Non-equilibrium evolution and characteristics of the serrated microchannel hydrogen knudsen compressor

The hydrogen Knudsen compressor has great potential to transport hydrogen and provide the required pressure in MEMS and microfluidic systems. The microchannel composed of cold and hot serrated surfaces is beneficial to the temperature control of the multistage Knudsen compressor. In the present study, a serrated hydrogen Knudsen compressor model is established initially, and the non-equilibrium evolution is numerically studied by using the method of N–S equations with the slip boundary. The key factors affecting the non-equilibrium evolution are comprehensively analyzed. The flow behaviors and performance of the serrated hydrogen Knudsen compressor in different times are studied. It is found that the main factors affecting the non-equilibrium evolution are the thermal expansion flow, thermal transpiration flow, and Poiseuille flow. Meanwhile, the serrated structure affects the local flow in the serrated microchannel at different times. Under the interaction of the thermal transpiration flow and the Poiseuille flow, the pressure difference between the two containers first increases rapidly and then decreases slowly, and finally approaches 1886 Pa. The research reveals the flow mechanisms of the hydrogen Knudsen compressor in the non-equilibrium evolution, which provides theoretical support for the safety and reliability of the hydrogen Knudsen compressor.