Abstract

Effervescent atomization in quiescent air and in a subsonic crossflow are experimentally studied. The spray angle of an effervescent atomizer with an elliptical orifice is measured by employing the shadowgraph technique. Spray images were captured from both the minor and major axis views. The gas-liquid mass flow rate ratio (GLR) is in the range of 0.55-2.55 %. It is found that an increase in the aeration level results in an increase in the spray angle from both minor and major axis views. The results indicate that the spray angle from the minor axis view is wider than that from the major axis view and the difference increases as GLR rises.
Furthermore, the effervescent atomization in a gaseous crossflow is studied using circular and elliptical orifices with aspect ratios of 1, 3, and 0.3. Gas-liquid mass flow rate ratio varies between (0-7%) and liquid-air momentum flux ratio,q, is in the range of 2-23. The high-speed shadowgraph technique and image processing were utilized to visualize the spray trajectory and measure the spray penetration height. Moreover, an empirical correlation is developed as a function of GLR, q, aspect ratio and downstream location. Additionally, the laser diffraction technique is employed to analyze the spray droplet size distribution in a crossflow.