Full Content is available to subscribers

Subscribe/Learn More  >

Ignition Delay Time Modulation as a Contribution to Thermo-Acoustic Instability in Sequential Combustion

[+] Author Affiliations
Alexander Ni

ABB Alstom Technology Ltd., Baden-Dättwil, Switzerland

Wolfgang Polifke

Technical University of Munich, Garching, Germany

Franz Joos

Fachhochschule Köln, Köln, Germany

Paper No. 2000-GT-0103, pp. V002T02A023; 9 pages
  • ASME Turbo Expo 2000: Power for Land, Sea, and Air
  • Volume 2: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations
  • Munich, Germany, May 8–11, 2000
  • Conference Sponsors: International Gas Turbine Institute
  • ISBN: 978-0-7918-7855-2
  • Copyright © 2000 by ASME


Pressure pulsations due to combustion instabilities have been encountered in a premixed sequential gas turbine combustor. Measured noise spectra display one or several distinct peaks at Strouhal numbers significantly larger than unity. Height and location of the peaks depend in a sensitve manner on fuel type and/or operating conditions.

The paper identifies a possible mechanism of the observed combustion instability and presents a mathematical model of acoustic self-excitation. The mechanism of self-excitation comprises interactions between the acoustic field in the fuel injector / burner with the ignition delay time of the fuel-air mixture and the heat release intensity:

• pressure drop in the fuel injector nozzle changes with variations of the acoustic pressure in the burner,

• variations of pressure drop and air flow velocity modulate the fuel concentration,

• acoustic perturbations in the pre-flame region influence the delay time for self-ignition and consequently lead to fluctuations of flame velocity and -position.

• fluctuations of flame velocity influence the refracation of acoustic waves at the flame front.

• fuel inhomogeneities modulate the heat release rate and consequently the rate of volume production by the flame.

Based on this structure of a self-excitation mechanism, an analytical model has been developed and used to compute eigenfrequencies and growth rates of instabilities. Some characteristics of the suggested self-excitated instabilities as they are predicted by the model match well with empirical information.

Copyright © 2000 by ASME



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In