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N-Heptane-Nitromethane:
This is a collaboration work of the Brandenburg University of Technology (Germany),
Georg-August-Universität Göttingen (Germany)
RENAULT SAS (France)
Centre National de la Recherche Scientifique (CNRS-INSIS) (France)
LOGE Deutschland GmbH (Germany).
In this work, we report a detailed investigation of the CH3NO2 chemistry effect on fuel-NO interactions for the fuels methane and n-heptane using a recently developed and extensively validated H2/O2/CO/NOx/NH3/ CH3NO2 baseline chemistry. In general, the model predictions show good agreement with temperature profiles of major and intermediate species in jet-stirred reactor experiments and they capture the subtle effect of NO addition. For both fuels, the CH3NO2 kinetics retard the system reactivity in the low temperature range by delaying the production of key radicals like OH and HO2. This explains the retarding effect of NO for n-heptane low temperature ignition and the overprediction of reactivity enhancement by NO in earlier studies on methane combustion. For methane, the recently explored roaming mediated dissociation channel of CH3NO2 to CH3O + NO is a major reaction pathway for CH3NO2 consumption. Our analysis suggests that at higher pressure, relevant to engine conditions, the two key intermediate species HONO and CH3NO2 feature strongly increased concentrations during n-heptane combustion and they may be detectable under such conditions in combustion experiments of this fuel-NOx system. The results of this work call for detailed future investigations of the CH3NO2 chemistry effect in the context of exhaust gas recirculation, also with regard to the suppression of engine knock.
In this work, we report a detailed investigation of the CH3NO2 chemistry effect on fuel-NO interactions for the fuels methane and n-heptane using a recently developed and extensively validated H2/O2/CO/NOx/NH3/ CH3NO2 baseline chemistry. In general, the model predictions show good agreement with temperature profiles of major and intermediate species in jet-stirred reactor experiments and they capture the subtle effect of NO addition. For both fuels, the CH3NO2 kinetics retard the system reactivity in the low temperature range by delaying the production of key radicals like OH and HO2. This explains the retarding effect of NO for n-heptane low temperature ignition and the overprediction of reactivity enhancement by NO in earlier studies on methane combustion. For methane, the recently explored roaming mediated dissociation channel of CH3NO2 to CH3O + NO is a major reaction pathway for CH3NO2 consumption. Our analysis suggests that at higher pressure, relevant to engine conditions, the two key intermediate species HONO and CH3NO2 feature strongly increased concentrations during n-heptane combustion and they may be detectable under such conditions in combustion experiments of this fuel-NOx system. The results of this work call for detailed future investigations of the CH3NO2 chemistry effect in the context of exhaust gas recirculation, also with regard to the suppression of engine knock.
Krishna Prasad Shrestha, Lars Seidel, Thomas Zeuch, Gladys Moreac, Philippe Dagaut,Fabian Mauss
On the implications of nitromethane – NOx chemistry interactions for combustion processes
Fuel 289 (2021) 119861. https://doi.org/10.1016/j.fuel.2020.119861
Ammonia-Hydrogen:
This is a collaboration work of the Brandenburg University of Technology (Germany),
University Orléans (France)
Vrije Universiteit Brussel (Belgium)
Materials and Civil Engineering (iMMC), UCLouvain (Belgium)
LOGE Deutschland GmbH (Germany).
In this work laminar flame speeds of ammonia with oxygen-enriched air (oxygen content varying from 21 to 30 vol.%) and ammonia-hydrogen-air mixtures (fuel hydrogen content varying from 0 to 30 vol.%) at elevated pressure (1–10 bar) and temperature (298–473 K) were determined experimentally using a constant volume combustion chamber. Ammonia laminar flame speeds with helium as an inert were measured for the first time. We have developed a newly compiled kinetic model for the prediction of the oxidation of ammonia and ammonia-hydrogen blends in freely propagating and burner stabilized premixed flames, as well as in shock tubes, rapid compression machines and a jet-stirred reactor. The reaction mechanism also considers the formation of nitrogen oxides, as well as the reduction of nitrogen oxides depending on the conditions of the surrounding gas phase. The experimental results from the present work and the literature are interpreted with the help of the kinetic model derived here. The experiments show that increasing the initial temperature, fuel hydrogen content, or oxidizer oxygen content causes the laminar flame speed to increase, while it decreases when increasing the initial pressure. The proposed kinetic model predicts the same trends than experiments and a good agreement is found with measurements for a wide range of conditions. The model suggests that under rich conditions the N2H2 formation path is favored compared to stoichiometric condition.
