A two-stage stirling cryocooler driven by opposed piston linear compressor for space applications

Abstract

A two-stage, split Stirling cryocooler with a capacity of 2 W at 100 K and 0.5 W at 50 K is designed. A second order cyclic analysis is used to decide the final geometry of the unit. A compressor with an opposed piston configuration is developed. A flexure stack suspended piston and displacer are used. A moving coil linear motor is developed. Sensors are installed for measuring strokes of pistons and displacer; and pressure at the outlet of the compressor. A 10-channel oscilloscope provides the variations of parameters. The load tests indicated that the cooling capacity is close to the design values. The power input for the compressor is 110 W as compared to 69 W predicted by the analysis. The experimental no-load temperature for the first stage is observed to be close to the predicted temperature. Two identical expanders are developed to check the repeatability. For Expander I, the temperatures attained for a load of 3.33 W on Stage I and 0.95 W on Stage II are 106 K and 74 K, respectively, with a power input of 110 W. The corresponding values for Expander II are 128 K and 66.7 K, respectively, with a power input of 105.6 W. © 2008 American Institute of Physics.