Journal of Thermal Science and Technology
Online ISSN : 1880-5566
ISSN-L : 1880-5566
Papers
Linear Instability Analysis of Lean Premixed Combustion
Kazufumi IKEDAKeisuke MATSUYAMAMitsunori ISONOMasaharu NISHIMURA
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2012 Volume 7 Issue 4 Pages 649-664

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Abstract

Combustion oscillation of a self excited combustion-acoustic phenomenon occurs inside the gas turbine combustor. In general, excessive pressure fluctuation of combustion oscillation may impair the gas turbine engine operation and may result in hardware damages. Therefore, combustion oscillation has been one of the problems of the gas turbine development. In this paper, for predicting combustion-acoustic instability on the designing stage, we have developed one-dimensional linear instability analysis method and verified the analysis accuracy by premixed combustor laboratory tests. The phase lag between combustion dynamics and acoustic system is considered to affect whether combustion acts to destabilize the whole system. Heat release fluctuation is considered to be influenced from fuel/air ratio fluctuation, which generates at fuel nozzle position and flows to combustion region. Its advection delay time is one of the important parameters in the instability. Further, even if heat source itself is steady, the heat release can fluctuate because gas flow rate fluctuates acoustically, and as results, combustion-acoustic instable can occur. At this mechanism, the flame position and the reaction delay time have important roles. By theoretical discussions and laboratory verifications, we conclude that analysis models of this paper have captured the basic framework needed to predict combustion-acoustic instability.

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© 2012 by The Japan Society of Mechanical Engineers and The Heat Transfer Society of Japan
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