Session: 04-36: Combustion Dynamics - Spray Flames

Paper Number: 104208

104208 - Spray Swirling Flame Dynamic Under Fuel Modulation 

Combustion instability is still a main challenge in developing advanced gas turbine combustors. It is essential to conduct combustion instability control once it occurs. In this paper, liquid-fuel modulation by a high-speed valve is used to control combustion instability. Spray swirling flame dynamics under fuel modulation is experimentally studied. A photomultiplier is used to measure flame global OH* chemiluminescence, velocity fluctuation upstream the swirler is measured with a two-microphone method and a high-speed ICCD camera is employed to capture unsteady flame behavior. Experimental results show the fluctuation of flame heat release rate is decreased by 90% under fuel modulation. The dynamic pressure fluctuation in the combustor is decreased by 7.8 dB. The modulation phase is a key parameter to the flame dynamic. The fluctuation of heat release rate is well controlled with modulation phase being 40 deg while the flame oscillation is enhanced at 220 deg. This is caused by the out of phase and in phase superpositions of the original flame heat release rate fluctuation and that induced by the fuel modulation. POD analysis shows the flame longitudinal mode is well controlled while the spiral mode is not affected by the fuel modulation. The results shed light on the mechanism of flame dynamic control with fuel modulation and shows potential application in further closed-loop control of combustion instability.

Presenting Author: Weijie Liu Aero Engine Academy of China

Presenting Author Biography: Weijie Liu recieved his Ph D. degrees in Power Machinery and Engineering from Shanghai Jiao Tong University, China, in 2017. He is currently an senior engineer at Aero Engine Academy of China. His research interests include lean premixed combustion, multi-nozzle combustion and theromacoustic instabilities.

Authors:

Weijie Liu Aero Engine Academy of China
He Su Aero Engine Academy of China
Liang Zhang Aero-Engine Academy of China
Peng Zhang Aero Engine Academy of China
Ranran Xue Aero Engine Academy of China
Qian Yang Aero Engine Academy of China