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Electroconvective vortex on an Ion Exchange Membrane under Shear Flow

전단흐름 하에 이온교환막 위에서 발생하는 전기수력학적 와류

  • Kwak, Rhokyun (Department of Mechanical Engineering, Hanyang University)
  • Received : 2018.04.01
  • Accepted : 2018.04.25
  • Published : 2018.04.30

Abstract

Ion exchange membrane can transfer only cation or anion in electrically conductive fluids. Recent studies have revealed that such selective ion transport can initiate electroconvective instability, resulting vortical fluid motions on the membrane. This so-called electroconvective vortex (a.k.a. electroconvection (EC)) has been in the spotlight for enhancing an ion flux in electrochemical systems. However, EC under shear flow has not been investigated yet, although most related systems operate under pressure-driven flows. In this study, we present the direct visualization platform of EC under shear flow. On the transparent silicone rubber, microscale channels were fabricated between ion exchange membranes, while allowing microscopic visualization of fluid flow and ion concentration changes on the membranes. By using this platform, not only we visualize the existence of EC under shear flow, its unique characteristics are also identified: i) unidirectional vortex pattern, ii) its advection along the shear flow, and iii) shear-sheltering of EC vortices.

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