Movement initiation of millimeter particles on a rotating rough surface: The role of adhesion_中国颗粒学会

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Partic. vol. 53 pp. 92-99 (December 2020)
doi: 10.1016/j.partic.2020.02.004

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

Karina de los Ángeles Valenzuela Aracenaa, Rodolfo O. Uñaca, Irene Ippolitob, Ana M. Vidalesa,*

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avidales@unsl.edu.ar

Highlights

    • Experiments for movement initiation of beads by centrifugation. • Evidence that adhesion forces are important in millimeter particles for certain materials. • A simple theoretical model with an adhesion term between surfaces can describe the results. • Up to one order of magnitude difference in forces is needed for detachment of 3- to 8-mm particles.

Abstract

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.

Keywords

Detachment; Adhesion; Centrifugation