Simulating Atomization in Rotary Atomizers

Atomization is the transformation of a bulk liquid into a spray of liquid droplets. We can observe atomization in various household devices and even in the industry, atomization is a process crucial to many applications like fuel injection, flue gas cleaning, fire suppressant systems and the central application in this project - automobile painting.

Motor vehicle production is fast approaching 100 million units a year [OICA, 2019]. Each one of these vehicles is produced at an automobile manufacturing facility and one of the processes in production is painting. A number of tasks are performed in an automobile manufacturing facility, one of which is painting. Automobile paint shops are a major energy-consuming area and the most expensive operational aspect of an automobile assembly plant. Obviously, manufacturers are looking for ways to minimize costs and the environmental impacts and the paint shop is a great place to begin.

A device that is extensively used for painting vehicles is called a Rotary Bell Atomizer (RBA). In addition to atomizing paint by rotating at high speeds (10k-100k RPM), RBAs electrically charge the liquid and operate in a background electric field. Atomized charged droplets are directed towards the target surface by the electric field. The atomization process heavily influences transfer efficiency (TE) and surface finish quality.

In this work, a computational approach is used to simulate three-dimensional RBA near-bell atomization to understand the complex physical phenomena behind the operating of this device.