Numerical and experimental investigations on a single stage GM-type double inlet pulse tube refrigerator for nitrogen liquefaction

In this study, a set of non-linear partial differential equations representing the inside fluid flow, and thermal characteristics of a GM-type double inlet pulse tube refrigerator are transformed into algebraic equations by adopting "finite volume method". Those sets of equations are solved by using Gauss-Siedel iterative methods. By using the numerical model, influences of waiting time of rotary valve, orifice and bypass opening coefficients on cooling capacity, COP and mass flow ratios are studied. The mass flow rate at the pulse tube is obtained from numerical analysis, and then used to design shell-and-tube and mesh-filled hot heat exchangers. A test-rig is constructed to validate the numerical results. The performance of both the hot heat exchangers are studied experimentally. Numerical results show that the proposed numerical model is capable of producing 32.5 W of refrigeration power at 75 K. However, preliminary experimental results show a no-load temperature of 133 K.