Abstract: The micro total-energy-based double-distribution-function lattice Boltzmann (LB) model with viscous dissipation and compression work was developed to simulate the gaseous flow and heat transfer in a microchannel with uniform wall temperature boundary condition and uniform heat flux boundary condition. The rarefaction effect on gaseous flow and heat transfer characteristic was studied intensively for different uniform Knudsen numbers. The numerical results show that the rarefaction effects on gaseous flow with these two thermal boundary conditions are similar，which can increase the gaseous flow velocity and reduce the friction coefficient. However, due to the different temperature distributions caused by different boundary conditions, the rarefaction effect will have different influences on the heat transfer characteristics. The heat transfer process is enhanced with uniform wall temperature boundary condition and deteriorated with uniform heat flux boundary condition, respectively.

Key words: microchannel, heat transfer characteristic, lattice Boltzmann (LB) method, rarefaction effect