Collisional Quenching of CH(A), OH(A), and NO(A) in Low Pressure Hydrocarbon Flames

Tamura, Masayuki; Berg, Pamela A.; Harrington, Joel E.; Luque, Jorge; Jeffries, Jay B.; Smith, Gregory P.; Crosley, David R.

doi:10.1016/s0010-2180(97)00324-6

Cited by 304 publications

(151 citation statements)

References 38 publications

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“…In the simulation, except the effect of Ar and H 2 O on quenching, VET, and RET, the energy transfer and quenching of OH(A) induced by N 2 and O 2 are also considered. The quenching cross-section for N 2 is 3.2 Å 2 (k ¼ 3.16 Â 10 À11 cm 3 s À1 , T g ¼ 500 K) 27 and for O 2 17.8 Å 2 (k ¼ 17.2 Â 10 À11 cm 3 s À1 , T g ¼ 500 K), 22 respectively. The dependence of quenching rate on rotational number J of OH(A) is described by empirical law derived by Kienle 21,23 QðJÞ ¼ Q 0 expðÀJðJ þ 1ÞðA þ T g BÞ;…”

Section: Spatially Resolved Lif and Absolute Oh Densitymentioning

confidence: 99%

OH radicals distribution in an Ar-H2O atmospheric plasma jet

Nikiforov

Xiong

et al. 2013

Physics of Plasmas

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Recently, plasma jet systems found numerous applications in the field of biomedicine and treatment of temperature-sensitive materials. OH radicals are one of the main active species produced by these plasmas. Present study deals with the investigation of RF atmospheric pressure plasma jet in terms of OH radicals production by admixture of H 2 O into argon used as a feed gas. Generation of OH radicals is studied by laser-induced fluorescence spectroscopy. The excitation dynamics of OH radicals induced by the laser photons is studied by time-resolved spectroscopy. It is shown that vibrational and rotational energy transfer processes, which are sensitive to the surrounding species, can lead to the complication in the OH radicals diagnostics at high pressure and have to be considered during experiments. The axial and radial 2D maps of absolute densities of hydroxyl radicals at different water contents are obtained. The highest density of 1.15 Â 10 20 m À3 is measured in the plasma core for the case of 0.3% H 2 O. In the x-y-plane, the OH density steeply decreases within a range of 62 mm from its maximum value down to 10 18 m À3 . The effect of H 2 O addition on the generation of OH radicals is investigated and discussed. V C 2013 AIP Publishing LLC. [http://dx

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Section: Spatially Resolved Lif and Absolute Oh Densitymentioning

confidence: 99%

OH radicals distribution in an Ar-H2O atmospheric plasma jet

Nikiforov

Xiong

et al. 2013

Physics of Plasmas

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“…where the quenching-rate coefficient, τ i , for each species, i, is provided by Tamura et al [25]. Corrections for quenching to all LIF measurements were performed by dividing the LIF signal by the appropriate LIF efficiency.…”

Section: Quenching and Power Correctionsmentioning

confidence: 99%

Comparison of line-peak and line-scanning excitation in two-color laser-induced-fluorescence thermometry of OH

Kostka¹,

Roy²,

Lakusta³

et al. 2009

Appl. Opt.

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Two-line laser-induced-fluorescence (LIF) thermometry is commonly employed to generate instantaneous planar maps of temperature in unsteady flames. The use of line scanning to extract the ratio of integrated intensities is less common because it precludes instantaneous measurements. Recent advances in the energy output of high-speed, ultraviolet, optical parameter oscillators have made possible the rapid scanning of molecular rovibrational transitions and, hence, the potential to extract information on gas-phase temperatures. In the current study, two-line OH LIF thermometry is performed in a wellcalibrated reacting flow for the purpose of comparing the relative accuracy of various line-pair selections from the literature and quantifying the differences between peak-intensity and spectrally integrated line ratios. Investigated are the effects of collisional quenching, laser absorption, and the integration width for partial scanning of closely spaced lines on the measured temperatures. Data from excitation scans are compared with theoretical line shapes, and experimentally derived temperatures are compared with numerical predictions that were previously validated using coherent anti-Stokes-Raman scattering. Ratios of four pairs of transitions in the A 2 Σ+←X 2 Π (1,0) band of OH are collected in an atmospheric-pressure, near-adiabatic hydrogen-air flame over a wide range of equivalence ratios-from 0.4 to 1.4. It is observed that measured temperatures based on the ratio of Q 1( 14)/Q 1( 5) transition lines result in the best accuracy and that line scanning improves the measurement accuracy by as much as threefold at lowequivalence-ratio, low-temperature conditions. These results provide a comprehensive analysis of the procedures required to ensure accurate two-line LIF measurements in reacting flows over a wide range of conditions. Keywords coherent scattering, fluid structure interaction, fluorescene, gas absorption, laser produced plasmas, microlenses, scanning, temperature sensors, coherent anti-Stokes, collisional quenching, comprehensive analysis, energy output, equivalence ratios, gasphase, laser absorption, laser induced fluorescence, LIF thermometry, low temperatures, measurement accuracy, numerical predictions RightsThis paper was published in Applied Optics and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: https://www.osapublishing.org/ ao/abstract.cfm?uri=ao-48-32-6332. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law. Two-line laser-induced-fluorescence (LIF) thermometry is commonly employed to generate instantaneous planar maps of temperature in unsteady flames. The use of line scanning to extract the ratio of integrated intensities is less common because it precludes instantaneous measurements. Recent advances in the energy output of high-speed, ultraviolet, optical parameter oscillators have made p...

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“…Here, the quenching species CH 4 , CO, CO 2 , H 2 , H 2 O, O 2 , N 2 and OH were considered and the correlation and quenching cross section for OH according to Tamura et al [27] were used.…”

Section: Computation Of Lif and Rayleigh Signalsmentioning

confidence: 99%