Chemical kinetics of the high pressure oxidation of n-butane and its relation to engine knock

Pitz, William J.; Westbrook, Charles K.

doi:10.1016/0010-2180(86)90115-x

Cited by 179 publications

(52 citation statements)

References 10 publications

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“…If CO is formed, the oxygen atom in the fuel sequesters one carbon atom in the fuel, CO is produced, and the formation of soot precursors from the sequestered carbon atom is avoided. If CO 2 is formed, one of the two oxygen atoms in the fuel is "wasted" because it does not sequester a carbon atom and thereby prevent it from contributing to soot precursor species [33]. If this new branching ratio is correct, the use of esters and di-carbonates to reduce soot in diesel engines would be less effective from a chemical kinetic point of view, than previously thought.…”

Section: Radical Decompositionmentioning

confidence: 74%

An experimental and modeling study of diethyl carbonate oxidation

Nakamura

Curran

Córdoba

et al. 2015

Combustion and Flame

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Diethyl carbonate (DEC) is an attractive biofuel that can be used to displace petroleum-derived diesel fuel, thereby reducing CO 2 and particulate emissions from diesel engines. A better understanding of DEC combustion characteristics is needed to facilitate its use in internal combustion engines. Towards this goal, ignition delay times for DEC were measured at conditions relevant to internal combustion engines using a rapid compression machine (RCM) and a shock tube. The experimental conditions investigated covered a wide range of temperatures (660-1300 K), a pressure of 30 bar, and equivalence ratios of 0.5, 1.0 and 2.0 in air.To provide further understanding of the intermediates formed in DEC oxidation, species concentrations were measured in a jet-stirred reactor at 10 atm over a temperature range of 500-1200 K and at equivalence ratios of 0.5, 1.0 and 2.0. These experimental measurements were used to aid the development and validation of a chemical kinetic model for DEC.The experimental results for ignition in the RCM showed near negative temperature coefficient (NTC) behavior. Six-membered alkylperoxy radical (R 2 ) isomerizations are conventionally thought to initiate low-temperature branching reactions responsible for NTC behavior, but DEC has no such possible 6-and 7-membered ring isomerizations. However, its molecular structure allows for 5-, 8-and 9-membered ring R 2 isomerizations. To provide accurate rate constants for these ring structures, ab initio computations for R 2 QOOH isomerization reactions were performed. These new R 2 isomerization rate constants have been implemented in a chemical kinetic model for DEC oxidation. The model simulations have been compared with ignition delay times measured in the RCM near the NTC region. Results of the 3 simulation were also compared with experimental results for ignition in the high-temperature region and for species concentrations in the jet-stirred reactor. Chemical kinetic insights into the oxidation of DEC were made using these experimental and modeling results.

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Section: Radical Decompositionmentioning

confidence: 74%

An experimental and modeling study of diethyl carbonate oxidation

Nakamura

Curran

Córdoba

et al. 2015

Combustion and Flame

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“…This elementary reactions set consists of 140 elementary reactions and the available data obtained from previous references (Pitz and Westbrook, 1986;Dagaut et al, 1996). The rate parameters containing three Arrhenius coefficients (pre-exponential factor, A; temperature exponent, n; and activation energy, Ea) for the forward reaction paths are also based on those studies.…”

Section: Modeling Descriptionmentioning

confidence: 99%

“…Note：(1) Reaction mechanism and rate constants expressed as: k ＝A T n exp(-Ea / RT). (2) Combining the neutral reactions (Pitz and Westbrook, 1986;Dagaut et al, 1996) with the electronneutral reactions, we construct a complete mechanism, shown in Table 1, for EO decomposition in this RF plasma reactor. The rate constants of electron-neutral impact dissociation reactions at various O 2 /EO ratios are shown in Table 2.…”

Section: Kinetic Parameters Of Electron-neutral Reactionsmentioning

confidence: 99%

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Reaction Mechanism of Ethylene Oxide at Various Oxygen/Ethylene Oxide Ratios in an RF Cold Plasma Environment

Liao

Wei

Hsieh

et al. 2005

Aerosol Air Qual. Res.

