Abstract
Turbulent combustion of two-phase flows is studied by 2D direct numerical simulation. A spray of droplets is injected inside a jet with a preheated coflow. Triple flames appear to represent the global structure of the flame around the spray. Attention is focused upon global and local flame structures and droplet histories. A whole range of combustion phenomena are observed and described. The observed prevailing occurrence, for example, of the rich premixed flame compared to the diffusion flame is of great importance for any turbulent combustion model which must accurately estimate the heat release rate. This prevailing structure depends strongly on the droplet size and combustion. A competition between premixed and diffusion regimes may also occur. It has been shown that in some cases, local clusters of droplets are able either to cross the main flame front and burn in pure oxidizer or to break through the diffusion flame. It is observed that very complex interactions can emerge locally between premixed flames, diffusion flames and droplets.
Flow topologies in different regimes of premixed turbulent combustion: A direct numerical simulation analysis
