压力驱动微流道内流动电势及壁面滑移效应  

Streaming potential and wall slip effects on pressure-driven microchannel flow

作　　者：刘莹[1] 谭德坤[1,2] 

机构地区：[1]南昌大学机电工程学院,江西南昌330031 [2]南昌工程学院信息学院,江西南昌330099

出　　处：《化工学报》2013年第5期1743-1749,共7页CIESC Journal

基　　金：国家自然科学基金重点项目(50730007)~~

摘　　要：微流体系统在不同的工程领域获得了广泛应用,例如化学分析、生物和医学检测、能源供应及电子芯片散热等。在微流体系统中,微流道是介质输运的基础,各种功能部件之间均由它连接。微流道的水力直径在1μm～1mm,具有极大的表面积/体积比值,与常规尺度流道相比,微流道内最重要的现象就是固-液处的表面效应。This study investigated the streaming potential and wall slip effects on pressure-driven liquid flow in hydrophobic microchannels.The Poisson-Boltzmann equation for the electrical double layer（EDL）and Navier-Stokes equation for incompressible viscous fluid were established.For those microchannels with high wall zeta potential,the traditional Debye-Hückel linear approximation for solving the potential distributions of EDL would produce big error,therefore,analytical expression for potential distributions and Navier slip boundary condition were introduced to solve the N-S equation analytically,then analytical solution of streaming potential could be obtained by using the electrical current balancing condition.The influences of electrokinetic parameter（K）,wall zeta potential and slip coefficient on streaming potential and velocity distributions were discussed in detail.The results showed that streaming potential decreased with increasing electrokinetic parameter,while increased significantly with increasing slip coefficient.It also tended to reach a maximum value at a certain zeta potential and then decreased rapidly with increasing zeta potential.Streaming potential and wall slip both affected fluid flow in microchannels,the former retained the development of liquid flow,but the latter accelerated flow velocity.Wall slip effect played a major role at lower zeta potentials,that is,flow velocity increased at lower zeta potentials when the combined effects of streaming potential and hydrodynamic slippage appeared in microchannels.Wall slip velocity gradually reduced to zero at higher zeta potential,then wall slip effect on pressure-driven flow in microchannels could be ignored.

关 键 词：流动电势 壁面滑移效应 zeta电势 动电参数 微流道 

分 类 号：O647[理学—物理化学] TQ021[理学—化学]