Tribo-electric Charging Particle in a Shaker

Powder flow could give rise to tribo-electrification, causing segregation and adhesion of particles to the containing walls. This leads to operational problems and reduction in process efficiency. In order to mitigate the undesirable effects of tribo-elecric charging, a fundamental understanding of charge transfer is essential. In order to model the charge transfer due to collision of particles against the walls, various simple experiments are carried out, based on which a model of single particle charging has been developed, which is then incorporated into Distinct Element method (DEM) to predict the bulk behavior. The experiments consist of shaking various numbers of plastic particles in a stainless steel cubic capsule. The parameter windows are number of particles and sizes of particles. During shaking, the particles get charge, when they contact the walls. The charge on individual particles accumulates until the saturation charge is reached. When the number of particles increases, the saturation level decreases because of space charge effect. In the simulation, LIGGGHTS is used for the DEM simulations, in which the model of charge transfer and space charging effect are incorporated. To calculate the electric force applied to particles due to electrostatic inductions from the walls and other charges on particles, the simulation charge method is used. The results of the simulations and experiments are compared, and simulation results capture the tendency of experimental results.