THEORETICAL AND EXPERIMENTAL INVESTIGATION
OF A 4 K SINGLE-STAGE STIRLING TYPE PULSE TUBE
CRYOCOOLER WITH PRECOOLING

Z.P. Li, J. Chen, Z.H. Gan*, and L.M. Qiu

Institute of Refrigeration and Cryogenics, Zhejiang University
Hangzhou, Zhejiang, 310027, P.R. China

ABSTRACT: The efficiency of 4 K Stirling type pulse tube cryocoolers (SPTC) is rather low compared with that of 80 K SPTCs. Real gas effects and low specific heat capacity ratio of regenerator matrix to helium near 4 K are the main reasons that lead to the low efficiency of 4 K Stirling type PT. A single-stage Stirling type PTC precooled by a two-stage G-M type PTC is developed to study the performance of 4 K Stirling type PTC with a focus on the performance of the regenerator working at 4 K-10 K. In order to reduce loss associated with real gas effects, relatively low average pressure was used. In order to reduce the regenerator loss caused by ineffective heat transfer between regenerator matrix and helium, Gd₂O₂S (GOS) was used as regenerator matrix to replace HoCu₂ around 4 K. A systematic comparison between the two types of regenerator matrix was made theoretically and experimentally including effect of frequency, average pressure and precooling temperature. Performance of the linear compressor is also presented in this paper.

IEEE/CSC & ESAS EUROPEAN SUPERCONDUCTIVITY NEWS FORUM (ESNF), No. 10, October 2009
On June 29, 2009, this manuscript was submitted for possible publication in “Advances of Cryogenic Engineering”