Response of partially premixed flames to acoustic velocity and equivalence ratio perturbations

K. T. Kim, J. G. Lee, B. D. Quay, D. A. Santavicca

    Research output: Contribution to journalArticle

    90 Scopus citations

    Abstract

    This article describes an experimental investigation of the forced response of a swirl-stabilized partially premixed flame when it is subjected to acoustic velocity and equivalence ratio fluctuations. The flame's response is analyzed using phase-resolved CH* chemiluminescence images and flame transfer function (FTF) measurements, and compared with the response of a perfectly premixed flame under acoustic perturbations. The nonlinear response of the partially premixed flame is manifested by a partial extinction of the reaction zone, leading to rapid reduction of flame surface area. This nonlinearity, however, is observed only when the phase difference between the acoustic velocity and the equivalence ratio at the combustor inlet is close to zero. The condition, ΔΦ'-V'≈0°, indicates that reactant mixtures with high equivalence ratio impinge on the flame front with high velocity, inducing large fluctuations of the rate of heat release. It is found that the phase difference between the acoustic velocity and equivalence ratio nonuniformities is a key parameter governing the linear/nonlinear response of a partially premixed flame, and it is a function of modulation frequency, inlet velocity, fuel injection location, and fuel injector impedance. The results presented in this article will provide insight into the response of a partially premixed flame, which has not been well explored to date.

    Original languageEnglish (US)
    Pages (from-to)1731-1744
    Number of pages14
    JournalCombustion and Flame
    Volume157
    Issue number9
    DOIs
    StatePublished - Sep 1 2010

    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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