DROPLET BREAKUP QUANTIFICATION AND PROCESSES IN CONSTANT AND PULSED AIR FLOWS

In recent years, Cardiff University has researched droplet breakup mechanisms both numerically and experimentally. This work was initially undertaken to investigate the use of water sprays in explosion suppression, but latterly the renewed interest in Pulse Detonation Engines (PDEs) and more pertinently liquid fuelled PDEs has added a further relevance to this work. This paper relates primarily to the experimental studies with water in air. High Speed Video and Laser Diagnostics have been used to characterise droplet breakup when a droplet falls under gravity into a constant air stream. The air flows were generated using basic techniques to generate low subsonic flow. When the droplet fell into a constant airflow, classical droplet breakup mechanisms were observed which included bag-breakup. Post break-up droplet sizes have been quantified, droplet size distributions and SMDs were found for several cases. The affect of viscosity has also been investigated on the induction time and the Critical Weber Number for various Ohnesorge Numbers was found and compared to previously published relations. Paper ID ILASS08-4-4