微流道壁面粗糙度影响的电渗流数值模拟

Numerical Simulation of Surface Roughness Effect on Electroosmotic Flow in Microchannels

基于微流控动力学理论,应用有限元分析方法求解二维平板粗糙壁面微流道模型内矩形截面双电层场和速度场的耦合控制方程。从数值模拟角度研究不同矩形粗糙元对称分布微流道内的电渗流流动特性,分析了粗糙度对微流体流动的影响机理。结果表明:由于粗糙元的阻力作用,粗糙壁面流道内流体速度减小,引起的压力突变导致壁面附近速度出现波动。随着粗糙元高度、宽度的增加,电渗流流速相应地降低或升高。

Based on the kinetic theory of micro-fluidic control, the coupling equations governing the electric double layer field and the velocity field in the cross-section of rectangular microchannels are numerically solved by applying the finite element analysis method in the 2D microchannel with rough surface between two parallel plates. From the numencal simulation aspect, the electroosmotic flow in microehannels has been simulated, while rectangular roughness element can be symmetrically, asymmetrically or randomly distributed in the channels. The key effect of surface roughness on the mierofluid is also studied. The result presents that ： because of the resistance of roughness, the electroosmotic flow velocity in the microchannel reduces; and the negative pressure, which is due to the roughness element, leads to the fluctuation of the velocity curve. With the increase of the height or the width, the flow velocity reduces or increases correspondingly.