Abstract.
Using laser-induced fluorescence (LIF), spatially resolved concentration profiles of formaldehyde (H2CO) were obtained in the preheating zone of atmospheric-pressure premixed CH4/air flames stabilized on the central slot of a multiple-slot burner similar in construction to domestic boilers. The isolated pQ1(6) rotational line (339.23 nm) in the 21 041 0 vibronic combination transition in the Ã1A2-\tilde{X} 1A1 electronic band system around 339 nm was excited in the linear LIF intensity regime. For a quantification of quenching effects on the measured LIF signal intensities, relative fluorescence quantum yields were determined from direct fluorescence lifetime as a function of height above the slot exit. Absolute H2CO number densities in the flames were evaluated from a calibration of measured LIF signal intensities versus those obtained in a low-pressure sample with a known H2CO vapor pressure. Peak concentrations in the slightly lean and rich flames reached (994±298) and (174±52) ppm, respectively.
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Received: 25 September 2000 / Published online: 30 November 2000
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Shin, D., Dreier, T. & Wolfrum, J. Spatially resolved absolute concentration and fluorescence-lifetime determination of H2CO in atmospheric-pressure CH4/air flames . Appl Phys B 72, 257–261 (2001). https://doi.org/10.1007/s003400000479
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DOI: https://doi.org/10.1007/s003400000479