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Mutual synchronization of two flame-driven thermoacoustic oscillators: Dissipative and time-delayed coupling effects
Kihun Moon1, Yu Guan2, Larry K B Li2
1Department of Aerospace Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea.
Chaos (Woodbury, N.Y.)
|March 2, 2020
Summary
This study reveals how coupling affects thermoacoustic oscillations in gas turbines. Stronger coupling synchronizes oscillations, while weaker coupling leads to desynchronization, offering insights for control strategies.
Area of Science:
- Combustion science
- Acoustics
- Turbomachinery
Background:
- Low-emissions gas turbines experience thermoacoustic oscillations due to combustor coupling.
- These oscillations increase wear and thermal stress, impacting engine longevity.
- Understanding synchronization is crucial for mitigating these effects in can-annular gas turbines.
Purpose of the Study:
- To experimentally investigate the mutual synchronization of two thermoacoustic oscillators in a can-annular gas turbine configuration.
- To analyze the influence of dissipative and time-delayed coupling on oscillation behavior.
- To explore the impact of cross-talk geometry on synchronization dynamics.
Main Methods:
- Utilized two model combustors with turbulent lean-premixed flames.
- Employed stationary and transient measurements to study coupling effects.
- Varied cross-talk diameter and length, and combustor length to assess parameter influence.
Main Results:
- Strengthening dissipative coupling promotes mutual synchronization; weakening it leads to desynchronization.
- Observed significant reduction in oscillation amplitude under specific coupling conditions.
- Identified spontaneous mode transitions and a rhomboid phase plane structure due to in-phase and out-of-phase synchronization (push-push and push-pull modes).
Conclusions:
- Dissipative and time-delayed coupling significantly influence thermoacoustic oscillation synchronization.
- Synchronization dynamics are complex, involving mode transitions and coexistence of different synchronization types.
- Findings provide a basis for developing advanced control strategies to manage thermoacoustic instabilities in gas turbines.
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