The charging characteristics of particle–particle contact

Abstract

Particle–particle collisions play a crucial role in the triboelectric charging in particle-laden flows. However, the mechanism of the charging pattern is still poorly understood. In the present work, electrostatic charging experiments of particle–particle collisions were conducted to explore the charge transfer with different-sized particles. The experimental results show that the polarity of the transferred charge varies with the material type. The influence of the initial charges on the charge transfer was observed, and the influence degree was compared for different materials. The charging behaviors were analyzed based on the charge transfer model driven by the electric potential difference. Through electrostatic analysis, the electric potential difference arising from the electric field of the preexisting surface charges was numerically calculated for the dielectric materials with polarization effects and the ideal non-polarizable material. It was revealed that the potential difference alters significantly owing to the surface charge redistribution of dielectric materials. Dielectric polarization was numerically investigated by varying particle size and relative permittivity of the material. The numerical results explain the discrepancies in the charging tendency of various materials in the experiments.