Imperial College London
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ProfessorAlexTaylor

Faculty of Engineering, Department of Mechanical Engineering

Professor
 
 
 
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Contact

 

+44 (0)20 7594 7042a.m.taylor

 
 
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Location

 

618City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@inproceedings{Karlis:2019:10.2514/6.2019-0672,
author = {Karlis, E and Hardalupas, I and Taylor, AMKP},
doi = {10.2514/6.2019-0672},
publisher = {American Institute of Aeronautics and Astronautics},
title = {Effects of inert fuel diluents on the dynamic state of a thermoacoustically unstable gas turbine combustor},
url = {http://dx.doi.org/10.2514/6.2019-0672},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - CPAPER
AB  - The effects of inert diluents in the fuel mixture of a model swirl stabilized gas turbine com-bustor, under thermoacoustically unstable limit cycle operation, were studied experimentally.The measurements included Particle Image Velocimetry (PIV), high speed CH∗chemilumines-cent imaging and dynamic pressure signals. The paper focuses on the dynamic phenomenon ofthe period doubling bifurcation, which came about when the equivalence ratio (φ) of undilutedflames was enriched from 0.55 to 0.60 under constant Reynolds number (Re). The bifurcationfeatured an emergence of an aerodynamically related timescale in addition to the fundamentaltimescale which was induced from an unstable acoustic eigenmode. The aerodynamic timescaleis introduced by azimuthal convection of a high heat release rate region, and is linked in theliterature with a precessing motion of the recirculation zone. Prior to the bifurcation, theflame anchored between the wall and the outer shear layers of the recirculation zone assuminga V-shape. The dynamics were attracted to a Period-1 limit cycle. Post the bifurcation the flameexpanded in the inner shear layers of the recirculation zone assuming an M-shape, while thedynamics were attracted to a Period-2 limit cycle. The latter operational condition was subjectto nitrogen dilution in order to parametrically increase the molar fraction of inert diluent inthe fuel stream. It was found that on increasing the diluent molar fraction the amplitude andthe frequency of the limit cycle fundamental acoustic mode decreased. Also, inert dilution sup-pressed the aerodynamic timescale and the flame assumed a V-shape again. A mechanism tointerpret this mechanism is suggested. Increasing the diluent molar fraction of the fuel makesthe flame susceptible to quenching because the extinction strain rate of the mixture decreased.Thus, the flow imposed strain rates quenched the flame when it attempted to anchor on theinner shear layers of the vortex breakdown induced r
AU  - Karlis,E
AU  - Hardalupas,I
AU  - Taylor,AMKP
DO  - 10.2514/6.2019-0672
PB  - American Institute of Aeronautics and Astronautics
PY  - 2019///
TI  - Effects of inert fuel diluents on the dynamic state of a thermoacoustically unstable gas turbine combustor
UR  - http://dx.doi.org/10.2514/6.2019-0672
UR  - http://hdl.handle.net/10044/1/66946
ER  -
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