Time-Resolved, NIR Two-Tone Frequency Modulation Spectroscopy for Quantitative Measurement of HO₂ Radical in Fuel Oxidation Reactions

Technical Report · Fri May 01 00:00:00 EDT 2015

DOI:https://doi.org/10.2172/1810048· OSTI ID:1810048

Huang, Haifeng ^[1]; Carlen, Christopher R. ^[1]; Rotavera, Brandon ^[1]; Taatjes, Craig A. ^[1]

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1. Sandia National Lab. (SNL-CA), Livermore, CA (United States)

Time-resolved two-tone frequency modulation (TTFM) absorption spectroscopy has been used to measure, in situ and quantitatively, hydroperoxy (HO₂) radical in fuel oxidation reactions at the first overtone transitions (2v₁) of HO₂ near 1509nm. Typical HO₂ detection limit is on the order of 10¹¹ molecule cm^-3, which corresponds to a relative absorption of 10^-5. TTFM method successfully removes low frequency thermal lensing noise in measured HO₂ kinetic time traces, which is a general noise source in fuel oxidation absorption experiments. Compared with previous works, we have upgraded the TTFM experiment with a NIR distributed feedback (DFB) diode laser, a fiber-coupled broadband phase modulator, and a two-channel wave generator, which have improve the performance of our experiment substantially.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 1810048
• Report Number(s): SAND2015-3484; 697381
• Country of Publication: United States
• Language: English

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