Electrokinetic Assisted Mixing in a Microchannel with Lateral Electrodes

P.      Kemprai; A.      K. Sen

Abstract

Mixing of fluids in microchannels is challenging due to the inherent laminar nature of the fluid flows. This work presents numerical investigations of an active micromixer with an array of lateral electrode pattern along the microchannel. The proposed micromixer is simulated using a numerical model that solves the coupled flow, electric field and diffusion equations with appropriate boundary conditions. The geometry of the micromixer is illustrated and the numerical model is described. The simulation model is validated by comparing the model predictions with experimental results. The performance of the active micromixer is compared with that of an equivalent passive micromixer indicating the advantage. An extensive parametric study is carried out to investigate mixing performance of the proposed micromixer with respect to various geometrical and operational parameters. The layout of the electrodes parallel and staggered electrode arrangements are studied and compared. Effects of electric potential, Reynolds number, Peclet number, Zeta potential, electrode arrangements, gap between electrodes, and number electrode pairs on the mixing performance is studied and discussed.

Keywords: Electrokinetic, mixing, active micromixing, microchannel, microscale, Micro fluidic mixing, chaotic advection, Electro-osmotic flow, dissipative forces, electro-osmotic velocity, cross-sectional geometry, perturbs, non-zero electric field, recirculation zone, Zeta potential