Invited Paper: Liquid flow electrification phenomenon: Review

Flow electrification phenomenon is particularly complex as it involves materials, physics, chemistry, and fluid mechanics. It originates from the electric double layer (EDL) present at each solid/liquid interface, which results in a polarization of the interface. This physics equilibrium is determined by the nature of the materials and their physico-chemical properties. It is disrupted by the liquid flow toward a new equilibrium, described by the flow electrification phenomenon. Studied within the research framework in electrochemistry, colloid chemistry, and electrical engineering, EDL remains poorly understood. It relies on models whose viability has yet to be confirmed, as well as on often indirect experimental approaches. Zeta-metry and the flow electrification measurements constitute the main methods of study.

The evaluation and control of electrostatic hazard in an industrial and applied context can be achieved either by acting on the genesis of charge generation at interfaces or by addressing the various parameters governing the phenomenon of electrification through flow. Thus, after a description of the EDL, the phenomenon of electrification through flow will be analyzed in detail for both laminar and turbulent regimes. Particular attention will be given to studying this phenomenon in the context of electrostatic hazard in power transformers. Then, a new theoretical analysis of the flow electrification phenomenon under turbulent flows is described. Finally, an overview of new experimental approaches for analyzing the EDL will be presented.