CONTROL OF DC GAS-FLOW IN A SINGLE-STAGE DOUBLE-INLET PULSE TUBE COOLER

The use of double-inlet mode in the pulse tube cooler opens up a possi bility of DC gas flow circulating around the regenerator and pulse tub e. Numerical analysis shows that effects of DC flow in a single-stage pulse tube cooler are different in some aspects from that in a 4 K pur se tube cooler. For highest cooler efficiency, DC flow should be compe nsated to a small value, i.e. DC flow over average AC flow at regenera tor inlet should be in the range -0.0013 to +0.00016. Dual valves with reversed asymmetric geometries were used for the double-inlet bypass to control the DC flow in this paper. The experiment, performed in a s ingle-stage double-inlet pulse tube cooler, verified that the cooler p erformance can be significantly improved by precisely controlling the DC flow. (C) 1998 Elsevier Science Ltd. All rights reserved.