Particle-Fluid Dynamics in Narrow Slit Settler Driven by Asymmetric Feed

Abstract

The asymmetric feed addition of a slurry consisting of water and ballotini particles (glass beads), 63–75 μm in diameter, into a narrow slit settler was investigated. The vessel was 2.5 m long, 1.2 m high, and 0.015 m in horizontal depth. The presence of the solid particles in the feed caused a shift in the plume angle, from the vertical direction to a near horizontal direction. The change in the angle increased sharply to an asymptotic value as the solids loading was increased and more gradually as the position of the feed entry was shifted farther from the position of symmetry. Apart from producing an interesting phenomenon, this study demonstrated clearly that, in modeling sedimentation it is sometimes necessary to consider the effect of solids concentration gradients on convection of the suspension. Coupling of the hydrodynamic and particle transport equations may therefore become necessary. The shift in the feed plume angle was a consequence of a pressure gradient associated with having, effectively,...