Large eddy simulation of a two-phase staged swirling burner using an Euler-Lagrange approach: Validation of the injection strategy

A two-staged swirling burner is numerically simulated using Large Eddy Simulation (LES). This combustor uses two types of injection: a multipoint system that consists in 10 holes in a crossflow configuration, and a pilot system that uses a pressure-swirl atomizer. The relation between the rate of fuel injected from each injection system was found to be related with flame shape transition and hysteresis phenomena[4]. Also, the pilot spray was found to have a major role on these transitons, so it is of paramount importance to correctly reproduce its behavior on the numerical modeling, if one is interested in simulating these flame bifurcations. To describe the spray, a point-droplet approximation is used in a Lagrangian framework with the FIM-UR model [1], that has already proven its accuracy for several configurations. However, in this application it fails to reproduce the droplet size distribution, especially in the Central Recirculation Zone (CRZ), as it uses an arbitrary expression to impose the spray opening limits (which are not input parameters). In the present work, the input parameters of the FIM-UR model are modified to enable the recovery of the right droplet size distribution and improve the description of the liquid velocity field, resulting in a better numerical representation of the experimental results, essential for further studies