Molecular Dynamics Simulation of the Phase Shift Mechanism on Inertance Pulse Tube Refrigerator

At present, it has become a hot spot to study the thermodynamic mechanism of the pulse tube from the perspective of microscopic particles, but the explanation of the phase shift mechanism on inertance pulse tube is not clear enough. In this paper, the inertance pulse tube and the basic pulse tube model were constructed by the molecular dynamics simulation method. A reflect wall moving at a sinusoidal velocity was used as the driving piston. The instantaneous temperature, pressure, mass flow and particle velocity of the pulse tube were statistically analyzed. The simulation results show that, due to the existence of the inertance tube and the gas reservoir, the inertance pulse tube used the inertia effect of the oscillating airflow to adjust the phase difference between the pressure wave and the velocity wave, making it smaller than that in the basic pulse tube and the cooling efficiency of the pulse tube refrigerator was improved. At the same time, the amplitude of the temperature of the inertance pulse tube was lower. The results of the current work were helpful to deeply understand the phase shift mechanism on inertance pulse tube from the microscopic perspective.