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Title: Comparison of equivalence ratio transients on combustion instability in single-nozzle and multi-nozzle combustors

Abstract

Low-emissions gas turbine combustion, achieved through the use of lean, premixed fueling strategies, is susceptible to combustion instability. The driving mechanism for this instability arises from fluctuations of pressure, fuel/air flow rate, and heat release rate. If these fluctuations are relatively in-phase, the combustion system will evolve to a self-excited state. The self-excited instability frequency and amplitude depend mainly on the operating condition and the geometry of the combustor. In this study, we consider the onset and decay of self-excited instabilities, resulting from transients in fuel/air ratio, in both single-nozzle and multi-nozzle combustors. In particular, we examine the differences in the instability onset and decay processes between these two flame configurations, as most gas turbine combustors have multiple nozzles, but most gas turbine combustor experiments utilize a single-nozzle. A nonlinear logistic regression analysis is applied to study the timescales of the decay and onset transients. Variations in the equivalence ratio change the heat release rate distribution inside the combustor, which is captured using chemiluminescence imaging. The normalized Rayleigh index, which shows the spatial distribution of the instability driving, is calculated to analyze the driving strength in different regions of the flame. Comparisons between the single- and multi-nozzle flame transients, includingmore » both center and outer flames for the multi-nozzle combustor, suggest that both confinements from the wall and flame-flame interaction are crucial to determining flame dynamics as the equivalence ratio transient changes the heat release rate distribution near corner recirculation zone and flame shear layers.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pennsylvania State Univ., University Park, PA (United States)
Sponsoring Org.:
USDOE Office of Fossil Energy (FE)
OSTI Identifier:
1462985
DOE Contract Number:  
FE0025495
Resource Type:
Conference
Resource Relation:
Conference: ASME Turbo Expo 2018, Oslo, Norway
Country of Publication:
United States
Language:
English
Subject:
20 FOSSIL-FUELED POWER PLANTS

Citation Formats

Chen, Xiaoling, Culler, Wyatt, Peluso, Stephen, Santavicca, Domenic, and O'Connor, Jacqueline. Comparison of equivalence ratio transients on combustion instability in single-nozzle and multi-nozzle combustors. United States: N. p., 2018. Web.
Chen, Xiaoling, Culler, Wyatt, Peluso, Stephen, Santavicca, Domenic, & O'Connor, Jacqueline. Comparison of equivalence ratio transients on combustion instability in single-nozzle and multi-nozzle combustors. United States.
Chen, Xiaoling, Culler, Wyatt, Peluso, Stephen, Santavicca, Domenic, and O'Connor, Jacqueline. Mon . "Comparison of equivalence ratio transients on combustion instability in single-nozzle and multi-nozzle combustors". United States.
@article{osti_1462985,
title = {Comparison of equivalence ratio transients on combustion instability in single-nozzle and multi-nozzle combustors},
author = {Chen, Xiaoling and Culler, Wyatt and Peluso, Stephen and Santavicca, Domenic and O'Connor, Jacqueline},
abstractNote = {Low-emissions gas turbine combustion, achieved through the use of lean, premixed fueling strategies, is susceptible to combustion instability. The driving mechanism for this instability arises from fluctuations of pressure, fuel/air flow rate, and heat release rate. If these fluctuations are relatively in-phase, the combustion system will evolve to a self-excited state. The self-excited instability frequency and amplitude depend mainly on the operating condition and the geometry of the combustor. In this study, we consider the onset and decay of self-excited instabilities, resulting from transients in fuel/air ratio, in both single-nozzle and multi-nozzle combustors. In particular, we examine the differences in the instability onset and decay processes between these two flame configurations, as most gas turbine combustors have multiple nozzles, but most gas turbine combustor experiments utilize a single-nozzle. A nonlinear logistic regression analysis is applied to study the timescales of the decay and onset transients. Variations in the equivalence ratio change the heat release rate distribution inside the combustor, which is captured using chemiluminescence imaging. The normalized Rayleigh index, which shows the spatial distribution of the instability driving, is calculated to analyze the driving strength in different regions of the flame. Comparisons between the single- and multi-nozzle flame transients, including both center and outer flames for the multi-nozzle combustor, suggest that both confinements from the wall and flame-flame interaction are crucial to determining flame dynamics as the equivalence ratio transient changes the heat release rate distribution near corner recirculation zone and flame shear layers.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {6}
}

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