DESIGN OF SINGLE STAGE AND TWO STAGE MINIATURE STIRLING CRYOCOOLERS USING CYCLIC SIMULATION

摘要

Small capacity Stirling cryocoolers for space-borne applications generally use linear electromagnetic drives (also called linear motor) for long life, maintenance free operation and high reliability. Such motors are normally of moving coil type. The performance prediction of such small capacity (miniature) Stirling cryocoolers is very critical and is governed by principal design parameters. The performance of a cryocooler depends on various losses such as loss due to regenerator ineffectiveness, temperature swing loss, shuttle conduction loss, P-V loss etc. In this paper, performance prediction of single stage and two stage miniature split Stirling cycle cryocoolers has been carried out considering above losses using cyclic simulation reported by Atrey et al. The systematic approach for performance prediction using cyclic simulation is explained in detail. The gross refrigerating capacity of a single stage cryocooler as predicted by the cyclic analysis is 5.4 W. The losses work out as 4.35 W. Thus the net refrigerating effect is 1.05 W. This net refrigerating effect is compared with the net refrigerating effect measured during experimental investigations. The comparison shows a good agreement. Thus, the cyclic simulation has been further utilized for design of a miniature two stage cryocooler to meet the specification of 2 W at 100 K (stage Ⅰ) and 0.5 W at 50 K (stage Ⅱ).