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Description
High capacity Stirling-type pulse tube cryocooler (PTC) has promising application in high temperature superconductor cooling and gas liquefaction. However, with the increase of cooling capacity, its performance deviates much from that simulation by well-accepted one-dimensional model, such as Sage and Regen, mainly due to the strong field nonuniformity. In this study, several flow straighteners placed at both ends of the pulse tube are investigated in order to improve the flow distribution. A two-dimensional model of the pulse tube based on the computational fluid dynamic method has been built to study the expansion efficiency of the pulse tube under different flow straighteners including stainless steel screens, copper screens, taper transition and taper copper slots. The gas temperature, flow and pressure distributions are compared and analyzed. A PTC set-up which has more than one hundred watts cooling power at 80 K has been built and tested. The flow straighteners mentioned above have been applied and tested. The results showed that with the best flow straightener, the cooling performance of the PTC can be significantly improved. Both CFD simulation and experiment show that the straighteners have much great impacts on the flow distribution and the performance of the high capacity PTC.