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Vortices, sound and flames — a damaging combination

Published online by Cambridge University Press:  04 July 2016

A. P. Dowling*
Affiliation:
Department of Engineering, University of Cambridge, Cambridge, UK

Abstract

The interaction between vortices, sound and combustion can lead to self-excited oscillations of such large amplitudes that structural damage is done. These occur because any small unsteadiness in the rate of combustion is a source of sound, generating pressure and velocity fluctuations. However, the velocity fluctuations perturb the flame, thereby altering the instantaneous rate of heat release. Instability is then possible because while acoustic waves perturb the combustion, the unsteady combustion generates yet more sound! Combustion oscillations can occur in afterburners and at idle in conventional aeroengine combustors. Lean premixed, prevapourised technology has tremendous potential to reduce NOx emissions, but is proving highly susceptible to self-excited oscillations. An overview of the physics of the interaction between vortices, sound and flames is presented, and illustrated by examples of instability in generic premixed ducted flames and in aeroengine combustors. The potential for both passive and active control is discussed.

Type
The 1999 Lanchester lecture
Copyright
Copyright © Royal Aeronautical Society 2000 

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References

1. Ackroyd, J.A.D. The 31st Lanchester lecture: Lanchester — the man, Aeronaut J, 1992, 96, (954), pp 119140.Google Scholar
2. Kingsford, P.W. F.W. Lanchester, a Life of an Engineer, Edward Arnold, London, 1960.Google Scholar
3. Lanchester, F.W. Aerodonetics, Constable, London, 1917.Google Scholar
4. Rayleigh, J.W.S. The Theory of Sound, Macmillan, London, 1896.Google Scholar
5. Chu, B.T. On the energy transfer to small disturbances in fluid flow (Part I), Acta Mechanica, 1964, 1, pp 215234.Google Scholar
6. Williams, F.A. CombustionTheory, Addison-Wesley, Reading, Massachusetts, 1965.Google Scholar
7. Lanchester, F.W. Aerodynamics, Constable, London, 1918.Google Scholar
8. Bloxsidge, G.J., Dowling, A.P., and Langhorne, P.J. Reheat buzz: an acoustically coupled combustion instability. Part 2. Theory, J Fluid Mech, 1988, 193, pp 445473.Google Scholar
9. Dowling, A.P Nonlinear self-excited oscillations of a ducted flame, J Fluid Meek, 1997, 346, pp 271290.Google Scholar
10. Macquisten, M.A. and Dowling, A.P. LOW frequency combustion oscillations in a model afterburner, Combust Flame, 1993, 94, pp 253 264.Google Scholar
11. Macquisten, M.A. and Dowling, A.P. Combustion oscillations in a twin-stream afterburner, J Sound Vib, 1995, 188, pp 545560.Google Scholar
12. Bloxsidge, G.J. Reheat Buzz: An Acoustically Driven Combustion Instability, PhD thesis, University of Cambridge, 1987.Google Scholar
13. Dowling, A.P. A kinematic model of a ducted flame, J Fluid Mech, 1999, 394, pp 5172.Google Scholar
14. Smart, A.E., Jones, B. and Jewel, N.T. Measurements of unsteady parameters in a rig designed to study reheat combustion instabilities, AIAA Paper 76-141, 1976.Google Scholar
15. Lanchester, F.W. Improvements in Gas Motor Engines, Patent No 5479, 1890.Google Scholar
16. Lanchester, F.W. The 24th Thomas Hawksley Lecture: The gas engine and after, Proc IMechE, 1937, 136, pp 195244.Google Scholar
17. Langhorne, P.J. Reheat buzz: an acoustically coupled combustion instability. Part 1. Experiment, J Fluid Mech, 1988, 193, pp 417443.Google Scholar
18. Brookes, S.J., Cant, R.S., and Dowling, A.P. Modelling combustion instabilities using computational fluid dynamics, ASME 99-GT-112, 1999.Google Scholar
19. Zhu, M., Dowling, A.P. and Bray, K.N.C. Forced oscillations in combustors with spray atomisers, ASME 99-GT-302, To appear ASME J Eng Gas Turb Power, 2000.Google Scholar
20. Lefebvre, A.H. Gas Turbine Combustion, 2nd Edition, Taylor & Francis, Philadelphia, 1998.Google Scholar
21. Abu-Orf, G.M. and Cant, R.S. Proc Joint meeting of Spanish, Portuguese, Swedish and British sections of Comb Inst, 1996.Google Scholar
22. Hubbard, S. and Dowling, A.P. Acoustic instabilities in premix burners, 4th AIAA/CEAS Aeroacoustics Conference, AIAA 98-2272, 1998.Google Scholar
23. Dowling, A.P. and Hubbard, S. Instability in lean premixed combustors, To appear Proc IMechE, Part A, J Power Energy, 2000.Google Scholar
24. Straub, D.L. and Richards, G.E. Effect of fuel nozzle configurations on premix combustor dynamics, ASME 98-GT-492, 1998.Google Scholar
25. Dines, P.J. Active Control of Flame Noise, PhD Thesis, University of Cambridge, 1983.Google Scholar
26. Langhorne, P.J., Dowling, A.P. and Hooper, N. Practical active control system for combustion oscillations, Prop Power, 1990, 6, pp 324333.Google Scholar
27. Seume, J.R., Vortmeyer, N., Krause, W., Hermann, J., Hantschk, C-C, Zangl, P., Gleis, S., Vortmeyer, D. and Orthmann, A. Application of active combustion instability control to a heavy duty gas turbine, ASME J Eng Gas Turb Power, 1998, 120, pp 721726.Google Scholar
28. Billoud, G., Galland, M.A., Huynh Huu, C. and Candel, S. Adaptive active control of combustion instabilities, Comb Sci Tech, 1992, 81, pp 257283.Google Scholar
29. Kemal, A. and Bowman, C.T. Real-time adaptive feedback control of combustion instability, 26th Symposium (International) on Combustion, 2803-2809, 1996.Google Scholar
30. Evesque, S.M.N, and Dowling, A.P. LMS algorithm for adaptive control of combustion oscillations, Submitted to Combust Sci Tech, 1999.Google Scholar
31. Feintuch, P. An adaptive recursive filter, Proc IEEE, 1976, 64, pp 16221624.Google Scholar
32. Evesque, S.M.N., Chu, Y.C, Dowling, A.P. and Glover, K. Feedback control of a premixed ducted flame, Proceedings of the ISABE XIV International Symposium, IS-7187, Florence, Italy, September 1999.Google Scholar
33. Chu, Y.C, Dowling, A.P. and Glover, K. Robust control of combustion oscillations. Proc of the IEEE International Conference on Control Applications, pp 11651169, 1998.Google Scholar
34. Chu, Y.C., Glover, K. and Dowling, A.P. Control of combustion oscillations via H, loop-shaping, μ-analysis and integral quadratic constraints, submitted to Automatica, 2000.Google Scholar