Mixed Pressure - Driven and Electrohydromagnetic flows of Power Law Fluids through narrow confinements at high zeta potentials

Abstract

We investigate the flow a non – Newtonian (power law fluid) through a parallel plate microchannel under the combined action of a pressure gradient, axial electric field and perpendicular magnetic field (electromagnetohydrodynamic EMHD flow). We examine the interplay of both favourable adverse pressure gradients, high zeta potentials and the superimposed magnetic field. It is observed that the perpendicular magnetic field suppresses the velocity profile is aided by an adverse pressure gradient. The magnetic field competes against both favourable pressure gradient and high zeta potential. At low magnetic field strengths, a significant flow reversal is observed at the channel centre and the strength of the magnetic field increases, the extent to which the flow is reversed reduces. The effect of fluid viscosity is also investigated by varying the dimensionless flow consistency index of the power law fluid. We find that EMHD flow is very sensitive to the viscous properties of the fluid and that even small variations in the flow consistency index can result in a large change in the flow speed.