CFD Analysis of Stirling Cryocoolers

Abstract

The application of cryocoolers are in various fields of modern day applications for adequate refrigeration at specified temperature with low power input, long lifetime, high reliability and maintenance free operation with minimum vibration and noise, compactness and light weight. The demand of Stirling cryocoolers has increased due to the ineffectiveness of Rankin cooling systems at lower temperatures. With the rise in applications of Stirling cryocoolers, especially in the field of space and military, several simulations of Stirling cryocoolers were developed. In this project, so far a detailed analysis has been carried out on previous developed model with computed lengths of different sections of the cryocooler. The previous models have been developed by solving governing partial differential equations mathematically. The regenerator efficiency had been taken 100% in the previous analysis and with performing Schmidt analyses taking sinusoidal variations of pressure and volume, previous model geometry parameters were calculated. The CFD analysis has been done in this project taking the previous model and a UDF for the movement of the piston has been developed in C++ language. The regenerator parameters have been calculated from the results of the analysis.
Simulations are done on Stirling cryocooler with adiabatic conditions at the cold space side and later with a heat load of 0.25 W at cold end and their results were compared. An attempt has also been made in determining the optimum frequency of operation of the proposed model of Stirling cryocooler by comparing the minimum cool down temperature attained by them with different frequencies of operation.