In this work laminar flame speeds of ammonia with oxygen-enriched air (oxygen content varying from 21 to 30 vol.%) and ammonia-hydrogen-air mixtures (fuel hydrogen content varying from 0 to 30 vol.%) at elevated pressure (1–10 bar) and temperature (298–473 K) were determined experimentally using a constant volume combustion chamber. Ammonia laminar flame speeds with helium as an inert were measured for the first time. We have developed a newly compiled kinetic model for the prediction of the oxidation of ammonia and ammonia-hydrogen blends in freely propagating and burner stabilized premixed flames, as well as in shock tubes, rapid compression machines and a jet-stirred reactor. The reaction mechanism also considers the formation of nitrogen oxides, as well as the reduction of nitrogen oxides depending on the conditions of the surrounding gas phase. The experimental results from the present work and the literature are interpreted with the help of the kinetic model derived here. The experiments show that increasing the initial temperature, fuel hydrogen content, or oxidizer oxygen content causes the laminar flame speed to increase, while it decreases when increasing the initial pressure. The proposed kinetic model predicts the same trends than experiments and a good agreement is found with measurements for a wide range of conditions. The model suggests that under rich conditions the N2H2 formation path is favored compared to stoichiometric condition.
Krishna Prasad Shrestha, Charles Lhuillier, Amanda Alves Barbosa,Pierre Brequigny, Francesco Contino, Christine Mounaïm-Rousselle, Lars Seidel, Fabian Mauss
An experimental and modeling study of ammonia with enriched oxygen content and ammonia/hydrogen laminar flame speed at elevated pressure and temperature.
Proceedings of the Combustion Institute 38 (2021). https://doi.org/10.1016/j.proci.2020.06.197
Dimethyl ether-Dimethoxymethane-NOx:
This is a collaboration work of the Brandenburg University of Technology (Germany),
Technical University Bergakademie Freiberg (Germany)
LOGE Deutschland GmbH (Germany) and King Abdullah University of Science and Technology (Saudi Arabia).
In this work, a detailed kinetic mechanism for the oxidation dimethyl ether and dimethoxymethane has been developed. Laminar flame speeds of dimethyl ether and dimethoxymethane at pressures from 1 to 5 bar and initial temperatures from 298 to 373 K were determined experimentally using a constant volume spherical vessel and a heat flux burner setup. Using our experimental data along with data available in the literature, a new kinetic model for the prediction of the oxidation behavior of dimethyl ether and dimethoxymethane in freely propagating and burner stabilized premixed flames, in shock tubes, rapid compression machines, flow reactors, and a jet-stirred reactor has been developed. The experimental results from the present work and literature are interpreted with the help of the derived kinetic model. This newly developed reaction mechanism considers the redox chemistry of NOx to accommodate the influence of the oxygen level on the onset of fuel conversion and interconversion of NO and NO2. The current model suggests that an increased O2 level promotes the HO2 production, which in turn leads to the formation of OH radicals, which promotes the combustion of the fuel/air mixture under lean conditions. The increase of OH radical concentrations is mainly via the NO/NO2 interconversion reaction channel, NO+HO2=NO2+OH, NO2+H=NO+OH, CH3OCH3+NO2=CH3OCH2+HONO, followed by the thermal decomposition of HONO. This work extends the kinetic database and helps to improve the understanding of dimethyl ether and dimethoxymethane combustion behavior. The kinetic model presented in this work can serve as a base model for hydrocarbons and oxygenated fuels higher than C2.
In this work, a detailed kinetic mechanism for the oxidation dimethyl ether and dimethoxymethane has been developed. Laminar flame speeds of dimethyl ether and dimethoxymethane at pressures from 1 to 5 bar and initial temperatures from 298 to 373 K were determined experimentally using a constant volume spherical vessel and a heat flux burner setup. Using our experimental data along with data available in the literature, a new kinetic model for the prediction of the oxidation behavior of dimethyl ether and dimethoxymethane in freely propagating and burner stabilized premixed flames, in shock tubes, rapid compression machines, flow reactors, and a jet-stirred reactor has been developed. The experimental results from the present work and literature are interpreted with the help of the derived kinetic model. This newly developed reaction mechanism considers the redox chemistry of NOx to accommodate the influence of the oxygen level on the onset of fuel conversion and interconversion of NO and NO2. The current model suggests that an increased O2 level promotes the HO2 production, which in turn leads to the formation of OH radicals, which promotes the combustion of the fuel/air mixture under lean conditions. The increase of OH radical concentrations is mainly via the NO/NO2 interconversion reaction channel, NO+HO2=NO2+OH, NO2+H=NO+OH, CH3OCH3+NO2=CH3OCH2+HONO, followed by the thermal decomposition of HONO. This work extends the kinetic database and helps to improve the understanding of dimethyl ether and dimethoxymethane combustion behavior. The kinetic model presented in this work can serve as a base model for hydrocarbons and oxygenated fuels higher than C2.
