Abstract

The direct simulation Monte Carlo method was applied to simulate the flows in uniform, parallel, series, and T-shape microchannels. For the uniform microchannel case, both the supersonic and subsonic flows have been considered. The effect of the Knudsen number (Kn) on the flow properties and the heat transfer characteristics were investigated. Some significant flow features, such as the flow acceleration along the channel, the nonlinear pressure distribution, and the velocity slip near the wall, due to the compressibility and the rarefaction of the microflow were specified. Most of the wall heat flux occurs within the channel entrance region when the wall temperature is higher than the bulk flow temperature. Furthermore, in supersonic flow case, the wall heat flux is mainly caused by the deceleration of the flow due to the wall friction.