The effect of transient fuel staging on self-excited instabilities in a multi-nozzle model gas turbine combustor

Wyatt Culler, Janith Samarasinghe, Bryan D. Quay, Domenic A. Santavicca, Jacqueline O'Connor

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations

Abstract

Combustion instability in gas turbines can be mitigated using active techniques or passive techniques, but passive techniques are almost exclusively used in industrial settings. While fuel staging, a common passive technique, is effective in reducing the amplitude of self-excited instabilities in gas turbine combustors at steady-state conditions, the effect of transients in fuel staging on self-excited instabilities is not well understood. This paper examines the effect of fuel staging transients on a laboratory-scale five-nozzle can combustor undergoing self-excited instabilities. The five nozzles are arranged in a fouraround-one configuration and fuel staging is accomplished by increasing the center nozzle equivalence ratio. When the global equivalence ratio is φ = 0.70 and all nozzles are fueled equally, the combustor undergoes self-excited oscillations. These oscillations are suppressed when the center nozzle equivalence ratio is increased to φ = 0.80 or φ = 0.85. Two transient staging schedules are used, resulting in transitions from unstable to stable operation, and vice-versa. It is found that the characteristic instability decay times are dependent on the amount of fuel staging in the center nozzle. It is also found that the decay time constants differ from the growth time constants, indicating hysteresis in stability transition points. High speed CH chemiluminescence images in combination with dynamic pressure measurements are used to determine the instantaneous phase difference between the heat release rate fluctuation and the combustor pressure fluctuation throughout the combustor. This analysis shows that the instability onset process is different from the instability decay process.

Original languageEnglish (US)
Title of host publicationCombustion, Fuels and Emissions
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791850848
DOIs
StatePublished - Jan 1 2017
EventASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition, GT 2017 - Charlotte, United States
Duration: Jun 26 2017Jun 30 2017

Publication series

NameProceedings of the ASME Turbo Expo
Volume4A-2017

Other

OtherASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition, GT 2017
CountryUnited States
CityCharlotte
Period6/26/176/30/17

All Science Journal Classification (ASJC) codes

  • Engineering(all)

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    Culler, W., Samarasinghe, J., Quay, B. D., Santavicca, D. A., & O'Connor, J. (2017). The effect of transient fuel staging on self-excited instabilities in a multi-nozzle model gas turbine combustor. In Combustion, Fuels and Emissions (Proceedings of the ASME Turbo Expo; Vol. 4A-2017). American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/GT201763479