Krishna Prasad Shrestha, Sven Eckart, Ayman M. Elbaz, Binod Raj Giri, Chris Fritsche, Lars Seidel, William L. Roberts, Hartmut Krause, Fabian Mauss.
A comprehensive kinetic model for Dimethyl ether and Dimethoxymethane oxidation and NOx interaction utilizing experimental laminar flame speed measurements at elevated pressure and temperature.
Combustion and Flame 218 (2020) 57–74. https://doi.org/10.1016/j.combustflame.2020.04.016
Nitromethane (CH3NO2):
This is a collaboration work of the Brandenburg University of Technology (Germany),
Laboratoire Réactions et Génie des Procédés, CNRS, Université de Lorraine (France)
LOGE Deutschland GmbH (Germany) and Georg-August-Universitat GÖttingen (Germany).
In this work, a detailed kinetic mechanism for the oxidation and pyrolysis of nitromethane has been developed. The pyrolysis of nitromethane highly diluted in helium was studied in a plug flow reactor and in a jet-stirred reactor at 1.07 bar and over the temperature range from 500 to 1100 K. Experiments were conducted at Université de Lorraine. We have developed a newly compiled model for the prediction of the pyrolysis and of the oxidation of nitromethane in jet-stirred and flow reactors, freely propagating, and burner-stabilized premixed flames, as well as in shock-tubes. The experimental results from the this work and from the literature are interpreted with the help of the kinetic model derived here. This study mainly focuses on the analysis of speciation in different reactors. Among the nitrogenous species, NO is found to be a major product for pyrolysis and oxidation. The model suggests that for nitromethane pyrolysis and oxidation the thermal dissociation channel to CH3 and NO2 is the main reaction path for the nitromethane degradation followed by the H-atom abstraction channel. The most sensitive reactions for nitromethane pyrolysis in a flow reactor and during pyrolysis and oxidation in a jet-stirred reactor are found to be CH3NO2(+M) = CH3 + NO2(+M) and CH3 + NO2 = CH3O + NO. The reaction CH3 + NO2 = CH3O + NO is found to be the most important reaction for all conditions studied. In a burner-stabilized premixed flame, as the mixture gets richer, the thermal dissociation channel CH3NO2(+M) = CH3 + NO2(+M) becomes more important as the contribution of the H-atom abstraction channel is decreased. Furthermore, in the burner-stabilized premixed flames, it was found that NO is mainly formed via NO2: NO2 + H = NO + OH, NO2 + CH3 = CH3O + NO. The model provided an overall reasonable agreement with the experimental data.
In this work, a detailed kinetic mechanism for the oxidation and pyrolysis of nitromethane has been developed. The pyrolysis of nitromethane highly diluted in helium was studied in a plug flow reactor and in a jet-stirred reactor at 1.07 bar and over the temperature range from 500 to 1100 K. Experiments were conducted at Université de Lorraine. We have developed a newly compiled model for the prediction of the pyrolysis and of the oxidation of nitromethane in jet-stirred and flow reactors, freely propagating, and burner-stabilized premixed flames, as well as in shock-tubes. The experimental results from the this work and from the literature are interpreted with the help of the kinetic model derived here. This study mainly focuses on the analysis of speciation in different reactors. Among the nitrogenous species, NO is found to be a major product for pyrolysis and oxidation. The model suggests that for nitromethane pyrolysis and oxidation the thermal dissociation channel to CH3 and NO2 is the main reaction path for the nitromethane degradation followed by the H-atom abstraction channel. The most sensitive reactions for nitromethane pyrolysis in a flow reactor and during pyrolysis and oxidation in a jet-stirred reactor are found to be CH3NO2(+M) = CH3 + NO2(+M) and CH3 + NO2 = CH3O + NO. The reaction CH3 + NO2 = CH3O + NO is found to be the most important reaction for all conditions studied. In a burner-stabilized premixed flame, as the mixture gets richer, the thermal dissociation channel CH3NO2(+M) = CH3 + NO2(+M) becomes more important as the contribution of the H-atom abstraction channel is decreased. Furthermore, in the burner-stabilized premixed flames, it was found that NO is mainly formed via NO2: NO2 + H = NO + OH, NO2 + CH3 = CH3O + NO. The model provided an overall reasonable agreement with the experimental data.
