Numerical Simulation of 3 Buffer type Pulse tube Cryocooler

Abstract

The pulse tube refrigerator (PTR) is one of the cryocoolers which are used to produce very low temperatures. Since there are no moving parts (only moving part is piston which induces periodic motion to the working fluid), pulse tube refrigerator is therefore highly reliable and has long life -span than other cryocoolers. So, pulse tube refrigerator has been popularly used in various applications over other cryocoolers. To design the pulse tube refrigerator accurate model is required to predict its performance, such models are available in literature with their own limitations which makes them useful for certain applications only. The experimental evaluation of pulse tube refrigerator is very difficult and costly while analytical evaluation is very complex and time -consuming. The numerical analysis by using CFD tools is suitable option for evaluation of the pulse tube refrigerator. The present work is focused on orifice pulse tube refrigerator (OPTR) analysis by using software ANSYS FLUENT. An axisymmetric model is created in workbench with appropriate dimensions, which is then simulated evaluate the performance of the orifice pulse tube refrigerator. Further orifice pulse tube refrigerator is modified i.e. 2 more reservoirs are added to the above design and valves to connect them alternatively. The performance of this new type of pulse tube refrigerator is evaluated and compared with orifice pulse tube refrigerator. The present work refers this new type of pulse tube refrigerator as 3 reservoir pulse tube ref rigerator (3RPTR). The numerical analysis is further extended by operating 1 reservoir only in 3RPTR to compare its
performance with above two PTRs.