Super-quadric CFD-DEM study of spout deflection behaviour of non-spherical particles in a spout fluidized bed

Abstract

Non-spherical particles are commonly encountered in chemical engineering processes including fluidization processes, yet their instability phenomena still lack understanding. In this study, the spout deflection – a typical instability phenomenon of non-spherical particles in a pseudo-two-dimensional (pseudo-2D) spout fluidized bed is first studied by a super-quadric computational fluid dynamics-discrete element method (super-quadric CFD-DEM) model. The intensity of spout deflection is quantified by the spout deflection angle concept. The effect of particle shape (i.e., sphere, cubic, ellipsoid, and cylinder) on the flow in terms of flow pattern, spout deflection, pressure drop, particle orientation, and normal contact force is systematically studied and compared by the time- and frequency-domain analysis. It shows that the spout channel becomes narrower for cubic, ellipsoid and cylinder particles where the particle aspect ratio increases. With the increase of spouting gas velocity, the median value of the spout deflection angle decreases and increases for cubic and ellipsoid particles, respectively. Furthermore, the pressure drops in the vertical and horizontal directions of the cubic, ellipsoid, and cylinder particles are different from each other. At last, In the bed of cubic particles, the ordered arrangements appear close to the wall region and random arrangements occur in the other regions. This work reveals the influences of non-spherical particles on spout deflection and offers insights into practical applications through optimal operation.