采用层流Navier—Stokes方程和离子分布Boltzmann方程建立圆形微通道内压力驱动流的数学模型,分别采用Navier滑移条件和电流密度平衡条件描述微流动边界速度滑移和动电效应,应用有限元法分析边界效应对微流动的影响。结果表明:微流动受边界效应的作用不容忽视,圆形微通道边界滑移效应对流动有促进作用而动电效应有阻滞作用;当微通道内同时存在2种边界效应时,边界滑移效应对流动的影响随着壁面ζ电势的增大而逐渐减弱,在高壁面ζ电势时影响甚微,几乎可以忽略。
The Navier-Stokes equation for liquid flows and the Poisson-Bohzmann equation for ion distribution were established for a mathematic model of pressure-driven flow through circular microehannels. The boundary slip and electrokinetic effects were described by the Navier slip condition and electric current density balancing condition. Using the finite element simulation, the electrokinetic flow behaviors with wall velocity slip were discussed. The results showed that the boundary effects on fluid flow in circular microchannels could not be ignored, and the boundary slip effects promote the flow development while the electrokinetic effects restrain the development of liquid, and considered two kinds of boundary effects, the effect of boundary slip effects gradually weakened with the wall ζ potential, even it could be ignored under a high wall ζ potential.