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Dispersion of Entropy Perturbations Transporting through an Industrial Gas Turbine Combustor

In the context of combustion noise and combustion instabilities, the transport of entropy perturbations through highly simplified turbulent flows has received much recent attention. This work performs the first systematic study into the transport of entropy perturbations through a realistic gas turb...

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Detalles Bibliográficos
Autores principales: Xia, Yu, Duran, Ignacio, Morgans, Aimee S., Han, Xingsi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Netherlands 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6044250/
https://www.ncbi.nlm.nih.gov/pubmed/30069141
http://dx.doi.org/10.1007/s10494-017-9854-6
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author Xia, Yu
Duran, Ignacio
Morgans, Aimee S.
Han, Xingsi
author_facet Xia, Yu
Duran, Ignacio
Morgans, Aimee S.
Han, Xingsi
author_sort Xia, Yu
collection PubMed
description In the context of combustion noise and combustion instabilities, the transport of entropy perturbations through highly simplified turbulent flows has received much recent attention. This work performs the first systematic study into the transport of entropy perturbations through a realistic gas turbine combustor flow-field, exhibiting large-scale hydrodynamic flow features in the form of swirl, separation, recirculation zones and vortex cores, these being ubiquitous in real combustor flows. The reacting flow-field is simulated using low Mach number large eddy simulations, with simulations validated by comparison to available experimental data. A generic artificial entropy source, impulsive in time and spatially localized at the flame-front location, is injected. The conservation equation describing entropy transport is simulated, superimposed on the underlying flow-field simulation. It is found that the transport of entropy perturbations is dominated by advection, with both thermal diffusion and viscous production being negligible. It is furthermore found that both the mean flow-field and the large-scale unsteady flow features contribute significantly to advective dispersion — neither can be neglected. The time-variation of entropy perturbation amplitude at combustor exit is well-modelled by a Gaussian profile, whose dispersion exceeds that corresponding to a fully-developed pipe mean flow profile roughly by a factor of three. Finally, despite the attenuation in entropy perturbation amplitude caused by advective dispersion, sufficient entropy perturbation strength is likely to remain at combustor exit for entropy noise to make a meaningful contribution at low frequencies.
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spelling pubmed-60442502018-07-30 Dispersion of Entropy Perturbations Transporting through an Industrial Gas Turbine Combustor Xia, Yu Duran, Ignacio Morgans, Aimee S. Han, Xingsi Flow Turbul Combust Article In the context of combustion noise and combustion instabilities, the transport of entropy perturbations through highly simplified turbulent flows has received much recent attention. This work performs the first systematic study into the transport of entropy perturbations through a realistic gas turbine combustor flow-field, exhibiting large-scale hydrodynamic flow features in the form of swirl, separation, recirculation zones and vortex cores, these being ubiquitous in real combustor flows. The reacting flow-field is simulated using low Mach number large eddy simulations, with simulations validated by comparison to available experimental data. A generic artificial entropy source, impulsive in time and spatially localized at the flame-front location, is injected. The conservation equation describing entropy transport is simulated, superimposed on the underlying flow-field simulation. It is found that the transport of entropy perturbations is dominated by advection, with both thermal diffusion and viscous production being negligible. It is furthermore found that both the mean flow-field and the large-scale unsteady flow features contribute significantly to advective dispersion — neither can be neglected. The time-variation of entropy perturbation amplitude at combustor exit is well-modelled by a Gaussian profile, whose dispersion exceeds that corresponding to a fully-developed pipe mean flow profile roughly by a factor of three. Finally, despite the attenuation in entropy perturbation amplitude caused by advective dispersion, sufficient entropy perturbation strength is likely to remain at combustor exit for entropy noise to make a meaningful contribution at low frequencies. Springer Netherlands 2017-09-21 2018 /pmc/articles/PMC6044250/ /pubmed/30069141 http://dx.doi.org/10.1007/s10494-017-9854-6 Text en © The Author(s) 2017 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Article
Xia, Yu
Duran, Ignacio
Morgans, Aimee S.
Han, Xingsi
Dispersion of Entropy Perturbations Transporting through an Industrial Gas Turbine Combustor
title Dispersion of Entropy Perturbations Transporting through an Industrial Gas Turbine Combustor
title_full Dispersion of Entropy Perturbations Transporting through an Industrial Gas Turbine Combustor
title_fullStr Dispersion of Entropy Perturbations Transporting through an Industrial Gas Turbine Combustor
title_full_unstemmed Dispersion of Entropy Perturbations Transporting through an Industrial Gas Turbine Combustor
title_short Dispersion of Entropy Perturbations Transporting through an Industrial Gas Turbine Combustor
title_sort dispersion of entropy perturbations transporting through an industrial gas turbine combustor
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6044250/
https://www.ncbi.nlm.nih.gov/pubmed/30069141
http://dx.doi.org/10.1007/s10494-017-9854-6
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