Molecular Dynamics Analysis of Influence of Geometric Factors on Microchannel Pulse Tube Refrigerationn Performance

The molecular dynamics simulation method is used to study the microscopic refrigeration effect inside microchannel vessels,and the influence of microchannel pulse geometry on refrigeration performance is discussed.A rectangular cross-section microchannel vessel model is established.The Inflation and deflation process of the working fluid He gas in the microchannel is simulated,and the axial pressure,velocity and temperature distribution inside the channel are obtained.The influence of the inherent size of the vessel on the temperature of the cold and hot end of the microchannel vessel is analyzed.The study shows that the pressure gradient is gradually reduced in the model 1B-2L,as the process progresses and finally reaches equilibrium in the model 1B-2L,as the process progresses.At the same time,a slight reverse gradient phenomenon occurs.The axial velocity is 434 m/s at 200 ps,followed by the axial velocity peak moves toward the inside of the tube and decreases.Maintaining a constant width of the model to increase the length or maintaining a constant length of the model increases the width of the hot end and the temperature of the cold end decreases.The increase of length and width has a certain effect on the performance of microchannel vessels.Maintaining the aspect ratio and scaling the model can optimize the performance of the vessel to some extent,and there is an optimal vessel volume.