Calculations of the interaction of electrostatic forces and fluid dynamics are presented in this study. The models are adopted to the process of electrostatic powder coating, which is a method of painting with solid powder. The advantages of this technique are shown in an improved environmental quality, caused by total elimination of VOC's, reduced overspray and the possibility to reclaim this overspray in most applications. Although there are a lot of different application techniques used in powder coating, we selected two typical and widely used ones. Hence, in the present study calculations of two different nozzle types are presented: a flat fan and a round spray. The influence of the electrostatic field on the particle motion is rather low for the flat nozzle typ, as expected due to the geometrical conditions, whereas it leads to a modification of the particle cloud in the round spray case. A critical point is the determination of the charge of the particles. To take this essential feature into account, experimental investigations made at Epping GmbH, Munich, were used as a basis to perform the calculations.
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