Further characterization of the disturbance field in a transversely excited swirl-stabilized flame

Jacqueline O'Connor, Tim Lieuwen

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

This paper describes an analysis of the unsteady flow field in swirl flames subjected to transverse acoustic waves. This work is motivated by transverse instabilities in annular gas turbine combustors, which are a continuing challenge for both power generation and aircraft applications. The unsteady flow field that disturbs the flame consists not only of the incident transverse acoustic wave, but also longitudinal acoustic fluctuations and vortical fluctuations associated with underlying hydrodynamic instabilities of the base flow. We show that the acoustic and vortical velocity fluctuations are of comparable magnitude. The superposition of these waves leads to strong interference patterns in the velocity field, a result of the significantly different wave propagation speeds and axial phase dependencies of these two disturbance sources. Vortical fluctuations originate from the convectively unstable shear layers and absolutely unstable swirling jet. We argue that the unsteady shear layer induced fluctuations are the most dynamically significant, as they are the primary source of flame fluctuations. We also suggest that vortical structures associated with vortex breakdown play an important role in controlling the time-averaged features of the central flow and flame spreading angle, but do not play an important role in disturbing the flame at low disturbance amplitudes. This result has important implications not only for our understanding of the velocity disturbance field in the flame region, but also for capturing important physics in future modeling efforts.

Original languageEnglish (US)
Article number011501
JournalJournal of Engineering for Gas Turbines and Power
Volume134
Issue number1
DOIs
StatePublished - Jan 1 2012

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Unsteady flow
Flow fields
Acoustics
Acoustic waves
Combustors
Wave propagation
Power generation
Gas turbines
Vortex flow
Hydrodynamics
Physics
Aircraft

All Science Journal Classification (ASJC) codes

  • Nuclear Energy and Engineering
  • Fuel Technology
  • Aerospace Engineering
  • Energy Engineering and Power Technology
  • Mechanical Engineering

Cite this

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Further characterization of the disturbance field in a transversely excited swirl-stabilized flame. / O'Connor, Jacqueline; Lieuwen, Tim.

In: Journal of Engineering for Gas Turbines and Power, Vol. 134, No. 1, 011501, 01.01.2012.

Research output: Contribution to journalArticle

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