Krishna Prasad Shrestha, NicolasVin, Olivier Herbinet, Lars Seidel, Frédérique Battin-Leclerc, Thomas Zeuch, and Fabian Mauss.
Insights into nitromethane combustion from detailed kinetic modeling – Pyrolysis experiments in jet-stirred and flow reactors.
Fuel 261 (2020) 116349. https://doi.org/10.1016/j.fuel.2019.116349
Methanol-Ethanol-NOx:
This is a collaboration work of the Brandenburg University of Technology (Germany),
LOGE Deutschland GmbH (Germany) and Georg-August-Universitat GÖttingen (Germany).
In this work, a detailed kinetic mechanism for the oxidation of methanol/ethanol and NOx interaction has been developed. This work presents a newly developed model for the oxidation of methanol and ethanol and their fuel interaction with NOx (NO and NO2) chemistry in jet-stirred and flow reactors, freely propagating and burner-stabilized premixed flames as well as shock-tubes. The paper mainly focuses on fuel interaction with nitrogen chemistry and NO formation in laminar premixed flames but also considers the formation and reduction of nitrogen oxides depending on the conditions of the surrounding gas phase. In agreement with previous experimental work, we find that doping of fuel blends with NO shifts the onset of fuel oxidation to lower temperatures depending on the gas conditions. The model suggests that the reactivity promoting effect of NO is mainly due to the net increase of OH radical concentrations, which causes increased fuel oxidation via the NO/NO2 interconversion reaction channel, NO+HO2=NO2+OH, NO2+H=NO+OH, NO2+HO2=HONO+O2, followed by the thermal decomposition of HONO. In burner-stabilized premixed ethanol flames NO is mainly formed via a NCN pathway for all equivalence ratios, while for methanol flames the NCN pathway is only favoured at rich conditions and the N2O pathway is favoured at lean conditions.
In this work, a detailed kinetic mechanism for the oxidation of methanol/ethanol and NOx interaction has been developed. This work presents a newly developed model for the oxidation of methanol and ethanol and their fuel interaction with NOx (NO and NO2) chemistry in jet-stirred and flow reactors, freely propagating and burner-stabilized premixed flames as well as shock-tubes. The paper mainly focuses on fuel interaction with nitrogen chemistry and NO formation in laminar premixed flames but also considers the formation and reduction of nitrogen oxides depending on the conditions of the surrounding gas phase. In agreement with previous experimental work, we find that doping of fuel blends with NO shifts the onset of fuel oxidation to lower temperatures depending on the gas conditions. The model suggests that the reactivity promoting effect of NO is mainly due to the net increase of OH radical concentrations, which causes increased fuel oxidation via the NO/NO2 interconversion reaction channel, NO+HO2=NO2+OH, NO2+H=NO+OH, NO2+HO2=HONO+O2, followed by the thermal decomposition of HONO. In burner-stabilized premixed ethanol flames NO is mainly formed via a NCN pathway for all equivalence ratios, while for methanol flames the NCN pathway is only favoured at rich conditions and the N2O pathway is favoured at lean conditions.
Krishna P. Shrestha, Lars Seidel, Thomas Zeuch, and Fabian Mauss.
Kinetic Modeling of NOx Formation and Consumption during Methanol and Ethanol Oxidation.
Combustion Science and Technology, 191(2019), 1628-1660. https://doi.org/10.1080/00102202.2019.1606804
Ammonia-NOX :
This is a collaboration work of the Brandenburg University of Technology (Germany),
LOGE Deutschland GmbH (Germany) and Georg-August-Universitat GÖttingen (Germany).
