WaLBerla: Investigation of Electrostatic Effects in Particulate and Electro-Osmotic Flows

The understanding of electrokinetic transport of fluid or particles in microchannel plays an important role in the design and the optimization of microand nanofluidic devices. Two important electrokinetic phenomena are electro-osmosis and electrophoresis. In order to study these phenomena, the lattice Boltzmann solver is coupled with the iteration solver for the Poisson equation. Using these numerical schemes, the transient behavior of the electro-osmotic flows is investigated for various physicochemical parameters. Additionally, the effect of non-Newtonian fluids and microchannels with surface roughness on the electro-osmotic flows are studied. For electrophoresis phenomenon, the agglomeration of particles on an electrode is simulated. Numerical results reveal that the electro-osmotic flow velocity is directly proportional to the applied electric field and the surface zeta potential. However, for particular external electric fields and surface zeta potentials, there exists an optimal ionic concentration and an optimal channel height and width that maximize the flow velocity. For rough microchannels, heterogeneously charged surfaces increase the electro-osmotic flow velocity, which can be used to enhance pumping or mixing characteristics of microchannels. The results of electrophoretic transport in fluids shows that the particles agglomerate uniformly on the electrode for particular particle charges and flow velocities.