Resistance effect of electric double layer on liquid flow in microchannel
Resistance effect of electric double layer on liquid flow in microchannel
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DOI：
10.1007/s10483-006-1011-1
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发表时间：
2006
影响因子：
--
通讯作者：
Lei Gong;Jian-kang Wu
中科院分区：
文献类型：
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作者：
Lei Gong;Jian-kang Wu
通过数值求解双电层的泊松-玻尔兹曼方程和液体流动的纳维-斯托克斯方程，研究了双电层的阻力对微通道内液体流动的影响。维数分析表明，双电层的电阻效应可以用电阻数来估计，电阻数与液体介电常数和固体表面zeta电位的平方成正比，与液体动态粘度、电导率和通道宽度的平方成反比。提出了一种“电流密度平衡”（ECDB）条件来评价流致流势，取代了传统的“电流平衡”（ECB）条件，后者可能在微通道固体壁面附近引起虚假的局部回流。文中还给出了流量损失比和速度分布的数值结果，以证明双电层在微通道中的电阻效应。
Poisson-Boltzmann equation for EDL (electric double layer) and Navier-Stokes equation for liquid flows were numerically solved to investigate resistance effect of electric double layer on liquid flow in microchannel. The dimension analysis indicates that the resistance effect of electric double layer can be estimated by an electric resistance number, which is proportional to the square of the liquid dielectric constant and the solid surface zeta potential, and inverse-proportional to the liquid dynamic viscosity, electric conductivity and the square of the channel width. An “electric current density balancing” (ECDB) condition was proposed to evaluate the flow-induced streaming potential, instead of conventional “electric current balancing” (ECB) condition which may induce spurious local backflow in neighborhood of the solid wall of the microchannel. The numerical results of the flow rate loss ratio and velocity profile are also given to demonstrate the resistance effect of electric double layer in microchannel.