Laminar flame speeds, counterflow ignition, and kinetic modeling of the butene isomers

Zhao, Peng; Yuan, Wenhao; Sun, Hongyan; Li, Yuyang; Kelley, Andrew; Zheng, Xiaolin; Law, Chung K.

doi:10.1016/j.proci.2014.06.021

Cited by 56 publications

(30 citation statements)

References 38 publications

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“…The estimated uncertainty [21] of the temperature measurement at each test condition ranges within ±25-40 K. The global strain rate of the oxidizer flow was calculated by dividing the boundary velocity of the oxidizer flow, measured using laser Doppler velocimetry, by the distance between the oxidizer and the liquid fuel boundaries. In data interpretation, the global strain rate was weighted by pressure to isolate the chemical effects of the pressure change from the physical effects of the strain rate change [22] . transport [23] .…”

Section: Measurement Of Flame Propagation Speeds and Ignition Temperamentioning

confidence: 99%

Laminar flame propagation and nonpremixed stagnation ignition of toluene and xylenes

Han

Deng

Liang

et al. 2017

Proceedings of the Combustion Institute

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Using the constant-pressure expanding spherical flame and nonpremixed stagnation pool experiments, the laminar flame speeds and nonpremixed ignition temperatures of toluene and the xylenes were experimentally determined at atmospheric and elevated pressures. The experimental situations were then computationally simulated using the kinetic models of Metcalfe et al. and of Narayanaswamy et al., and interrogated through sensitivity, reaction path and chemical explosive mode analyses. For the laminar flame speed study, both present and literature experimental results show that the toluene flame propagates faster than the xylene flames at all pressures, while the computation analyses show that this is primarily due to the fuel chemistry, with the attendant controlling reaction paths identified. For the nonpremixed stagnation ignition, experimental results show that toluene has lower ignition temperatures than the xylenes, and numerical analysis identifies that it is mainly due to the higher fuel diffusivity of toluene. Furthermore, the ignition temperatures of o-xylene are lower than those of m-and p-xylenes, and are suggested to be due to the formation of dimethylphenyl radicals with isolated H abstraction sites, which react with O 2 for further chain branching. The computed ignition temperatures for all fuels are consistently higher than the experimental values, and chemical explosive mode analysis shows that the C 1 /H 2 chemistry plays the dominant role in the ignition.

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Section: Measurement Of Flame Propagation Speeds and Ignition Temperamentioning

confidence: 99%

Laminar flame propagation and nonpremixed stagnation ignition of toluene and xylenes

Han

Deng

Liang

et al. 2017

Proceedings of the Combustion Institute

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“…Several research groups have investigated isobutene pyrolysis and oxidation in shock tubes [4][5][6][7][8][9][10], a turbulent flow reactor [11], a jet-stirred reactor [12] and in premixed laminar flames [13][14][15]. Yasunaga et al [9] investigated the pyrolysis and oxidation of isobutene behind reflected shock waves over a temperature range of 1000-1800 K, measuring the product distribution using infrared laser absorption spectroscopy and gas-chromatography.…”

Section: Introductionmentioning

confidence: 99%

“…There have been several kinetic mechanisms published in the literature that can be used to simulate isobutene combustion [12,[14][15][16]. Dagaut and co-workers [12] studied the oxidation of isobutene in a jet-stirred reactor at high temperature (~800-1230 K) and at 1, 5 and 10 atm.…”

Section: Introductionmentioning

confidence: 99%

“…However this study did not include some reactions essential to the ignition process in the low-to intermediate-temperature range. Most recently, Law and co-workers [15] reported laminar flame speeds and ignition temperatures for non-premixed counterflow flames at normal and elevated pressures. Their mechanism was built on previous studies by Zhang et al [16] and Cai et al [17] and included additional rate constants for the reactions of isobutene with Ḣ and Ö atoms and ȮH, HȮ 2 and ĊH 3 radicals.…”

Section: Introductionmentioning

confidence: 99%

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A comprehensive experimental and modeling study of isobutene oxidation

