Prediction of drop size from liquid film thickness during rotary disc atomization process

- Film thickness is obtained from liquid flow field on the rotating disc by VOF method.
- A correlation to predict the liquid film thickness on the disc surface is proposed.
- A correlation to relate the droplet size and the liquid film thickness is developed.

Rotary disc atomization is a process in which a liquid jet continuously impinges on a rotating disc, which then spreads over its surface to form a film. This liquid film leaves the disc tangentially and breaks up to form ligaments and/or droplets. Variation of the droplet size with film thickness is very important for droplet size prediction. In the present work, a steady state, three dimensional and two phase CFD model is used to simulate this process and to obtain the liquid film thickness. The effect of different parameters like inlet flow rate, disc rotational speed, etc. on the thickness of the liquid film is studied using dimensional analysis. A correlation is developed for obtaining the liquid film thickness at the disc edge using linear least square analysis. Further correlation is obtained, using which the droplet size is predicted from the film thickness at varying operating parameters.