Experimental analysis of free warm expander pulse tube Original Research Article

In this paper we report on the development of a prototype of a miniature free warm expander pulse tube (FWEPT), a novel configuration of the orifice pulse tube cooler with the orifice and the reservoir replaced by a secondary piston. It is shown that the motion of the secondary piston can be driven with the appropriate amplitude and phase by the pneumatic force of the pressure cycle. Investigation of the loss mechanisms has shown that the dominant contributions to the heat leak are heat conduction through the regenerator mesh and regenerator ineffectiveness loss, and are ultimately related to the fact that the mass flow rate in pulse tube coolers is large due to the relatively large void volume.