Electroosmotic flow of a power law fluid in an elliptic microchannel

In this paper the two dimensional electroosmotic flow of a non-Newtonian fluid governed by the power law model is studied for circular and elliptic microchannels. The electric potential and the velocity distribution inside the microchannel are solved without invoking the Debye-Huckel linear approximation. The solutions are sought for different aspect ratio (E), power law index (n), Debye-Huckel parameter (K) and the wall zeta potential (zeta). The effect of these parameters is studied on the ratio of flow rates Q/Q(cir) and friction parameter. The comparison of a circular geometry (E=1) and an elliptical geometry (E not equal 1) is made on an equal cross sectional area basis. Elliptic microchannels always reduce the flow rate when compared to circular microchannels. This reduction is much more significant at lower values of K and Shear thickening fluids affect the reduction in flow rates much more when compared to shear thinning ones. This reduction in flow rates becomes larger as the aspect ratio increases. The frictional parameter increases with K and zeta for all E. Shear thickening fluids have larger frictional parameter values compared to shear thinning fluids. (C) 2015 Elsevier B.V. All rights reserved.