 54 K, an average pressure of 0. 775 MPa and an operating frequency of 40 Hz, the Stifling type PTC reaches a no-load temperature of 4.23 K with helium-4 as working fluid.