Wide range modeling study of dimethyl ether oxidation

A detailed chemical kinetic model has been used to study dimethyl ether (DME) oxidation over a wide range of conditions. Experimental results obtained in a jet-stirred reactor (JSR) at I and 10 atm, 0.2 < 0 < 2.5, and 800 < T < 1300 K were modeled, in addition to those generated in a shock tube at 13 and 40 bar, 0 = 1.0 and 650 :5 T :5 1300 K. The JSR results are particularly valuable as they include concentration profiles of reactants, intermediates and products pertinent to the oxidation of DME. These data test the Idnetic model severely, as it must be able to predict the correct distribution and concentrations of intermediate and final products formed in the oxidation process. Additionally, the shock tube results are very useful, as they were taken at low temperatures and at high pressures, and thus undergo negative temperature dependence (NTC) behavior. This behavior is characteristic of the oxidation of saturated hydrocarbon fuels, (e.g. the primary reference fuels, n-heptane and iso- octane) under similar conditions. The numerical model consists of 78 chemical species and 336 chemical reactions. The thermodynamic properties of unknown species pertaining to DME oxidation were calculated using THERM

Kinetics of methane oxidation in a high pressure jetstirred reactor : experimental results

In this paper are reported the recent kinetic results obtained on methane oxidation in our high pressure jet stirred reactor. The experiments were carried out in the pressure range 1 to 10 atm, at temperatures between 1025 and 1285 K, for equivalence ratios of 0.1 to 2 at initial hydrocarbon mole fraction of 0.003. By means of computer modeling, the main reaction channels involved in methane oxidation have been delineated. Such results are used to interprete the present data

The ignition, oxidation, and combustion of kerosene: A review of experimental and kinetic modeling

International audienceFor modeling the combustion of aviation fuels, consisting of very complex hydrocarbon mixtures, it is often necessary to use less complex surrogate mixtures. The various surrogates used to represent kerosene and the available kinetic data for the ignition, oxidation, and combustion of kerosene and surrogate mixtures are reviewed. Recent achievements in chemical kinetic modeling of kerosene combustion using model-fuels of variable complexity are also presented

Kinetics of ethane oxidation in a high pressure jet-stirred reactor : experimental results

In this paper are reported the recent kinetic results obtained on ethane oxidation In our high pressure jet stirred reactor. The experiments were carried out in the pressure range 1 to 10 atm, at temperatures between 800 and 1200 K, for equivalence ratios of 0.1 to 1.5 at initial hydrocarbon mole fraction of 0.00125 to 0.0015. By means of computer modeling, the main reaction channels involved in ethane oxidation have been delineated. Such results are used for interpreting the present data

Kinetic modeling of ethanol pyrolysis and combustion

This article reports new kinetic modeling results concerning ethanol pyrolysis and oxidation. We propose a comprehensive kinetic reaction mechanism for ethanol pyrolysis and oxidation issued from detailed modeling of today’s available data including species concentration profiles measured in flow reactors during the pyrolysis and oxidation of ethanol, ignition delays measured in shock tube and ethanol-air flame speeds. The same mechanism is able to reproduce available combustion data concerning hydrogen, methane, ethylene, ethane, propene, and propane in similar conditions (1-10 atm, 800-2000K). The agreement between the data and the computed results is generally good and confirms the comprehensiveness of our C1-C3 detailed reaction mechanism

Derivation of a global chemical kinetic mechanism for methane ignition and combustion

A new method for the reduction of chemical kinetic detailed mechanisms is presented. It is based on atomic fluxes calculations and reaction pathways analyses. The method was applied to a CH4/O2/Nx2 comprehensive combustion mechanism, including NOx reactions, previously validated for several types of experiments (flow reactors, shock tubes, laminar flames). A global mechanism for methane combustion and NO formation has been elaborated involving 6 chemical reactions among 10 species. This mechanism is able to reproduce accurately the ignition delays, temperature profiles and concentration profiles of major species and NO over a wide range of experimental conditions (P = 1 atm, 60% ≤ N2 ≤ 80%, 0.2 ≤ ϕ ≤ 2.2 and 900 K ≤ Tinitial ≤ 1500 K)

