Kinetic approach to gas flows in microchannels

A two-dimensional linearized Bhatnagar, Gross, and Krook (BGK) model for the Boltzmann equation has been used to evaluate the damping forces exerted by a gas on the moving surfaces of a micromechanical structure. A very good agreement has been found between our numerical results and the experimental data collected on a silicon biaxial accelerometer in the transitional flow regime. Furthermore, it has been shown that the one-dimensional Reynolds equation fails to predict the squeeze film damping in the two-dimensional structures typical of real MEMS