2013 年 28 巻 4 号 p. 264-270
Relation among transfer efficiency of paint particles, characteristics of coated film and operation condition of electrostatic powder coating with corona spray gun was investigated by both experiment and computer simulation.The computer simulation of electrostatic powder coating process was developed by hybridization of distinct element method (DEM) and large eddy simulation (LES). DEM calculates the trajectories of paint particles having both particle size distribution and particle charge distribution based on the equation of motion of each paint particle and LES is the simulation method for three dimensional turbulent flow. Electric field between the coating spray gun and coating plate is estimated by solving Poisson’s equation under given boundary conditions. The numerical results, such as the velocity profiles of jet stream from the spray gun, the particle size distribution of coated paint particles on the target plate, were in good agreement with experimental data. We found that there is an appropriate particle size distribution for given coating condition because smaller particles have lower transfer efficiency of paint particles. A higher applied voltage to the coating gun led to a flatter surface of coated plate a higher transfer efficiency. Fundamental understanding on electrostatic powder spray coating condition can be deepened by the developed computer simulation.
