Mechanics of Particle Motion in a Standing Wave Electric Curtain: A Numerical Study

Electrostatic curtains can be simple and yet efficient devices to manipulate micronized particles on flat surfaces. This paper aims to investigate the motion of a 60 mu m dielectric particle on the surface of a standing-wave conveyor. The study is based on a numerical model that accounts for the many forces that could potentially influence the particle motion. For that purpose, a numerical calculation of electric field and particle movement was carried out. The particle position above the curtain surface is obtained by a resolution of the dynamic equations using the Runge-Kutta method. The electric field distribution in the space above the curtain is obtained by a finite element calculation of the Laplace equation. The simulation results demonstrated a net dependence of the particle trajectory and movement modes on applied voltage frequency. Overall, low frequencies, typically below 50 Hz, allow for higher levitation and better displacement of the particle over long distances. Conversely, higher frequencies significantly reduce levitation and displacement distance. Moreover, at higher frequencies (around 500 Hz), the particle can vibrate between electrodes without any displacement at all. It is then inferred that low frequency is needed to better carry particles using a standing-wave curtain.