Predicting flow mode in cylindrical hopper

Most of the problems associated with industries handling solids are related to hopper flow. Hoppers may develop slow and sluggish zones, commonly known as stagnant zones, leading to funnel flow which reduces the efficiency of the process. Modelling can be used to predict the hopper flow based on material properties and hopper design. We have simulated the flow in a cylindrical hopper and validated it by performing 3D experiments. Further the model is used to investigate the effect of material properties and hopper design. It was found that stagnant zone size increases with increase in internal friction angle and decrease in ability of granular material to transfer load. It is also observed that stagnant zone size decreases as hopper angle is increased. Optimum hopper angle can be calculated from the simulation to minimise hopper height. This model can further be used for predicting flow for more complex conditions.

► Stagnant zone size increases with increase in internal friction angle.
► Stagnant zone size increases with decrease in ability of granular material to transfer load.
► Stagnant zone size decreases as hopper angle is increased.
► Optimum hopper angle can be calculated from the simulation to minimize the hopper height.