Mid-infrared PS and LIF detection of CH4 and C2H6 in cold flows and flames at atmospheric pressure

• Mid-IR polarization spectroscopy (IRPS) and laser-induced fluorescence were applied for detection of CH4 and ethane in 1 atm cold flows and flames. The dependence of IRPS and IRLIF signal of CH4 on different buffer gases, including He, Ar, N2, and CO2 were studied. Simultaneous measurements of IRPS and IRLIF signals allowed a direct comparison of the two techniques. IRPS was superior in detection sensitivity and background discrimination. IRPS excitation scans of a CH4 and ethane mixture diluted in argon were also carried out in a jet at ambient pressure and temperature. Lines in the spectrum belonging to CH4 and ethane were fully recognized and assigned. From the ethane lines in the IRPS excitation spectrum, a detection limit of 50 ppm was conservatively estimated, indicating that IRPS is a promising sensitive technique for hydrocarbon identification and detection. CH4 IRPS detection in a CH4/H2/air premixed flat flame was demonstrated, with spatially resolved IRPS CH4 measurements along different heights in the flame. This is an abstract of a paper presented at the 30th International Symposium on Combustion (Chicago, IL 7/25-30/2004).

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

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