In this work, a detailed kinetic mechanism for the oxidation of ammonia has been developed. The kinetic mechanism also takes into account the formation and reduction of the nitrogen oxides. The state-of-the-art hydrogen/syngas mechanism was developed first, later the ammonia mechanism was coupled with the developed hydrogen/syngas mechanism. The hydrogen/syngas kinetic mechanism is validated against experimental data from the literature, which include 87 sets of laminar flame speeds, 39 sets of ignition delay times from shock tubes, 16 sets of species concentrations in jet-stirred reactors, 27 sets of species concentrations in flow reactors, 8 sets of species concentrations in burner stabilized flames, and 4 sets of species concentrations in shock-tube experiments. Only, hydrogen/syngas mechanism developed in this work with validation can also found within this web page. The developed mechanism is also validated for hydrogen/NOx, syngas/NOx, and ammonia/NOx interaction. The mechanism also includes methane as fuel and is validated for methane oxidation prediction which is shown in supplementary material available in the journal website as well here. The mechanism is capable of predicting methane/NOx interaction and prompt NOx in flames. However, methane was not the main target of discussion in the published paper. In the published version of the mechanism, there were some format issues which is fixed in the mechanism attached here. The manuscript is also available for readers.
In this work, a detailed kinetic mechanism for the oxidation of ammonia has been developed. The kinetic mechanism also takes into account the formation and reduction of the nitrogen oxides. The state-of-the-art hydrogen/syngas mechanism was developed first, later the ammonia mechanism was coupled with the developed hydrogen/syngas mechanism. The hydrogen/syngas kinetic mechanism is validated against experimental data from the literature, which include 87 sets of laminar flame speeds, 39 sets of ignition delay times from shock tubes, 16 sets of species concentrations in jet-stirred reactors, 27 sets of species concentrations in flow reactors, 8 sets of species concentrations in burner stabilized flames, and 4 sets of species concentrations in shock-tube experiments. Only, hydrogen/syngas mechanism developed in this work with validation can also found within this web page. The developed mechanism is also validated for hydrogen/NOx, syngas/NOx, and ammonia/NOx interaction. The mechanism also includes methane as fuel and is validated for methane oxidation prediction which is shown in supplementary material available in the journal website as well here. The mechanism is capable of predicting methane/NOx interaction and prompt NOx in flames. However, methane was not the main target of discussion in the published paper. In the published version of the mechanism, there were some format issues which is fixed in the mechanism attached here. The manuscript is also available for readers.
Krishna P. Shrestha, Lars Seidel, Thomas Zeuch, and Fabian Mauss.
Detailed Kinetic Mechanism for the Oxidation of Ammonia Including the Formation and Reduction of Nitrogen Oxides.
Energy Fuels 2018, 32, 10202−10217. https://doi.org/10.1021/acs.energyfuels.8b01056
2-methyl-2-butene and n-pentane :
This is a collaboration work of the Brandenburg University of Technology (Germany), the University Bielefeld (Germany), Physikalisch Technische Bundesanstalt (PTB) (Germany),
LOGE Deutschland GmbH (Germany) and Combustion Research Facility, Sandia National Laboratories (USA).
In this work a reaction scheme for pentene isomers was developed in collaboration with the university of Bielefeld and Sandia National Laboratories. A hierarchically assembled mechanism has been developed to specifically target speciation data from low-pressure premixed flames of 2-methyl-2-butene [Ruwe et al., Combust. Flame, 175, 34-46, 2017] and newly measured mole fraction data for a fuel-rich (ɸ=1.8) n-pentane flame, in which species profiles up to phenol were quantified. The presented model, which includes a newly determined, consistent set of the thermochemistry data for the C5 species, presents overall satisfactory capabilities to predict the mole fraction profiles of common combustion intermediates. The analysis of the model predictions revealed the fuel-structure dependencies (i.e. saturated vs. unsaturated and linear vs. branched) of the formation of small aromatic species that are considered as soot precursors. The propensity of the 2-methyl-2-butene flame to form larger concentrations of aromatic species was traced back to the readily available formation routes of several small precursor molecules and the efficient formation of “first aromatic rings” beyond benzene.
