Direct numerical simulations of high-pressure impinging-jet atomization: Interfacial evolutions and spray characteristics

This study presents a numerical investigation of impinging-jet atomization across various Weber numbers (We) under high backpressure conditions. Using the volume-of-fluid method, adaptive mesh refinement, and the isoAdvector interface reconstruction technique, atomization characteristics are simulated and analyzed for different values of We. The results indicate that the geometry induces turbulent jets, which drive turbulent atomization through the shear interactions at the gas–liquid interface. The key observed phenomena include the interaction of impact waves with liquid sheet perforation and the breakup of web of ligaments, both of which are prominent under high backpressure conditions. A novel method, based on the threshold velocity of spray droplet groups, is employed to quantitatively measure the spreading angle, showing that the angle increases with We in both front and side views. Additionally, the Sauter mean diameter of droplets follows power-law scaling with exponents of -1/3 in the upstream region and -1/2 in the downstream region, while the droplet size distribution conforms to a log-normal profile. This research provides valuable insights into interface evolution and droplet characteristics during impinging-jet atomization under high backpressure, offering essential guidance for optimizing industrial atomization processes.