Spray Characteristics of Two-phase Feed Nozzles

The present study focuses on understanding the spray characteristics of a turbulent gas-liquid jet (Reliq = 24,000). Air and water are used as the test fluids. The angles of injection of the two phases upstream of the nozzle are varied ((theta) = 20(degree), 45(degree) and 90(degree)) and the effect of carrier gas on the droplet characteristics is are also investigated. The droplet size and velocity are nonintrusively measured using a Phase-Doppler Particle Analyzer (PDPA). In some respects, the characteristics of the present two-phase jet are similar to those noticed in previous studies, while revealing some important differences. The centreline mean droplet velocities (15 ~ 20 m/s) increase in the initial region of the jet, attain a maximum and then decrease at larger distances from the nozzle exit. Most of the entrainment occurs at the tip of the nozzle and the jet expansion rate decreases significantly at distances where the spray velocity profiles become self-similar. A Lorentz-type fit has been used to model the normalized radial velocity profiles. The results indicate that the test configuration with (theta) = 45(degree) may be beneficial for the scenario discussed.