Hoppers are widely used in many engineering processes. The discharging of granular mate- rials from a hopper is a critical topic of industrial importance, and the discharge flow rate from hoppers is the focus of the current work. Many parameters influence the discharge rate including: the hopper outlet width, the angle of the hopper wall, the particle size, and particle friction, and so on. Due to the expensive of examining a large variety of particle types and hopper conditions, computational simulation has been widely studied in an effort to establish an alternative method of determining critical factors impacting hopper flow.
In this thesis, the process of hopper discharge has been simulated by the Discrete Element Method (DEM), which is one of the most popular methods for granular flow simulation. To validate against existing experiments, all conditions were matched as closely as possible to those in the experiment. The particles used in our simulation are spheroids with diameters of 0.77 cm. The angles of the hoppers examined range from 0◦ to 90◦, while the opening sizes vary from 2.9 cm to 4.3 cm. Computationally, the friction coefficient has been adjusted several times and finally is set to 0.5 in the simulation in order to fit the experimental resultsas closely as possible. As a quantitative test of the simulation fidelity we compare the hopper empty time t – which is related to the hopper discharge rate – for these different hopper angles and hopper opening size. As a secondary test of the fit, the survival time τ, the normal force profile, the velocity profile, and the probability of jamming Ps are also computed and compared to existing experimental data from collaborators at Duke University. Ultimately, the goal of the work is to establish the degree of model fidelity necessary in order to closely mimic the experimental results obtained
