CFD Analysis of Stirling Type Inertance Tube Pulse Tube Refrigerator

Abstract

Pulse tube cryocooler are generally one dimensional flow fields.By using two stage pulse tube cryocooler one can reach up to very low temperature.In it the compression and expansion of gas inside the pulse tube generates the required temperature.The main advantage of using pulse tube is that it does not have any moving parts inside the pulse tube rather oscillations of gas inside it does the job.All pulse tube cryocooler are of closed cycle type so no mass gets exit during the complete cycle.There is only one moving component named as piston which goes to and fro motion to generate the required pressure variation. Generally helium is used as the working fluid to reach a very low temperature of around 4.2k.The calculations for design are done based on one dimensional flow model.In the Stirling type pulse tube cryocooler an inertance tube,two number of opposed piston compressor,Regenerator,pulse tube, cold end heat exchanger and hot end heat exchanger mainly. The simulation work is done of a fully coupled system operating in steady mode.In this ANSYS Fluent is used to study the flow analysis and heat transfer phenomena inside the pulse tube cryocooler.A 2D axis symmetry geometry of the pulse tube is considered for the CFD simulation.The external boundary condition used is a sinusoidal oscillating piston velocity by developing an UDF,which is accompanied by thermal and adiabatic condition with a known heat flux at the cold end heat exchanger.The aim is to check the performance of ITPTR based on CFD simulations.