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2025 Vol.30, Issue 3 Preview Page

Research Article

Numerical Study of Flame Length Effects on Low-Order Thermoacoustic Models

화염 길이가 저차원 열음향 모델에 미치는 영향에 대한 수치적 연구

Juwon Kim1
,
Seungmin Guk1
,
Minwoo Lee1†
김 주원1
,
국 승민1
,
이 민우1†
1Department of Mechanical Engineering, Hanbat National University
1국립한밭대학교 기계공학과
*Corresponding Author
30 September 2025. pp. 26-33
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Abstract

The thermoacoustic network model is a low-order modeling approach used to analyze and predict thermoacoustic instabilities arising from the positive interaction between unsteady heat release and a combustor’s acoustic field. In this study, we question the conventional assumption of a compact flame in thermoacoustic network models by systematically analyzing the effect of flame length on this low-order framework. We first compare the growth rates and mode frequencies of thin and long flames using a three-dimensional analysis tool, revealing a clear discrepancy between the two cases. We then evaluate a one-dimensional network modeling strategy that segments the flame. The results indicate that both the thin-flame assumption and the segmented-flame approach fail to reproduce the full thermoacoustic dynamics within the combustor. We also investigate the influence of varying gain and time delay parameters on growth rates and mode frequencies. The findings of this study demonstrate that flame length has a significant impact on thermoacoustic behavior, and this influence should be appropriately incorporated into low-order thermoacoustic models. Based on these observations, we suggest future research directions for improving existing thermoacoustic network models.

Keywords
Thermoacoustic instability
Network model
Flame length
Low-order modeling
Ammonia flame
References
1

A.P. Dowling, S.R. Stow, Acoustic analysis of gas turbine combustors, J. Propul. Power, 19 (2003) 751-764.

10.2514/2.6192
2

T. Lieuwen, Modeling premixed combustion-acoustic wave interactions: A review, J. Propul. Power, 19 (2003) 765-781.

10.2514/2.6193
3

M. Lee, K.T. Kim, V. Gupta, L.K.B. Li, System identification and early warning detection of thermoacoustic oscillations in a turbulent combustor using its noise-induced dynamics, Proc. Combust. Inst., 38 (2021), 6025-6033.

10.1016/j.proci.2020.06.057
4

M. Sirshendu, V.R. Unni, R.I. Sujith, Onset of thermoacoustic instability in turbulent combustors: an emergence of synchronized periodicity through formation of chimera-like states, J. Fluid Mech., 811 (2017) 659-681.

10.1017/jfm.2016.770
5

M. Lee, Early warning detection of thermoacoustic instability using three-dimensional complexity-entropy causality space, Exp. Therm. Fluid Sci., 130 (2022) 110517.

10.1016/j.expthermflusci.2021.110517
6

M. Mazur, H.T. Nygård, J.R. Dawson, N.A. Worth, Characteristics of self-excited spinning azimuthal modes in an annular combustor with turbulent premixed bluff-body flames, Proc. Combust. Inst., 37 (2019) 5129-5136.

10.1016/j.proci.2018.07.080
7

H. Son, M. Lee, A PINN approach for identifying governing parameters of noisy thermoacoustic systems, J. Fluid Mech., 984 (2024) A21.

10.1017/jfm.2024.219
8

S. Guk, S. Seo, M. Lee, An image-based spatiotemporal approach for detecting coherence resonance in annular model gas-turbine combustor, Phys. Fluids, 36 (2024) 054121.

10.1063/5.0208950
9

B. Franzelli, E. Riber, L.Y.M. Gicquel, T. Poinsot, Large Eddy Simulation of combustion instabilities in a lean partially premixed swirled flame, Combust. Flame, 159 (2012) 621-637.

10.1016/j.combustflame.2011.08.004
10

O. Schulz, U. Doll, D. Ebi, J. Droujko, C. Bourquard, N. Noiray, Thermoacoustic instability in a sequential combustor: Large eddy simulation and experiments, Proc. Combust. Inst., 37 (2019) 5325-5332.

10.1016/j.proci.2018.07.089
11

Y. Sun, D. Zhao, C. Ji, T. Zhu, Z. Rao, B. Wang, Large-eddy simulations of self-excited thermoacoustic instability in a premixed swirling combustor with an outlet nozzle, Phys. Fluids, 34 (2022) 044112.

10.1063/5.0087055
12

A.P. Dowling, A kinematic model of a ducted flame, J. Fluid Mech., 394 (1999) 51-72.

10.1017/S0022112099005686
13

M. Lee, V. Gupta, L.K.B. Li, Fokker–Planck modeling of the stochastic dynamics of a Rijke tube, Chaos, 34 (2024) 083117.

10.1063/5.0211656
14

X. Han, J. Li, A. S. Morgans, Prediction of combustion instability limit cycle oscillations by combining flame describing function simulations with a thermoacoustic network model, Combust. Flame, 162 (2015) 3632-3647.

10.1016/j.combustflame.2015.06.020
15

D.J. Cha, J.K. Song, J.G. Lee, A case study on combustion instability of a model lean premixed gas turbine combustor with open source code OSCILOS, J. Korean Soc. Combust., 20 (2015) 10-18.

10.15231/jksc.2015.20.4.010
16

J. Park, M. Yoon, D. Kim, Development of thermoacoustic network model using transfer matrix method, J. Korean Soc. Combust., 24 (2019) 9-16.

10.15231/jksc.2019.24.2.009
17

S. Guk, J. Lee, J. Kim, M. Lee, Advances and challenges in thermoacoustic network modeling for hydrogen and ammonia combustors, Energies, 18 (2025) 346.

10.3390/en18020346
18

J. Li, Y. Xia, A.S. Morgans, X. Han, Numerical prediction of combustion instability limit cycle oscillations for a combustor with a long flame, Combust. Flame, 185 (2017) 28-43.

10.1016/j.combustflame.2017.06.018
19

D. Yang, F.M. Sogaro, A.S. Morgans, P.J. Schmid, Optimising the acoustic damping of multiple Helmholtz resonators attached to a thin annular duct, J. Sound Vib., 444 (2019) 69-84.

10.1016/j.jsv.2018.12.023
20

A. Valera-Medina, H. Xiao, M. Owen-Jones, W.I.F. David, P.J. Bowen, Ammonia for power, Prog. Energy Combust. Sci., 69 (2018) 63-102.

10.1016/j.pecs.2018.07.001
21

J. Li, Y. Xia, A.S. Morgans, X. Han, Numerical prediction of combustion instability limit cycle oscillations for a combustor with a long flame, Combust. Flame, 185 (2017) 28-43.

10.1016/j.combustflame.2017.06.018
22

D. Wei, H. Fang, H. Zhou, Investigation on self-excited thermoacoustic instability and emission characteristics of premixed CH4/NH3/air flame. Therm. Sci. Eng. Prog., 51 (2024) 102614.

10.1016/j.tsep.2024.102614
Information
  • Publisher :The Korean Society of Combustion
  • Publisher(Ko) :한국연소학회
  • Journal Title :Journal of the Korean Society of Combustion
  • Journal Title(Ko) :한국연소학회지
  • Volume : 30
  • No :3
  • Pages :26-33
  • Received Date : 2025-07-16
  • Revised Date : 2025-08-04
  • Accepted Date : 2025-08-04
  • DOI :https://doi.org/10.15231/jksc.2025.30.3.026
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