0
Research Papers: Gas Turbines: Combustion, Fuels, and Emissions

Characterization and Modeling of a Spinning Thermoacoustic Instability in an Annular Combustor Equipped With Multiple Matrix Injectors

[+] Author and Article Information
Jean-François Bourgouin

CNRS,
UPR 288 – Laboratoire EM2C,
Châtenay-Malabry 92295, France;
Ecole Centrale Paris,
Châtenay-Malabry 92295, France;
SNECMA (Safran Group),
Centre de Villaroche,
Moissy-Cramayel 77550, France

Daniel Durox, Thierry Schuller

CNRS,
UPR 288 – Laboratoire EM2C,
Châtenay-Malabry 92295, France;
Ecole Centrale Paris,
Châtenay-Malabry 92295, France

Jonas P. Moeck

TU Berlin,
Institut für Strömungsmechanik
& Technische Akustik,
Berlin 10623, Germany

Sébastien Candel

CNRS,
UPR 288 – Laboratoire EM2C,
Châtenay-Malabry 92295, France;
Ecole Centrale Paris,
Châtenay-Malabry 92295, France
e-mail: sebastien.candel@ecp.fr

1Corresponding author.

Contributed by the Combustion and Fuels Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 9, 2014; final manuscript received July 16, 2014; published online September 4, 2014. Editor: David Wisler.

J. Eng. Gas Turbines Power 137(2), 021503 (Sep 04, 2014) (11 pages) Paper No: GTP-14-1339; doi: 10.1115/1.4028257 History: Received July 09, 2014; Revised July 16, 2014

Oscillations in fully annular systems coupled by azimuthal modes are often observed in gas turbine combustors but not well documented. One objective of the present study is to characterize this type of oscillation in a laboratory scale system, allowing detailed pressure measurements and high speed visualization of the flame motion. The experiment is designed to allow detailed investigations of this process at a stable limit cycle and for an extended period of time. Experiments reported in the present article are carried out in the MICCA facility which was used in our previous work to analyze instabilities arising when the chamber backplane was equipped with multiple swirling injectors (Bourgouin et al., 2013, “Self-Sustained Instabilities in an Annular Combustor Coupled by Azimuthal Acoustic Modes,” ASME Paper No. GT2013-95010). In the present study, these units are replaced by a set of matrix injectors. The annular plenum feeds 16 such devices confined by two cylindrical quartz tubes open to the atmosphere. The multiple flames formed by the matrix injectors are laminar and have a well documented describing function. This constitutes an ideal configuration allowing systematic investigations of thermo-acoustic oscillations coupled by longitudinal or azimuthal modes while avoiding complexities inherent to swirling turbulent flames studied previously. Optical access to the chamber allows high speed imaging of light emission from the flames providing instantaneous flame patterns and indications on the heat release rate fluctuations. Eight waveguide microphones record the pressure signal at the combustor injection plane and in the plenum. Among the unstable modes observed in this setup, this analysis focuses on situations where the system features a spinning azimuthal mode. This mode is observed at a frequency which is close to that associated with the 1A mode of the plenum. A theoretical analysis is then carried out to interpret the angular shift between the nodal lines in the plenum and chamber, and the measured flame describing function (FDF) is used to quantify this shift and determine the linear growth rate.

FIGURES IN THIS ARTICLE
<>
Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Top: photograph of the MICCA combustor and detailed view of the matrix injectors. A waveguide outlet is located at equal distances from the two injectors. Bottom: schematic representation of the experimental setup.

Grahic Jump Location
Fig. 2

Schematic of the top view of the experimental setup with microphone and photomultiplier measurement locations indicated

Grahic Jump Location
Fig. 3

Pressure signal recorded by microphones in the chamber (a) and in the plenum (b) for the spinning mode obtained at φ=0.96 and ub = 1.49 m · s−1

Grahic Jump Location
Fig. 4

Phase average of 1000 images recorded by the ICMOS camera for the spinning mode φ=0.96 and ub = 1.49 m · s−1. The direction of reading is from left to right and from top to bottom.

Grahic Jump Location
Fig. 5

Pressure and photomultiplier signals corresponding to a spinning mode for a bulk velocity ub = 1.49 m · s−1 and an equivalence ratio φ=0.96. In the on-line version, microphone signals MC1 and MC7 appear in black while photomultiplier signals H1 and H7 are plotted in red.

Grahic Jump Location
Fig. 6

Histogram of the nodal line corresponding to the spinning mode. The vertical black lines represent the injection feedlines azimuthal positions.

Grahic Jump Location
Fig. 7

Time evolution of the nodal lines angular positions in the plenum and in the chamber for the pressure waves

Grahic Jump Location
Fig. 8

Schematic representations of the MICCA combustor with 16 burners (left) and the fully symmetric combustor model (right). In these diagrams, the chamber length is reduced by a factor of 2 compared to the other dimensions to zoom on the region of interest.

Grahic Jump Location
Fig. 9

Angular shift β as function of the FTF phase lag ϕ for |K|=0, 0.5, 1, and 1.1 calculated with a numerical version of the model and with the analytical formula Eq. (16)

Grahic Jump Location
Fig. 10

Angular shift β as function of the FTF phase lag ϕ for |K|=4, and 7 calculated with a numerical version of the model and with the analytical formula Eq. (16)

Grahic Jump Location
Fig. 11

FDF of the matrix burner. G, ϕ, u, and u' denote, respectively, the gain, the phase, the bulk velocity in the matrix injectors and the RMS velocity fluctuating level.

Grahic Jump Location
Fig. 12

Plenum and chamber microphone signals and heat release rate signals recorded during a spinning mode. The plenum and chamber microphone signals have been shifted to correspond to the azimuthal position of the center of the burner corresponding to H1.

Grahic Jump Location
Fig. 13

Plenum and chamber pressure signals and heat release rate signals predicted by the present model with |K|=1.64 (G2 = 0.41) and ϕ2=1.73π. The exponential growth is suppressed in this plot to highlight the phase shift between the signals. The microphone and heat release rate signals are plotted in arbitrary units.

Tables

Errata

Discussions

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 Journal Articles
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