Imperial College London
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Professor Aimee S. Morgans

Faculty of Engineering, Department of Mechanical Engineering

Professor of Thermofluids
 
 
 
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Contact

 

+44 (0)20 7594 9975a.morgans

 
 
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Location

 

621City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Han:2018:10.1016/j.proci.2018.06.147,
author = {Han, X and Laera, D and Morgans, A and Sung, CJ and Hui, X and Lin, Y},
doi = {10.1016/j.proci.2018.06.147},
journal = {Proceedings of the Combustion Institute},
pages = {5377--5384},
title = {Flame macrostructures and thermoacoustic instabilities in strati fied swirling flames},
url = {http://dx.doi.org/10.1016/j.proci.2018.06.147},
volume = {37},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - The present article investigates the correlation between flame macrostructures and thermoacoustic combustion instabilities in stratified swirling flames. Experiments are carried out in a laboratory scale longitudinal test rig equipped with the Beihang Axial Swirler Independently-Stratified (BASIS) burner, a novel double-swirled combustion system developed by adapting an industrial lean premixed prevaporized (LPP) combustor. At first, the flame macrostructures are investigated and discussed for various total equivalence ratios (total) and stratification ratios (SRs). Depending on operating conditions, three different flame types are stabilized in the combustor: two attached flames comprising a stratified flame and a V-shaped flame (V-flame), as well as a lifted flame. Thermoacoustic instabilities are then investigated. The amplitude of the oscillations is found to be more sensitive to SR than the total. Large amplitude limit cycles are found for low and high values of SR, for which the V-flame and the lifted flame are observed in the combustor, respectively. The flame dynamics are also investigated using local Rayleigh index maps. It is found that for both the lifted flame and V-flame, the major driving force comes from the flame-to-wall impingement region. Coherent structures associated with flame wrinkling are found along the flame brushes of the V-flame. On the contrary, the stratified flame is found to be more thermo-acoustically stable. Finally, incompressible Large Eddy Simulations is used to obtain the flame responses to forcing at 300 Hz, which is very close to the frequencies at which limit cycle oscillations occur. The results show that the global heat release rate response of the stratified flame exhibits a significant phase shift compared to the responses of the other two flame types, and this is the most likely cause of thermoacoustic stabilization.
AU  - Han,X
AU  - Laera,D
AU  - Morgans,A
AU  - Sung,CJ
AU  - Hui,X
AU  - Lin,Y
DO  - 10.1016/j.proci.2018.06.147
EP  - 5384
PY  - 2018///
SN  - 1540-7489
SP  - 5377
TI  - Flame macrostructures and thermoacoustic instabilities in strati fied swirling flames
T2  - Proceedings of the Combustion Institute
UR  - http://dx.doi.org/10.1016/j.proci.2018.06.147
UR  - http://hdl.handle.net/10044/1/61590
VL  - 37
ER  -
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