(146e) DEM and Experimental Study of the Flow of Wet Granular Assemblies Under Dynamic Conditions

When added to flowing particles, liquid has a significant effect on the flow of granular assemblies. Using a combination of experimental study and discrete particle method simulations (DEM), we investigate the effects of capillary force, liquid viscosity and particle size on wet granular flows, and we establish a methodology that ensures the control of the bed flow motion in a rotating drum.

We show that the strength of capillary forces between two adjacent particles can be altered through surface modification of the glass beads. Thus, under the right conditions; we demonstrate that the bed flow motion in a rotating drum can be controlled and scaled. Liquid viscosity effect on the bed flow motion is also investigated under low capillary forces. The capillary force between the particles is significantly reduced by making the glass beads hydrophobic via chemical silanization. We find that liquid-induced cohesion decreases both, the width of the flowing region and the velocity of the particles in the free surface, but increases the width of the creeping region as well as the dynamic angle of repose. We show that the local granular temperature in the flowing region is affected by the capillary force. We then propose a scaling methodology that ensures the conservation of the bed flow using the Weber number. The scaling methodology in the flow regimes considered (rolling and cascading) yields similar bed flow for different particle sizes.