Detailed Kinetic Reaction Mechanism Research Articles

Normal butane oxidation: Measurements of autoxidation products in a jet-stirred reactor

The autoxidation of n-butane was studied experimentally in a jet-stirred reactor at 1 atm (560–720 K) and 10 atm (530–1030 K) for an equivalence ratio of 1. Samples of reacting mixtures were analysed in the gas phase by gas chromatography (GC) using several detectors (Flame ionization detector, thermal conductivity detector, quadrupole mass spectrometer), hydrogen peroxide analyser, and Fourier transform infrared spectroscopy. In addition to the fuel and oxygen, 37 products were quantified. Liquid phase samples were obtained by trapping the reacting mixtures in cooled acetonitrile (273 K). The liquid samples were analysed by high resolution mass spectrometry (HRMS Orbitrap Q-Exactive), either after flow injection or separation by high pressure liquid chromatography (HPLC). Besides stable species, several other low-temperature oxidation products, such as hydroperoxides and ketohydroperoxides, were detected. Products of third O2 addition on fuel’s radicals were also detected by high resolution mass spectrometry. To assess the presence of hydroxyl or hydroperoxyl groups in the products of oxidation we performed H/D exchange with D2O. Qualitative and quantitative results showed the same trends in terms of variation of mole fractions and signal intensities versus reacting temperature. Kinetic modelling was performed using a literature detailed kinetic reaction mechanism already used to simulate previous n-butane oxidation experiments in the cool-flame regime, showing that improvements are needed to better describe the oxidation of n-butane under the present conditions.

Experimental investigation on laminar burning velocities of ammonia/hydrogen/air mixtures at elevated temperatures

The present study introduces new laminar burning velocity data for ammonia/hydrogen/air mixtures measured by means of the outwardly propagating spherical flame method at atmospheric pressure, for previously unseen unburned gas temperatures ranging from 298 to 473 K, hydrogen fractions ranging from 0 vol% to 60 vol% in the fuel and equivalence ratios in the range [0.8–1.4]. Results show increasing velocities with increasing hydrogen fraction and temperature, with maximum values obtained for rich mixtures near stoichiometry. The new experimental dataset is compared to dedicated laminar burning velocity correlations from the literature and to simulations using detailed kinetic mechanisms. The ammonia/air correlation presents a good agreement with measurements over the whole range of experimental conditions. The ammonia/hydrogen/air correlation captures the effect of the initial temperature satisfactorily for equivalence ratios below 1.3 and hydrogen fractions below 50 vol% in the fuel, but discrepancies are observed in other conditions. The effect of hydrogen addition is reproduced satisfactorily for hydrogen fractions between 20 and 40 vol% in the fuel, but discrepancies are observed for rich mixtures below 20 vol% hydrogen and for all mixtures containing 50 vol% hydrogen and more. An optimization of both correlations is proposed thanks to the experimental data obtained, but only with partial improvement of the ammonia/hydrogen/air correlation. State-of-the-art detailed kinetic reaction mechanisms yield values in close agreement with the present experiments. They could thus be used along with additional experimental data from different techniques to develop more accurate correlations for time-effective laminar burning velocity estimates of NH3/H2/air mixtures.

Solutions for a laminar jet diffusion flame of methyl formate using a skeletal mechanism obtained by applying ANNs

Numerical simulations involving detailed kinetic combustion reaction mechanisms for long chain fuels are associated with prohibitive computational costs. Thus, there is the need for reduced kinetic mechanisms for the effective numerical simulation of these fuels. The objective of this work is the development of a skeletal mechanism of moderate stiffness for the methyl formate (MF). MF is not indicated as a biodiesel surrogate due to its very short chain, but its study allows to understand its role in the combustion process. Then, based on a detailed mechanism composed of 950 reactions and 176 species, Directed Relation Graph, Depth First Search and a model of Artificial Neural Networks are employed to obtain a skeletal mechanism with 43 reactions and 23 species. The results obtained are satisfactory.

