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Share  Collection Title: Combustion Instability
 

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Abstract

An integrated collection in the area of combustion instability is presented. Lord Rayleigh [1] noted that the generation of thermoacoustic oscillations in combustion systems was dependant on the relative phasing between pressure and heat release oscillations. When the heat release oscillations and pressure oscillations are sufficiently in phase with one another, small amplitude pressure perturbations rapidly grow into large amplitude pressure waves. Various experiments monitotring pressure and heat release in laboratory combustors and industrial burners have confirmed the applicability of this criterion [2]. For the particular case of combustion inside a dump combustor, coherent vorical structures shed from the dump plane have been recognized as a potential source of unsteady heat release [3-6] which could couple with pressure oscillations inside the combustor leading to instability. Excess unburnt fuel trapped inside the vortex core could be ignited when the vortex, convecting away from the dump plane, strikes against the walls of the combustor or impinges on the exit nozzle. This sudden combustion of unburnt fuel leads to the generation of a very well defined heat release oscillation whose periodicity depends on the time scales associated with vortex convection and ignition delay upon impingement. Yu et al. (1998) experimentally verified that such a scenario could give rise to a combined convective-acoustic mode that could essentially drive the oscillations [7].In liquid rocket engines on the other hand, the interaction between transverse pressure waves and the flow field in the vicinity of the injector is critical to the instability problem. Acoustic fluctuations, for instance, in the neighborhood of the injector affect injection, atomization, vaporization, mixing and subsequent combustion of propellants and thereby influence the combustion characteristics and stability behavior of the entire engine. In this collectio, some important papers to introduce a researcher into this field is attempted.

 1.Rayleigh,J.W.S.,(1896) The Theory of Sound, Vol. 2, 232, MacMillan & Co.

2. Putnam, A.A. (1971) Combustion-Driven Oscillations in Industry, Elsevier, New York.

 3.Schadow,K.C., and Gutmark, E., (1992) " Combustion instability related to vortex shedding in dump combustors and their passive control," Progress in Energy Combustion Science 18,117-132

4. Poinsot, T.,J., Trouve, A.C.,Veynante,D.P.,Candel,S.,M., and Esposito,E.J. (1987) "Vortex-driven acoustically coupled combustion instabilities," Journal of Fluid Mechanics 177, 265-292

5.Schadow,K.C.,Gutmark,E.,Parr,T.,P.,Wilson,K.J., and Crump,J.E., (1989) "Large-scale coherent structures as drivers of combustion instability," Combustion Science and Technology 64, 167-186

6. Langhorne, P.,J., (1988) "Reheat buzz: An Acoustically coupled instability. Part I. Experiment.,"Journal of Fluid Mechanics 193, 417-443.

7. Yu,K.H., Trouve, A., and Daily, J.W., (1991) "Low-frequency pressure oscillations in a model ramjet combustor," Journal of Fluid Mechanics, 232:47-72

 

 

 

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