Magnetohydrodynamic flow of RedOx electrolyte

Abstract

Magnetohydrodynamic MHD flow of a RedOx electrolyte in a straight conduit is investigated theoretically. Inert electrodes are deposited along segments of the opposing walls of a straight conduit that is filled with a RedOx electrolyte solution. The conduit is positioned in a uniform magnetic field. When a potential difference is applied across the opposing electrodes, the resulting current interacts with the magnetic field to induce Lorentz forces. The species' mass transport and the momentum equation are coupled and must be solved simultaneously. We compute the various species' concentration distributions, the current flux distribution, and the liquid's motion in the absence and presence of pressure gradients. The pressure gradients may either assist or oppose the MHD flow. At low potential differences, the current and the induced MHD flow increase nearly linearly as the potential difference increases. When the potential difference exceeds a certain critical value, the current and the flow rate saturate. We demonstrate that it is advantageous to use multiple electrode pairs with dielectric gaps between adjacent electrodes rather than a single electrode pair with an equivalent length. Finally, MHD flow with RedOx solution in the presence of abundant supporting electrolyte under limiting current conditions is analyzed using boundary layer theory. The approximate analytical solutions for the ions concentrations and the current agree well with the numerical solutions. Magnetohydrodynamic ͑MHD͒ flow of a RedOx electrolyte in a straight conduit is investigated theoretically. Inert electrodes are deposited along segments of the opposing walls of a straight conduit that is filled with a RedOx electrolyte solution. The conduit is positioned in a uniform magnetic field. When a potential difference is applied across the opposing electrodes, the resulting current interacts with the magnetic field to induce Lorentz forces. The species' mass transport and the momentum equation are coupled and must be solved simultaneously. We compute the various species' concentration distributions, the current flux distribution, and the liquid's motion in the absence and presence of pressure gradients. The pressure gradients may either assist or oppose the MHD flow. At low potential differences, the current and the induced MHD flow increase nearly linearly as the potential difference increases. When the potential difference exceeds a certain critical value, the current and the flow rate saturate. We demonstrate that it is advantageous to use multiple electrode pairs with dielectric gaps between adjacent electrodes rather than a single electrode pair with an equivalent length. Finally, MHD flow with RedOx solution in the presence of abundant supporting electrolyte under limiting current conditions is analyzed using boundary layer theory. The approximate analytical solutions for the ions' concentrations and the current agree well with the numerical solutions.

Thermal and flow analysis of two-dimensional fully developed flow in an AC magneto-hydrodynamic micropump

“…Eijkel et al (2003) developed and fabricated an AC magnetohydrodynamic micropump for chromatographic application. A new study of (MHD) flow is presented by Qian and Bau (2005). They studied theoretically the (MHD) flow of a RedOx electrolyte in a straight conduit, and solved the coupled momentum and advection equation.…”

Thermal and flow analysis of a magneto-hydrodynamic micropump

“…A new study of MHD flow is presented by Qian et al (2005). They studied theoretically the MHD flow of a RedOx electrolyte in a straight conduit, and solved the coupled momentum and advection equation.…”

Preparation of alpha sources using magnetohydrodynamic electrodeposition for radionuclide metrology

“…Mechanical stirring, however, may be inefficient and inappropriate in the analysis of small-volume samples, such as those in a microscale electrochemical cell. MHD convection can induce extremely fine mixing [18][19][20][21][22][23][24][25][26] and is nonintrusive, obviating the need to insert any moving part into the electrochemical cell for electroplating radioactive sources to the surface of the cathode. The fluid motion is generated by the Lorentz force, induced by the interactions of an external magnetic field and the electric current transmitted through the electrolyte solution in the electrochemical cell.…”