The dynamic response of turbulent dihedral v Flames: An amplification mechanism of swirling flames

Kyu Tae Kim, Jong Guen Lee, Bryan D. Quay, Dom A. Santavicca

    Research output: Contribution to journalArticlepeer-review

    12 Scopus citations

    Abstract

    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.

    Original languageEnglish (US)
    Pages (from-to)163-179
    Number of pages17
    JournalCombustion science and technology
    Volume183
    Issue number2
    DOIs
    StatePublished - Feb 1 2011

    All Science Journal Classification (ASJC) codes

    • Chemistry(all)
    • Chemical Engineering(all)
    • Fuel Technology
    • Energy Engineering and Power Technology
    • Physics and Astronomy(all)

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