An analysis of unstable flow dynamics and flashback mechanism inside a swirl-stabilised lean burn combustor
An analysis of unstable flow dynamics and flashback mechanism inside a swirl-stabilised lean burn combustor
A modern lean burn combustor for propulsion application using a multi-swirler fuel injector system is studied under partially premixed combustion conditions. Combustion induced vortex breakdown (CIVB) plays an important role in establishing the near-field aerodynamic characteristics of lean burn fuel injectors, influencing fuel/air mixing and flame stability. The precise nature of the vortex breakdown can take on several forms mainly consisting of a precessing vortex core in the swirl stream shear layer. In the present study a numerical investigation is carried out with an unsteady Reynolds-averaged Navier Stokes (URANS) solver to capture the evolution of the PVC in the vicinity of the air blast atomizer of the injector and the helical vortex patterns inside the combustor. PVC suppression is captured causing upstream flame propagation and a sudden rise in the temperature near the injector end which can increase NOx production and also cause possible damage to the injector assembly itself. The unsteady dynamics of the PVC, which significantly influences fuel efficiency and emissions, are analyzed for a relatively long period of real time. The variation of velocity along the axis of the combustor confirming upstream flame propagation in to the injector is plotted. Mass weighted average temperatures across different planes in the combustor are monitored as target functions. The influence of different time-step sizes on the prediction of the temperature across these different planes is also presented. For this lean burn combustor using a complex multi-swirler fuel injector system, the results demonstrate the formation of a start-up PVC in the vicinity of the air blast atomizer of the injector, its unstable mode of excitation, sustainment and suppression due to CIVB over a period of time and its strong influence on injector near-field aero-thermodynamics.
9780791838723
The American Society of Mechanical Engineers
Wankhede, Moresh J.
e04360d2-f5b9-4f3d-b036-3d2380384f5d
Bressloff, Neil W.
4f531e64-dbb3-41e3-a5d3-e6a5a7a77c92
Keane, Andy J.
26d7fa33-5415-4910-89d8-fb3620413def
Caracciolo, Luca
e69179a3-8ef0-4d25-8403-5c70bda6c3e9
Zedda, Marco
f2de059a-e577-4b2b-bbdf-d2cd07a0045d
15 June 2010
Wankhede, Moresh J.
e04360d2-f5b9-4f3d-b036-3d2380384f5d
Bressloff, Neil W.
4f531e64-dbb3-41e3-a5d3-e6a5a7a77c92
Keane, Andy J.
26d7fa33-5415-4910-89d8-fb3620413def
Caracciolo, Luca
e69179a3-8ef0-4d25-8403-5c70bda6c3e9
Zedda, Marco
f2de059a-e577-4b2b-bbdf-d2cd07a0045d
Wankhede, Moresh J., Bressloff, Neil W., Keane, Andy J., Caracciolo, Luca and Zedda, Marco
(2010)
An analysis of unstable flow dynamics and flashback mechanism inside a swirl-stabilised lean burn combustor.
In Proceedings of ASME Turbo Expo 2010: Power for Land, Sea and Air.
The American Society of Mechanical Engineers.
11 pp
.
Record type:
Conference or Workshop Item
(Paper)
Abstract
A modern lean burn combustor for propulsion application using a multi-swirler fuel injector system is studied under partially premixed combustion conditions. Combustion induced vortex breakdown (CIVB) plays an important role in establishing the near-field aerodynamic characteristics of lean burn fuel injectors, influencing fuel/air mixing and flame stability. The precise nature of the vortex breakdown can take on several forms mainly consisting of a precessing vortex core in the swirl stream shear layer. In the present study a numerical investigation is carried out with an unsteady Reynolds-averaged Navier Stokes (URANS) solver to capture the evolution of the PVC in the vicinity of the air blast atomizer of the injector and the helical vortex patterns inside the combustor. PVC suppression is captured causing upstream flame propagation and a sudden rise in the temperature near the injector end which can increase NOx production and also cause possible damage to the injector assembly itself. The unsteady dynamics of the PVC, which significantly influences fuel efficiency and emissions, are analyzed for a relatively long period of real time. The variation of velocity along the axis of the combustor confirming upstream flame propagation in to the injector is plotted. Mass weighted average temperatures across different planes in the combustor are monitored as target functions. The influence of different time-step sizes on the prediction of the temperature across these different planes is also presented. For this lean burn combustor using a complex multi-swirler fuel injector system, the results demonstrate the formation of a start-up PVC in the vicinity of the air blast atomizer of the injector, its unstable mode of excitation, sustainment and suppression due to CIVB over a period of time and its strong influence on injector near-field aero-thermodynamics.
More information
Published date: 15 June 2010
Venue - Dates:
Proceedings of ASME Turbo Expo 2010: Power for Land, Sea and Air, Glasgow, United Kingdom, 2010-06-15
Identifiers
Local EPrints ID: 161747
URI: http://eprints.soton.ac.uk/id/eprint/161747
ISBN: 9780791838723
PURE UUID: 00ae8e5f-3e08-4f06-b6f4-84b2789feb9d
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Date deposited: 05 Aug 2010 10:21
Last modified: 14 Mar 2024 02:39
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Contributors
Author:
Moresh J. Wankhede
Author:
Luca Caracciolo
Author:
Marco Zedda
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