Comparison of different numerical models for the analysis of two stage pulse tube cryocooler

In the recent years, for several applications such as cooling of sensors, super conducting magnets, cryo-pumping etc., there are worldwide efforts to replace cooling with liquid helium by cooling with closed cycle cryocoolers. The internal working processes in pulse tube cryocoolers are quite complex due to unsteady, oscillating compressible gas flow in the pulse tube. Although, considerable theoretical studies have been carried out, as on date, phenomena occurring in pulse tube are still to be understood. Three different numerical models namely isothermal model, adiabatic model and energy equation model are compared to analyze a two stage pulse tube cryocooler. The various experimental parameters have been incorporated in the models to carry out the analysis. The various losses of the pulse tube cryocooler are being calculated separately and incorporated into the models. The numerical results are compared with the experimental results obtained for a two stage pulse tube cryocooler for validation.