Tomographic Reconstruction of OH Density Maps for Jet-A1 Spray Flame in a Vitiated Crossflow

This paper aims at describing the effects of the variation of air-to-liquid ratio (ALR) on the morphology, reaction zone and combustion regime of a Jet A-1 spray flame in a vitiated turbulent crossflow. The variation of these characteristics as a function of the ALR is a result of the effect of the parameter on both the droplets size and jet-to-crossflow momentum ratio. At low ALR, the spray is characterised by larger droplets and weaker crossflow entrainment. The large-inertia droplets tend not to follow the air jet and penetrate independently in the vitiated crossflow, where they burn in a single droplet combustion regime. On the other hand, the better atomisation and the high fuel-oxidisers mixture obtained through crossflow entrainment favour the formation of a MILD combustion regime. The experimental investigation is performed by means of OH* chemiluminescence and a discrete tomographic reconstruction of the OH- and Jet A-1 Planar laser induced fluorescence of the reaction zone