Impact of spatial harmonic waves on dielectric particles displacement in standing and traveling wave electric fields

Abstract

The purpose of this work is to investigate the effect of spatial harmonic waves on dielectric particles displacement process using standing and traveling electric wave electric conveyors. This investigation is divided into two main parts. The first one is an experimental study, where the efficiency of conveyors for the displacement of micrometer sized PMMA particles is analyzed. The second part consists of a numerical and theoretical study in which the spatial electric potential distribution and the consequences on the spatial harmonics on particles displacement are investigated. The results show that the displacement efficiency and the particles direction depend basically on the particles size, the charge to mass ratio, the applied voltage and the frequency. In the standing wave conveyor, the particles move toward both right and left directions. In the traveling wave conveyor, at high voltage, low frequency, small particles or high charge to mass ratio conditions particles move toward the traveling wave direction. In the case of low applied voltage, high frequency or if the particles have a low charge to mass ratio, some particles move toward the opposite direction because of the backward harmonic wave that appears near to the surface. The magnitude of the harmonic waves depends on the levitation height of particles; it can be controlled by varying the number of phases, the gap spacing or the thickness of electrodes or by adding a dielectric barrier over the surface.