交流电场作用下具有导电率梯度的两相微流体驱动

姜洪原^1,2, 任玉坤¹, A.Ramos³

1.哈尔滨工业大学机械设计系;2.浙江大学流体传动及控制国家重点实验室;3.西班牙塞维利亚大学电子电磁学院



摘要:

为探讨微通道内多相流体驱动路径的控制方法,进行具有导电率梯度的交流电场致两相流体驱动实验,对沉积在微通道底部的指型交叉电极施加交流电信号,发现具有高导电率的流体会将低导电率流体挤出通道,并且占据整个通道,当不加电信号时,两相流体流动路径恢复初始状态.建立实验系统的二维理论模型,对两相流体交界面处由于电场与导电率梯度综合作用产生的净电荷和库仑力进行了推导,分析实验机理.利用电荷守恒方程、对流扩散方程以及Navier-Stokes方程对实验进行数值分析,通过仿真求解,得出微通道内流体的瞬时以及稳态变化规律,并重点分析频率对于两相流体控制过程的影响.结果表明:通过合理配制两相流体的导电率梯度,施以交流电场,能够有效控制两相微流体的流动路径,能够实现芯片在实验室系统中的多模块集成.

关键词:  导电率梯度  两相微流体控制  理论模型  数值分析

DOI：10.11918/j.issn.0367-6234.2011.02.022

分类号:O361.4

基金项目:国家自然科学基金资助项目(51075087);浙江大学流体传动及控制国家重点实验室资助项目(GZKF-201004)



Two-phase microfluid flow based on AC electric field and conductivity gradient



1.Department of Mechanical Design,Harbin Institute of Technology,150001 Harbin,China;2.The State Key Lab of Fluid Power Transmission and Control,Zhe Jiang University,310027 Hangzhou,China;3.Department of Electronics and Electromagnetism,University of Seville,41012 Seville,Spain)

Abstract:

To explore control method of multiphase fluid path,experiments of two-phase fluid path driving were carried out,during which when applying AC electric signal on the electrodes subjected on the microchannel,the fluid with higher conductivity would occupy the microchannel,and when the signals disappeared,the fluid path restored.A 2D analytical geometry model of the experimental system was proposed to deduce the net charges and Coulomb force at the interface and to analyze the system itself.By the charge conversation equation,convection-diffusion equation and Navier-Stokes equation,a numerical analysis has been done and the results show that the control of two-phase microfluid path can be achieved efficiently based on the logical conductivity gradient and electric field,which provides a theory basis for the integrated functions on lab-on-a-chip system.

Key words:  conductivity gradient  two-phase microfluid control  theoretical model  numerical analysis