Effect of electrostatic interactions on particle dispersion in a rotating spherical container

Triboelectric charging and electrostatic interactions are commonly encountered in many powder handling pro-cesses. In this paper, the electrostatic behaviours of particles in a rotating spherical container were examined, in particular, the electrostatic dispersion of particles was recorded with a camera and then quantitatively analysed. The effects of the Coulomb's repulsive force and the attractive image force on the degree of particle dis-persion, the motion of individual particles, formation and geometrical shape of particle clusters were analysed. The results show that the degree of particle dispersion increases with the charging time until it achieves a satu-ration value. The particle cluster formation undergoes five distinctive regimes and is governed by the external forces from the container wall, while the collective effect of both the extra-particle force and the Coulomb's re-pulsive force determines the evolution of the cluster shape.(c) 2021 Elsevier B.V. All rights reserved.