Numerical simulation of a two-stage pulse tube cryocooler considering influence of abrupt expansion/contraction joints

The accuracy of local energy loss correlations in simulation of abrupt expansion/contraction joints under oscillating flow conditions of pulse tube cryocoolers (PTCs) is investigated in this paper. Different friction losses of non-porous media are investigated as well. In this respect, detailed analyses of the flow and heat transfer in various components of a two-stage PTC under oscillating flow conditions are carried out by a developed 1-D code and also FLUENT software. Comparison of 2-D and 1-D simulations results shows that steady friction factors do not possess sufficiently accurate predictions of losses under oscillating flow conditions. Whereas, oscillating friction factors and steady local energy loss coefficients are successful in calculating of losses under oscillating flow conditions of the PTCs. Furthermore, considering flow streamlines in all components of the PTC, 2-D flow effects occurring in the abrupt expansion/contraction joints of the pulse tube sections with small aspect ratios (length to diameter ratio) reduces the accuracy of the supplied coefficients results in 1-D CFD code.