FLOW OF A RAREFIED-GAS IN A RECTANGULAR CHANNEL WITH A MOVING PLATE

Flow of a rarefied gas in a rectangular groove faced with a moving plate is analyzed numerically, using a linearized Boltzmann equation focussing on the flow in the transition regime, and flow conductances at arbitrary Knudsen numbers, as well as the gas velocity fields, are made clear. Free molecule iteration and slip-continuum solutions are also given to investigate the asymptotic behaviors in the two limitting regimes and to check the validity of the numerical solution. Flow conductances. in the cases of Couette and of Poiseuille flows, are found to take greater values as the aspect ratio of the channel becomes larger. The Couette flow conductance is almost insensitive to the Knudsen number, though it shows a tendency to increase very slightly with Knudsen number when the aspect ratio is small and vice versa. The Poiseuille conductance increases with Kn at high Knudsen numbers, decreases at low Knudsen numbers, and has a minimum (the Knudsen minimum) at the transition regime. The present results will be applied to designing various types of gas lubrication systems and mechanical molecular pumps.