ID 104

Experimental Characterization of Droplet Breakup Evolution in a Continuously Accelerated Flow Field

 

Abstract:

Droplets in a continuously accelerated flow field, under certain conditions, deform as oblate spheroids and breakup. Droplet breakup starts when the droplet is no longer an oblate spheroid, and from that point on, they undergo the breakup process. Traditionally, both bag and shear breakups features have been widely studied. However bag and stamen breakup is somehow a mixture between previous breakup types and there is still a gap of quantitative information regarding the features encountered for each flow condition. For the particular situation of a continuously accelerated flow field for droplets that undergo bag and stamen breakup, droplet breakup process is investigated. Droplets were allowed to fall in the path of an incoming airfoil at velocities up to 90m/s and a high speed camera recorded images at 75 000 fps. Five controls points were selected to track the droplet during the breakup process. The positions of the controls points were measured at each frame and the velocities and accelerations were obtained during the post-processing of the data. The influence of the droplets diameter (between 0.6 mm and 1.4 mm) and the airfoil leading edge radius (0.070 m and 0.103 m) were investigated. The present work provides not only experimental data on the features during the breakup process, but additionally it provides insight in the underlying physics of the problem.