Atomization of a liquid jet in transonic crossflow

The fragmentation process and droplet atomization characteristics of liquid jets are studied when the crossflow velocity is set at 1 Ma, and the influence of small-scale changes in Mach numbers (Ma = 0.9–1.1) in the transonic range is explored on the liquid jet in crossflow (LJIC). The LJIC field is obtained through a large eddy simulation turbulence model in this study. The jet morphology, liquid mist distribution, and flow field structure of liquid jets in transonic airflow are analyzed, and the main differences between them and jet atomization in common subsonic incompressible low-speed airflow are discussed. The results show that in the case of transonic inflow, small liquid blocks, liquid filaments, and droplets continuously detach from the top of the liquid jet. Wrinkles and finger-like protrusions formed on both sides of the windward of the jet, where liquid accumulates and is accompanied by droplet detachment. The atomized droplets are uniformly distributed in space without obvious clusters of liquid mist. A detached bow shock wave is generated in front of the jet, and a reverse flow of gas occurs at the root of the jet, forming a horseshoe vortex structure. The small-scale changes in the Mach number within the transonic range have significant impact on the penetration depth of the jet, but little effect is made on the spanwise boundary of the jet. Moreover, the intensity of the detached shock wave formed at the front end of the jet increases with the increase in the Mach number.