Experimental discovery and verification of the third type of DC gas flow in pulse tube cryocooler

DC gas flow in pulse tube cryocooler (PTC) is a crucial problem both in theory and application which considerably affects the refrigeration performance. We have experimentally discovered and verified the third type of DC gas flow in PTC which is formed due to hydrodynamic and thermodynamic asymmetry of the regenerator and other flow channels. This new type of DC gas flow is possible to be identified in other regenerative engines or refrigerators. We also introduced a highlighting method which can suppress this kind of DC gas flow effectively in most cases, with the best result of 30 K temperature drop at the cold end of the PTC.