Lift-off region temperature field and planar flow field of a twin-nozzle reacting jet in hot crossflow

Secondary fuel injection affects the combustion organization and flame dynamic in axial fuel staging gas turbines. Here, we experimentally investigate a front-fuel rear-air twin-nozzle configuration in which the fuel and air can be independently injected to stabilize a lifted flame front, control the jet trajectory and tune the combustion mode in a very flexible way. A high repetition two-line formaldehyde planar laser induced fluo-rescence thermometry technique is used to measure the lift-off preheat zone temperature field of the flame with different amount of secondary air injection. The combustion flow field and the flame front dynamics are investigated using particle image velocimetry and CH* chemiluminescence. When the air to fuel ratio increases from 0 to 3, the preheat zone temperature, which is affected by the local equivalence ratio and injec-tion air cooling, increases from 1300 K to 1600 K and then slightly declines. The lift-off region temperature and flow field dynamics are related to the variation of lift-off height, heat release rate and stability of the reacting jet in hot crossflow.& COPY; 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

Secondary fuel injection has an impact on the combustion structure and flame dynamics in axial fuel staging gas turbines. In this study, a front-fuel rear-air twin-nozzle configuration is examined, where the fuel and air can be injected independently to stabilize the lifted flame front and control the jet trajectory. Experimental techniques including formaldehyde planar laser induced fluorescence thermometry, particle image velocimetry, and chemiluminescence are used to investigate the temperature field, flow field dynamics, and combustion mode in the presence of secondary air injection.