Particle-Scale Characterization of Spout Deflection in a Spout Fluidized BED

Spout deflection is a common instabilityphenomenon in spoutfluidizedbeds. However, spout deflection wasnot well characterizedand quantified in the past. In this work, spout deflection in a flat-bottomed spout fluidizedbed is investigatedat the particle scale by means ofComputer Fluid Dynamic-Discrete Element Method (CFD-DEM) coupling approach. Two types of spout deflections - alternating and non-alternating spout deflections are captured by the CFD-DEM simulationsandqualitatively analyzedin terms ofvoidage distributionsand particle momentum profiles. Spout deflection angle is defined and used to characterizethe intensity of spout deflection quantitatively. Then, the effects of spouting velocity on alternating spout deflection are investigated quantitativelyusing the spout deflection angle. The simulation results indicate that spouting velocity has a limitedeffect on the amplitude and frequency of alternating spout deflection. Thecomparisons between solid flow pattern and spout deflection anglealso show that spout deflection angle is highly relevant to particle distribution non-uniformity at the upper region of the bed. The study offers a cost-effective tool to characterizeand quantify spout deflection in a spout fluidized bed.