Combustion instabilities near the lean extinction limit
File(s)
Accepted version
Author(s)
Milosavljevic, VD
Lindstedt, Rune
Cornwell, MD
Gutmark, EJ
Vaos, EM
Type
Chapter
Abstract
The most effective and common method utilized to reduce NOx production in gas turbines is to reduce the temperature at which combustion occurs by dilution with excess air. Lean Pre-vapourized Premixed (LPP) combustion systems are, however, susceptible to thermoacoustic instabilities. The current contribution is primarily concerned with exploring techniques for maximizing the stability of LPP combustion in gas turbine engines under low flame temperature conditions. An improved understanding of the fundamental processes causing combustion instabilities near the lean extinction limit allows for improvements of existing combustion systems and aids the development of new systems that are intrinsically more stable. In the present study, combustion systems that achieve flame stability through improved aerodynamics, coupled with the introduction of small amounts of chemically active species to reduce the combustion induction time, are considered. The current contribution suggests that the thermochemical state of the mixture at the forward stagnation point of the main inner re-circulation zone becomes critical when the bulk combustion temperature becomes very low and, as a consequence, the flame becomes more sensitive to aerodynamic strain. The study also shows that the removal of the main axial instability modes through anchoring of the flame will significantly reduce the difficulties associated with combustion control strategies. Examples are given of supporting experimental and computational studies with reference to improvements over existing designs.
Editor(s)
Roy, GD
Yu, KH
Whitelaw, JH
Witton, JJ
Date Issued
2005-01-01
Citation
Advances in Combustion and Noise Control, 2005, pp.149-165
ISBN
9781871315929
1871315921
Publisher
Cranfield University Press
Start Page
149
End Page
165
Journal / Book Title
Advances in Combustion and Noise Control
Copyright Statement
© 2005 Cransfield University Press.
Article Number
10