微通道内交变电场电渗流有限元分析

Finite Element Analysis of Electroosmotic Flow in Alternating Electric Field of Microchannels

基于有限元方法,以粘性不可压缩流体N-S方程和双电层P-B方程为基础,建立交变电场驱动微通道电渗流模型,并进行数值模拟,分析溶液浓度、电场强度和微通道高度对电渗流的影响。结果表明,微通道内双电层滑移速度与电场强度成正比,受微通道高度影响较小,随溶液浓度的增大非线性减小。同时,微通道高度和溶液浓度的增加使双电层相对厚度减小,交变电场电渗流瞬时速度的波峰更加尖锐。该结论为微通道内交变电场电渗流精确控制提供了理论参考。

The mathematical models of electroosmotic flow in the alternating electric field is established based on the N-S e-quation for viscous incompressible fluid and the P-B equation for electric double layer, and numerical simulation of electroos-motic flow in microchannels is also completed based on the finite element method.The influence to EOF by the solution con-centration, the electric field intensity and the microchannel height are analyzed.The simulation results show that the slip ve-locity of electric double layer in microchannel is proportional to the electric field intensity, and it is less affected by the micro-channel height, and nonlinearly decreases with the increasing of solution concentration.Besides, the thickness of electric double layer is decreasing with increases of the microchannel height and solution concentration, and the wave crest of transient velocity distribution is more spiculate.The conclusion provides theoretical reference for accurately controlling the electroosmot-ic flow of the alternating electric field in microchannels.