Spray Characteristics of Impinging Jet Injectors at High Back-Pressure.

摘要

Atomization characteristics of an impinging jet injector were studied over a range of injection velocities and back-pressures typical of liquid rocket injectors. Sheet breakup length was measured by strobe light imaging and was found to decrease with increasing injection velocity and chamber pressure. The experimentally measured breakup length was compared to linear stability theory and agreement was found to improve with increasing chamber gas density. At low chamber pressures, disturbances due to impact waves were believed to be the primary breakup mechanism. Measurements of droplet size distribution were made with a combination of laser diffraction and droplet imaging instruments. Droplet size was found to be a highly non-linear function of chamber pressure and axial distance from the impingement point. Sauter mean diameter was found to decrease with increasing chamber pressure and axial distance. Secondary atomization was believed to be the breakup mechanism responsible for this dependence. The width of the droplet size distribution was also found to be a function of chamber pressure.