Influence of flow topology on instability and atomization of liquid jets

In the combustion process of liquid fuels, jet instabilities and atomization are the starting points, which can have significant effects on following processes such as evaporation and combustion. There remain gaps in our under standing of the turbulent jet atomization mechanism despite the extensive prior research. This work aims to reveal the atomization mechanism of turbulent liquid planar jets through the use of flow topology. A high-resolution direct numerical simulation method is used to solve the atomization process of a liquid plane jet in a still air environment. In order to clarify the process by which flow topology affects the atomization of liquid plane jets, the interaction between various topologies in the flow field and the curvature of the gas-liquid interface is analyzed. It is found that all flow topologies contribute to the generation of compressive and extensive strain rate, among which the UFC topology has the greatest effect on the flow field strain rate; the curvature of the liquid volume fraction iso-surface shows a negative correlation with the strain rate under the influence of the flow topology. In addition, the UFC structure mainly generates extensive strain, while the remaining flow topologies mainly generate compressive strain. These results suggest that the jet atomization process is mainly influenced by the UFC topology, which facilitates a large extensive strain at the gas-liquid interface, which in turn promotes the generation of sheet or saddle structures, thus causing liquid jet fragmentation. © 2022 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.