Synchronization framework for modeling transition to thermoacoustic instability in laminar combustors

Weng, Yue; Unni, Vishnu R.; Sujith, R. I.; Saha, Abhishek

doi:10.1007/s11071-020-05706-3

Cited by 22 publications

(17 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Kashinath et al [38] used multi-mode simulations to show the significant contributions of the higher harmonics to the nonlinear dynamics and were able to replicate similar results as observed in experiments conducted by Kabiraj et al [32]. Later, models based on synchronisation of oscillators have been developed to explain the transition to chaos in laminar thermoacoustic systems [39].…”

Section: Transitions In Laminar Systemsmentioning

confidence: 62%

See 1 more Smart Citation

Critical transitions and their early warning signals in thermoacoustic systems

Pavithran

Unni

Sujith

2021

Eur. Phys. J. Spec. Top.

Self Cite

View full text Add to dashboard Cite

Many complex systems undergo critical transitions. A thermoacoustic system is one such system which exhibits a catastrophic transition to a state of oscillatory instability known as thermoacoustic instability. So far, several early warning signals have been devised to detect the transition from stable operation to thermoacoustic instability in both laminar and turbulent systems. We focus on these early warning signals, and the challenges faced while detecting oscillatory instabilities in practical systems. In contrast to the transition from a fixed point to limit cycle oscillations in laminar systems, turbulent systems exhibit a transition from a chaotic state to limit cycle via a state of intermittency. In this review, we highlight the importance of the inherent fluctuations in the system in providing early warning signals for critical transitions.

show abstract

Section: Transitions In Laminar Systemsmentioning

confidence: 62%

“…More recently, Weng et al [39] developed a synchronisation-based model which captures the multiple bifurcations in a thermoacoustic system. They considered the acoustic field and heat release rate as nonlinearly coupled damped simple harmonic oscillators.…”

Section: Synchronisation-based Modelsmentioning

confidence: 99%

Critical transitions and their early warning signals in thermoacoustic systems

Pavithran

Unni

Sujith

2021

Eur. Phys. J. Spec. Top.

Self Cite

View full text Add to dashboard Cite

show abstract

“…To investigate the dynamics of thermoacoustic instability, the intermediate complex states need to be analyzed, such as the periodic limit cycle oscillations, quasi-periodic oscillations, chaotic oscillations and intermittency oscillations [17][18][19]. Thus, the specific intermediate complex states can comprehend.…”

Section: Nonlinear Time Series Analysismentioning

confidence: 99%

“…These stochastic properties make the study of thermoacoustic instability more challenging [16]. The modelling, characterizing and predicting of thermoacoustic instability are crucial for the safe operation of the combustor, thus there are many qualitative and quantitative studies on thermoacoustic nonlinearity [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Effects of operating parameters on the combustion oscillation behaviour in a lean premixed CH4 combustor

Tao

Zhou

2021

J Mech Sci Technol

View full text Add to dashboard Cite

This article experimentally studies the influence of operating parameters on thermoacoustic instability in a lean premixed combustor. The combustion chamber length and methane flow rate were selected as the operating parameter. Experimental results show that the flame experienced different oscillation modes as the combustion chamber length varies. With the nonlinear time-series analyzing tools, such as phase space reconstruction or recurrence plot, the dynamic characteristics of thermoacoustic instability can be acquired. As the methane flow rate increased from 2.0 L/min to 4.5 L/min, the thermoacoustically flame evolves from a chaotic state to a limit cycle state. There exists extreme oscillation point as the combustion chamber length increased from 100 mm to 800 mm. The maximum thermoacoustic instability point occurred at 600 mm. The flame shape is tightly connected with the thermoacoustic instability process, and a hollow inner recirculation region emerged. This article can promote the application of passive control methods in the prevention of combustion instability.

show abstract

“…The assumption is drastic, but is justified on the reason that decoupled oscillators result in oscillations at their own intrinsic frequency leading to stable combustion. Whereas coupled oscillators, with coupling provided through parametric or functional means [31,32,33], result in synchronized behavior. Further, a range of qualitatively similar dynamical states that range from combustion noise to limit cycle oscillations have been reproduced by such models [32,33], thereby providing reliable lower order models for less demanding physical and computational resources.…”

Section: Introductionmentioning

confidence: 99%

Understanding dynamical states observed in a thermo-acoustic system from perspective of frequency-phase relationship derived from a probabilistic oscillator model

Ramanan

Ramankutty

Sreed

et al. 2022

Preprint

View full text Add to dashboard Cite

We perform lab scale experiments in a swirl combustor by reducing the equivalence ratio for two cases involving slightly different inlet air flow rates. Reduction in equivalence ratio at a constant air flow results in the combustor transiting from stable to unstable combustion. The transition passes through stable, type-2 intermittency and beat oscillations. The beat oscillations are seen to fluctuate at a single frequency, and hence suggestive of a process involving spatio-temporal variations in the phase of the driver (i.e., heat release rate fluctuations). This is understood in the manner of a reduced order model, where the driver is considered to an ensemble of phase oscillators with time delays and a probabilistic distribution of natural frequencies, similar to Kuramoto oscillator. The acoustic field is modeled as a Van-der-pol Duffing system, with natural frequency equal to the duct acoustic mode. The coupling between the oscillators is varied based on the physical premise of Rayleigh criterion. The coupled system is seen to qualitatively and quantitatively match the pressure data obtained from experiments. Insights into various conditions illustrate the role of mean and fluctuating instantaneous frequency amongst the phase oscillators in determining the modeled pressure oscillations. By quantifying the extent of fluctuating frequency coupling among the phase oscillators, it is observed that beat oscillations have high correlation with lower deviation compared to intermittency and stable oscillations.

show abstract

Synchronization framework for modeling transition to thermoacoustic instability in laminar combustors

Cited by 22 publications

References 32 publications

Critical transitions and their early warning signals in thermoacoustic systems

Critical transitions and their early warning signals in thermoacoustic systems

Effects of operating parameters on the combustion oscillation behaviour in a lean premixed CH4 combustor

Understanding dynamical states observed in a thermo-acoustic system from perspective of frequency-phase relationship derived from a probabilistic oscillator model

Contact Info

Product

Resources

About