Experimental investigation of step piston type series pulse tube refrigerator

Abstract

Recovering the expansion power at the hot end of the pulse tube is an effective method to improve the performance of the pulse tube refrigerator. In this paper, a new power recovery type pulse tube refrigerator, named step piston type series pulse tube refrigerator, is presented. It includes two cold heads in series and a step piston linear compressor. Each compression chamber of the step piston linear compressor drives one cold head separately, and each cold head is connected with an inertance tube. The secondary compression chamber is also connected with the hot end of the primary stage pulse tube. Part of the expansion power of the primary stage cold head dissipates in the primary stage inertance tube, the remaining expansion power plus the acoustic power from the secondary compression chamber drives the secondary stage. A thermoacoustic model was built to study the mechanism of step piston type series pulse tube refrigerator and an experiment was set up to verify the feasibility.