Extinction of premixed flames of practical liquid fuels: Experiments and simulations

Holley, Adam T.; Dong, Yubing; Andac, M. Gurhan; Egolfopoulos, Fokion N.

doi:10.1016/j.combustflame.2005.08.001

Cited by 96 publications

(59 citation statements)

References 21 publications

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“…The oxidation of n-heptane was previously studied in engines [1][2][3][4][5] and in several types of laboratory reactors such as shock tubes [6][7][8][9][10][11], rapid compression machines [12,13], jetstirred reactors [14][15][16], flow reactors [17], and flames [18][19][20][21][22]. Most of these studies were carried out under conditions of high temperature oxidation (temperature typically above 800 K) and relatively little attention was paid to the low-temperature oxidation of n-heptane, especially regarding the characterization of oxygenated reaction products [12,13,[15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Experimental and modeling investigation of the low-temperature oxidation of n-heptane

Herbinet

Husson

Serinyel

et al. 2012

Combustion and Flame

179

240

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The low-temperature oxidation of n-heptane, one of the reference species for the octane rating of gasoline, was investigated using a jet-stirred reactor and two methods of analysis: gas chromatography and synchrotron vacuum ultra-violet photo-ionization mass spectrometry (SVUV-PIMS) with direct sampling through a molecular jet. The second method allowed the identification of products, such as molecules with hydroperoxy functions, which are not stable enough to be detected using gas chromatography. Mole fractions of the reactants and reaction products were measured as a function of temperature (500-1100K), at a residence time of 2s, at a pressure of 800 torr (1.06 bar) and at stoichiometric conditions. The fuel was diluted in an inert gas (fuel inlet mole fraction of 0.005). Attention was paid to the formation of reaction products involved in the low temperature oxidation of n-heptane, such as olefins, cyclic ethers, aldehydes, ketones, species with two carbonyl groups (diones) and ketohydroperoxides. Diones and ketohydroperoxides are important intermediates in the low temperature oxidation of n-alkanes but their formation have rarely been reported. Significant amounts of organic acids (acetic and propanoic acids) were also observed at low temperature. The comparison of experimental data and profiles computed using an automatically generated detailed kinetic model is overall satisfactory. A route for the formation of acetic and propanoic acids was proposed. Quantum calculations were performed to refine the consumption routes of ketohydroperoxides towards diones.

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Section: Introductionmentioning

confidence: 99%

Experimental and modeling investigation of the low-temperature oxidation of n-heptane

Herbinet

Husson

Serinyel

et al. 2012

Combustion and Flame

179

240

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“…Such considerations also apply in far more complex fuel systems, in which the detailed chemical kinetics are sometimes extremely complicated [13][14][15][16][17][18], and where kinetics and diffusion often play critical and competing roles [17,18]. Fig.…”

Section: Ojb-extinction "Flameholding Scale" For Pure and Mixed Gaseomentioning

confidence: 99%

Opposed Jet Burner Extinction Limits: Simple Mixed Hydrocarbon Scramjet Fuels vs Air

Pellett

Vaden²,

Wilson

2007

43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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Opposed Jet Burner tools have been used extensively by the authors to measure Flame Strength (FS) of laminar non-premixed H 2 -air and simple hydrocarbon (HC)-air counterflow diffusion flames at 1-atm. FS represents a strain-induced extinction limit based on air jet velocity. This paper follows AIAA-2006-5223, and provides new HC-air FSs for global testing of chemical kinetics, and for characterizing "idealized flameholding potentials" during early scramjet-like combustion. Previous FS data included six HCs, pure and N 2 -diluted; and three HC-diluted H 2 fuels, where FS decayed very nonlinearly as HC was added to H 2 , due to H-atom scavenging. This study presents FSs on mixtures of (candidate surrogate) HCs, some with very high FS ethylene. Included are four binary gaseous systems at 300 K, and a "hot" ternary system at ~ 600 K. The binaries are methane + ethylene, ethane + ethylene, methane + ethane, and methane + propylene. The first three also form two ternary systems. The hot ternary includes both 10.8 and 21.3 mole % vaporized nheptane and full ranges of methane + ethylene. Normalized FS data provide accurate means of (1) validating, globally, chemical kinetics for extinction of non-premixed flames, and (2) estimating (scaling by HC) the loss of "incipient" flameholding in scramjet combustors. The n-heptane is part of a proposed "baseline simulant" (10 mole % with 30% methane + 60% ethylene) that "mimics" the ignition of endothermically cracked JP-7 "like" kerosene fuel, as suggested by Colket and Spadaccini in 2001 in their shock tube "Scramjet Fuels Autoignition Study." Presently, we use FS to gauge idealized flameholding, and define HC surrogates. First, FS was characterized for hot nheptane + methane + ethylene; then a hot 36 mole % methane + 64% ethylene surrogate was defined that mimics FS of the "baseline simulant" system. A similar hot ethane + ethylene surrogate can also be defined, but it has lower vapor pressure at 300 K, and thus exhibits reduced gaseous capacity. The new FS results refine our earlier "idealized reactivity scale" that shows wide ranging (50 x) diameter-normalized FSs for various HCs. These range from JP-10 and methane to H 2 -air, which produces an exceptionally strong flame that agrees within ~1% of recent 2-D numerically simulations. Finally, we continue advocating the FS approach as more direct and fundamental, for assessing idealized scramjet flameholding potentials, than measurements of "unstrained" laminar burning velocity or blowout in a Perfectly Stirred Reactor.

