A model for temperature-dependent collisional quenching of NO A2 Σ+

Paul, Phillip H.; Gray, Jeffrey A.; Durant, Joseph L.; Thoman, John W.

doi:10.1007/bf00325203

Cited by 106 publications

(33 citation statements)

References 46 publications

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“…A temperature profile is also shown. Other parameters influence the spatial variation of the collected signal magnitude: the transition probability of absorbance and spontaneous emission, variations in the X 2 Π initial state population with the local thermodynamic state, and quenching of the excited A 2 Σ + state by water [24]. The absorption of the light sheet energy by OH can also gradually decrease the fluorescence intensity behind the shock.…”

Section: Resultsmentioning

confidence: 99%

Direct observations of reaction zone structure in propagating detonations

Pintgen

Eckett

Austin

et al. 2003

Combustion and Flame

162

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We report experimental observations of the reaction zone structure of self-sustaining, cellular detonations propagating near the Chapman-Jouguet state in hydrogenoxygen-argon/nitrogen mixtures. Two-dimensional cross sections perpendicular to the propagation direction were imaged using the technique of planar laser induced fluorescence (PLIF) and in some cases, compared to simultaneously acquired schlieren images. Images are obtained which clearly show the nature of the disturbances in an intermediate chemical species (OH) created by the variations in the strength of the leading shock front associated with the transverse wave instability of a propagating detonation. The images are compared to two-dimensional, unsteady simulations with a reduced model of the chemical reaction processes in the hydrogen-oxygenargon system. We interpret the experimental and numerical images using simple models of the detonation front structure based on the "weak" version of the flow near the triple point or intersection of three shock waves, two of which make up the shock front and the third corresponding to the wave propagating transversely to the front. Both the unsteady simulations and the triple point calculations are consistent with the creation of keystone-shaped regions of low reactivity behind the incident shock near the end of the oscillation cycle within the "cell".

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Section: Resultsmentioning

confidence: 99%

Direct observations of reaction zone structure in propagating detonations

Pintgen

Eckett

Austin

et al. 2003

Combustion and Flame

162

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“…The main T-dependence arises from the population of the laser-coupled ground-state levels. T, p, and x i also affect the frequency and cross-section of collisions that NO molecules encounter, influencing the excitation efficiency via broadening and shifting of the absorption lines [18,19], and the fluorescence quantum yield via collisional quenching [20,21]. These effects are calculated using the LIFSim software package [22].…”

Section: Dependence Of No-lif Signal On Temperature Pressure and Gamentioning

confidence: 99%

Quantitative in-cylinder NO-LIF imaging in a realistic gasoline engine with spray-guided direct injection

Bessler

Hofmann

Zimmermann

et al. 2005

Proceedings of the Combustion Institute

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“…The concentrations of the quenching partners and temperature were measured using Raman scattering, as described below, and the appropriate corrections were applied following Refs. [12,13].…”

Section: Experimental Apparatusmentioning

confidence: 99%

“…The process of quantification of the NO signal is well established and described in the text with relevant references (Refs. [10][11][12][13] in paper). NO laser-induced fluorescence signals are fairly strong.…”

Section: Commentsmentioning

confidence: 99%

Nitric oxide formation during flame/vortex interaction

Santoro

Kyritsis

Smooke

et al. 2002

Proceedings of the Combustion Institute

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The formation of nitric oxide was investigated in methane diffusion flames under the perturbation of laminar vortices. Laser-induced fluorescence and Raman spectroscopy were used to measure nitric oxide, major species, and temperature, and to obtain the time evolution of the scalar dissipation rate at the stoichiometric surface during the flame/vortex interaction. Vortices with two characteristic times were thrust into the flame and their effects were compared with steady flames at the same scalar dissipation rate. The experimental measurements showed that the vortex did not affect significantly the peak temperature, CO, and CO 2 mass fraction during the interaction. NO, instead, was strongly affected. The peak mass fraction of NO in flames under vortex perturbation differed by almost a factor of 2 from steady flames with similar scalar dissipation rates. One-dimensional numerical simulations, used under the well-justified assumption that the vortices induced negligible curvature, yielded results in good agreement with the experimental measurements. The numerical computations were also used to investigate the effect of the characteristic time of the vortex on the different NO formation paths, that is, thermal, and prompt. The peak mass fraction of thermal NO was shown to be strongly dependent on the timescale of the unsteady perturbation, while prompt NO was almost independent. The emission index, that is, the production of NO normalized by the consumption of the fuel, behaved quasi-steadily for the two formation paths. The results were rationalized by considering the flame structure and the activation energy of the different formation paths.

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A model for temperature-dependent collisional quenching of NO A2 Σ+

Cited by 106 publications

References 46 publications

Direct observations of reaction zone structure in propagating detonations

Direct observations of reaction zone structure in propagating detonations

Quantitative in-cylinder NO-LIF imaging in a realistic gasoline engine with spray-guided direct injection

Nitric oxide formation during flame/vortex interaction

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