Effect of Geometric Configuration and Cooling Performance in Stirling- ype Pulse Tube Refrigerator

For a given linear compressor, the geometric configuration of the PTR (pulse tube refrigerator) affects the dynamic behavior of the linear compressor as well as the cooling performance of the PTR. The geometric configuration of each component precisely determines the flow impedance which contains the flow resistance, the inertance effect, and the compliance effect. In this paper, several simulation sets are performed with an analysis code in consideration of the dynamics of the linear compressor and the thermal losses. For the same magnitude of input current, the swept volume and the resonant frequency of a linear compressor vary with the geometric configuration of the PTR; this is because the flow impedance determines the amount of the gas spring effect and the gas damping effect to the piston. For a linear compressor, a larger swept volume generally results in a higher acceptance of the input power and a better compression efficiency. However, a higher compression power and compression efficiency for a linear compressor do not always guarantee a better cooling performance of the PTR. The simulation results clearly show the existence of the optimum geometric configuration of the PTR for a given linear compressor. The underlying physical reasons are explained with the power transfer from the input power to the cooling capacity.