Chapter 46 - Experimental Investigation on DC Flow Suppression and Refrigeration Characteristics of a High-Performance Single-Stage GM-Type PTC

Abstract

This chapter examines the influence of DC flow induced by the introduction of double-inlet on the refrigeration performance of the pulse tube cooler. A double-valved double-inlet configuration instead of conventional single-valved one is successfully used in experiments to reduce the DC flow. Besides, the performance of the cooler with various regenerator matrices and supply power of compressors has been extensively investigated under different operation modes. The effect of the regenerator matrices on performance of the cooler not only depends on the material thermodynamic property, but also on the operation mode of the cooler. Operating under double-inlet mode, 18.4K and 14.7K minimum temperature has been reached driven by RW2 and CP4000 compressor respectively. The introduction of the double inlet usually leads to an increased performance of the pulse tube cooler. However, the asymmetric flow impedance of the double-inlet valve, regenerator and pulse tube will cause a DC flow around the loop of them. The DC flow from the warm end to the cold end adds an additional thermal load to the cold end of the cooler, and greatly deteriorates the refrigeration performance due to the large temperature difference between two ends, although its value is quite small compared with AC flow.