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“…Previous research [33][34][35][36][37][38][39][40][41][42][43] in opposed-flow laminar flames indicates that fuel reactivity is more sensitive to diffusivity estimates than to kinetic rate parameters because transport processes are rate controlling in these systems. Therefore, tuning rate and thermochemical constants to fit nonpremixed flame data is not recommended.…”

Section: Modeling Uncertaintiesmentioning

confidence: 99%

“…Both Holley et al [33] and Smallbone et al [42] argue that the molecular diffusion model used in flame simulations is inaccurate because it assumes that the spherical potential of molecules is valid at elevated temperatures. They propose that the LJ transport parameters obtained at low temperature are not expected to accurately predict high temperature diffusivity.…”

Section: Modeling Uncertaintiesmentioning

confidence: 99%

“…For stable species (e.g., n-octane and 2-methylheptane), this study used the correlations developed by Tee, Gotoh, and Stewart [32], as described in Holley and coworkers for hydrocarbons [33], to calculate the LJ collision diameter and potential well depth using the critical pressure (P c ), critical temperature (T c ), and boiling point (T b ) of the species. P c , T c , and T b for stable species were obtained from [33]. The polarizability in cubic Angstroms of stable species was obtained experimentally measured values available in [22].…”

Section: Transport Propertiesmentioning

confidence: 99%

See 1 more Smart Citation

An experimental and kinetic modeling study of n-octane and 2-methylheptane in an opposed-flow diffusion flame

Sarathy

Yeung

Westbrook

et al. 2011

Combustion and Flame

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Fischer-Tropsch (FT) fuels derived from biomass syngas are renewable fuels that can replace conventional petroleum fuels in jet engine and diesel engine applications. FT fuels typically contain a high concentration of lightly methylated iso-alkanes, whereas petroleum derived jet and diesel fuels contain large fractions of n-alkanes, cycloalkanes, and aromatics plus some lightly methylated iso-alkanes. In order to better understand the combustion characteristics of FT and petroleum fuels, this study presents new experimental data for 2-methylheptane and noctane in an opposed-flow diffusion flame. The high temperature oxidation of 2-methylheptane and n-octane has been modeled using an extended transport database and a reaction mechanism consisting of 3081 reactions involving 608 species. The proposed model shows good qualitative and quantitative agreement with the experimental data. The measured and predicted concentrations of 1-alkenes and ethylene are higher in the n-octane flame, while the concentrations of iso-alkenes (especially iso-butene) and propene are higher in the 2-methylheptane flame. The proposed chemical kinetic model is used to delineate the reactions pathways leading to these observed differences in product species concentrations. An uncertainty analysis was conducted to assess experimental and modeling uncertainties. The results indicate that the simulations are sensitive to the transport parameters used to calculate fuel diffusivity.3

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Extinction of premixed flames of practical liquid fuels: Experiments and simulations

Cited by 96 publications

References 21 publications

Experimental and modeling investigation of the low-temperature oxidation of n-heptane

Experimental and modeling investigation of the low-temperature oxidation of n-heptane

Opposed Jet Burner Extinction Limits: Simple Mixed Hydrocarbon Scramjet Fuels vs Air

An experimental and kinetic modeling study of n-octane and 2-methylheptane in an opposed-flow diffusion flame

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