Gas Flow Simulations in Rough Micro Channels by Lattice Boltzmann Method

Understanding the gas flow in rough micro channels is highly desirable in shale gas researches. In this paper Poiseuille gas flows in the rough surface micro channel model are investigated employing the Lattice Boltzmann method. The main conclusions obtained from numerical simulations are as follows: (1) velocity profiles in rough micro channels are different from those in rough macro channels, and velocity vectors reversed and the streamlines distorted near rough surfaces in velocity fields, while the streamlines near the flat surface are paralleled; (2) the slip velocity and the centerline velocity increase noticeably with the reducing bounce-back probability, and the slip length on the wall tends to nonlinearly decrease when the bounce-back probability increases; (3) the slip length grows with enhancing surface roughness and pressure, and surface roughness appears to promote micro flow and reduce the flow resistance in rough micro channels, which is quite opposite to macro flow in rough channels, but pressure effects on rough channels are not as significant as that on smooth channels.