Obtaining a reduced kinetic mechanism for Methyl Butanoate

The computational treatment of detailed kinetic reaction mechanisms for combustion is expensive, especially in the case of biodiesel fuels. In this way, great efforts in the search of techniques for the development of reduced kinetic mechanisms have been observed. As Methyl Butanoate (MB, $$C_3H_7COOCH_3$$ ) is an essential model frequently used to represent the ester group of reactions in saturated methyl esters of large chain, this paper proposes a reduction strategy and uses it to obtain a reduced kinetic mechanism for the MB. The reduction strategy consists in the use of artificial intelligence to define the main chain and produce a skeletal mechanism, apply the traditional hypotheses of steady-state and partial equilibrium, and justify these assumptions through an asymptotic analysis. The main advantage of the strategy employed here is to reduce the work required to solve the system of chemical equations by two orders of magnitude for MB, since the number of reactions is decreased in the same order.

Kinetics of oxidation of levulinic biofuels in a jet-stirred reactor: Methyl levulinate

The first kinetic study of the oxidation of methyl levulinate is reported. Fuel-lean, stoichiometric and fuel-rich mixtures were oxidized at constant mean residence time (70 ms) and fuel concentration (1000 ppm), and variable temperature (740–1250 K) in a jet-stirred reactor at atmospheric pressure. A detailed kinetic reaction mechanism was proposed based on previous kinetic models for other oxygenated fuels and theoretical calculations. The model was tested successfully against new speciation data consisting of 16 species concentration profiles vs. temperature obtained by gas chromatography (detection by mass spectrometry, flame ionization, thermal conductivity) and Fourier transform infrared spectrometry after sonic probe sampling. Some discrepancies between modeling and experiments were observed for minor species. Reaction pathways and sensitivity analyses were used to interpret the results. This study indicates that for the fuel, under the present conditions, molecular elimination is an important reaction pathway competing with H-atom abstraction by radicals (mainly OH).

Kinetic modeling and experimental study on the combustion, performance and emission characteristics of a PCCI engine fueled with ethanol-diesel blends

The combustion process in the Premixed Charge Compression Ignition (PCCI) engine is basically restricted by the in cylinder charged mixture components. Also, the homogeneity of the charged mixture is determining the quality and process of the chemical reaction during the first stage of combustion which establish the auto-ignition process. In the present work, the engine experimental setup is equipped with a new suggested modification on the original fuel system device in order to produce a perfect commixture of diesel/ethanol at different blends ratio with the charged air. The obtained laboratory results are used to validate the simulation's data of the PCCI engine ignition. The prediction is performed using a detailed kinetic reaction mechanism. The simulation study has been achieved to predict the auto-ignition timing and the combustion characteristics of the PCCI engine fueled with different blends of ethanol and diesel at different volume percentage. The obtained results show that the premixed ratio of the ethanol in the ethanol/diesel fuel blends can be used to control the auto-ignition timing and the combustion characteristics at different engine air/fuel ratios. Also, the main pathway of this work is to establish the influence of the engine operating parameters which including the premixed ratio, fuel–air equivalence ratio on the engine performance, combustion and emission characteristics of the PCCI engine. These effects are studied and traced through the simulation result data of the in-cylinder pressure, temperature, and gas phase heat release at different a premixed ratio of ethanol-diesel fuels blends of 0, 10, 20, 30,40 and 50% (by volume).

