Investigationof Mixing by Nonlinear-Induced Electrokinetic Flow in a Micro Channel

Mixing plays an important role in many micro devices; therefore, increasing of mixing in micro devices is important. In this paper, the physics of mixing due to non-linear induced-charge electrokinetic flow in a rectangular microchannel with embedded conducting hurdles is studied. Since most previous studies have focused on non-conductive objects with fixed charges, in the present study, mixing with conductive hurdles and induced charges is investigated. Numerical results show flow circulation near the conductive hurdles which leads to an increase in the mixing. The vortices are generated due to non-uniform distribution of zeta potential on the hurdles. The Mixing efficiency is also reported based on hurdles location, ratio of hurdles height to the channel height and angle of triangular hurdles. When location and angles of the hurdles are fixed, by increasing the ratio of hurdles height to channel height, the mixing efficiency is increased. In addition, with increasing of the angle, the mixing efficiency is decreased. Finally, effect of electric field on mixing is completely analyzed.