Preventing a global transition to thermoacoustic instability by targeting local dynamics

George, Nitin Babu and Raghunathan, Manikandan and Unni, Vishnu R and et al, . (2022) Preventing a global transition to thermoacoustic instability by targeting local dynamics. Scientific Reports, 12 (1). pp. 1-11. ISSN 2045-2322

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Abstract

The burning of fossil fuels to generate power produces harmful emissions. Lowering such emissions in gas turbine engines is possible by operating them at fuel-lean conditions. However, such strategies often fail because, under fuel-lean conditions, the combustors are prone to catastrophic high-amplitude oscillations known as thermoacoustic instability. We reveal that, as an operating parameter is varied in time, the transition to thermoacoustic instability is initiated at specific spatial regions before it is observed in larger regions of the combustor. We use two indicators to discover such inceptive regions: the growth of variance of fluctuations in spatially resolved heat release rate and its spatiotemporal evolution. In this study, we report experimental evidence of suppression of the global transition to thermoacoustic instability through targeted modification of local dynamics at the inceptive regions. We strategically arrange slots on the flame anchor, which, in turn, reduce the local heat release rate fluctuations at the inceptive regions and thus suppress the global transition to thermoacoustic instability. Our results open new perspectives for combustors that are more environmental-friendly. © 2022, The Author(s).

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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 Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST) (Grant no: CRG/2020/003051), Government of India and also by the IoE initiative (SB/2021/0845/AE/MHRD/002696), IIT Madras India. N.B.G 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.

Uncontrolled Keywords:

article; flame; heat

Subjects:

Physics > Mechanical and aerospace

Divisions:

Department of Mechanical & Aerospace Engineering

Depositing User:

. LibTrainee 2021

Date Deposited:

15 Oct 2022 08:02

Last Modified:

15 Oct 2022 08:02