The characteristics of current density distribution during corona charging processes of different particulates

With a negative point-to-plane geometry and two (coarse and fine) particulate systems, the current densities during corona charging of particulates were investigated. Results disclosed that, due to the addition of powder particles, both particulate systems incur strong corona quenching in currents. At low charging voltage the coarse and the fine systems present similar behaviours in current density with a slight deformation of the distribution, mainly attributed to inefficient particle charging and weak shielding effect of charged particles. At high charging voltage, however, in comparison with the fine system, the coarse system produces weaker quenching effect on its current density but more severe deformation on its current density distribution, due to its inferiority in particle amount and more concentrated charged particles in the internal space of the powder cloud. It was demonstrated that the characteristics of the current density during corona charging are closely related to particulate properties, but charging voltage also produces some influence.