Effect of flame response asymmetries on the modal patterns and collective states of a can-annular lean-premixed combustion system

Yu Guan, Larry K.B. Li, Hyunwook Jegal, Kyu Tae Kim

Research output: Journal article publicationJournal articleAcademic researchpeer-review

5 Citations (Scopus)

Abstract

We experimentally study the effect of rotational asymmetries in the flame response distribution on the thermoacoustic oscillations of four turbulent lean-premixed combustors coupled in a ring network. The asymmetries are created via different combinations of high-swirl (HS) and low-swirl (LS) nozzles. By analyzing the inter-combustor acoustic interactions in terms of discrete thermoacoustic modes, we find a variety of modal patterns: (i) global alternating push-pull modes emerge for most pair-wise asymmetric nozzle combinations, (ii) 2-can push-pull modes emerge for an alternating 2-fold symmetric nozzle combination, and (iii) strong mode localization and global push-push modes emerge when the HS nozzles outnumber the LS nozzles. Using a complex systems framework, we reinterpret these modal patterns as collective states, such as a weak breathing chimera, a weak anti-phase chimera, and in-phase/anti-phase synchronization. This study shows that changing the flame response distribution of a multi-combustor system, via changes in the nozzle swirl distribution, can induce a variety of modal patterns and collective states. This sets the stage for the potential use of rotational asymmetries in the passive control of thermoacoustic modes in can-annular combustion systems.

Original languageEnglish
Article numberVolume 39, Issue 4
Pages (from-to)4731-4739
JournalProceedings of the Combustion Institute
DOIs
Publication statusPublished - 12 Nov 2022
Externally publishedYes

Keywords

  • Can-annular
  • Combustion instability
  • Complex systems
  • Gas turbines
  • Thermoacoustics

ASJC Scopus subject areas

  • General Chemical Engineering
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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