Experimental Investigation on the Atomization Characteristics of a Doublet Impinging-Jet Injector

Experimental investigations on the spray pattern and breakup characteristics of like­doublet impinging-jet injectors have been conducted by employing photographic imaging technology and a light diffraction device. Purified tap water is used as the test liquid. The velocity of impinging jets is up to 45 meter per second (Re = 15,000). Experimental results obtained from the present study reveal that four spray patterns as reported previously are exhibited for doublet impinging jet spray. However, the closed-rim spray pattern is accompanied with the periodic-drop one in the present study. Mean droplet size decreases sharply with increasing jet Reynolds numbers in the low Reynolds number branch and flatly in the high Reynolds number branch, in agreement with the observations by Dombrowski and Hooper[5] for the laminar and turbulent jet impingement, respectively. The breakup mechanisms responsible for the mean drop size variations with jet Reynolds numbers are addressed.