In this work a reaction scheme for pentene isomers was developed in collaboration with the university of Bielefeld and Sandia National Laboratories. A hierarchically assembled mechanism has been developed to specifically target speciation data from low-pressure premixed flames of 2-methyl-2-butene [Ruwe et al., Combust. Flame, 175, 34-46, 2017] and newly measured mole fraction data for a fuel-rich (ɸ=1.8) n-pentane flame, in which species profiles up to phenol were quantified. The presented model, which includes a newly determined, consistent set of the thermochemistry data for the C5 species, presents overall satisfactory capabilities to predict the mole fraction profiles of common combustion intermediates. The analysis of the model predictions revealed the fuel-structure dependencies (i.e. saturated vs. unsaturated and linear vs. branched) of the formation of small aromatic species that are considered as soot precursors. The propensity of the 2-methyl-2-butene flame to form larger concentrations of aromatic species was traced back to the readily available formation routes of several small precursor molecules and the efficient formation of “first aromatic rings” beyond benzene.
Larisa León, Lena Ruwe, Kai Moshammer, Lars Seidel, Krishna P.Shrestha, Wang Xiaoxiao, Fabian Mauss, Katharina Kohse-Höinghaus, Nils Hansene (2019).
Chemical insights into the larger sooting tendency of 2-methyl-2-butene compared to n-pentane. Combustion and Flame, 208, 182–197. https://doi.org/10.1016/j.combustflame.2019.06.029
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Hydrogen and Syngas :
This is a collaboration work of the Brandenburg University of Technology and LOGE (Sweden and Germany).
In this work the Hydrogen and Syngas model used in previous works was revised. An extensive literature research on reaction rates and available experiments for pure fuels and mixtures has been performed. The reaction scheme was validated against published experiments in different setups: shock tube, jet stirred reactor and different flame configurations. The developed model shows a good agreement over a wide range of conditions (fuel / equivalence ratio, pressure, temperature, different inert gases and concentrations). A comparison of the selected rate constants and a comparison can be found in the pdf file below.
In this work the Hydrogen and Syngas model used in previous works was revised. An extensive literature research on reaction rates and available experiments for pure fuels and mixtures has been performed. The reaction scheme was validated against published experiments in different setups: shock tube, jet stirred reactor and different flame configurations. The developed model shows a good agreement over a wide range of conditions (fuel / equivalence ratio, pressure, temperature, different inert gases and concentrations). A comparison of the selected rate constants and a comparison can be found in the pdf file below.
Higly reduced n-Heptane reaction scheme for Diesel combustion prediction:
This is a collaboration work of the Brandenburg University of Technology, LOGE (Sweden and Germany) and the University of Chalmers (Sweden).
In this work we apply a sequence of concepts for mechanism reduction on one reaction mechanism including novel quality control. We introduce a moment based accuracy rating method for species profiles. The concept is used for a necessity based mechanism reduction utilizing 0D reactors. Thereafter a stochastic reactor model for internal combustion engines is applied to control the quality of the reduced reaction mechanism during the expansion phase of the engine. This phase is sensitive on engine out emissions, and is often not considered in mechanism reduction work. The proposed process allows to compile highly reduced reaction schemes for CFD application for internal combustion engine simulations. It is demonstrated that the resulting reduced mechanisms predict combustion and emission formation in engines with accuracies comparable to the original detailed scheme.
In this work we apply a sequence of concepts for mechanism reduction on one reaction mechanism including novel quality control. We introduce a moment based accuracy rating method for species profiles. The concept is used for a necessity based mechanism reduction utilizing 0D reactors. Thereafter a stochastic reactor model for internal combustion engines is applied to control the quality of the reduced reaction mechanism during the expansion phase of the engine. This phase is sensitive on engine out emissions, and is often not considered in mechanism reduction work. The proposed process allows to compile highly reduced reaction schemes for CFD application for internal combustion engine simulations. It is demonstrated that the resulting reduced mechanisms predict combustion and emission formation in engines with accuracies comparable to the original detailed scheme.
The reduction method and the performance of the reaction scheme are published in:
Seidel, L., Netzer, C., Hilbig, M., Mauss, F., Klauer, C., Pasternak, M., Matrisciano, A., SYSTEMATIC REDUCTION OF DETAILED CHEMICAL REACTION MECHANISMS FOR ENGINE APPLICATIONS. ASME. J. Eng. Gas Turbines Power. 2017;():. doi:10.1115/1.4036093. IN PRESS
It was first presented at the ASME 2016 Internal Combustion Engine Division Fall Technical Conference: Seidel, L., Netzer, C., Hilbig, M., Mauss, F., Klauer, C., Pasternak, M., Matrisciano, A. "Systematic Reduction of Detailed Chemical Reaction Mechanisms for Engine Applications" Paper No. ICEF2016-9304, ASME 2016 Internal Combustion Engine Division Fall Technical Conference
The developed mechanism is a reduced version of the detailed scheme published by Seidel et al. in 2016:: Seidel, L, Moshammer, K, Wang, X., Zeuch, T., Kohse-Höinghaus, K. , Mauss, F., "Comprehensive kinetic modeling and experimental study of a fuel-rich, premixed n-heptane flame", Combust. Flame, Vol 162, pp. 2045-2058, 2015.
