Effect of boundary slip on electroosmotic flow in a curved rectangular microchannel

Abstract

The aim of this study is to numerically investigate the impact of boundary slip on electroosmotic flow (EOF) in curved rectangular microchannels. Navier slip boundary conditions were employed at the curved microchannel walls. The electric potential distribution was governed by the Poisson-Boltzmann equation, whereas the velocity distribution was determined by the Navier-Stokes equation. The finite-difference method was employed to solve these two equations. The detailed discussion focuses on the impact of the curvature ratio, electrokinetic width, aspect ratio, and slip length on the velocity. The results indicate that the present problem is strongly dependent on these parameters. The results demonstrate that by varying the dimensionless slip length from 0.001 to 0.01 while maintaining a curvature ratio of 0.5, there is a two-fold increase in the maximum velocity. Moreover, this increase becomes more pronounced at higher curvature ratios. In addition, the velocity difference between the inner and outer radial regions increases with increasing slip length. Therefore, the incorporation of the slip boundary condition results in an augmented velocity and a more non-uniform velocity distribution. The findings presented here offer valuable insights for the design and optimization of EOF performance in curved hydrophobic microchannels featuring rectangular cross-sections.