Microflow has become a popular field of interest due to the advent of microelectromechanical systems. In this work, the lattice Boltzmann method, a particle-based approach, is applied to simulate the two-dimensional isothermal pressure driven microchannel flow. Two boundary treatment schemes are incorporated to investigate their impacts to the entire flow field. We pay particular attention to the pressure and the slip velocity distributions along the channel in our simulation. We also look at the mass flow rate which is constant throughout the channel and the overall average velocity for the pressure-driven flow. In addition, we include a simulation of shear-driven flow in our results for verification. Our numerical results compare well with those obtained analytically and experimentally. From this study, we may conclude that the lattice Boltzmann method is an efficient approach for simulation of microflows.

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We propose a lattice Boltzmann BGK model for simulation of micro flows. This model is based on the kinetic theory and the entropic lattice Boltzmann method (S. Ansumali and I. V. Karlin, J. Stat. Phys., 107 (2002) 291) but the relaxation time is re-defined in terms of the Knudsen number, and a diffuse-scattering boundary condition (DSBC) is adopted to consider the velocity slip at the wall. Simple theoretical analysis and numerical validation show that the proposed model gives good predictions of the micro fluidic behaviors.

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