Flows of granular particulates are important in many fields of engineering, such as the processing of chemical powders and construction materials. Recently, the use of granular material has been considered in high temperature solar energy systems. The design of chutes and hoppers for particulates is important to such applications.
To support the design of such components, combined experimental and computer simulated investigations have been conducted. Flow regimes of small glass marbles draining out of a hopper are studied both in physical lab-scale experiments, and using discrete element method (DEM) computer simulations. First, the discrete element method and previous studies of granular flow from hoppers are reviewed. Then, an experimental apparatus is built and used to study the flow of small glass marbles from two different hopper geometries: a quasi-three dimensional wedge hopper, and a three dimensional tetragonal hopper. In addition, using sand paper, each hopper geometry is studied under the effects of smooth walls and rough walls. These experiments and then duplicated using DEM software. The results of the computer simulations are compared with the results of the lab scale flow tests, and with each other. The DEM simulations show reasonable agreement with the appropriate experimental flow. However, uncertainty in certain material properties is shown to produce results that can diverge significantly. Finally, the feasibility of using DEM as a means of simulating granular flows is discussed.