DEM simulations of rice grain flow by multi-sphere particles

Abstract

Discrele Element simulation of a rice grain flow was investigated. The multi-sphere (MS) model was developed for modelling elongated non-spherical particles and implemented into the DEM code DEMMAT. The main aim of the investigation was to study the performance of the model in numerical simulations of the rice grain flow and to validate it by experiments. A set of fixed 5000 poly-dispersed milled rice grains with measured dimensions were selected for the investigation purposes. They were characterised by constant aspects ratio 3.5, while their maximum size was ranging from 6.4 to 7.3 mm. Eleven sub-spheres were employed for modelling of each MS particle. Grains were poured into a wedged-shaped hopper made of plexiglass. Filling and discharge flow as well as piling were simulated numerically with and without rolling resistance of particles. Good agreement of numerical and experimental results in terms of the discharge time and repose angle of the pile was reached simultaneously, when rolling resistance was introduced.