Development of a reduced mechanism for ethanol using directed relation graph and sensitivity analysis

Numerical simulations involving detailed kinetic reaction mechanisms of combustion for conventional fuels are associated with computational costs prohibitive and, therefore, a lot of effort for obtaining reduced kinetic mechanisms has been observed. Among the known strategies, the Directed relation graph (DRG) method and the sensitivity analysis have proven to be very powerful tools, in addition to the traditional and efficient assumptions of steady-state and of partial equilibrium. The present work proposes a reduction strategy with these techniques for reduction of a mechanism for ethanol. Based on a mechanism of 377 reactions among 56 reactive species a skeletal mechanism, consisting of 24 species and 26 reactions, was obtained through the application of the DRG method and performing a sensitivity analysis. Using the assumptions of partial equilibrium and steady-state, which are justified by an asymptotic analysis, an additional reduction leads to a reduced mechanism of ten steps. Results of the new mechanism for a jet diffusion flame compare favorably with data found in the literature. The computational cost for simulation of jet diffusion flames with the reduced model is one order of magnitude less than necessary in the complete model, which is the principal contribution of this work.

Effect of Ethanol–Diesel Fuel Blends on Autoignition and Combustion Characteristics in HCCI Engines

The combustion process in homogeneous charge compression ignition (HCCI) is mainly controlled by the chemical kinetics reactions of the fuel-air mixture. So, the HCCI combustion process is sensitive to the charge temperature, pressure, and the mixture composition during the compression stroke. In the present work, the simulations results of the HCCI combustion are performed using a single zone model with detailed kinetic reaction mechanism. The simulation study is achieved to predict the auto-ignition timing and the combustion characteristics of the HCCI engine fueled with blends of ethanol and diesel at different volume percentage. The premixed ratio of the ethanol–diesel fuel blends is used in this study to control the auto-ignition timing and the combustion characteristics at a wide range of the engine load. The main pathway of this work is to study the influence of engine operating parameters which including the premixed ratio, fuel-air equivalence ratio on the combustion characteristics of HCCI engine. These effects are studied and traced through the simulation result data of the in-cylinder pressure, temperature, and heat release at different premixed ratios of ethanol-diesel fuels blends of 0, 10, 20, 30,40 and 50% (by volume). The engine speed is kept constant at 1500 RPM. The obtained results show that the increase of the premixed ratio of ethanol in diesel fuel blends in the range up to 50% will decrease the peak cylinder pressure and temperature and decrease the combustion duration.

The single-zone numerical model of homogeneous charge compression ignition engine performance

The single-zone model of methane-air mixture combustion in the Homogeneous Charge Compression Ignition engine was developed. First modeling efforts resulted in the selection of the detailed kinetic reaction mechanism, most appropriate for the conditions of the HCCI process. Then, the model was completed so as to simulate the performance of the four-stroke engine and was coupled by physically reasonable adjusting functions. Validation of calculations against experimental data showed acceptable agreement.

Experimental and Kinetic Modeling of the Oxidation of Synthetic Jet Fuels and Surrogates

ABSTRACTThe interest for synthetic and/or bio-derived jet fuels is increasing with the aim of reducing air transportation dependence on fossil fuels, soot emissions, and carbon footprint. Jet fuels can be produced through Fischer–Tropsch synthesis of paraffins followed by post-processing or blending to meet jet fuel specifications. Synthetic jet fuels mainly contain n-alkanes, iso-alkanes, and cyclo-alkanes, with possible aromatic fractions. The aim of this work is to study the kinetics of oxidation of gas-to-liquid (GtL) and coal-to-liquid (CtL) alternative jet fuels and representative surrogates in a jet-stirred reactor (JSR) operating under the same conditions of temperature, pressure, and equivalence ratio. To experimentally represent the selected synthetic jet fuels, we have designed surrogates consisting of 3–5 representative species. We experimentally studied the oxidation of these representative mixtures (n-decane, iso-octane, and decalin for GtL; n-decane, iso-octane, n-propylcyclohexane, decalin, and n-propylbenzene for CtL), a 100% GtL, and a 100% CtL in a JSR at 10 atm and an equivalence ratio φ = 1. A detailed kinetic reaction mechanism (2430 species versus 10,962 reversible reactions) and model fuels (4–7 components) were developed and validated by comparison with experimental results.