High pressure oxidation of normal decane and kerosene in dilute conditions from low to high temperature

The oxidation of n-decane in a high-pressure jet-stirred reactor (JSR) has been investigated experimentally in a wide range of conditions covering the low and high temperature oxidation regimes (550-1150K, 10atm, Ф = 0.1 to 1.5). The oxidation of kerosene TRO has been investigated in the same conditions of temperature and equivalence ratio and for pressures ranging from 10 to 40atm. Reactants, intermediates and final products have been measured for the oxidation of the two fuels. Cyclic ethers resulting from the cool flame of n-decane were identified. At 10atm, the present study shows that the oxidation of n-decane is similar to that of kerosene TRO. The results are interpreted in terms of reaction mechanism. A detailed chemical kinetic modeling of the high-temperature oxidation of n-decane is used to assess the influence of low temperature chemistry in the intermediate temperature range and is used to represent kerosene oxidation in a JSR

Kinetic modeling of n-butane oxidation using detailed mechanisms

A chemical kinetic reaction mechanism has been developed previously to reproduce the experimental data of an analytical study of n-butane oxidation in a jet-stirred flow reactor, in the temperature range 900-1200 K at pressures extending from 1 to 10 atm for a wide range of fuel-oxygen equivalence ratios (0.15 to 4.0).This large mechanism consisting of 344 reversible reactions among 51 species is reduced to 46 species and 133 reactions. The agreement between computed and measured concentrations of major chemical species remains correct in the entire experimental area.Experimental ignition delays of n-butane measured behind reflected shock waves up to 1400K by other authors are also reproduced by the same mechanism. In addition the mechanism can be further reduced to 76 reactions among 40 species for the prediction of the ignition delay times

Kinetic modeling of pressure and equivalence ratio effects on methane oxidation

The kinetics of methane oxidation in a jet-stirred reactor was modeled using a comprehensive kinetic reaction mechanism including the most recent findings concerning the kinetics of the reactions involved in the oxidation of C1-C4 hydrocarbons. The computed results are discussed in terms of pressure and equivalence ratio (ø) effects on methane oxidation. The previously validated mechanism is able to reproduce experimental data obtained in our high-pressure jet stirred reactor (concentration profiles for CH4, CO, CO2, H2, C2H4, C2H6, et C2H2 ; 900 ≤ T/K ≤ 1300 ; 1 ≤ P/atm ≤ 10 ; 0.1 ≤ ø ≤ 2) and methane ignition delay times measured in shock tube (800 ≤ T/K ≤ 2000 ; 1 ≤ P/atm ≤ 13 ; 0.1 ≤ ø ≤ 2). It is also able to reproduce H and O atoms concentrations measured in shock tube at ≈ 2 atm. Burning velocities of methane in air between 1 and 3 atm and methane-air flame structures were also modeled. The same detailed kinetic mechanism can also be used to model the oxidation of ethane, ethylene, propene, and propane in similar conditions

Pyrolysis, oxidation and ignition of C

The kinetics of the oxidation of natural gas blends (CH4/C2H6) and of ethylene and ethane has been studied in a jet stirred reactor (850 ≤ T/K ≤ 1240, 1 ≤ P/atm ≤ 10, 0.02 ≤ equivalence ratio ≤ 2.0) for the first time. The concentration profiles of reactants, intermediates and products measured in a JSR have been used to validate a detailed kinetic reaction mechanism. Literature ignition delay times of CH4/C2H6 mixtures measured in shock tube have also been modeled as well as shock tube pyrolysis of ethylene. A general good agreement between the data and the model is found. The same mechanism has also been used to successfully represent the oxidation of methane, ethyne, ethene, ethane, propene, and propane in various conditions including JSR, shock tube and flame. The present study clearly shows the importance of traces of ethane on the oxidation of methane. The computations indicate that the oxidation of methane is initiated by its reaction with O2 and by thermal dissociation when no other hydrocarbon is present. However, in the studied CH4/C2H6 mixtures, ethane reacts before methane leading to the formation of OH, H and O radicals which initiate methane oxidation. The major importance of ethyl radical reactions is demonstrated by the computations