  In the CLB method, a Bosanquet-type effective viscosity is employed to
account for the rarefaction effect on the gas viscosity. To gain accurate
simulations and to match the Bosanquet-type effective viscosity, the combined
bounce-back/specular-reflection boundary scheme with a modified second-order
slip boundary condition is adopted in the CLB method. The present method is
applied to study gas flow in a microchannel with periodic boundary condition
and gas flow in a long microchannel (the ratio of the length to the height
L/H=100) with pressure boundary condition over a wide range of Knudsen numbers.
The influence of the rarefaction effect on the velocity profile, the mass flow
rate, and the non-linear pressure deviation distribution along the long
microchannel are investigated.
