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The electrification mechanism inside the electrostatic atomizers and the constituted layers adjacent to the electrode are investigated both theoretically and numerically. The formation of the compact and diffuse layers across the electrode and inside the atomizer is taken into account through appropriate, realistic models. The potential drop across the compact layer and its thickness are calculated through a novel approach developed based on the Brunauer-Emmett-Teller (BET) mechanism. This approach allows for multi-layer non-specific adsorption of co- and counter-ions inside the compact layer. The significant potential drop across the compact layer is due to the leaky dielectric liquids (here canola oil) flowing inside the electrostatic atomizers. By implementing the compact layer model, the formation of a diffuse layer next to the compact layer is predicted with a novel numerical model. This model accounts for the discharge of the counter-ions at the interface of the diffuse and compact layers through well-known faradaic reactions. These reactions at the interface are taken into account through Frumkin-Butler-Volmer kinetics equation derived from our previous experimental measurements. Fixed flux boundary conditions for the ions predict the concentrations at the interface of the diffuse and compact layers and inside the diffuse layer. The computational domain starts from the interface of the compact and diffuse layers toward the bulk domain inside the electrostatic atomizer. Also, the convection of ions and subsequently charges in a sample two-dimensional micro-channel is studied. The numerical solver is developed based on the OpenFOAM platform and is previously validated through available numerical benchmarks.
