Electrokinetic Flow in a Surface Corrugated Microchannel

Abstract

A numerical investigation is made into the characteristics of the electrokinetic flow and its effect in the vicinity of a surface corrugated microchannel. A transformation have been used to transform the present physical domain to rectangular computational domain in order to simplify the application of boundary conditions on the channel walls. The characteristics for the electrokinetic flow are obtained by numerically solving the Laplace equation for the distribution of external electric potential; the Poisson equation for the distribution of induced electric potential; the Nernst-Planck equation for the distribution of ions and the Navier-Stokes equations for fluid flow simultaneously. These non-linear coupled set of governing equations are solved numerically by control volume method over staggered system. Our results show that the form of the vortical flow, which develops in the vicinity of the channel wall depends on the surface roughness and thickness of the Debye layer along the homogeneous channel wall. The occurrence of electrical neutrality of fluid outside the Debye layer and recirculating vortex near channel wall suggests that the fluid flow is influenced by the induced electric field and vice-versa.