Design and investigations on rotary valve for GM type pulse tube cryocooler

Abstract

The rotary valve is one of the key components of GM-type pulse tube cryocooler and the cooling performance of GM-type pulse tube cryocooler depends on the rotary valve performance. In order to get better cooling power during steady-state operation of GM-type pulse tube cryocooler, the pressure ratio should be sufficiently high. The efficient rotary valve design should provide such a high-pressure ratio during the operation at steady state condition. The investigations are aimed at getting better pressure ratio and hence better cooling power. The present work involves the design of a rotary valve for two stage pulse tube cryocooler for 20 K applications based on the mass requirements at steady state operation and valve timing with the help of numerical modeling. With 3.65 pressure ratio,18.52 K no load temperature and 1 W cooling power at 19.51 K was obtained at optimum valve timing without using any rare earth materials in second stage regenerator.