Volume 8, Issue 1 (January 2011)
Triboelectrification of Metallic Dust Particles: Experiment and Modeling
Particles acquire electrostatic charges due to repeated collisions with a wall or surface due to a phenomenon termed as tribocharging. Triboelectric separation involves the charging of particles by impact or friction with the walls of a container or a pipe or between each other. It is suspected to be the cause of many industrial incidents and accidents and is recognized to be an industrial hazard. The contamination of particles in an unclean oxygen system, particularly with bends, valves, and regulators, makes it vulnerable to a fire hazard. Particles (both metallic and non-metallic) may be generated over years of operation inside an initially clean system. The particles are added through fresh gases, turning of screws and valves, abrasion, and wear of surfaces either by personnel or by production equipment. The phenomenon of electrostatic charge generation due to the impact between metallic particles and the pipe wall is investigated experimentally and theoretically. The experimentation and simulations have been performed with mild steel particles. The effects of air velocity, pipe diameter, and pipe length on the extent of tribocharging of particles have been determined. The velocity profiles of particles have been found out utilizing the FLUENT 6.3.26 code, and the charges generated are calculated from this velocity. Numerical results for the tribocharging of particles have been validated with the experimental ones.