Investigation on the electrostatic characteristics and discharge dynamics of non-uniformly charged powder in silos

Abstract

Electrostatic discharges of charged powders in silos can lead to fires or even explosions, however, the effect of different charging parameters on the characteristics of electrostatic discharges has not been sufficiently investigated. The electrostatic and discharge characteristics under different powder conditions in silos are investigated by developing a discharge plasma fluid model. The results show that the filling height significantly affects the heap surface electric field, which causes the different discharge locations and patterns. The effects of charge differences and particle segregation on the heap surface electric field are explored. The maximum value of the electric field strength under bipolar charge distribution increases by 28.5 % compared to the uniformly charged powder. Particle segregation significantly increases the heap surface electric field strength at the center of the silo. In addition, the discharge dynamics of the different polarity powders under non-uniform charging conditions are indicated. The discharge pattern, discharge velocity and electric field variation of different polarity discharges are comparably analyzed.