Numerical Simulation of Electroosmotic Flow in Flat Microchannels with Lattice Boltzmann Method

Abstract

In the present work, a new Lattice Boltzmann model has been developed to study the electroosmotic flows in a 2-D flat microchannel. The governing equations are presented in the continuum model, while a set of equivalent equations in Lattice Boltzmann model is introduced and solved numerically. In particular, the Poisson and the Nernst–Planck (NP) equations are solved by two new lattice evolution methods. In the analysis of electroosmotic flows, when the convective effects are not negligible or the electric double layers have overlap, the NP equations must be employed to determine the ionic distribution throughout the microchannel. The results of this new model have been validated by available analytical and numerical results. The model has also been used to examine the electroosmotic flows in a heterogeneous flat microchannel. Furthermore, the predictions of the NP model are compared with those of the Poisson Boltzmann (PB) equation to identify the applicability of the PB equations for such flows, which can also serve as validations for the present model.