Analytical study of the performance of pulse tube refrigerator with symmetry-nozzle

Abstract

This paper analyzes the mechanism of the symmetry-nozzle instead of needle valve or orifice to improve the performance of pulse tube refrigerator in experiments. Their identifications are to result in a similar reciprocal movement in the hot end of the pulse tube; their differences are that their flow coefficients have different characteristics. The flow coefficient of the symmetry-nozzle has a positive feedback to flow rate while the orifice has little relation to flow rate generally. Further analysis shows that this feature results in large refrigeration when the pressure ratio and mass flow amount are same, which explains the reason for even lower temperature and a larger refrigeration amount when using the symmetry-nozzle.