Numerical simulations of transport processes in a pulse tube cryocooler: Effects of taper angle

A numerical model is developed for the prediction of the performance and transport characteristics in an orifice pulse tube refrigerator (OPTR). The OPTR is studied for a two specific geometries. In the first geometry (A), only the taper angle of the pulse tube is changed. In the second geometry (B), the taper angle of the pulse tube is varied along with the diameter of the hot heat-exchanger. The taper angle of the pulse tube is shown to have significant effects on the secondary streaming patterns observed in the pulse tube. Tapering the pulse tube improved the performance of the OPTR only for Geometry-B. In this case, suppression of velocity streaming is achieved in the warm end of the pulse tube.