Zhou

O'Connor

et al. 2016

Combustion and Flame

287

185

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Isobutene is an important intermediate in the pyrolysis and oxidation of higher-order branched alkanes, and it is also a component of commercial gasolines. To better understand its combustion characteristics, a series of ignition delay time (IDT) and laminar flame speed (LFS) measurements have been performed. In addition, flow reactor speciation data recorded for the pyrolysis and oxidation of isobutene is also reported. Predictions of an updated kinetic model described herein are compared with each of these data sets, as well as with existing jet-stirred reactor (JSR) species measurements.IDTs of isobutene oxidation were measured in four different shock tubes and in two rapid compression machines (RCMs) under conditions of relevance to practical combustors. The combination of shock tube and RCM data greatly expands the range of available validation data for isobutene oxidation models to pressures of 50 atm and temperatures in the range 666-1715 K. Isobutene flame speeds were measured experimentally at 1 atm and at unburned gas temperatures of 298-398 K over a wide range of equivalence ratios. For the flame speed results, there was good agreement between different facilities and the current model in the fuel-rich region.Ab initio chemical kinetics calculations were carried out to calculate rate constants for important reactions such as H-atom abstraction by hydroxyl and hydroperoxyl radicals and the decomposition of 2-methylallyl radicals.A comprehensive chemical kinetic mechanism has been developed to describe the combustion of isobutene and is validated by comparison to the presently considered experimental measurements. Important reactions, highlighted via flux and sensitivity analyses, include: (a) hydrogen atom abstraction from isobutene by hydroxyl and hydroperoxyl radicals, and molecular oxygen; (b) radical-radical recombination reactions, including 2-methylallyl radical self-recombination, the recombination of 2-methylallyl radicals with hydroperoxyl radicals; and the recombination of 2-methylallyl radicals with methyl radicals; (c) addition reactions, including hydrogen atom and 2 hydroxyl radical addition to isobutene; and (d) 2-methylallyl radical decomposition reactions. The current mechanism accurately predicts the IDT and LFS measurements presented in this study, as well as the JSR and flow reactor speciation data already available in the literature.The differences in low-temperature chemistry between alkanes and alkenes are also highlighted in this work. In normal alkanes, the fuel radical Ṙ adds to molecular oxygen forming alkylperoxyl (RȮ 2 ) radicals followed by isomerization and chain branching reactions which promote low-temperature fuel reactivity. However, in alkenes, because of the relatively shallow well (~20 kcal mol -1 ) for RȮ 2 formation compared to ~35 kcal mol -1 in alkanes, the Ṙ + O 2 ⇌ RȮ 2 equilibrium lies more to the left favoring Ṙ + O 2 rather than RȮ 2 radical stabilization. Based on this work, and related studies of allylic systems, it is apparent that reactivity fo...

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“…See Table 1 for the labels of the models used for predictions. Symbols: present data; Davis and Law, 1998 [3]; Jomaas et al, 2005 [4]; , , Burke et al, 2015 [48]; Kelley, 2011 [32]; Fenard et al, 2015 [49]; Zhao et al, 2015 [64]. …”

Section: Figurementioning

confidence: 99%

Chemical kinetic model uncertainty minimization through laminar flame speed measurements

Park

Veloo

Sheen

et al. 2016

Combustion and Flame

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Laminar flame speed measurements were carried for mixture of air with eight C3-4 hydrocarbons (propene, propane, 1,3-butadiene, 1-butene, 2-butene, iso-butene, n-butane, and iso-butane) at the room temperature and ambient pressure. Along with C1-2 hydrocarbon data reported in a recent study, the entire dataset was used to demonstrate how laminar flame speed data can be utilized to explore and minimize the uncertainties in a reaction model for foundation fuels. The USC Mech II kinetic model was chosen as a case study. The method of uncertainty minimization using polynomial chaos expansions (MUM-PCE) (D.A. Sheen and H. Wang, Combust. Flame 2011, 158, 2358–2374) was employed to constrain the model uncertainty for laminar flame speed predictions. Results demonstrate that a reaction model constrained only by the laminar flame speed values of methane/air flames notably reduces the uncertainty in the predictions of the laminar flame speeds of C3 and C4 alkanes, because the key chemical pathways of all of these flames are similar to each other. The uncertainty in model predictions for flames of unsaturated C3-4 hydrocarbons remain significant without considering fuel specific laminar flames speeds in the constraining target data set, because the secondary rate controlling reaction steps are different from those in the saturated alkanes. It is shown that the constraints provided by the laminar flame speeds of the foundation fuels could reduce notably the uncertainties in the predictions of laminar flame speeds of C4 alcohol/air mixtures. Furthermore, it is demonstrated that an accurate prediction of the laminar flame speed of a particular C4 alcohol/air mixture is better achieved through measurements for key molecular intermediates formed during the pyrolysis and oxidation of the parent fuel.

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Laminar flame speeds, counterflow ignition, and kinetic modeling of the butene isomers

Cited by 56 publications

References 38 publications

Laminar flame propagation and nonpremixed stagnation ignition of toluene and xylenes

Laminar flame propagation and nonpremixed stagnation ignition of toluene and xylenes

A comprehensive experimental and modeling study of isobutene oxidation

Chemical kinetic model uncertainty minimization through laminar flame speed measurements

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