Aeration and cohesive effects on flowability in a vibrating powder conveyor

A CFD-DEM model for aerated vibratory convection was developed to explore the coupled gas-solid interactions governing bulk powder bed dynamics. Each simulation was prepared by carefully characterizing the rough, porous conveyor baseplate and four candidate particle sizes representative of typical powder beds. Trends in the vibratory convection of particles between 20 and 250 mu m in diameter could be explained by considering each powder's minimum fluidization velocity and the magnitude of van der Waals cohesive forces. Simulations of fine powders under high cohesive forces exhibited competing effects from drag and cohesion; drag promotes powderfrit liftoff while cohesion suppresses contact separation. Experimental convection velocities were observed to be in good agreement with the simulated mean powder velocity for throw numbers between 0.25 and 0.50.

Automated summary

A CFD-DEM model was developed to investigate the interactions between gas and solid particles in bulk powder beds. The simulations considered the minimum fluidization velocity and van der Waals cohesive forces of different powder sizes, and explained the trends in particle convection. The simulations showed that fine powders under high cohesive forces experienced competition between drag and cohesion effects.