A study on the influence of particle shape and shape approximation on particle mechanics in a rotating drum using the discrete element method

• Increase of the dynamic angle of repose with decreasing particle sphericity
• Faster mixing of spheres, no significant differences between the dices
• Good DEM predictions of dynamic angle of repose, but overprediction of mixing rates
• Sharply-edged geometries promote interlocking and formation of pile ups.

In this study experimental and numerical investigations with the discrete element method (DEM) on the mechanical interactions of spheres and polyhedral dices in a rotating drum are conducted. In DEM the dices are approximated by polyhedra and smoothed polyhedra respectively and hence allow examining the influence of sharply-edged and smooth particle geometries on the mechanical behavior. Simulation results are in good general agreement with the experiments and hence demonstrate the adequacy of DEM as well as polyhedral and smoothed polyhedral approximation schemes to simulate non-spherical particle geometries. It was observed that an increase of particle angularity leads to an increase of the dynamic angle of repose. On the other hand, while spheres mix faster than the polyhedral dices, no significant difference in the mixing behaviors of the dices can be observed.

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