Ammonia Measurements with Femtosecond Two-Photon Laser-Induced Fluorescence in Premixed NH3/Air Flames

• Ammonia (NH3), which can be a hydrogen carrier, is a promising alternative to fossil fuels in the future carbon-free economy. In situ techniques feasible for the remote and non-intrusive detection of NH3 will provide strong support for developing clean NH3 combustion. Here, we demonstrated a femtosecond two-photon laser-induced fluorescence (fs-TPLIF) technique for interference-free in situ NH3 measurements in laminar premixed NH3/air flames. The two-head band of NH3 at ∼565 nm was observed, which verifies the feasibility of fs-TPLIF for NH3 measurements in a combustion environment. The single-shot NH3 fs-TPLIF images with efficient signal-to-noise ratios were obtained. The variation of the thickness of the reaction zone with the equivalence ratio of NH3 flames was also obtained. As a result of the broad line width of the femtosecond laser, the OH fluorescence was also observed together with the NH3 fluorescence. The potential of fs-TPLIF for simultaneous measurements of NH3 and OH with only one laser was analyzed. The laser power dependence of NH3 and NH emissions was investigated. The radial distributions of NH3, NH, and OH in the flame were also discussed. This work is the first attempt of fs-TPLIF for NH3 measurements in a combustion environment, and the results indicate that fs-TPLIF is a feasible tool for NH3 measurements in combustion diagnostics.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Energiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Energy Engineering (hsv//eng)

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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