Concentration dependence of cation-induced electrohydrodynamic flow passing through an anion exchange membrane
Concentration dependence of cation-induced electrohydrodynamic flow passing through an anion exchange membrane
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DOI：
10.7567/jjap.56.097201
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发表时间：
2017-09-01
影响因子：
1.5
通讯作者：
Kawano, Satoyuki
中科院分区：
文献类型：
--
作者：
Yano, Ayako;Shirai, Hiroki;Kawano, Satoyuki
电液动力(EHD)流动是一种由外加电力驱动的液体流动。在电解质溶液中，阴离子和阳离子通常相互作用以保持电中性。在这种情况下，很难通过施加1V数量级的电位来驱动液体流动；至少需要几十伏才能产生EHD流动，这可能不是水溶液的首选。在这项研究中，我们提出了一种新的方法来产生液体流通过横截面尺寸为1×1 mm(2)的通道，该通道被放置在离子交换膜中以分离阳离子和阴离子的传输路径。采用优化设计的实验装置，在2.2V的较低电势下，成功地在水溶液中产生了EHD流动，并用粒子图像测速仪在较宽的电解液浓度范围内测量了流动速度。结果表明，高浓度梯度导致离子通过通道的快速放电，并有助于获得约1 mm/S的流动速度。本文还用N-S方程对外电场中非平衡离子输运驱动的离子阻力流进行了理论解释。只有当离子传输路径得到很好的控制和有效的整改时，这种流量产生方法才是实用的。这一发现将有助于开发一种有前景的多尺度流道中液体流动的控制技术。(C)2017日本应用物理学会
Electrohydrodynamic (EHD) flow is a type of liquid flow driven by an external electric force. In electrolyte solutions, anions and cations usually interact with each other to maintain electroneutrality. Under such a condition, it is difficult to drive a liquid flow by applying electric potentials on the order of 1 V; at least a few tens of volts is required to generate EHD flows, which may not be preferable for aqueous solutions. In this study, we propose a novel method of generating a liquid flow through a channel with cross-sectional dimensions of 1 x 1 mm(2), which is placed in an ion exchange membrane to separate the cation and anion transport pathways. When the optimized design of the experimental apparatus was used, EHD flows were successfully generated in aqueous solutions by applying a relatively low electric potential of 2.2 V, and the flow velocity was measured over a wide range of electrolyte concentrations by particle image velocimetry. It was found that high concentration gradients caused the rapid discharge of ions passing through the channel and contributed to achieving a flow speed on the order of 1 mm/s. EHD flows were also theoretically explained using the Navier-Stokes equations to model an ion-drag flow driven by nonequilibrium ion transport in external electric fields. This flow generation method is practical only when ion transport pathways are well controlled and effectively rectified. The present findings will lead to the development of a promising technology to control liquid flows in multiscale fluidic channels. (C) 2017 The Japan Society of Applied Physics