Simulation of flow behavior of particles in liquid–solid fluidized bed with uniform magnetic field

Flow behavior of solid phases is simulated by means of DEM–CFD in a liquid–solid fluidized bed with magnetization of preliminarily fluidized bed (LAST) mode along an axial uniform magnetic field. By changing the magnetic field strength, the distribution of particles is studied within the bed. The distributions of velocity and concentration of ferromagnetic particles are analyzed at the different magnetic field intensities. When the magnetic field strength is increased to a value at which the fluidization of strings starts, the particles are found to form straight-chain aggregates along the direction of the magnetic field. At very high magnetic field strengths, the defluidization is observed at which particles are fixed in the bed. Simulations indicate that the granular temperature of particles increases, reaches a maximum, and then decreases with the increase of magnetic-flux density. The moderate strength magnetic field gives a high fluctuation of particles. The predicted solid pressure increases with the increase of concentration of particles.

It is demonstrated that the bed passes through three principal states with the different magnetic intensities: particulate fluidization at the low magnetic intensity and a magnetically aggregated or magnetically condensed bed at the high magnetic intensity. As liquid pass through the bed, it causes the formation of large channels across the bed. The chains are frozen in the bed.Figure optionsDownload as PowerPoint slideHighlights
► DEM–CDF is introduced into the numerical simulation of liquid–solid two-phase flow.
► By changing the magnetic field strength, the distribution of particles is studied.
► At very high magnetic field strengths, the defluidization is observed.
► The solid volume fraction is high near the inlet, and low at the bed surface.
► The granular temperature increases, reaches a maximum, and then decreases.