Gas–surface interaction effects on the flowfield structure of a high speed microchannel flow

This work describes a computational study on rarefied flow in a microchannel composed of two parallel plates. Effects of incomplete surface accommodation on the flowfield structure have been investigated by employing the Direct Simulation Monte Carlo (DSMC) method in combination with the Cercignani–Lampis–Lord (CLL) gas–surface interaction model. The aim of this work is to investigate the arising of disturbances due to differences in the accommodation coefficients of the lower and upper surfaces of the microchannel. The results highlight the sensitivity of the primary properties to changes on the gas–surface accommodation coefficients. It was found that accommodation coefficients have different influence on velocity, density, pressure and temperature for the conditions investigated.

► We model a supersonic flow in a microchannel.
► We investigate the effects of different upper surface accommodation coefficients.
► Changes in the normal accommodation coefficient have a minor effect in the flow structure.
► Changes in the tangential accommodation coefficient have a large effect in the flow structure.