Pulse-tube refrigerators are widely used in our society today

but research on the microscopic mechanism of the dynamic process of gas flow inside the pulse tube is lacking. In this study

the molecular dynamic simulation method was used to establish a channel model

and the channel was inflated and deflated to simulate the compression and expansion of a pulse tube. Subsequently

with variations in time

the axial pressure

density

velocity

and temperature of the pulse tube were studied. The results show that the pressure and density gradient in the axial direction of the gas gradually decreased until a balance was reached when the process continued

but a slight reversed gradient occurred. Expansion and compression processes occurred at 64 ps

and the maximum velocities near the channel exit were 775 and 864 m/s

respectively. As the reaction progressed

the maximum velocity gradually moved toward lower pressure. The phases of the pressure and velocity waves in the channel varied with the position. In the compression process

the high temperature of the channel near the closed end reached up to 500 K. Simultaneously

the temperature away from the closed end could be reduced to 223 K

and the expansion process was opposite that in the previous condition. The average time integral at the hot end was 375 K at the time of one temperature cycle superposition

and the average time integral at the cold end was 244 K. Thus

cooling of the environment at the hot and cold ends of refrigeration was facilitated.