Three-color vibrational CARS thermometry of fuel-rich ethylene/air flames using a potassium gadolinium tungstate Raman-active crystal as a source of narrowband probe radiation.

Author(s) Meißner, C.; Tröger, J.W.; Kozlov, D.N.; Beyrau, F.; Seeger, T.
Journal Appl Opt
Date Published 2017 Apr 10

Three-color broadband vibrational coherent anti-Stokes Raman scattering (CARS) temperature measurements were carried out in laminar fuel-rich sooting ethylene/air flames. Stimulated Raman scattering (SRS) of a picosecond pump laser pulse in a Raman-active potassium gadolinium tungstate [KGd(WO4)2] crystal was employed as a source of narrowband probe radiation. In the three-color CARS experiment, this wavelength-shifted radiation enables N2-based vibrational CARS temperature measurements in sooting flames free of the signal interference with the absorption/emission bands of the flame intermediate radicals C2. Spatial temperature profiles for different fuel-rich atmospheric pressure ethylene/air flames are presented in comparison with the results of two-color broadband vibrational and dual-broadband pure rotational CARS temperature measurements. The comparison shows the suitability of the three-color CARS measurement technique employing the KGd(WO4)2 crystal for accurate, C2 interference-free, temperature measurements in sooting flames.

DOI 10.1364/AO.56.000E77
ISSN 1539-4522
Citation Appl Opt. 2017;56(11):E77E83.

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