Numerical analysis of diaphragm type pulse tube refrigerator

Abstract

In present study a new modeling approach for the performance of a pulse tube refrigerator is proposed. A single stage Stirling type diaphragm type pulse tube refrigerator is considered for CFD simulation using Fluent software. The two-dimensional geometry is taken for simulation. In this simulation the physical dimensions of all the components are kept constant and pressure input is generated from the different UDF (User Defined Function) for compressor and diaphragm. Generally, DC gas flow in pulse tube refrigerator created a crucial problem at the time of application, which will affect the cooling down performance because DC gas flow carries heat away from the HHX and deposits at the cold end reading an additional heat loss and unwanted thermal load to CHX , which degrades the cooling performance and doctorates the refrigeration stability of pulse tube cryocooler. For obtaining better temperature stability at CHX end, suppress the DC flow by eliminating the closed loop by using a diaphragm in between HHX and orifice valve. This simulation starts with an assumed uniform system temperature, and continued until steady periodic conditions are achieved by varying the pressure amplitude and getting the better stabilization temperature. The result shows that amplitude of 0.0045 produces a better cooling effect on the cold end of the pulse tube refrigerator.