Application of CFD-DSMC coupling method in H₂ flow and heat transfer in microtube

In the research of porous media and the interior of microelectronic devices, fluids frequently shuttle among pores and wall cracks, therefore it is of great significance to explore the influence of media wall on fluid flow and heat transfer. In this paper, CFD-DSMC coupled iterative algorithm is first used in the research of the flow and heat transfer of gas near the wall in the porous media, which simplified into the flow and heat transfer in micron-scale tube with smooth and rough wall conditions. It is found that compared with the pure CFD method, the velocity field obtained by the coupled method is quite different in the region close to the wall, and this will affect the flow field in the mainstream region, that is, with the higher roughness of the wall, the velocity in the central region will be smaller. There is no significant difference in the temperature distribution in the microtube before and after coupling, but the temperature in the mainstream decreases with the increase of the roughness of the wall. In addition, the temperature jump was found from some of the coupling results close to the wall. The results will contribute to a deeper understanding of the influence of rough surfaces on gas flow and heat transfer near the wall, and provide guidance for the regulation of flow and heat transfer in porous media.