An Euler–Lagrange coupling strategy for pressurized liquid jet atomization in Large Eddy Simulation

The atomization process is crucial for numerous industrial and engineering applications, ranging from fuel injection systems to spray coating technologies and remains a challenge for numerical prediction. This study presents a coupled Euler/Lagrange methodology to model the atomization processes, at affordable numerical costs. An Eulerian framework is used to resolve the liquid core and the largest liquid structures, while a Lagrangian approach tracks the smallest droplets and their interactions, addressing transport, secondary breakup, and evaporation phenomena. The Eulerian two-phase flow method considered here is a multi-fluid diffuse interface approach that assumes equilibrium of temperature, pressure, velocity, and Gibbs potentials at the liquid–gas interface. An originality of this paper is the transfer of liquid from the under resolved Eulerian liquid structures to the Lagrangian formalism when user-defined geometrical criteria are met. A validation of the coupling strategy is performed on a jet in cross flow configuration. Although the spatial distribution of the droplet volumetric flux is not exactly retrieved, other key characteristics of the spray, such as the Sauter Mean Diameter (SMD) and the outer trajectory, show very encouraging results. Finally, this paper shows the importance of taking into account the liquid core in the simulation, rather than directly injecting already atomized droplets.