Locally ionized MHD flows in the nonuniform magnetic field

Sheikin, E. G.

doi:10.1088/0022-3727/42/3/035201

Cited by 6 publications

(1 citation statement)

References 22 publications

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“…This MHD force, F B (N m −3 ), occurs when charged particles move at right angles to a magnetic field and is calculated as the cross product F B = j × B, where j represents ionic current density (A m −2 ) and B is magnetic induction (T). [1][2][3][4] In MHD, the moving charges can be those in ionized gas (plasma), 5,6 electronic current in liquid metals, 7 and ionic current in molten 8 and solvent-dissolved [1][2][3]9,10 salts. Its effect is to alter the direction of the moving charge, imparting momentum to the surrounding fluid, and so leads to increased mass transfer.…”

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confidence: 99%

Redox-Magnetohydrodynamics for Microfluidic Control: Remote from Active Electrodes and Their Diffusion Layers

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Gerner

Weston

et al. 2013

J. Electrochem. Soc.

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Localized, directed microfluidic flow in bulk solution, far from diffusion layers at active electrodes, was induced by redox-magnetohydrodynamics (MHD) using a magnet smaller than the distance between the electrodes to tune the flow. This “remote MHD” indicates that redox species are required only at active electrodes to sustain a faradaic current, not in the bulk where microfluidic control is desired. Thus, complete separation of redox species from sample and analyte, which can be achieved by ion-conducting barriers or electrode surface modifications, will boldly expand applications of redox-MHD in micro total analysis systems. Flow was effected in a model solution of ferricyanide/ferrocyanide and potassium chloride, between two sets of electrodes located 17.5 mm apart on a chip. A stack of two permanent magnets, 6-mm wide (one-third of the interelectrode distance), was positioned under the chip between electrodes, and a 30 μA electronic current was applied to the electrodes. The resulting ionic current led to a MHD force causing fluid flow of ≤16.9 μm/s above the magnet, determined by video microscopy of 10-μm latex-polystyrene microbeads and particle image velocimetry software. Calculations indicate that MHD is the major source of the observed flow, although the magnetic field gradient may affect the flow profile.

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