Department of Mechanical and Automotive Engineering, MS Ramaiah School of Advanced Studies, New BEL Road, MSR Nagar, Bangalore-560 054, INDIA
Dept. of Aerospace Engineering, Indian Institute of Science, Bangalore-560012, INDIA
In this paper a comprehensive review of flow visualization techniques used for the analysis of spray characteristics is presented and an experimental demonstration of different lighting techniques has been made. Still photographs of sprays from an airblast atomizer and a swirl atomizer are taken under backlighting, slit lighting, incident lighting (front flash) and a new method of capturing scattered light image at 1200 to the incident light is introduced in the present work. Photographs taken by these methods are shown to be useful for deriving useful observations such as jet breakup phenomenon, the internal details and the external appearance of the spray. It is demonstrated that the information obtainable from each technique is different and that a combination of different techniques may be necessary for proper diagnosis. The article also includes a discussion on the jet breakup phenomenon as observed in the photographs and in addition a new concept of shear formation of smaller droplets from the surface of a liquid jet by the co-flowing air stream in an airblast atomizer has been proposed.