TÉCNICAS MATEMÁTICAS NA REDUÇÃO DE MECANISMOS CINÉTICOS COM ILUSTRAÇÃO PARA CHAMAS DO METANO

The computational treatment of detailed kinetic reaction mechanisms of combustion is very expensive, especially when the objective is the implementation of CFD (Computational Fluid Dynamics) models; therefore, major effort in searching for methods of mechanisms reduction has been observed. In the pursuit of efficient techniques, various ideas and theories have emerged in recent years. Sensitivity analysis, lumping and DRG (Directed Relation Graph) are some of these techniques, which seem to be powerful tools that can assist in this challenge. This paper shows these strategies, objectively describing their applications on reduction of reaction mechanisms. A reduced mechanism for methane flames consisting of six-step among nine reactive species is obtained from the skeletal mechanism, which consists of 25 reactions.

Chemistry acceleration with tabulated dynamic adaptive chemistry in a realistic engine with a primary reference fuel

Detailed kinetic reaction mechanisms are necessary for accurate prediction of combustion characteristics such as ignition and emissions in realistic engines. However, the calculation of chemically reacting flows with detailed chemistry is computational expensive due to the large number of species and reactions involved. In this study, a combined approach of dynamic adaptive chemistry (DAC) and in situ adaptive tabulation (ISAT) for efficient chemistry calculations has been implemented into a three-dimensional flow solver to simulate a homogenous charged compression ignition (HCCI) engine with a primary reference fuel (PRF). In the combined method, ISAT speeds up the chemistry calculation by reducing the number of integrations of ordinary differential equations (ODEs) governing chemical kinetics through tabulating and re-using the ODE solutions. At the meantime, DAC accelerates the necessary ODE integrations via the use of locally valid reduced mechanisms, which are obtained using the direct relation graph (DRG) method. The study shows that ISAT–DAC can achieve a speedup factor of about three with accurate prediction of composition and heat release even for the pressure-varying transient engine simulation with significant composition inhomogeneity resulting from wall heat loss. A detailed analysis reveals that the combined method effectively reduces the computational cost through taking advantage of the respective acceleration characteristics of DAC and ISAT at different combustion stages. In the low temperature combustion stage between about 650K and 1000K, even though the reduction in the mechanism size and consequently the ODE integration of the chemical kinetics by DAC is not significant, the combined method can still reach a speed-up factor of more than 100 due to the fact that the tabulated entries can effectively be reused. For the high temperature region, even though the tabulated entries cannot be reused due to the rapid change of the pressure and large composition inhomogeneity resulting from the active combustion and heat loss, DAC can effectively reduce the size of the needed ODE integrations by freezing a significant number of unimportant species and reactions. The study further quantifies the effect of composition inhomogeneity on the computation efficiency in detailed chemistry calculations in realistic engine simulations. For the case considered, the temperature inhomogeneity due to the wall heat loss obviously increases at around top dead center (TDC), reaching a level of 350K difference in temperature within the combustion chamber. Consequently, the overall computational efficiency in chemistry calculation by the combined method has been reduced by 40% compared to the case without heat loss.

Combustion of a Gas-to-Liquid–Based Alternative Jet Fuel: Experimental and Detailed Kinetic Modeling

The kinetics of oxidation of blends of gas-to-liquid (GtL) jet fuel with 20% vol. of 1-hexanol was studied. New experimental results were obtained using a jet-stirred reactor (p = 10 bar, constant mean residence time of 1 s, over the temperature range 550–1150 K, and for equivalence ratios of 0.5, 1, and 2). Concentration profiles of reactants, stable intermediates, and final products were obtained by probe sampling followed by on-line and off-line gas chromatography analyses and on-line Fourier transformed infra-red spectrometry. A comparison with corresponding results for Jet A-1 and pure GtL showed these fuels have similar combustion properties. The oxidation of the GtL-hexanol fuel under these conditions was modeled using a detailed kinetic reaction mechanism consisting of 8217 reactions and 2185 species and a 4-component surrogate fuel mixture (n-decane, iso-octane, n-propyl cyclohexane, and 1-hexanol). The proposed kinetic model showed good agreement with the presently reported jet-stirred reactor concentration profiles.

