Modeling of electrokinetically driven flow mixing enhancement in microchannels with patterned heterogeneous surface and blocks

Mixing in microchannels is an important process since certain microfluidic applications require the rapid mixing of species. This paper investigates the mixing in the microchannels via the possibility of utilising the spatial zeta potential variations with the opposite sign to that of the homogeneous surface to create the circulation zones within the bulk flow. The effects of the number of heterogeneous patches, the strength of applied external voltage and zeta potential are analyzed to determine the mixing efficiency. In addition, the replacement of patches with heterogeneous surface blocks shows the improvement of mixing efficiency. The fluid flow is simulated via the single relaxation time lattice Boltzmann method (LBM) with a forcing term from the electric field. The concentration of species within the channel is governed by an advection-diffusion equation with Peclet number of the order 1000.