It was first presented at the ASME 2016 Internal Combustion Engine Division Fall Technical Conference: Seidel, L., Netzer, C., Hilbig, M., Mauss, F., Klauer, C., Pasternak, M., Matrisciano, A. "Systematic Reduction of Detailed Chemical Reaction Mechanisms for Engine Applications" Paper No. ICEF2016-9304, ASME 2016 Internal Combustion Engine Division Fall Technical Conference
The developed mechanism is a reduced version of the detailed scheme published by Seidel et al. in 2016:: Seidel, L, Moshammer, K, Wang, X., Zeuch, T., Kohse-Höinghaus, K. , Mauss, F., "Comprehensive kinetic modeling and experimental study of a fuel-rich, premixed n-heptane flame", Combust. Flame, Vol 162, pp. 2045-2058, 2015.
Butadiene:
Study of butadiene oxidation in a opposed-flow diffusive flames in co-operation with the
Combustion Research Facility (Sandia National Laboratories - USA) and the Clean Combustion Research Center
(King Abdullah University - Saudi Arabia).
This paper is concerned with the formation of one- and two-ring aromatic species in near atmosphericpressure opposed-flow diffusion flames of 1,3-butadiene (1,3-C4H6). The chemical structures of two different 1,3-C4H6/Ar–O2/Ar flames were explored using flame-sampling molecular-beam mass spectrometry with both electron and single-photon ionization. We provide mole fraction profles of 47 components as function of distance from the fuel outlet and compare them to chemically detailed modeling results. To this end, the hierarchically developed model described by Seidel et al. [16] has been updated to accurately comprise the chemistry of 1,3-butadiene. Generally a very good agreement is observed between the experimental and modeling data, allowing for a meaningful reaction path analysis. With regard to the formation of aromatic species up to naphthalene, it was essential to improve the fulvene and the C5 chemistry description in the mechanism. In particular, benzene is found to be formed mainly via fulvene through the reactions of the C4H5 isomers with C2H2. The n-C4H5 radical reacts with CH3 forming 1,3-pentadiene (C5H8), which is subsequently oxidized to form the naphthalene precursor cyclopentadienyl (C5H5). Oxidation of naphthalene is predicted to be a contributor to the formation of phenylacetylene (C8H6), indicating that consumption reactions can be of similar importance as molecular growth reactions.
This paper is concerned with the formation of one- and two-ring aromatic species in near atmosphericpressure opposed-flow diffusion flames of 1,3-butadiene (1,3-C4H6). The chemical structures of two different 1,3-C4H6/Ar–O2/Ar flames were explored using flame-sampling molecular-beam mass spectrometry with both electron and single-photon ionization. We provide mole fraction profles of 47 components as function of distance from the fuel outlet and compare them to chemically detailed modeling results. To this end, the hierarchically developed model described by Seidel et al. [16] has been updated to accurately comprise the chemistry of 1,3-butadiene. Generally a very good agreement is observed between the experimental and modeling data, allowing for a meaningful reaction path analysis. With regard to the formation of aromatic species up to naphthalene, it was essential to improve the fulvene and the C5 chemistry description in the mechanism. In particular, benzene is found to be formed mainly via fulvene through the reactions of the C4H5 isomers with C2H2. The n-C4H5 radical reacts with CH3 forming 1,3-pentadiene (C5H8), which is subsequently oxidized to form the naphthalene precursor cyclopentadienyl (C5H5). Oxidation of naphthalene is predicted to be a contributor to the formation of phenylacetylene (C8H6), indicating that consumption reactions can be of similar importance as molecular growth reactions.
Moshammer, K, Seidel, L., Yu, W., Selim, H., Sarathy, S.M., Mauss, F., Hansen, N. "Aromatic ring formation in opposed-flow diffusive 1,3-butadiene flames", Proc. Comb. Inst., 2016 (IN PRESS) DOI: http://dx.doi.org/10.1016/j.proci.2016.09.010.
