Thermodynamic performance prediction of pulse tube refrigeration with mixture fluids

摘要

A refrigeration cycle with two isentropic and two isobaric processes, referred to as the modified Brayton cycle, is introduced for predicting the thermodynamic performance of pulse tube refrigeration with a binary mixture refrigerant. The corresponding theoretical expressions of cooling power, thermodynamic efficiency and required work of a refrigeration cycle are established. Based on the prediction calculations for a number of cryogenic fluids, promising mixture pairs of working refrigerants are recommended. The computed results show that 9.5 percent of the coefficient of performance (COP) and 6.7 percent of the cooling power at 80K could be gained if a mixture pair of 10 percent nitrogen and 90 percent helium is used instead of pure helium for the pulse tube refrigeration. The minor mixture pairs which have a positive effect on pulse tube refrigeration at temperatures near 80 K, including hydrogen-helium, argon-helium and neon-helium, are also discussed.