Spatially Resolved Measurement of Triboelectric Charging in Turbulent Particle-Laden Flows*

Triboelectrification in pneumatic conveyors leads to particle charging, which can alter flow patterns, influence particle trajectories, and potentially cause hazards like spark discharges. Existing charge measurement methods lack the ability to provide detailed charge distribution information necessary for a comprehensive understanding of triboelectric charging in turbulent flows and for validating numerical simulations.

Our novel method overcomes these limitations by spatially resolving the charge in a turbulent powder flow. The experimental setup integrates a particle tracking velocimetry (PTV) system with electrode plates that generate an electric field. By comparing particle velocities and accelerations with and without the electric field, we derive the time-averaged local particle charge profile. Our measurement results show that this approach reveals a bipolar particle flow and demonstrates significantly higher peak charge values compared to the average particle charge measured using a conventional Faraday cup while maintaining overall agreement. This spatially resolved charge measurement method provides critical insights into the triboelectric charging process in turbulent particle-laden flows and offers a reliable validation tool for numerical simulations.