Simulation of flow behaviour of bulk solids in bins .2. Shear bands, flow corrective inserts and velocity profiles

Flow behaviour of idealized particles (discs) in parallel wall model bins of various shapes is simulated using the discrete element method. The emphasis is on two distinct aspects: occurrence of shear bands and use of flow corrective inserts. The results indicate that there exist voids in the bulk mass and discontinuities in the velocity field of idealized bulk solids flowing out of bins. The localized failure modes in the form of narrow layers are interpreted as shear bands characterized by three mechanisms, viz., heterogeneity, intensive rotation and dilatancy. The results of parametric studies show that particle properties and outlet size influence the formation and development of shear bands. Flow corrective insert placed at an optimum height can reduce stagnant zones, stabilize discharge rate and enhance uniform flow. (C) 1995 Silsoe Research Institute