SuperDEM Simulation and Experiment Validation of Nonspherical Particles Flows in a Rotating Drum

Understanding the flow behaviors of nonspherical particles is critical for rotating drum design and optimization. Rotating drum experiments of particles of different properties were conducted and the flow behavior was investigated by high-resolution camera recordings. The superquadric discrete element method (SuperDEM) was employed to simulate the spherical and nonspherical particle flows and validated by comparing the simulation results with the experimental data. A sensitivity study shows that angles of repose of spheres, cubes, and green beans were approximately constant when the friction coefficient was larger than 0.3, while for cylindrical shape particles, angles increased continuously until μ was 0.6. To study the impact of shapes, the validated model was applied to simulate particles of different shapes with the same density and volume. It was found that cylindrical particles with smaller sphericity had larger repose angles and were packed more densely than spheres, and the relationship between sphericity and angle was nonlinear. Nonspherical particles had a higher kinetic energy conversion efficiency, and cylinders’ and cubes’ average rotational kinetic energies were also larger than that for spheres. The ratio of the rotational kinetic energy to the total kinetic energy of cylinders was up to 10.59%, which indicated the significant impacts of particle shapes. Besides, particle shapes significantly affect the anisotropic distribution of the normal contact forces, especially for cylinders and cubes.