(21g) Assessing the Discharge Performance of Hoppers Using the Discrete Element Method

The performance of hoppers has been fairly well studied both experimentally and theoretically. In this work, the discrete element method (DEM) is used to assess hopper performance and the results are compared to widely-used empirical or theoretical relations. These include the Beverloo correlation for hopper discharge rate and the Jenike hopper design charts that specify the necessary material properties and hopper wall angle required to obtain mass flow. The flow of frictional, non-cohesive, bidisperse granular mixtures through hoppers of various wall angles is modeled. In each case, the performance is assessed through measurement of the discharge rate and the extent of segregation during discharge, as well as characterization of the flow pattern as mass-flow, funnel-flow, or some intermediate. The flow pattern is characterized in a quantitative manner using the material velocity profile. The discharge rate results are in excellent agreement with those predicted by the Beverloo correlation. Similarly, the flow characterization results are in good agreement with the Jenike design charts. These favorable results indicate that DEM can not only reproduce the current estimates of hopper performance, but also provide additional insight into the flow ? such as the internal granular structure ? that may be difficult to obtain otherwise.