Rarefied Gas Flow in Rough Microchannels by Molecular Dynamics Simulation

The molecular dynamics simulation method is applied to investigate the rarefied gas flow in a submicron channel with surface roughness which is modelled by an array of triangle modules. The boundary conditions are found to be determined not only by the Knudsen number but also the roughness, which implies that the breakdown of the Maxwell slip model under the conditions that the surface roughness is comparable to the molecular mean free path. The effects of the rarefaction and the surface roughness on the boundary conditions and the flow characteristics are strongly coupled. The flow friction increases with increasing roughness and with decreasing Knudsen number.