Multi-scale Investigation and Modelling of hETerogeneous spraY Coupling with turbulent reacting flows – MIMETYC

The aim of the project is to develop modelling and numerical methods for the accurate prediction of the heterogeneous spray-flow coupling, in the scope of Large Eddy Simulation of turbulent spray flames. Today's simulations of realistic systems such as aeronautical combustors are relying on point-droplet assumption, which avoids the flow resolution at the droplet scale, and the description of spray-flow coupling must rely on modelling. A proper description requires a multi-scale approach, from the droplet interface to the interactions with the flame. As the main process to be accounted for is the vaporization of the droplets, the first goal will be the development and validation of accurate vaporization and heating models, using droplet-resolved simulations to properly characterize the heat and mass transfers between the droplets and the gaseous phase.
These models will be used for spray simulations, which can either be performed using Lagrangian or Eulerian methods. For the Lagrangian approach, spray-flow coupling strategies will be developed using the droplet-resolved simulations, in order to incorporate the macroscopic effects of the flow structure at the droplet scale in the Lagrangian simulations. For the Eulerian method, which considers the spray through its statistics and generally see it as a continuum, the heterogeneous character of the spray, i.e. the fact that droplets are local inclusions and not a continuum, will be incorporated in the statistical description. This aspect can have a great impact on spray flames, for instance when large droplets cross the flame.
These new modelling approaches will be extended to Large Eddy Simulation. The modelling of the subgrid scale effects will not only account for the unresolved dynamics, but also for the subgrid scale spray-flow coupling and spray heterogeneity. The developed LES approaches will be finally applied to the simulation of turbulent spray flames, and to a realistic aeronautical-type burner.