Mathematical modelling of powder paint particle trajectories in electrostatic painting

The trajectories of charged powder particles in an electrostatic powder coating system were modelled considering electrical and fluid forces. The mathematical model employed an iterative technique wherein the charge simulation method was used to compute the electric field strength and the method of characteristics was used to compute the charge density in the gun-to-target region. The fluid flow between the electrostatic gun and the target was modelled using interpolated experimental data assuming stagnation point flow. Particle trajectories were simulated for size range 10-40 μm and charge-to-mass ratios of 0.1-1 (-)μC/gram. The simulation results showed good agreement with experimental data (charge and mass measurements) at several collection points on the painting target and provided valuable information concerning particle deposition