TY - JOUR
T1 - The dynamic response of turbulent dihedral v Flames
T2 - An amplification mechanism of swirling flames
AU - Kim, Kyu Tae
AU - Lee, Jong Guen
AU - Quay, Bryan D.
AU - Santavicca, Dom A.
N1 - Funding Information:
Funding for this research was provided by the Department of Energy University Coal Research Program through Contract # DE-FG26–07NT43069 and the National Science Foundation through Award #0625970.
PY - 2011/2
Y1 - 2011/2
N2 - The authors analyze the dynamic response of swirl-stabilized flames submitted to upstream acoustic perturbation. Extensive measurements were performed in an optically accessible single-nozzle gas turbine combustor operating on natural gas-air at inlet temperatures of 200 and 300° C over a range of equivalence ratios from 0.55 to 0.70, a range of inlet velocities from 60 to 100m/s, and swirl angles of 30° and 45°. Temporal oscillations of inlet velocity and heat release rate in the whole flame were measured using the 2-microphone method and global OH*, CH*, and CO2* chemiluminescence emission intensities, respectively, whereas spatially resolved measurement of heat release rate was made using time-averaged CH* chemiluminescence flame images. For the dihedral V flames, amplification characteristic of the flame transfer function was observed. This effect is, unlike the amplification mechanism of a small laminar flame, controlled by the relative ratio of the two length scales, disturbance convective wavelength and flame length. The measured transfer functions show resonance-like behavior when a nondimensional number, the ratio of half the convective wavelength to flame length, approaches unity. It was found that the flame geometric properties, specifically flame angle, also play a crucial role in the flame transfer function. The frequency-dependent behavior of swirl-stabilized flames is closely related to eigenfrequency selection processes at limit cycle pressure oscillations.
AB - The authors analyze the dynamic response of swirl-stabilized flames submitted to upstream acoustic perturbation. Extensive measurements were performed in an optically accessible single-nozzle gas turbine combustor operating on natural gas-air at inlet temperatures of 200 and 300° C over a range of equivalence ratios from 0.55 to 0.70, a range of inlet velocities from 60 to 100m/s, and swirl angles of 30° and 45°. Temporal oscillations of inlet velocity and heat release rate in the whole flame were measured using the 2-microphone method and global OH*, CH*, and CO2* chemiluminescence emission intensities, respectively, whereas spatially resolved measurement of heat release rate was made using time-averaged CH* chemiluminescence flame images. For the dihedral V flames, amplification characteristic of the flame transfer function was observed. This effect is, unlike the amplification mechanism of a small laminar flame, controlled by the relative ratio of the two length scales, disturbance convective wavelength and flame length. The measured transfer functions show resonance-like behavior when a nondimensional number, the ratio of half the convective wavelength to flame length, approaches unity. It was found that the flame geometric properties, specifically flame angle, also play a crucial role in the flame transfer function. The frequency-dependent behavior of swirl-stabilized flames is closely related to eigenfrequency selection processes at limit cycle pressure oscillations.
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U2 - 10.1080/00102202.2010.508477
DO - 10.1080/00102202.2010.508477
M3 - Article
AN - SCOPUS:78650198525
SN - 0010-2202
VL - 183
SP - 163
EP - 179
JO - Combustion science and technology
JF - Combustion science and technology
IS - 2
ER -