Study on cold head structure of a 300 Hz thermoacoustically driven pulse tube cryocooler

Abstract

High reliability, compact size and potentially high thermal efficiency make the high frequency thermoacoustically-driven pulse tube cryocooler quite promising for space use. With continuous efforts, the lowest temperature and the thermal efficiency of the coupled system have been greatly improved. So far, a cold head temperature below 60K has been achieved on such kind of cryocooler with the operation frequency of around 300Hz. To further improve the thermal efficiency and expedite its practical application, this work focuses on studying the influence of cold head structure on the system performance. Substantial numerical simulations were firstly carried out, which revealed that the cold head structure would greatly influence the cooling power and the thermal efficiency. To validate the predictions, a lot of experiments have been done. The experiments and calculations are in reasonable agreement. With 500W heating power input into the engine, a no-load temperature of 63K and a cooling power of 1.16W at 80K have been obtained with parallel-plate cold head, indicating encouraging improvement of the thermal efficiency.