Simulation of particle trajectories in tribo-powder coating

The modeling of the tribo-powder coating process requires the solution of the electrostatic field problem and the equation for particle motion. Electric field distribution is a function of the space charge density, which is associated with the particle concentration. The particle movement results from the balance of electrical, inertial, air drag and gravitational forces. Therefore, both problems are mutually coupled. In this paper, an iterative algorithm is presented to simulate this problem; the electric field is determined by means of the finite element method, whereas the time-dependent explicit fourth order Runge-Kutta algorithm is used to predict the particle trajectories. Both problems are solved iteratively until a self-consistent solution is found. The results of simulation show the effects of different parameters which characterize the process such as the powder particle size, charge/mass ratio, distance to a coating object, powder outflow and assisted air velocity on the shape of the powder jet.