Seeds of phase transition to thermoacoustic instability

Raghunathan, M and George, N B and Unni, Vishnu R and et al, . (2022) Seeds of phase transition to thermoacoustic instability. New Journal of Physics, 24 (6). pp. 1-17. ISSN 1367-2630

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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. © 2022 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft.

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IITH Creators:

IITH Creators	ORCiD
Unni, Vishnu R	https://orcid.org/0000-0002-8830-9779

Item Type:

Article

Additional Information:

This research was supported by the Swarnajayanti Fellowship (Grant No. DST/SF/1(E C)/2006), by the IoE initiative (SB/2021/0845/AE/MHRD/002696), IIT Madras and also by the J C Bose Fellowship (Grant No. JCB/2018/000034/SSC) awarded by the Department of Science and Technology (DST), Government of India. NBG acknowledges the financial support of the East Africa Peru India Climate Capacities project (18_II_149_Global_A_Risikovorhersage) funded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety and the International Climate Initiative. ES acknowledges the financial support by RFBR, project number 20-07-01071. The authors would like to thank Mr Sundar Bharathi, PhD student from Chemical Engineering at IIT Madras, India for the helpful discussions in optimizing the code for parallel processing. The authors would like to thank Mr Midhun P R, Ms Reeja K V and Mr Thilagaraj S of Aerospace department, IIT Madras for their assistance in carrying out the experiments.

Uncontrolled Keywords:

critical transition; nonlinear dynamics; thermoacoustic instability

Subjects:

Physics

Divisions:

Department of Physics

Depositing User:

. LibTrainee 2021

Date Deposited:

17 Oct 2022 06:09

Last Modified:

17 Oct 2022 06:09