ANALYSIS OF GAS FLOW IN MICROCHANNEL OF ARBITRARY SHAPE IN SLIP FLOW REGIME
Micron size mechanical devices are becoming more prevalent, both in commercial and in scientific applications,such as in the area of micro heat exchangers, micro sensors, micro actuators, Micro-Electro-Mechanical System(MEMS) and so on. Computational modeling can provide effective predictive capability for momentum transfer in mocrodevice before hardware fabrication.In this paper a theoretical analysis for laminar flow in the microchannels of arbitrary shape in slip flow regime is presented. The momentum equation with the one-order slip boundary conditions is solved by using a computation-oriented method of the orthonormal function analysis for the fully developed laminar flow of the incompressible fluid in the microchannels. The dimensionless velocity profiles and the friction factors in the microchannels are obtained. As an example, the flow performance is calculated with the rectangle microchannel and compared with the experimental results. The agreement between analytic solutions and existing experimental results shows that in a definite extension of Knudsen number the traditional Navier-Stokes equations with the slip boundary conditions can govern the gaseous flow mechanisms in microchannels, and the orthonormal function method is available to study the slip flow characteristics in the microchannel of arbitrary shape.Slip flow occurs at the wall of the microchannel in the slip flow regime.The slip velocity of fluid on the channel wall increases as the Kn number increases,and the friction coefficient is substantially reduced for slip flow compared with the no-slip flow. The aspect affects the dimensionless drag coefficient at a fixed Kn number in the rectangle microchannel.