Computational fluid dynamics simulations and experimental investigations on a 1-2 K Joule-Thompson cryocooler precooled by a three-stage Stirling-type pulse tube cryocooler.

Abstract

The temperature of 1-2 K is crucial to the low-Tc superconducting and deep space exploration. The Joule-Thomson (JT) cryocooler coupled with a three-stage Stirling-type pulse tube cryocooler (SPTC) is an effective way of achieving the required low temperature and high efficiency. In this paper, a computational fluid dynamics (CFD) model is established for the JT cryocooler, in which the flow and heat transfer processes are simulated and analyzed. The distributions of precooling capacities are optimized by analyzing exergy losses caused by heat transfer. The effects of the three stage precooling temperatures, the precooling capacities and the high pressure before the JT valve on the cooling performance are also studied in depth. The no-load temperatures of 2.2 K and 1.42 K are achieved in the model with He-4 and He-3 as working fluids, respectively. The corresponding experimental verifications are underway.