Digital Holographic Analysis of the Near Field of Aerated-Liquid Jets in Crossflow

Abstract

Inline digital holographic microscopy is used to study the rapidly developing region near the injector of several sprays in subsonic crossflow. Pure liquid jets are compared to aerated-liquid jets for crossflow Mach numbers of 0.3 and 0.6. Gas-to-liquid ratios of 0, 4, and 8% with a fixed momentum flux ratio (based on liquid flow rate) of 10 are investigated. Three-dimensional representations of the present test cases of aerated injection in crossflow are produced for the first time for the rapidly developing near-injector region (15–25 injector diameters downstream) owing to the capability of holographic diagnostics in probing nonspherical droplets typical of those present in this region. The results are also presented for the stable far-field region of the injector (at 50 and 100 injector diameters downstream). The results include droplet equivalent-diameter distributions, Sauter mean diameter distributions, and droplet velocities.