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 language | English |
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Article number | Volume 39, Issue 4 |
Pages (from-to) | 4731-4739 |
Journal | Proceedings of the Combustion Institute |
DOIs | |
Publication status | Published - 12 Nov 2022 |
Externally published | Yes |
Keywords
- Can-annular
- Combustion instability
- Complex systems
- Gas turbines
- Thermoacoustics
ASJC Scopus subject areas
- General Chemical Engineering
- Mechanical Engineering
- Physical and Theoretical Chemistry