In-situ photoacoustic measurement of soot profiles in laminar flames using a high repetition-rate pulsed fibre laser

Humphries, Gordon S. and Roy, Robert and Black, John D. and Lengden, Michael and Burns, Iain S. (2019) In-situ photoacoustic measurement of soot profiles in laminar flames using a high repetition-rate pulsed fibre laser. Applied Physics B: Lasers and Optics, 125 (4). 60. ISSN 0946-2171

[img]
Preview
Text (Humphries-etal-APB-2019-In-situ-photoacoustic-measurement-of-soot-profiles-in-laminar-flames)
Humphries_etal_APB_2019_In_situ_photoacoustic_measurement_of_soot_profiles_in_laminar_flames.pdf
Final Published Version
License: Creative Commons Attribution 4.0 logo

Download (957kB)| Preview

    Abstract

    We present a photoacoustic technique for in situ sensing of particulates in reacting flows. The method is demonstrated by measuring soot distribution in laminar flat-flames. The excitation source is a high repetition-rate pulsed fibre laser. The resulting acoustic signals are measured using a uni-directional microphone and lock-in amplifier. Based on an Allan-Werle plot, the detection limit is estimated to be a soot volume fraction of 3 parts-per-billion. Fluence curves are presented, showing a plateau region similar to the behaviour typically observed for laser-induced incandescence. A dependence of the photoacoustic signal on pulse repetition rate is also demonstrated.