Influence of turbulence on the triboelectric charging of granular materials carried by an airflow.

Abstract

Electric charge transfer in particles transported by airflow is investigated using a custom three-dimensional-printed open-source small-scale wind tunnel. Particles are initially at rest in a dunelike bed and collide with a metallic plate while moving, enabling charge transfer measurements under controlled airflow conditions. The influence of particle properties, including material, size, and sample mass, is examined, showing that the nature of the contact materials governs both the polarity and the overall magnitude of charging, while particle size modulates the charge magnitude. The charge density is independent of the sample mass within the investigated range. The effects of airflow properties are examined using passive turbulence grids, allowing the influence of turbulence intensity to be assessed while keeping the same freestream velocity. The results demonstrate that turbulence, rather than the mean airflow velocity within the studied range, plays a dominant role in increasing the particle charge density.