Connection between the deformation of paint droplets during deposition on the surface being painted and the orientation of pigment particles (original) (raw)

2011, Theoretical Foundations of Chemical Engineering

In this work, we describe a new and more practically useful approach to finding the relationship between the reflective properties of a painted surface, the physical properties of the paint, and the technolog ical parameters of painting. A simple formal dynamic model of the deformation of a droplet of a "metallic" type paint during its interaction with the surface being painted is constructed. The physical model takes into account the main forces responsible for the deformation dynamics of a droplet, i.e., forces of surface tension, viscous friction, elasticity, and inertia; a new rheological model, which is suitable for approximating the vis cosity of paints in a wide range of deformation rates, is used. To construct the mathematical model, we employed the method of integral balance equations of mass, momentum, and energy. The model is used to calculate the most important stages of the deformation of paint droplets during their deposition on the surface being painted, which have an effect on the orientation of pigment particles. For these stages, we compose characteristic strain approximating functions of the Reynolds and Weber numbers, which are proved to be useful for summarizing the results of experimental studies of the entire real process of painting.