Hydrodynamics of electroosmotic flow in a microchannel with porous wall

TL;DR

This study derives an analytical solution for electroosmotic and pressure-driven flow in microchannels with porous walls, aiding better design of microfluidic devices by understanding velocity and pressure profiles.

Contribution

It presents a novel analytical solution for combined electroosmotic and pressure-driven flow in porous-walled microchannels, including effects of key parameters.

Findings

Velocity profiles reduce to known solutions in special cases

Pressure drop profile along the channel was obtained

Effects of wall suction, electrolyte concentration, and channel height were analyzed

Abstract

Microchannel with porous wall has various microfluidic applications including iontophoresis, diagnostic devices, etc. In order to have an efficient and better design of such devices, exact quantification of velocity field in the microchannel needs to be established. In the present study, an analytical solution of velocity field in a microchannel with porous wall was obtained for a Newtonian fluid in case of a combined electroosmotic and pressure driven flow using perturbation technique. The velocity profile was reduced to well known solutions for three asymptotic cases, namely, purely electroosmotic flow and purely pressure driven flow in an impervious conduit as well as pressure driven flow with permeable wall. The pressure drop profile along the channel length was also generated. Effects of operating parameters, i.e., wall suction velocity, electrolyte concentration and channel half height on velocity and pressure fields were also investigated.