Numerical simulation of the dynamic response due to discharge initiation of the grain silo
The evolution of the stress distribution inside storage silos is an inherent effect in the dynamic operations of handling granular materials. Opening a discharge gate may result in a sudden increase in the lateral pressure with a simultaneous ramp down of vertical pressure, which generates severe pulsations of bin structures.
In the reported study, numerical simulations of the discharge initiation of a grain silo were performed. Discrete element method (DEM) simulations were carried out in a flat-bottomed cylindrical container 0.12 m in diameter and 0.5 m high. One hundred eighteen thousand polydisperse spherical particles with a diameter of 3.79 ± 0.05 mm and material parameters of wheat were used. Based on DEM modeling, the propagation of a rarefaction–compaction wave up the silo height during the start of the bin discharge was studied. It was found that the passage of the rarefaction wave resulted in dynamic changes of all considered micro- and macro- variables describing the behavior of the bulk of solids: particle-to-particle forces, averaged stress tensor, pressure exerted by particles on the bin structure and bulk characteristics of the material: the mobilization of particle–wall and particle–particle frictions and the lateral-to-vertical pressure ratio.
Keywords: granular solids, silo discharge, dynamic pressure switch, pressure wave.