Atomization characteristics of secondary-flow impinging injector in the transonic flow of nozzle throat

In order to study atomization effects of secondary-flow impinging injector under the transonic condition on engine thrust, a series of cold-flow tests of fluidic nozzle throat were performed. The cumulative volume distribution, Sauter mean diameter (SMD) and droplet distribution index (N) of plume at the exit of engine nozzle were studied. The particle sizes in the plume were gained at different pressure ratios and injection cases. The test results show that with increasing pressure ratio, the SMD decreases and the uniformity of atomization improves; the best case of atomization quality is the throat expanding section injection, meanwhile, the ability to control the throat and thrust efficiency increases with increasing the secondary-flow mass flow ratio.