Experimental and numerical investigations of atomization processes in paint application using highspeed rotary bells

摘要

The paint material properties and the paint application process parameters determine the properties of the paint film.Here,high-speed rotary bells have increasing importance due to the combination of high qualitiy and improved process efficiency.A key point for the performance of paint atomizers is the atomization process itself,which,in the case of high-speed rotary bells,is located in a very narrow region close to the bell edge where a thin film is formed that further disintegrates.This process is investigated numerically and experimentally by the present contribution.Special focus is given to the rheology of the paint material and the surface tension.Regarding rheology,the simulation determines the relevant shear and elongation rates,discussing also the appropriate measurement methods for the viscosity(rotational,extensional,visco-elastic).Especially in the case of water-borne materials,the surface tension has to be treated time dependent.The paper describes the relevant time constants.