Performance Analysis and Optimization of High Capacity Pulse Tube Refrigerator

High capacity pulse tube refrigerator (HCPTR) is a new generation of cryocoolers tailored to provide more than 250 W of cooling power at cryogenic temperatures. The most important characteristics of HCPTR when compared with other types of pulse tube refrigerators are a powerful pressure wave generator, and an accurate design. In this paper the influence of geometrical and operating parameters on the performance of a double inlet pulse tube refrigerator (DIPTR) is studied. The DIPTR is modeled applying the nodal analysis technique, using mass, momentum and energy conservation equations. The model is able to compute instantaneous flow field throughout the system and calculate cooling capacity and COP. The model is validated with the existing experimental data. To perform the optimized mode of operation, the influence of both geometrical and operating parameters on cooling capacity and COP is investigated. The key geometrical parameters considered in this paper are aspect ratios of regenerator and tube section, length ratio of regenerator and tube, and type of screen mesh. The main operating parameters considered are average charge pressure, and position of opening of orifice and bypass. As a result of this optimization a new configuration of HCPTR is proposed. This configuration provides 300 W at 80 K cold end temperature with a frequency of 50 Hz and COP of 0.054.