High Speed Observations of the Near-Field Region from an Electrified Airblast Atomizer

Liquid sprays play a key role in many engineering processes (e.g., food processing, coating and painting, 3D printing, fire suppression, combustion systems, etc.). The dynamics at the nozzle exit have a large impact on the downstream spray characteristics. However, visualizing the spray in this region is extremely challenging because, under most operating conditions, the spray is optically dense. High intensity white beam X-rays, like those found at the Advanced Photon Source (APS) at Argonne National Laboratory, can be used to produce time-resolved visualizations of the liquid-gas structures in the spray near-field region. In this study, high speed, high spatially resolved X-ray images are acquired of a canonical airblast atomizer consisting of coaxial water and air jets. The liquid nozzle is electrified with up to -5 kV to enhance the atomization process. Features of this electrified atomizer will be described, discussed, and compared to a non-electrified condition, and the unique high speed X-ray imaging capabilities of APS will be stressed.