Effects of the atomization air on the topology of a Jet A-1 spray flame in a turbulent vitiated crossflow

Abstract

The effects of the air-to-liquid ratio on a Jet A-1 spray in a vitiated turbulent crossflow are investigated by means of OH* chemiluminescence and OH-PLIF. The turbulent crossflow is generated with a 4 X 4 matrix of CH4-H2-Air lean technically premixed flames operated at 50 kW, equivalence ratio 0.7 and with a 5% H2 enrichment by mass. A Jet A-1 spray, generated with an air-assisted atomizer and corresponding to 5 kW power is introduced in the crossflow. The current work focuses on the effects of atomization air on the flame topology and heat release. The time-averaged high-speed OH* chemiluminescence images provide an estimate of the flame location and global features. For more insights, OH-PLIF experiments are performed at the central plane of the spray. In addition to the on-resonance OH PLIF signature, the detuning of the laser from the OH excitation wavelengths provides the spatial information about the presence of Jet A-1 droplets/vapour. It is reported that for low ALR the isolated combustion of relatively large droplets creates a localised heat release region on the windward side and closer to the atomizer. Whereas with increase in the ALR, the spray flame manifests higher degree of spatial uniformity.