Simulation of gas flow and heat transfer in micro Poiseuille flow

The gas flow and heat transfer characteristics in micro Poiseuille flow in slip and transition regime were studied numerically using two methods: direct simulation Monte Carlo (DSMC) method and the Burnett equations. The traditional mathematical model of the Navier-Stokes equations becomes invalid because of their linear constitutive relations of viscous stress and heat flux. The molecule based DSMC method is widely used in transition flow regime and has achieved great success. The high- order continuum model of the Burnett equations is recently introduced to simulate the flow in small devices. These two methods are both adopted in the present study and they show good agreement with each other. But DSMC method is more expensive in computational time. The flow and heat transfer characteristics of Poiseuille flow in microchannels are then studied. It is found that with the increase of Knudsen number, the Poiseuille number decreases while Nusselt number increases. The local Poiseuille number decreases along the whole channel while the local Nusselt number decreases rapidly first and then increases slowly afterwards.