Numerical investigation of pulse tube refrigerator with inertance tube-gas reservoir phase modulation.

Abstract

This paper presents a numerical study on a coaxial pulse tube refrigerator(PTR) with inertance tube-gas reservoir as the phase modulation device. A two-dimensional model is developed to describe the oscillating flow in the regenerator, cold-end heat exchanger, pulse tube and warm-end heat exchanger, while a 1D model is employed to describe the phase modulation by the inertance tube. The boundary condition at the warm end of regenerator is the sinusoidal pressure wave of a mean value of 3.0 MPa, an amplitude of 0.07 MPa and a frequency of 34 Hz. Based on the simulation results, the influence of inertance tube-gas reservoir device on the temperature and velocity distribution profile is obtained. The transient variations of velocity near the wall lead that at the other points at the same cross section in the pulse tube. Velocity oscillations with large magnitudes are observed near the center of the cold end heat exchanger due to the presence of the empty volume. Besides, the anisotropy thermal conductivity of porous medium has a significant effect on the performance. The cryocooler can reach a minimum temperature of 86 K when a small value of axial thermal conductivity is applied, which is 15 K lower than that of the case with isotropic thermal conductivity.