The flow of granular solids through orifices

Abstract The factors affecting the flow of granular solids through orifices of different diameter and shapes under gravity conditions has been investigated at various heads. Different granular materials such as sand, sugar, rape seed, wheat and rice were used and the best equation was found to be:— where W is the weight discharged per second, ϱB the bulk density of the solids, A is the flow area of the orifice of hydraulic diameter Dhd is the average arithmetic screen diameter and λ is the average shape factor of the particles. The effect of head and container diameter was found to be insignificant in the 347 runs used in the statistical analysis. The equation allows the prediction of flow rates through various orifices with an over-all accuracy of ± 10 per cent.