Numerical simulation of the electrostatic powder coating process with a corona spray gun

In this paper results of investigations are described aiming to numerically simulate the electrostatic powder coating process using an extended commercial computational fluid dynamics (CFD) code. The fully three-dimensional turbulent flow was calculated. Based on the Lagrangian approach the trajectories of the powder particles were modelled considering electric and aerodynamic forces. In the calculations of the particle propagation both the particle size distribution and the particle charge distribution obtained through experiments have been applied. The model accounts for the space charge effect of the charged particles and the turbulence dispersion on the particle trajectories. It was found that the space charge plays an important role for the final spray pattern shape, also increasing the transfer efficiency. The numerical results, such as velocity profiles, static and dynamic film thickness on the target were in good agreement with experiment.