Numerical and experimental study of an annular pulse tube used in the pulse tube cooler

[摘要] Multi-stage pulse tube coolers normally use a U-type configuration. For compactness, it is attractive to build a completely co-axial multi-stage pulse tube cooler. In this way, an annular shape pulse tube is inevitable. Although there are a few reports about previous annular pulse tubes, a detailed study and comparison with a circular pulse tube is lacking. In this paper, a numeric model based on CFD software is carried out to compare the annular pulse tube and circular pulse tube used in a single stage in-line type pulse tube cooler with about 10 W of cooling power at 77 K. The length and cross sectional area of the two pulse tubes are kept the same. Simulation results show that the enthalpy flow in the annular pulse tube is lower by 1.6 W (about 11% of the enthalpy flow) compared to that in circular pulse tube. Flow and temperature distribution characteristics are also analyzed in detail. Experiments are then conducted for comparison with an in-line type pulse tube cooler. With the same acoustic power input, the pulse tube cooler with a circular pulse tube obtains 7.88 W of cooling power at 77 K, while using an annular pulse tube leads to a cooling power of 7.01 W, a decrease of 0.9 W (11.4%) on the cooling performance. The study sets the basis for building a completely co-axial two-stage pulse tube cooler.

[发布机构] Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Zhong Guan Cun Dong Road 29, Hai Dian Beijing; 100190, China^1;University of Chinese Academy of Sciences, Beijing; 100049, China^2

[效力级别] 物理学 [学科分类] 材料科学（综合）

[关键词] annular;circular;Co-axial;Expansion efficiency;Pulse tubes