微通道中电渗流滑移现象的数值模拟

Numerical Simulation of Electroosmotic Flow Slip in Microchannels

为了研究疏水表面微通道中电渗流(EOF)的输运及滑移特性,针对具有特定滑移长度的疏水表面微通道,建立了微通道EOF的控制方程。基于有限元分析方法对微通道EOF进行了数值模拟,分析了微通道高度、外加电场强度和固液界面边界滑移长度等对EOF的影响。结果表明,疏水表面和亲水表面微通道EOF的瞬态过程相似,稳态时间尺度在毫秒量级,大小与微通道尺度的平方成正比,符合黏性扩散定律;EOF速度大小与电场强度和边界滑移长度成正比,与微通道高度无关。

In view of the parallel-plate microchannel with the hydrophobic surface,the governing equations were solved using the finite element method,and the effects of microchannel height,electric strength and slip length on electroosmotic flow （EOF） were investigated,for studying the transporting and slip characterstics of EOF in hydrophobic microchannel. The simulation indicates that the transient characteristics of EOF are similar in hydrophobic and hydrophilic microchannels,the steady time of EOF is proportional to the square of microchannel height,and the scale is microsecond,which accords with the classical viscous theory.EOF velocity is proportional to the electric strength and slip length and independent of the channel height.