Exploration of Near-Field Plume Properties for Aerated-Liquid Jets Using X-Ray Radiography (Postprint)

Near-field structures of aerated-liquid jets discharged from specially contoured exit adapters were explored, using the plume properties derived from synchrotron X-ray radiography. A total of six adapters with various internal contours were selected for testing. Water and nitrogen were used as the injectant and aerating gas, respectively. It was demonstrated that the liquid-weighted plume properties, including density, velocity, and momentum flux, within the cross-sectional planes perpendicular to the jet axis can provide useful insights to the understanding of aerated-liquid jets. For the adapters with a typical straight contour, pressure drop plays a role in determining the macroscopic spray structures of aerated-liquid jets at a given injection condition. A long passage length leads to a greater pressure drop and a reduced exit pressure to expand the plume diameter. For the adapter with a convergent-divergent contour, the jet properties are strongly affected by the exit slope of the adapter contour. An increase in aeration can substantially increase the plume velocity and plume momentum flux with no increase in spray cone angle.