Magnetoviscous control of wall channeling in packed beds using magnetic nanoparticles—Volume-average ferrohydrodynamic model and numerical simulations

A theoretical framework for analyzing ferrofluid magnetoviscosity in anomalous non-magnetic porous media is constructed. Upscaling the pore-level ferrohydrodynamic model resulted in a volume-average model with 15 closure equations. A simplified zero-order three-dimensional axisymmetrical model for Forchheimer non-turbulent flows is cast for steady-state isothermal incompressible Newtonian ferrofluids through a Müller porous medium of spherically shaped grains and subjected to external constant gradient (bulk-flow oriented) magnetic fields, ferrofluid self-consistent demagnetizing field and induced magnetic field in the solid. The model reveals interesting potential chemical engineering applications of ferrofluids in contexts where wall flow maldistribution due to low column-to-particle diameter ratios exists. Judicious magnetic field arrangement mitigates wall channeling by inflating wall flow resistance through magnetoviscothickening and Kelvin body force density rerouting thus a fraction of wall flow towards bed core. Depending on whether the Kelvin force density acts against or in favor of the flow direction, the pressure drop is, respectively, larger or smaller than that without magnetic field, though, in all cases, magnetoviscothickening is the prevailing mechanism.