Kinetics of oxidation of cyclohexanone in a jet-stirred reactor: Experimental and modeling

The kinetics of oxidation of cyclohexanone (CAS 108-94-1) was studied experimentally in a fused silica jet stirred reactor (JSR) for the first time. The experiments were performed in the temperature range 530–1220K, at an operating pressure of 10atm, for equivalence ratios ranging from 0.5 to 4, and with an initial fuel concentration of 1000ppm (φ=0.5, 1.0 and 2.0) and 1500ppm (φ=4.0). Concentration profiles of reactants, stable intermediates and products were measured at fixed residence time and variable temperature by gas chromatography (GC) and Fourier transform infrared spectroscopy (FTIR) after sonic probe sampling. Cyclic intermediates experimentally observed include, 2-cyclohexen-1-one, cyclopentene, cyclopentadiene and aromatics such as benzene and toluene, the latter in trace amounts only for rich mixtures. The experimental data were used to validate a detailed kinetic reaction mechanism. A reasonable agreement between the present experimental results and the computations was observed. Kinetic analyses (sensitivity and reaction paths) were used to interpret the results.

Kinetic Effects of Hydrogen Addition on the Thermal Characteristics of Methane–Air Premixed Flames

A numerical investigation was implemented to evaluate the kinetic effects of hydrogen addition on the thermal characteristics of lean and stoichiometric premixed methane–air flames, on the basis of the detailed kinetic reaction mechanism GRI-Mech 3.0. The flame temperature profiles and the distributions of reactive species were predicted as a function of flame height by solving a freely propagating laminar premixed flame model. Some global properties of the premixed flame, i.e., the flame temperature gradient, the inner layer flame temperature, and the heat release rate, were estimated. Results showed that hydrogen enrichment in methane–air flames led to increases in the peak flame temperature, the peak temperature gradient, and the peak heat release rate, but a decrease in the inner layer flame temperature. Analyses of the interactions among heat release rates, radical production, and reaction progress rates were conducted. Analysis of the contribution of the heat release rate showed that the reactions concerning CH3 consumption consistently released a large proportion of heat, while significant contributions were found from the reactions of OH + H2 ⇔ H + H2O, H + O2 + H2O ⇔ HO2 + H2O, and H + HO2 ⇔ 2OH, when hydrogen was added. The rates of radical production were computed on the basis of the predicted species profiles. It was suggested that OH and H were the two important radicals, which had significant relevance to the heat release in the hydrogen-enriched flame. The analyses of the formation pathway were conducted for OH and H. It was shown that radical H was mainly produced in the reactions OH + H2 ⇔ H + H2O and O + H2 ⇔ H + OH, and the dominant reactions contributing to the production of radical OH were O + H2 ⇔ H + OH, O + CH4 ⇔ OH + CH3, and H + HO2 ⇔ 2OH. The progress rates of these preceding reactions were compared. Numerical results indicated that hydrogen had its kinetic effects on methane–air flames through promoting the formations and consumptions of OH and H, and the dominant reactions in terms of the contribution to heat release were OH + H2 ⇔ H + H2O, H + O2 + H2O ⇔ HO2 + H2O, and H + HO2 ⇔ 2OH.

