High-Speed Diagnostics For The Study Of Droplet Breakup

In this work, we demonstrate the use of planar laser-induced fluorescence (PLIF) and back-lit shadowgraph imaging at 1.75~MHz to study the breakup of a 1-mm-diameter liquid drop in the presence of an air jet intersecting the drop's velocity vector. For the PLIF, a 447-nm laser diode is focused to form a high-intensity sheet to excite the DCM dye suspended in the ethanol droplet. For the back-lit shadowgraphy, a 685-nm fiber-coupled laser diode is used to generate a collimated beam of light to illuminate a stream of droplets as they are disrupted by a jet of air. All the complications associated with performing experiments in a ballistic range (luminosity filter, single-event triggering, standoff distance, etc.) were taken into account in this laboratory setup.