INVESTIGATION OF MASS DISCHARGE RATE AND SEGREGATION FROM HOPPER BY DISCRETE ELEMENT METHOD

Hoppers of different shape and angle are widely used in different industries particularly in handling of solids as storage units and in unit operations, e.g. mixing, tableting, etc. It is a challenge to choose a right hopper to achieve desired flow and insignificant segregation due to difference in material properties. General approach for the selection of optimum hopper for a given unit operation is based on the trial-and-error experimental approach. To address this optimum hopper selection, combined experimental and numerical approach is presented in this study. The objective of this study is to analyze the effect of mixture composition and hopper angle on the flow rate and segregation behavior. The numerical simulation of granular flow out of various conical hoppers was also performed using the discrete element method (DEM). The materials considered include different particle size glass bead particles in different proportions by mass. The experimental study is done to validate the DEM results, particularly, mass flow rate. The results analyzed include temporal development of mass fraction of a given particle size during discharge. In addition, the mass flow rate is also computed. The results indicate that fines percentage in the mixture, ratio of smallest particle size to largest in the mixture, and hopper angle plays significant role in determining the segregation and mass flow rate. The flow pattern found to be influenced by the hopper angle and mean particle size of mixture. The results of discharge rate from DEM are also compared with existing empirical correlations and finite element method based elastoplastic model. The DEM prediction shows a good agreement with the existing correlations for a wide range of hopper angles, and with the experimental data.