OPTIMIZATION ANALYSIS OF ALTERNATE TUBE SECTION FOR PULSE TUBE REFRIGERATORS

摘要

In spite of numerous attempts which have been made during the last decade to optimize pulse tube refrigerators, still theoretical and analytical realization of this device needs to be thoroughly explained. In this paper, in addition to the oscillatory flow analysis in the pulse tube refrigerator through a simple analytical model, the performance of the alternate tube section of this device is analyzed using a generalized efficiency, based on the entropy generation rate. In this model, in order to extract the entropy generation rate and the dissipative terms caused by fluid friction and heat flow in alternate tube, simplified momentum and energy equations are solved analytically and velocity and temperature fields for the oscillatory flow are obtained. The method of entropy generation minimization is used to determine the optimum operation conditions that minimize process irreversibility. Based on the developed theoretical model, the influence of important parameters such as kinetic Reynolds number, ratio of tube length to its diameter, frequency of oscillations and temperature gradient along the tube on the pulse tube performance is investigated.