This paper presents new image analysis algorithms to measure the trajectories of breaking and coalescing bubbles in microscale bubbly flows. Image analysis of high-speed movies provides information on bubble dynamics and bubble interaction including bubble coalescence and breakage events. Individual bubbles that overlap in the image are recognized with a presented breakline method. The breakline method discriminates the overlapping bubbles with lines based on the bubble perimeter curvature analysis. Coalescence and breakage events are automatically recognized, and the path lines of bubbles travelling through the field of view are analyzed. The functionality of the algorithms was examined in bubbly flow in a microchannel encompassing two pin-fins in tandem.
Experiments in Fluids, November 2010.