Experimental study on triboelectric charging of granular materials influenced by chute parameters and surface strain

Triboelectric charging is a common issue in chute transportation of granular materials, leading to problems such as particles adhesion, blockage and discharge. In this work, we focus on the triboelectric charging of granular materials influenced by chute parameters and surface strain, and further reveal the underlying physical mechanisms. Parameters including sliding length, chute angle, vibration, and applied voltage are investigated for their impact on the triboelectric charging of various materials. Additionally, the influences of chute surface strain both on magnitude and direction are examined. Experimental results show that sliding length has a positive correlation with triboelectrification, while inclined angle exhibits a nonlinear relationship with the charge of PP particles. As the chute vibration frequency increases from 0 to 88.8 Hz, the particle charge rises from −20.55 nC to −38.52 nC. It is worth noting that, applying negative voltage to the chute significantly increases the particle charge, with glass beads showing a linear relation of 21.46 nC/kV. It is also found that surface strain strongly influences particle charging, governed by both magnitude and direction. Confocal microscopy reveals that this effect arises from changes in contact area, surface morphology, and particle motion. These results allow comparison of triboelectric charging of granular materials under different chute parameters, providing an experimental reference for reducing charging in industrial applications.