Electric charge generation and transport in turbulent wall bounded flows
(2022) 14th European Fluid Mechanics Conference — Location: Athens, Greece (13.September.2022)
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- Abstract
- Flow electrification during the transport of dielectric liquids constitutes a major safety hazard. This is particularly the case in petrochemical and process industries, in which several accidents have occurred in the past due to the dielectric properties of liquid hydrocarbons. For this reason, this phenomenon has been the subject of various research efforts in the past. Typically, flow electrification occurs via diffusion of electric-charge carriers (ions) from the electrical double layer, which is inevitably formed at a liquid-solid interface, to the bulk of the flow. This phenomenon is currently not well understood but it is generally accepted that flow turbulence plays a major role and can significantly increase the electrification rate. More specifically, at sufficiently high Reynolds numbers, and for low-conductivity fluids such as liquid hydrocarbons, the thickness of the hydrodynamic boundary layer becomes comparable to that of the electrical double layer. In turn, this leads to increased transport of charges away from the wall region and towards the bulk of the flow. However, quantitative information on the underpinning mechanisms of this phenomenon is still lacking. In the first part of this presentation we outline the governing equations for the problem of interest and discuss the physical significance of the various terms in the charge-density equation. In the second part, we present results from direct numerical simulations of turbulent flow electrification for friction Reynolds numbers ranging from 150 to 210. Our study focuses on the rate of accumulation of charge in the bulk, the statistical properties of the charge density distribution, and the budget of the charge-density variance.
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Calero, M., & Papalexandris, M. (2022). Electric charge generation and transport in turbulent wall bounded flows. 14th European Fluid Mechanics Conference, Athens, Greece.