Experimental investigation on the effects of hydrogen addition on thermal characteristics of methane/air premixed flames

This paper presented an experimental study on the measurements of premixed laminar methane/air flames with and without hydrogen addition. The premixed flames were stabilized on a McKenna flat fame burner at atmospheric pressure. The traveling thermocouple approach was used to measure the axial flame temperature profiles over ranges of equivalence ratios and hydrogen enriching ratios. The measured temperatures, corrected by considering radiation loss, were analyzed to estimate the rate of flame heat release, by solving the continuity equations of mass, energy, and species which were applied to a flat flame. Some of important flame properties, such as the peak temperature, the average temperature, the flame thickness, the thickness of reaction zone and combustion efficiency, were presented to characterize the effect of hydrogen enrichment on laminar flame propagation. It is shown that the presence of hydrogen in laminar flame can promote flame reaction to some extent. With an increase of hydrogen addition fraction in fuel, the peak rate of heat release and combustion efficiency show increases, while the average temperature gives decrease. The analysis of the heat release profiles suggested that hydrogen addition has significant effect on the early part of flame heat release profile. The flames enriched by hydrogen show linear approximations in the plots of the logarithmic heat release rate against the reciprocal of flame temperature. A modeling for one dimensional premixed laminar burner-stabilized flame had been implemented with GRI-Mech 3.0 detailed kinetic reaction mechanism, based on the measured temperature profiles of these premixed flames. And then an analysis on the heat release was performed for each reaction. It suggested that the reaction OH+H2⇔H+H2O gradually increases its contribution to the early heat release with the increase of hydrogen enrichment, which is due to the fact of hydrogen addition resulting in an increased concentration of radical H in flame. The promoted H formation accelerates the flame burning velocity, and then thins the thicknesses of flame and reaction zone to a great extent.

Oxidation of a Coal-to-Liquid Synthetic Jet Fuel: Experimental and Chemical Kinetic Modeling Study

The kinetics of oxidation of a Coal-to-Liquid (CtL) Fully Synthetic Jet Fuel (FSJF) was studied using three complementary experiments operating over a wide range of conditions: a jet stirred reactor (p = 10 bar), constant mean residence time of 1 s, over the temperature range 570–1070 K, and for equivalence ratios φ = 0.5, 1.0, and 2.0; a shock-tube (p ∼ 16 bar, temperature range between 900 and 1400 K, φ = 0.5 and φ = 1), and a conical flame burner (preheat temperature T0 = 473 K, and for two pressure regimes, p = 1 bar for equivalence ratios ranging from 0.95 to 1.4, and p = 3 bar for equivalence ratios ranging from 0.95 to 1.3). Concentration profiles of reactants, stable intermediates, and final products in the jet stirred reactor were obtained by probe sampling followed by online and off-line gas chromatography analyses and online Fourier transform infrared spectrometry. Ignition delay times were determined behind reflected shock waves by measuring time-dependent CH* emission at 431 nm. Flame speeds were determined by applying the cone angle method. Comparison with corresponding results for Jet A-1 was performed showing similar combustion properties. The oxidation of the CtL-fuel under these conditions was modeled using a detailed kinetic reaction mechanism consisting of 8217 reactions and 2185 species and a 4-component surrogate fuel mixture (n-decane, iso-octane, n-propylcyclohexane, and n-propylbenzene). A reasonable representation of the kinetics of oxidation of this FSJF was obtained. The model showed good agreement with concentration profiles measured in a jet stirred reactor at 10 bar over a range of temperatures (550–1150 K) and equivalence ratios (0.5–2). Acceptable agreement between measured and predicted ignition delay times was found for the investigated fuel air mixtures, with significantly longer ignition delay times predicted. Also, the ignition behavior of the surrogate is mainly influenced by the n-alkane and not by the addition of iso-alkanes, naphthenes, and aromatics. In general, a reasonable agreement between predicted and measured burning velocity data exists, with larger deviations at higher pressure. No deviation is to be seen between burning velocity data for Jet A-1 and CtL, within the uncertainty range. Within the parameter range studied, the measured data of burning velocity and ignition delay time agree with data obtained earlier for petrol-derived kerosene. Our findings support the potential of the CtL investigated to serve as an alternative aviation fuel.

