Implementation of lattice Boltzmann method to study mixing reduction in isothermal electroosmotic pump with hydrophobic walls

Abstract

The aim of the present work is to analyze the accuracy and to extend the capability of lattice Boltzmann method in slip EOF; a phenomenon which was previously studied by molecular dynamics and less considered by LBM. At the present work, a numerical experiment on boundary conditions of slip velocity is performed and the proportionality of slip with shear stress in electroosmotic pump is proved. Results show that LBM can capture the slip length in EOF with liquid operating fluid. Implementing slip velocity at the walls of a microchannel, the electroosmotic flow with adverse pressure gradient over a hydrophobic surface is investigated in view of mixing reduction. The fluid flow is assumed to be laminar, steady and viscous. Slip at the channel boundaries will decelerate the development process of the flow. Unlike no-slip condition, transverse change in velocity magnitude near the walls decreases and also more resistant pressure is required to create reverse centerline velocity; so mixing probability and performance of EOF pump can alter considerably.