Physics-based Computationally Efficient Spray Combustion Models for LES of Multiphase Reacting Flows

One important challenge for the reliable prediction of liquid fuel effects on the combustion in aviation combustors and augmentors is the accurate modeling of underlying physical processes, involving the evaporation of fuels, preferential vaporization, scalar mixing and ignition. LES methodologies are required to accurately capture these transient and inherently unsteady combustion processes. In the proposed STTR effort, the team of CFDRC and Stanford University propose to develop physics-based computationally efficient models for multiphase combustion. The models will incorporate most of the key physics of spray atomization that controls the combustion phenomena post injection. In Phase I, a mixture-fraction based combustion model will be implemented and demonstrated for Navy-relevant aviation fuels. The computational efficiency and accuracy of the model will be demonstrated by comparison with appropriate DNS data and available experiments. The Phase I effort will identify the current gaps in our modeling capabilities. In Phase II the spray combustion models will be advanced to include other key physical processes such as droplet breakup, interaction with turbulence, preferential evaporation, and the coupling with physics- and chemistry-adaptive combustion models. At the end of Phase II a well-validated multiphase combustion model will be available to the Navy and its contractors.