RedOx-based magnetohydrodynamic MHD flows in three-dimensional microfluidic channels are investigated theoretically with a coupled mathematical model consisting of the Nernst-Planck equations for the concentrations of ionic species, the local electroneutrality condition for the electric potential, and the Navier-Stokes equations for the flow field. A potential difference is externally applied across two planar electrodes positioned along the opposing walls of a microchannel that is filled with a dilute RedOx electrolyte solution, and a Faradaic current transmitted through the solution results. The entire device is positioned under a magnetic field which can be provided by either a permanent magnet or an electromagnet. The interaction between the current density and the magnetic field induces Lorentz forces, which can be used to pump and/or stir fluids for microfluidic applications. The induced currents and flow rates in three-dimensional 3D planar channels obtained from the full 3D model are compared with the experimental data obtained from the literature and those obtained from our previous two-dimensional mathematical model.Aclosed form approximation for the average velocity flow rate in 3D planar microchannels is derived and validated by comparing its predictions with the results obtained from the full 3D model and the experimental data obtained from the literature. The closed form approximation can be used to optimize the dimensions of the channel and to determine the magnitudes and polarities of the prescribed currents in MHD networks so as to achieve the desired flow patterns and flow rates.
Density; Electrolyte solutions; Lorentz force; Magnetohydrodynamics; Mathematical models; Microfluidics; Oxidation-reduction reaction; Speed
Aerodynamics and Fluid Mechanics | Applied Mathematics | Engineering | Fluid Dynamics | Mechanical Engineering | Nanoscience and Nanotechnology
Copyright AIP Publishing used with permission
Kabbani, H. S.,
Modeling RedOx-Based Magnetohydrodynamics in Three-Dimensional Microfluidic Channels.
Physics of Fluids, 19(8),