Discrete element model of nanoparticle deposition during electrospraying

Abstract

Electrospraying is a technique for the production and deposition of nanoparticles. However, deposited layer morphology is strongly dependent on the operating conditions and hard to predict. Here, we present a spatially 3D model based on the Discrete Element Method (DEM) with the analytical evaluation of interparticle forces and drag force and the numerical evaluation of electric force. The developed connection between mesh-free DEM and mesh-based Finite Volume Method (FVM) used for the evaluation of electric potential field enables to lower the computational time while maintaining accuracy of the predictions We focus on modelling the influence of interparticle forces on particle deposition and deposited layer morphology, which are phenomena usually neglected in the literature so far. Preferential landing of particles is indicated to be a consequence of both electric force and Van der Waals forces. Contact particle interactions allow particle stacking (creating thus fractal-like structure) or allow falling down of particles and their rearrangement (leading to compact layers).