Eulerian and Lagrangian spray simulations of an aeronautical multipoint injector

Lean-burn combustors developed for low NOXNOX aero-engines include staged fuel injectors, characterized by a complex geometry and often by the introduction of multipoint injection systems where fuel is injected by a series of liquid jets oriented perpendicularly to the airflow. Large Eddy simulations (LES) combined with methods to simulate liquid fuel sprays are well-adapted to the simulation of such flows. The present work compares Eulerian and Lagrangian methods for the simulation of the dispersed phase. The evaluation is carried out on a single injector mounted in an experimental rig installed at ONERA. The non-reactive operating condition corresponds to a partial load regime at 4.37 bar and 473 K in the chamber inlet. This allows to study droplet dynamics and evaporation under realistic conditions.The simulation cases include a purely gaseous flow, an Eulerian spray simulation as well as a monodisperse and a polydisperse Lagrangian simulation, all using the same grid. The analysis focuses on the comparison of gaseous and liquid phase velocities and fluctuations. Equivalence ratio fields are also visualized, allowing to identify regions suitable for ignition.