Numerical simulation of particle motion in a gradient magnetically assisted fluidized bed

Flow behavior of magnetizable particles is simulated in a two-dimensional gradient magnetically assisted bubbling fluidized bed. The motion of particles is simulated by discrete element method (DEM) with the consideration of external magnetic forces at a constant gradient magnetic field along bed height. The distributions of velocity and concentration of magnetizable particles are analyzed at the different magnetic field intensities. The simulations show a significant effect on the motion of particles with vertical magnetic-fields applied. 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 in the direction of the magnetic field. At very high magnetic field strengths, defluidization is observed. Gas pressure drop of bed decreases with the increase of magnetic-flux densities. The granular temperature of particles increases, reaches a maximum, and then decreases with the increase of magnetic-flux density. Through the analysis of the motion of particles, it is concluded that the moderate strength magnetic field gives a high fluctuation of particles and distribute gas more evenly in the bed.

Graphical AbstractNumerical simulations show that at moderate field strengths the granular temperature of particles increases, reaches maximum, and then decreases with the increase of concentration of particles in a gradient magnetically assisted fluidized bed. At very high field strength, the particles form visible strings throughout the bed, and the granular temperature of particles is close to zero in the bed.Figure optionsDownload as PowerPoint slide