Assessment of forces acting on fine particles on a traveling-wave electric field conveyor: Application to powder manipulation

The purpose of this work is to investigate the transport mechanism of fine dielectric particles using a traveling-wave electric field conveyor. In the first part of this study, an experimental bench is set up to evaluate the efficiency of particle displacement according to their size and to visualize their motion. The displacement efficiency is evaluated based on the ratio of the mass of transported particles to the total mass of particles deposited. The experimental setup allows us to measure the charge of particles as well. In the second part of this study, we discuss the experimental results based on the balance of forces exerted on particle in such a device. The particles studied are spherical PMMA particles having sizes ranging between 50 and 500 mu m. The results show that the displacement efficiency and charge per mass ratio of the particles decrease as the particle diameter increases. This is explained by the dominance of the gravitational force for large particles. The balance of forces also shows that the adhesion force is dominant for small particles. Coulomb's force is predominant in a certain particle size range. It is the only repulsive force, which make it the responsible of the particles movement. (C) 2018 Elsevier B.V. All rights reserved.