Hydrodynamic dispersion due to a magnetohydrodynamic-electroosmotic driven flow through a microchannel

In a parallel-flat plate microchannel, with nonuniform zeta potential of the wall, we analyse the dispersion of a passive solute under the simultaneous influence of electroosmotic (EOF), and magnetohydrodynamic (MHD) forces. The hydrodynamic of the flow was solved using the lubrication approximation theory (LAT) and we assume a Newtonian fluid. The solution of the electrical potential is based on the Debye-Hu¨ckel approximation for a weak potential of a symmetric (z: z) electrolyte solution. It is shown that the interaction between the non-uniform wall zeta potential induces a pressure gradient so as to satisfy the continuity of flow, generating a no plug like velocity profiles that contribute directly to dispersion. It is also shown that with the adding of the MHD the velocity flow increase two times its value, and the dispersion may increase more than four times as compared against the case of a purely electroosmotic forces.