Numerical Simulation of Low-Speed Gas Flows in a Microfluidic System

摘要

A kinetic theory analysis is made of low-speed gas flows in microfluidic systems consisting of microchannels in series. The Boltzmann equation, simplified by a collision model, is solved by means of a finite difference approximation with the discrete ordinate method. For the evaluation of the present method, the results for simple channels are compared with those from several different methods and available .experimental data. Calculations are made for various microfluidic systems such as a sudden expansion, a sudden contraction, and a 90-deg bend. The results compared well with those from the discrete simulation Monte Carlo method. The present method does not suffer from the statistical noise that is common in particle-based methods, and it requires a smaller amount of computational effort. It is also shown that the analytical solution of the Navier-Stokes equations with slip boundary conditions, which is suitable for fully developed flows, can give relatively good results in predicting geometrically complex flows such as a sudden expansion and a sudden contraction.