On the simplification of kinetic reaction mechanisms of air–ethanol under high pressure conditions

In the last decade, the interest towards non-petroleum based fuels is strongly increased due to the current concerns about the impact of the transport system on atmospheric pollutions, mainly due to CO2 emissions. Ethanol, either blended with conventional fuels or in its pure form, is one of such fuels already in use in the automotive industries. As an example, the flex-fuel engines are designed to employ gasoline from 10% up to 85% of ethanol (E10,E85). In this work, the oxidation kinetics of ethanol with air has been considered and analyzed in an ambient at high pressure, ranging from 4 to 6MPa, by means of a Computational Singular Perturbation methodology. This study starts from a detailed kinetic reaction mechanism, which is extensively used in the literature and is made up by 235 reversible reactions among 46 chemical species. This mechanism has been used to get several families of simplified (skeletal) mechanisms by considering equivalence ratios in the range 0.2–2.0 and two sets of initial temperatures (900–1200K and 1200–1700K). The skeletal mechanisms have been validated by comparing the temperature and major chemical species profiles and the ignition delay time with those obtained by employing the detailed mechanism. Advantages and limitations of these mechanisms are highlighted. The accuracy of the skeletal mechanisms is very good in the range of equivalence ratio and temperature considered in the simplification procedure. Moreover, it is shown that a further simplification of the reaction mechanism is obtained by narrowing the range of equivalence ratio instead of the range of temperature. The most simplified skeletal mechanisms show an error in the prediction of temperature and fuel profiles lower than 3%, except for the case of low temperature and lean mixtures, where the maximum error increases up to 14%. Finally, the main reaction pathways are analyzed to show how the most important intermediate chemical species and products characterize the skeletal mechanisms for different values of equivalence ratio and temperature. The skeletal mechanisms are given as Supplementary data. The reader can refer to such data for the entire set of the retained reactions and species for each skeletal mechanism.

Auto-ignition and combustion characteristics in HCCI and JSR using 1-butanol/ n-heptane and ethanol/ n-heptane blends

In this study, the characteristics of homogeneous charge compression ignition combustion of 1-butanol/ n-heptane blend fuels are demonstrated. To evaluate the potential of this alcohol, a comparison with pure n-heptane and ethanol/ n-heptane mixtures was carried out. The experiments were conducted in a mono-cylinder Diesel engine fueled with alcohol/ n-heptane blends by varying the volume percentage of the alcohols (0%, 18%, 37%, and 57%) at constant equivalence ratio, intake temperature and engine speed (0.3, 80 °C, and 1500 rpm, respectively). New experiments were also performed in a jet-stirred reactor for the fuel-lean ( φ = 0.3) oxidation of mixtures 1-butanol/ n-heptane and ethanol/ n-heptane 1:1 in mole. The experimental concentration profiles vs. temperature obtained at 10 bars and at a residence time of 0.7 s were used to validate a detailed kinetic reaction mechanism. The modeling of constant volume combustion, at two pressures (20 and 40 bars), was performed with this chemical kinetic mechanism (1046 species and 4398 reactions) to interpret the engine results.

ChemInform Abstract: Kinetic Modeling of Propane Oxidation and Pyrolysis

Propane oxidation in 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 C1C4 hydrocarbons. The present detailed mechanism is able to reproduce experimental species concentration profiles obtained in our high-pressure jet-stirred reactor (900 ⩽ T/K ⩽ 1200; 1 ⩽ P/atm ⩽ 10; 0.15 ⩽ ϕ ⩽ 4) and in a turbulent flow reactor at 1 atm; ignition delay times measured in shock tube (1200 ⩽ T/K ⩽ 1700; 2 ⩽ P/atm ⩽ 15; 0.125 ⩽ ϕ ⩽ 2); H-atoms concentrations measured in shock tube during the pyrolysis of propane and burning velocities of freely propagating premixed propane-air laminar flames. The computed results are discussed in terms of pressure and equivalence ratio (ϕ) effects on propane oxidation. The same detailed kinetic reaction mechanism can also be used to model the oxidation of methane, ethylene, ethane, and propene in similar conditions. © John Wiley & Sons, Inc.