Multidirectional Imaging of Liquid Jet Trajectory in Swirling Air Crossflow at Elevated Pressures

Abstract An experimental investigation is conducted to elucidate the trajectory evolution of a liquid jet subjected to a swirling air crossflow under elevated pressure conditions, representative of airblast atomization environments in modern aircraft combustor systems. The swirling flow, generated via a 30 deg axial swirler within an annular passage (swirl number, SN = 0.42), interacts with a liquid jet issuing from a circular orifice. The study systematically examines the influence of momentum flux ratio (2 ≤ q ≤ 25) and Weber number (55.2 ≤ We ≤ 128.1), achieved by varying the air injection pressure from 2 to 5 bar. A tomographic imaging methodology, incorporating synchronized endoscopic views at multiple azimuthal locations combined with backlight illumination, enables the three-dimensional reconstruction of the jet's trajectory and angular deflection characteristics. Results reveal that increasing the momentum flux ratio significantly enhances the liquid jet's maximum projected penetration, radial penetration, and angular deflection. Furthermore, elevated pressure conditions induce pronounced jet bending and early trajectory curvature compared to atmospheric conditions, driven by intensified aerodynamic loading and swirl-induced shear forces.