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An innovative method was used to simulate ethylene oxide (EO) oxidation in an RF plasma reactor. The objective of this work was to simulate the stable species mole fraction profiles measured in a flowing plasma system at constant temperature and pressure. The mechanism involved participation of 36 species in 140 elementary reactions. Sensitivity analysis was also performed to identify the order of significance of reactions in the mechanism of the model' s predictions. The results show that the main reactions for EO decomposition changed with a varying O 2 /EO ratio in the plasma system. That is to say, the most important reaction to the O 2 /EO ratio of zero was the electron dissociation reaction of EO, C 2 H 4 O + e- CH 3 CHO + e-. While, the most influential reaction for EO decomposition at O 2 /EO ratio of 5.0 was the formation reaction of HO 2 , which forms OH radicals, then enhances the decomposition of C 2 H 4 O by the reaction, C 2 H 4 O + OH = C 2 H 3 O + H 2 O.

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“…However, the reaction pathway from CH 3 to CH 2 O via CH 3 O through R4 produces OH, H or HO 2 radicals. Some studies have shown that the CH 3 + HO 2 reaction is an important source of the OH radical, particularly at high pressures and moderate temperatures (18)(19)(20)(21) . Therefore, the sensitivity coefficient of R2 is positive at the early stages of combustion.…”

Section: Journal Of Thermal Science and Technologymentioning

confidence: 99%

Experimental and Kinetic Studies of Chemical Role of CO2 in Hydrocarbon Oxidation during Fuel-Rich O2/CO2 Combustion

Watanabe

Kiatpanachart

Okazaki

2013

JTST

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Experimental and kinetic studies of the chemical role of CO 2 in hydrocarbon reactions were conducted in a fuel-rich CH 4 flat flame with air ratios varying from 0.60 to 0.74. Unburned hydrocarbons (CH 4 , C 2 H 2 , C 2 H 4 , and C 2 H 6 ) in O 2 /CO 2 combustion were found to be lower than those in air combustion. The differences in the CH 4 oxidation characteristics between the air and O 2 /CO 2 combustion were caused by the chemical role of CO 2 in the reaction R1 (CO 2 + H → CO + OH), R2 (CH 2 (S) + CO 2 → CH 2 O + CO), and higher third body efficiencies of CO 2 at an air ratio (= 0.62 where the concentrations of reactants were high. The role of CO 2 in R1, R2, and the higher third body efficiencies of CO 2 decreased the rate of CH 4 oxidation during the early stage of combustion, where O 2 was present. Even though R2 did not directly compete with the main chain branching reaction R3 (H + O 2 → H + OH) for H radicals, like R1 did, R2 changed the hydrocarbon reaction pathway, thereby decreasing the rate of R4 (CH 3 + HO 2 → CH 3 O + OH) which had negative sensitivity in CH 4 oxidation. However, we found that R1 and R2 advance CH 4 oxidation in the last stage of combustion where O 2 was mostly consumed. This is attributed to the fact that the reactions R1 and R2 were able to advance without the presence of O 2 , and that R1 produced OH radicals that were active in hydrocarbon oxidation in the specific temperature range and R2 enhanced hydrocarbon oxidation when the rate of R4 was insignificant. Although R1 was the dominant reaction to reduce unburned hydrocarbons in the O 2 /CO 2 combustion, the role of R2 was significant at  = 0.62. Meanwhile, when the air ratio was 0.74 where concentrations of reactants were relatively low, the chemical role of CO 2 is to only decrease the rate of CH 4 oxidation due to the presence of an excessive amount of O 2 .

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Chemical kinetics of the high pressure oxidation of n-butane and its relation to engine knock

Cited by 179 publications

References 10 publications

An experimental and modeling study of diethyl carbonate oxidation

An experimental and modeling study of diethyl carbonate oxidation

Reaction Mechanism of Ethylene Oxide at Various Oxygen/Ethylene Oxide Ratios in an RF Cold Plasma Environment

Experimental and Kinetic Studies of Chemical Role of CO<sub>2</sub> in Hydrocarbon Oxidation during Fuel-Rich O<sub>2</sub>/CO<sub>2</sub> Combustion

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