微通道周期流动电位势及电粘性效应

求解了双电层的Poisson-Boltzmann方程和流体运动的Navier-Stokes方程，得到在周期压差作用下，二维微通道的周期流动电位势，流动诱导电场和液体流动速度的解析解．量纲分析表明，流体电粘性力与以下3个参数有关:1) 电粘性数，它表示定常流动时，通道最大电粘性力与压力梯度的比；2) 形状函数，它表示电粘性力在通道横截面的分布形态； 3) 耦合系数，它表示电粘性力的振幅衰减特征和相位差．分析结果表明，微通道周期流动诱导电场、流动速度与频率Reynolds数有关．在频率Reynolds数小于1时，流动诱导电场随频率Reynolds数变化很慢．在频率Reynolds数大于1时，流动诱导电场随频率Reynolds数的增加快速衰减．在通道宽度与双电层厚度比值较小情况下，电粘性效应对周期流动速度和流动诱导电场有重要影响．

Periodical Streaming Potential and Electro-Viscous Effects in Microchannel Flow

An analytical solution of periodical streaming potential, flow-induced electric field and velocity of periodical pressure-driven flows in two-dimensional uniform microchannel based on Poisson-Boltzmann equations for electric double layer and Navier-Stokes equation for liquid flow was presented. Dimensional analysis indicates that electric-viscous force depends on three factors: 1) Electricviscous coefficient representing a ratio of maximum of electric-viscous force to pressure gradient in steady state; 2) Profile function describing distribution profile of electrio-viscous force in channel section; 3) Coupling coefficient reflecting behavior of the amplitude damping and the phase offset of electro-viscous force. Analytical results indicate that flow-induced electric field and flow velocity depend on frequency Reynolds number. Flowinduced electric field varies very slowly when frequency Reynolds number is less than 1, and rapidly decreases when frequency Reynolds number is larger than 1. Electro-viscous effect on flow-induced electric field and flow velocity are very significant when the rate of the channel width to the thickness of electric double layer is small.