ID 13

A numerical study on liquid charging in electrostatic atomizers

 

Abstract:

Electrostatic atomization has emerged as a desirable technology in many industrial applications such as oil coating, painting, and fuel injection in diesel engines. It provides controlled spray trajectories, increased disper-sion/deposition efficiency, and enhanced evaporation compared to other conventional atomization methods. Moreover, it avoids customary oil coating problems such as uneven or over-application of oil. In this work, the charging process of leaky dielectric liquids with faradaic reactions at the electrodes is studied as the physically sound electrification mechanism. A finite-volume based numerical solver is developed based on the OpenFOAM platform. The Poisson-Nernst-Planck equations are solved coupled with the fluid flow governing equations. The numerical solver implements ion boundary conditions accounting for the faradaic reactions occurring at the metallic electrodes. The ion flux values are calculated using an experimentally measured current-voltage correlation in the form of the Frumkin-Butler-Volmer law. A benchmark problem is used to validate the predictions of ion distributions in the near-electrode polarized layers and in the bulk. It is also shown that the effect of the steric terms on ion distributions is negligible when considering canola oil as the leaky dielectric liquid.