Granular Flow through a Wedge-shaped Hopper: Discrete Element Method Simulations for the Smooth Wall, Radial Gravity Problem

The gravity flow of particulate solids occurs in various industries. The simplest version of the flow is a wedge-shaped, quasi-two-dimensional geometry with smooth walls and a gravitational force that is directed radially towards the apex of the wedge. Theoretical analysis of the flow using the Mohr-Coulomb criterion

was carried out in the classical work of Savage (1965) and using a critical state theory by Ravi Prakash and Rao (1988). Discrete Element Method simulations are carried out on particles for the smooth-wall radial gravity (SWRG) hopper to test the existing theories. Our computational results match the predictions of the theories of Savage and Rao, except for the region close to the exit, where both frictional and viscous effects are present. To further comprehend this behaviour, a parametric study is performed. The conclusion is that velocity increases as the flow rate increases but decreases as the wedge angle and friction coefficient increase. It is anticipated that stresses at the exit are caused by the transfer of momentum transfer between collisions. It is shown that viscosity and volume fraction have power law relations with the inertial number and data collapsed into a single curve.