Periodical streaming potential and electro-viscous effects in microchannel flow

This paper presents an analytical solution to periodical streaming potential,flow-induced electric field and velocity of periodical pressure-driven flows in twodimensional uniform microchannel based on the Poisson.Boltzmann equations for electric double layer and Navier-Stokes equation for liquid flow.Dimensional analysis indicates that electric-Viscous force depends on three factors:(1)Electric-viscous number representing a ratio between maximum of electric-viscous force and pressure gradient in a steady state,(2)profile function describing the distribution profile of electro-viscous forcein channel section,and(3)coupling coefficient reflecting behavior of amplitude damping and phase Offset of electro-viscous force.Analytical results indicate that flow-induced electric field and flow velocity depend on frequency Reynolds number(Re=wh2/v).Flow-induced electric field varies very slowly with Re when Re＜1.and rapidly decreases when Re＞1.Electro-viscous effect on flow-induced electric field and flow velocity are very significant when the rate of the channel width to the thickness of electric double layer is small.