Experimental Investigation of a G-M Type Coaxial Pulse Tube Cryocooler

Abstract

A G-M type coaxial pulse tube cryocooler is first optimized from three aspects: the dimensional layout of the pulse tube and regenerator, the filling materials in the regenerator, and the structure of the cold end heat exchanger. Three different types of phase shifters: needle valves, capillaries and asymmetry-nozzles are then employed at the hot end of the pulse tube for the adjustment of the phase between the gas mass flow and the pressure oscillations. The influences of DC flow are investigated experimentally. It is found that a proper positive DC flow has positive effects on the cooling performance of the coaxial pulse tube cryocooler.