Movement initiation of millimeter particles on a rotating rough surface: The role of adhesion

We performed experiments to determine the critical moment for movement initiation of a millimeter bead on a rotating rough surface. The corresponding critical angular velocities were measured for glass and stainless-steel ball bearings over two different rough surfaces with glued glass beads. A basic theoretical analysis was developed to explain the observed results. Although the expectation of a simple approach with the presence of the obstacles offered by a rough surface could be sufficient to describe the problem, we prove here that the sole consideration of these obstacles, and even friction, are insufficient to explain the results in the range of a few-millimeter glass particles. Where the thermodynamic work of adhesion between surfaces is significant, the adhesion forces must be considered in the force balance for particle detachment. This effect is a determinant for describing theoretically and numerically the dynamics of millimeter particles. (C) 2020 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.