Jet Breakup Length to Impingement Distance Ratio for Like Doublet Injectors

摘要

Cold-flow experiments using water at atmospheric pressure were conducted to systematically determine the effect of the jet breakup length to impingement distance ratio for like-doublet injectors. The ratio had a large effect on the breakup characteristics of the spray. For ratios greater than one, a flat sheet was formed that subsequently disintegrated into waves of ligaments and droplets. The breakup length of the sheet increased with the Weber number . up to a transition point where it began to decrease with further increases of the Weber number. For ratios equal to one, an unsteady flat sheet was formed due to the jets intermittently disintegrating before reaching the impingement point New empirical sheet breakup length and transition correlations were developed for these configurations. For ratios less than one, no sheet was formed. In addition, measurements of the ligament wavelengths and centerline droplet diameters were conducted for jet breakup length to impingement distance ratios greater than or equal to one. The mean ligament wavelengths were nearly constant for all operating conditions, impingement angles, and ratios. However, larger impingement angles and jet velocities corresponded with smaller mean droplet diameters and reduced spray polydispersity. Mean droplet diameters were independent of the jet breakup length to impingement distance ratio.