A two-dimensional model of regenerator with mixed matrices and experimental verifications for improving the single-stage Stirling-type pulse tube cryocooler

A two-dimensional regenerator model based on Brinkman-Forchheimer equations is established to obtain a model with fast speed and acceptable accuracy. To improve the performance of the Stirling type pulse tube cryocooler (SPTC), the different filling proportions of mixed matrices made of stainless steel (SS) screens are simulated and compared, and then the optimal proportion is suggested. The analyses are mainly focused on the cooling performance and the losses caused by the different entropy generations. The experiments are then conducted to verify the theoretical investigations based on a single-stage coaxial SPTC, in which the cooling characteristics with various frequencies and temperatures are tested and then compared with the analyses. The results show a good agreement between the simulations and the experiments. The cooling performance can be enhanced based on the optimized mixed matrix, in which for a reject temperature of 300 K and an input electric power of 220 W, the SPTC has experimentally achieved the cooling capacity of 0.45 W at 30 K and a no-load temperature of 26.7 K. The performance is impressive considering that only the conventional SS matrices are employed and neither double-inlet nor multi-bypass phase-shifting approach is used. (C) 2017 Elsevier Ltd. All rights reserved.