Intermediate species profiles in low pressure premixed flames inhibited by fluoromethanes

L’Espérance, Drew; Williams, Bradley A.; Fleming, James W.

doi:10.1016/s0010-2180(98)00126-6

Cited by 29 publications

(32 citation statements)

References 36 publications

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“…This flame contained an equal number of fluorine atoms as the flame inhibited by 8.9% mole fraction of trifluoromethane, the standard condition for this agent used in Ref. 7. The overall equivalence ratio (taking into account the agent) was also nearly identical, ϭ 1.08 compared to 1.07 for the flame containing 8.9% CHF 3 .…”

Section: Methodsmentioning

confidence: 94%

“…The experimental apparatus and procedures were identical to those used in our study on flames containing fluoromethanes [7]. The HFP-inhibited flame maintained at 10 torr consisted of a stoichiometric methane/oxygen mixture with 4% mole fraction of HPF added.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, our laboratory has published profiles of several intermediate species in premixed low-pressure methane/oxygen flames containing the series of fluoromethanes [7]. These experimental data were compared to predictions of the NIST fluorocarbon mechanism, and some refinements to the kinetics were suggested on the basis of validation against both low-pressure species profile data and atmospheric pressure flame speed measurements.…”

Section: Introductionmentioning

confidence: 99%

“…These data were not included in Ref. 7, because the fluorine kinetic mechanism did not include any C 3 compounds, and only qualitative interpretations of the flame structure could be made. More recently, Hynes et al proposed a kinetic mechanism [8] for the initial breakdown of HFP into C 1 and C 2 fragments.…”

Section: Introductionmentioning

confidence: 99%

“…7), with experimental species profiles. The flame conditions of our study are quite different from those in Ref.…”

Section: Introductionmentioning

confidence: 99%

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Intermediate species profiles in low-pressure methane/oxygen flames inhibited by 2-H heptafluoropropane: comparison of experimental data with kinetic modeling

Williams

espÉrance

Fleming

2000

Combustion and Flame

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Experimental profiles of the intermediate species H, OH, CH, CF, CF 2 , and CHF are obtained in a 10 torr premixed flat flame of methane/oxygen in a 1:2 molar ratio, inhibited by a 4% mole fraction of 2-H heptafluoropropane (HFP, CF 3 CHFCF 3 ). These data are compared to calculations using a recently published kinetic mechanism describing the consumption of this fire suppression agent. The profiles in the flame inhibited by HFP are compared to previously published data for flames containing CHF 3 and CH 2 F 2 under the same conditions of stoichiometry and flux of fluorine atoms. The species profiles relative to the flames containing the fluoromethanes are accurately predicted and atmospheric pressure flame speeds are fairly well predicted by the kinetic mechanism. Under equal fluorine loadings, profiles of temperature and of H and OH mole fraction are virtually identical between the flames containing HFP and CHF 3 . The flame inhibited by HFP, however, has approximately twice as much CH* emission as the flame containing CHF 3 . The kinetic model predicts that thermal decomposition, rather than H atom abstraction, is the primary destruction mechanism for HFP under the conditions studied.

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Section: Methodsmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…7), with experimental species profiles. The flame conditions of our study are quite different from those in Ref.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Intermediate species profiles in low-pressure methane/oxygen flames inhibited by 2-H heptafluoropropane: comparison of experimental data with kinetic modeling

Williams

espÉrance

Fleming

2000

Combustion and Flame

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Comprehensive Theoretical and Experimental Studies on the CF₃H Fire‐extinguishing Mechanism

Zhou

2011

Chin. J. Chem.

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In order to clarify the chemical suppression mechanisms of CF3H, experimental and theoretical studies were conducted respectively in this paper. Firstly, the combustion species in low pressure laminar premixed flat methane flames with CF3H addition is measured by synchrotron radiation molecular beam mass spectrometry (SR‐MBMS) experimentally. Fire suppression chemistry of CF3H is investigated by selective detection of combustion radicals and intermediates in experimental process. Secondly, quantum chemistry calculations are performed to calculate the potential energy surfaces (PES) for the CF3H unimolecular dissociation reaction and reactions of CF3H with free radical OH and H at the B3LYP/6‐311++G** and QCISD(T)/6‐311++G** levels. Finally, the chemical suppression mechanism of CF3H was discussed by comparing the theoretical calculation with experimental measurement.

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A Chemical Kinetic Mechanism for 2‐Bromo‐3,3,3‐trifluoropropene (2‐BTP) Flame Inhibition

Burgess

Babushok

Linteris

et al. 2015

Int J of Chemical Kinetics

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In this work, we report a detailed chemical kinetic mechanism to describe the flame inhibition chemistry of the fire-suppressant 2-bromo-3,3,3-trifluoropropene (2-BTP), under consideration as a replacement for CF 3 Br. Under some conditions, the effectiveness of 2-BTP is similar to that of CF 3 Br; however, like other potential halon replacements, it failed an U.S. Federal Aviation Authority (FAA) qualifying test for its use in cargo bays. Large overpressures are observed in that test and indicate an exothermic reaction of the agent under those conditions. The kinetic model reported herein lays the groundwork to understand the seemingly conflicting behavior on a fundamental basis. The present mechanism and parameters are based on an extensive literature review supplemented with new quantum chemical calculations. The first part of the present article documents the information considered and provides traceability with respect to the reaction set, species thermochemistry, and kinetic parameters. In additional work, presented more fully elsewhere, we have combined the 2-BTP chemical kinetic mechanism developed here with several other submodels from the literature and then used the combined mechanism to simulate premixed flames over a range of fuel/air stoichiometries and agent loadings. Overall, the modeling results qualitatively predicted observations found in cupburner tests and FAA Aerosol Can Tests, including the extinguishing concentrations required and the lean-to-rich dependence of mixtures. With these data in hand, in a second phase of the present work, we perform a reaction path analysis of major species under several modeled conditions. This analysis leads to a qualitative understanding of the ability of 2-BTP to act as

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Intermediate species profiles in low pressure premixed flames inhibited by fluoromethanes

Cited by 29 publications

References 36 publications

Intermediate species profiles in low-pressure methane/oxygen flames inhibited by 2-H heptafluoropropane: comparison of experimental data with kinetic modeling

Intermediate species profiles in low-pressure methane/oxygen flames inhibited by 2-H heptafluoropropane: comparison of experimental data with kinetic modeling

Comprehensive Theoretical and Experimental Studies on the CF₃H Fire‐extinguishing Mechanism

A Chemical Kinetic Mechanism for 2‐Bromo‐3,3,3‐trifluoropropene (2‐BTP) Flame Inhibition

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Intermediate species profiles in low pressure premixed flames inhibited by fluoromethanes

Cited by 29 publications

References 36 publications

Intermediate species profiles in low-pressure methane/oxygen flames inhibited by 2-H heptafluoropropane: comparison of experimental data with kinetic modeling

Intermediate species profiles in low-pressure methane/oxygen flames inhibited by 2-H heptafluoropropane: comparison of experimental data with kinetic modeling

Comprehensive Theoretical and Experimental Studies on the CF3H Fire‐extinguishing Mechanism

A Chemical Kinetic Mechanism for 2‐Bromo‐3,3,3‐trifluoropropene (2‐BTP) Flame Inhibition

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Comprehensive Theoretical and Experimental Studies on the CF₃H Fire‐extinguishing Mechanism