Effect of zeta potential variation in single phase flow characteristics of a rectangular nanochannel

Abstract

This report presented a 2D model for electroosmotic (EOF) aqueous fluid flow analysis along nanochannels connecting two reservoirs. The model uses the Navier-Stokes equations with electroosmotic velocity boundary condition at nanochannel wall. Zeta potential of the wall surface is varied and the influences on the velocity profile are observed for various channel height. Shear stress rate near the nanochannel entrance of different width has also been investigated. The magnitude velocity lies on the magnitude of zeta potential or the surface charge of the wall. The increased charged on the solid wall, also increased the velocity flow. The decreased height of channel helps to increase the flow velocity along it. The maximum and minimum flow velocities are recorded at channel height of 50nm and 250nm respectively with 35% difference. At all simulated channel height, the flow at the entrance of nanochannel is increased and formed a peak velocity but it will decrease and become uniform at the position far from the channel wall. The shear stress at the reservoir-nanochannel edge is increased with the decreased of channel height due to low aspect ratio of reservoir-channel dimension.