Experimental Investigation of a Linear, Orifice Pulse Tube Expander

Abstract

Affordable, minimal vibration, long life and more capable active cryocoolers must be developed to meet many current and future commercial and military needs. Modern pulse tube refrigerators can potentially satisfy these combined advanced requirements better than other types of known coolers. This paper reports on the performance data measured from a single stage, linear pulse tube refrigerator expander at Hughes Aircraft Company. The measured expander performance included cold end temperature and total heat rejection rate as a function of heat lifting capacity at a fixed rejection temperature (330K), and for several fill pressures. Combining measured heat rejection rates and cold end heat input rates with other data, pulse tube expander input PV-power could be determined with an estimated accuracy of ± 10% or better. With 364 watts of PV-power supplied to the expander and rejecting heat at 330K, 21.5 watt heat lifting capacity was measured at 84K, corresponding to a expander thermodynamic efficiency of 0.174. Similarly, at 58K, the measured 10 watt capacity yields a thermodynamic efficiency of 0.0127. The minimum cold end temperature measured was 34.3K. The measured single orifice pulse tube performance was also found to be competitive with that of a similar size, hot piston pulse tube reported in the literature.