Prof. Junjie Wang (Technical Institute of Physics and Chemistry, CAS)
The pressure ratio of Vuilleumier(VM) cryocooler is generally smaller than GM cryocooler, which evidently affects its terminal temperature and refrigeration. In this paper, a detailed study on a VM cryocooler with larger pressure ratio is introduced. By increasing the hot displacer’s stroke distance and shortening its length on the original experimental system which could achieve a no-load temperature 9K, the pressure ratio raised from 1.4~1.8 to 1.7~2.1. Experimental results indicate that simply increasing the pressure ratio could not achieve a lower temperature and the cold end regenerator which has significant influence on the performance of VM cryocooler should be optimized in the energy storage capacity to adapt to the increased work mass. In addition, volume specific heat capacity, thermal penetration distance and flow resistance have to be comprehensive considered while selecting the regenerator materials. By optimizing the regenerator materials of the cold end regenerator, a no-load temperature at 9.2K was achieved so far. Finally, establish a simulation of the cryocooler using the software Sage. Comparing with the experimental results could verify the accuracy of the program and find the optimal way to improve the experimental system.
Tong Zhang (Technical Institute of Physics and Chemistry, CAS)