微通道内电场频率对电渗流影响的数值模拟  

Numerical Simulation of the Frequency of Electric Field Effecting on Electroosmotic Flow in Microchannels

作　　者：张磊[1,2] 刘莹[1] 

机构地区：[1]南昌大学机电工程学院,南昌330031 [2]青海大学机械系,西宁810016

出　　处：《机械设计与研究》2011年第3期35-38,共4页Machine Design And Research

基　　金：国家自然科学基金重点资助项目(50730007)

摘　　要：为研究二维微通道内交变电场电渗流速度特性,以双电层P-B方程和粘性不可压缩流体N-S方程为基础,建立交变电场电渗流的数学模型。应用有限元方法,对不同频率的交变电场电渗流进行数值模拟。结果表明,交变电场电渗流速度分布呈"波浪状",微通道中心区域速度滞后于壁面附近,当流体离壁面距离增大时,流体流速的滞后量增大。电场频率小于1 000 Hz时,交变电场电渗流与稳定电场电渗流具有相似的速度分布。随着电场频率的增大,"波浪状"速度流型更为明显,并且双电层滑移速度减小,尤其当电场频率大于3 000 Hz时,双电层滑移速度迅速下降。The mathematical models of electroosmotic flow driven by ac electric field based on P-B equation of electric double layer and N-S equation of viscous incompressible fluid were built,in order to study the velocity of alternant in 2D microchannels.Electroosmotic flow with different frequencies was numerically simulated by applying the finite element method.The results show that velocity distribution of alternant electroosmotic flow is ＂wave-like＂,the velocity in the middle of microchannels is lag behind that near the wall,and the lag of velocity increases as the distance between the fluid and the wall increases.The velocity distribution of alternant electroosmotic flow is similar to that of steady electroosmotic flow when the frequency of electric field is lower than 1 000Hz.With the increase of the frequency,the ＂wave-like＂ velocity distribution is more evident,and the slip velocity of double electric layer decreases.Especially,the slip velocity of double electric layer rapidly decreases when the frequency of electric field exceeds 3 000Hz.

关 键 词：微通道 双电层 交变电场 电渗流 电场频率 

分 类 号：O361.4[理学—流体力学]