Modeling Challenges in Computing Aeronautical Combustion Chambers

This article reviews the modeling challenges for performing Large Eddy Simulations of aero-nautical combustion chambers. Since the kerosene is injected in a liquid phase into the combustion chamber, the description of the atomization is of primary importance. The article first discusses the numerous numerical challenges encountered during this process, which leads to the formation of small droplets that constitute a spray. The existing numerical and modeling methods to describe a spray of kerosene droplets are then presented. The article then focuses on the description of the complex combustion kinetics. Hundreds of species and thousands of reactions have to be considered to predict ignition, flame stabilization and pollutant emissions. Due to lengthy computational times, detailed chemical schemes are too large to be directly used in CFD. This article then presents the major existing chemical reduction strategies. Significant interactions of the reactions layers with the flow vortices occur at the subgrid scale. The question of turbulent combustion modeling is therefore discussed in an LES context. Finally, the prediction of soot and NOx formation is presented. The review is illustrated by several examples representative of practical situations encountered in aeronautical combustors.