Determination of Electrostatic Charge Density and Adhesion Force of Particles on a Glass Surface Using an Electrostatic Detachment Method

Abstract

Attachment of particles to certain surfaces like glass plays a critical role in engineering and natural processes. An application can be found in the solar energy field as the accumulation of dust particles on the solar photo voltaic (PV) panel surface can reduce the efficiency of the solar panel with time. The main objective was to determine whether the electrostatic detachment method can be used to calculate electrostatic charge density and the upper limit of adhesion force of dust particles at various air humidity levels. The independent variables in this investigation were particle diameter and air humidity. The dependent variables were the electrostatic charge density and the upper limit of adhesion force between a particle and the glass surface. The apparatus used in the experiment included a microscope, a high-speed camera, a high voltage amplifier, a data acquisition system and ITO-coated glass plates housed in a 3D-printed chamber. Upon application of a steady uniform electric field, the particles traveled from the bottom glass plate to the top glass plate. The arrival of particles at the top glass plate was recorded using the high-speed camera at 4100 frames per second (fps) from which the time of flight was obtained. Using image analysis software, the particle size was extracted. The experiment was carried out at relative humidity (RH) levels of 10%, 30%, and 80% at atmospheric pressure. The results showed that the upper limit of adhesion force increased with increasing particle diameters at all humidity levels; the highest adhesion force magnitudes were found at 30% RH. On the other hand, electrostatic charge density decreased with increasing particle size. Additional experiments are needed to obtain more statistically meaningful results.