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Journal Article

Seeds of phase transition to thermoacoustic instability

Authors

Raghunathan,  M.
External Organizations;

/persons/resource/george

George,  Nitin Babu
Potsdam Institute for Climate Impact Research;

Unni,  V. R.
External Organizations;

Sujith,  R. I.
External Organizations;

/persons/resource/Juergen.Kurths

Kurths,  Jürgen
Potsdam Institute for Climate Impact Research;

/persons/resource/Elena.Surovyatkina

Surovyatkina,  Elena
Potsdam Institute for Climate Impact Research;

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27313oa.pdf
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Citation

Raghunathan, M., George, N. B., Unni, V. R., Sujith, R. I., Kurths, J., Surovyatkina, E. (2022): Seeds of phase transition to thermoacoustic instability. - New Journal of Physics, 24, 063008.
https://doi.org/10.1088/1367-2630/ac71bb


Cite as: https://publications.pik-potsdam.de/pubman/item/item_27313
Abstract
Tackling the problem of emissions is at the forefront of scientific research today. While industrial engines designed to operate in stable regimes produce emissions, attempts to operate them at 'greener' conditions often fail due to a dangerous phenomenon known as thermoacoustic instability. Hazardous high amplitude periodic oscillations during thermoacoustic instability lead to the failure of these engines in power plants, aircraft, and rockets. To prevent this catastrophe in the first place, identifying the onset of thermoacoustic instability is required. However, detecting the onset is a major obstacle preventing further progress due to spatiotemporal variability in the reacting field. Here, we show how to overcome this obstacle by discovering a critical condition in certain zones of the combustor, which indicates the onset of thermoacoustic instability. In particular, we reveal the critical value of the local heat release rate that allows us to distinguish stable operating regimes from hazardous operations. We refer to these zones as seeds of the phase transition because they show the earliest manifestation of the impending instability. The increase in correlations in the heat release rate between these zones indicates the transition from a chaotic state to a periodic state. Remarkably, we found that observations at the seeds of the phase transition enable us to predict when the onset occurs, well before the emergence of dangerous large-amplitude periodic acoustic pressure oscillations. Our results contribute to the operation of combustors in more environment-friendly conditions. The presented approach is applicable to other systems exhibiting such phase transitions.