Numerical Study of an Electro-Osmotically Driven Microchannel Flow with Joule Heating Effect

Abstract

A convection-diffusion reaction scheme is applied to solve the transient transport equations for the prediction of steady electro-osmotic microchannel flow behavior. The governing equations for the total electric field include the Laplace equation for the effective electrical potential and the Poisson-Boltzmann equation for the electrical potential established in the electric double layer. The transport equations governing the hydrodynamic field variables comprise mass conservation equation for the electrolyte and equations of motion for the incompressible charged fluid flow subject to an electro-osmotic body force. The main aim of the study is to elucidate the effect of Joule heating, which can affect the electrohydrodynamic behavior. Investigation into the region near the negatively charged channel wall is made through the simulated velocity boundary layer, diffuse layer, and electric double layer.

Financial support provided by the National Science Council under Grants NSC97-2221-E-002-250-MY3, NSC97-2628-M-002-022, and CQSE project 97R0066-69 are gratefully acknowledged.