Modelling of droplet behaviour during spray forming using fluent: R. Underhill et al. (Oxford Centre for Advanced Materials and Composites, Oxford, UK)

Abstract

A control volume based fluid dynamics software program, FLUENT, has been used to model the 2-dimensional dynamic and thermal behaviour of Udimet 720 droplets during gas atomization and spray forming. The effect of atomizing gas pressure, spray distance and melt mass flow rate (MFR) on the equilibrated droplet spray temperature has been examined and the predictions compared with measured maximum deposit temperatures from spray forming experiments performed under the same process conditions. The predicted spray temperatures at the substrate were consistently higher than the measured deposit temperatures, and in both cases increased with: (i) decreasing gas pressure; (ii) decreasing spray distance; and (iii) increasing MFR. Individual droplet temperatures and velocities were found to be strongly dependent on droplet size with droplet temperature decreasing and mean droplet axial velocities increasing with decreasing droplet size.