Title

Experimental Investigation Of Self-Excited Combustion Instabilities In A Lean, Premixed, Gas Turbine Combustor At High Pressure

Abstract

An experimental investigation of self-excited combustion instabilities in a high pressure, single-element, lean, premixed, natural gas dump-combustor is presented in this paper. The combustor is designed for optical access and is instrumented with high frequency pressure transducers at multiple axial locations. A parametric survey of operating conditions including inlet air temperature and equivalence ratio has been performed, which presents a wide range of peak to peak pressure fluctuations (p0) of the mean chamber pressure (pc). Two cases, Flame A and B with p0=pc = 28% and p0=pc = 15% respectively, both presenting self-excited instabilities at the fundamental longitudinal (1L) mode of the combustion chamber, are discussed to study the coupling mechanism between flame-vortex interactions and the acoustic field in the chamber. OH∗-chemiluminescence is used to obtain a map of global heat release distribution in the combustor. Phase conditioned analysis and Dynamic Mode Decomposition (DMD) analysis is performed, to highlight the contrasting mechanisms that lead to the two distinct instability regimes. Flame interactions with shear layer vortex structures just downstream of the dump plane during the compression phase of the acoustic cycle are found to augment the instability amplitude. Flame A engages strongly in this coupling, whereas Flame B is less affected and establishes a lower amplitude limit cycle.

Publication Date

1-1-2017

Publication Title

Proceedings of the ASME Turbo Expo

Volume

Part F130041-4B

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1115/GT2017-64614

Socpus ID

85030662469 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85030662469

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