Polarization spectroscopy applied to the detection of trace constituents in sooting combustion

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Abstract

The potential of polarization spectroscopy for the detection of trace constituents in sooting combustion was investigated. It was demonstrated that the directionality of the polarization spectroscopy signal can be exploited to efficiently suppress incoherent interferences, e.g., Rayleigh scattering at soot particles. We also show how polarization spectroscopy compares with laser-induced fluorescence in this type of environment by applying both techniques to atmospheric-pressure, premixed propane/oxygen flames. The acquired signals were spatially resolved along the centerline of the flame, and measurements were conducted at several heights above the burner head and for medium to very high fuel-to-oxidizer ratios. Through our work we found that polarization spectroscopy can be applied even in the presence of large soot fractions. For most conditions, where laser-induced fluorescence suffered from interferences like elastic scattering, spatially filtered polarization spectroscopy signals were virtually background-free, and only for high soot loads did a noticeable background on the latter signal appear. This background likely stems from Mie scattering at very large soot particles.

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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Atom and Molecular Physics and Optics

Keywords

  • fluorescence, laser-induced, combustion diagnostics, polarization spectroscopy, soot
Original languageEnglish
Pages (from-to)238-242
JournalApplied Spectroscopy
Volume58
Issue number2
Publication statusPublished - 2004
Publication categoryResearch
Peer-reviewedYes