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n-Heptane:
Detailed n-heptane mechanism developed in collaboration with the university Bielefeld and
Göttingen.
In this work an existing comprehensive kinetic hydrocarbon oxidation model has been augmented and revised for a detailed analysis of n-heptane flame chemistry. The analysis was enabled by experiments in which the detailed species composition in a fuel-rich flat premixed (phi = 1.69) n-heptane flame at 40 mbar has been studied by flame-sampling molecular-beam mass spectrometry using electron impact ionization. Mole fraction profiles of more than 80 different species have been measured and compared against the new detailed kinetic model consisting of 349 species and 3686 elementary reactions. For all major products and most of the minor intermediates, a good agreement of the modeling results with the experimentally-observed mole fraction profiles has been found. The presence of low- and intermediate-temperature chemistry close to the burner surface was consistently observed in the experiment and the simulation. With the same kinetic model, n-heptane auto-ignition timing, flame speeds and species composition in a jet-stirred reactor have been successfully simulated for a broad range of temperatures (500-2000 K) and pressures (1-40 bar). The comprehensive nature and wide applicability of the new model were further demonstrated by the examination of various target experiments for other C1 to C7 fuels.
In this work an existing comprehensive kinetic hydrocarbon oxidation model has been augmented and revised for a detailed analysis of n-heptane flame chemistry. The analysis was enabled by experiments in which the detailed species composition in a fuel-rich flat premixed (phi = 1.69) n-heptane flame at 40 mbar has been studied by flame-sampling molecular-beam mass spectrometry using electron impact ionization. Mole fraction profiles of more than 80 different species have been measured and compared against the new detailed kinetic model consisting of 349 species and 3686 elementary reactions. For all major products and most of the minor intermediates, a good agreement of the modeling results with the experimentally-observed mole fraction profiles has been found. The presence of low- and intermediate-temperature chemistry close to the burner surface was consistently observed in the experiment and the simulation. With the same kinetic model, n-heptane auto-ignition timing, flame speeds and species composition in a jet-stirred reactor have been successfully simulated for a broad range of temperatures (500-2000 K) and pressures (1-40 bar). The comprehensive nature and wide applicability of the new model were further demonstrated by the examination of various target experiments for other C1 to C7 fuels.
Seidel, L, Moshammer, K, Wang, X., Zeuch, T., Kohse-Höinghaus, K. , Mauss, F., "Comprehensive kinetic modeling and experimental study of a fuel-rich, premixed n-heptane flame", Combust. Flame, Vol 162, pp. 2045-2058, 2015.
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1-Hexene:
A reaction scheme for 1-Hexene. The mechanism was developed in collaboration with the
university Göttingen and Sandia National Laboratories.
An existing detailed and broadly validated kinetic scheme is augmented to capture the flame chemistry of 1-hexene under stoichiometric and fuel rich conditions including benzene formation pathways. In addition, the speciation in a premixed stoichiometric 1-hexene flame (flat-flame McKenna-type burner) has been studied under a reduced pressure of 20-30 mbar applying flame-sampling molecular-beam time-of-flight mass spectrometry and photoionization by tunable vacuum-ultraviolet synchrotron radiation. Mole fraction profiles of 40 different species have been measured and validated against the new detailed chemical reaction model consisting of 275 species and 3047 reversible elementary reactions. A good agreement of modelling results with the experimentally observed mole fraction profiles has been found under both stoichiometric and fuel rich conditions providing a sound basis for analyzing benzene formation pathways during 1-hexene combustion. The analysis clearly shows that benzene formation via the fulvene intermediate is a very important pathway for 1-hexene.
An existing detailed and broadly validated kinetic scheme is augmented to capture the flame chemistry of 1-hexene under stoichiometric and fuel rich conditions including benzene formation pathways. In addition, the speciation in a premixed stoichiometric 1-hexene flame (flat-flame McKenna-type burner) has been studied under a reduced pressure of 20-30 mbar applying flame-sampling molecular-beam time-of-flight mass spectrometry and photoionization by tunable vacuum-ultraviolet synchrotron radiation. Mole fraction profiles of 40 different species have been measured and validated against the new detailed chemical reaction model consisting of 275 species and 3047 reversible elementary reactions. A good agreement of modelling results with the experimentally observed mole fraction profiles has been found under both stoichiometric and fuel rich conditions providing a sound basis for analyzing benzene formation pathways during 1-hexene combustion. The analysis clearly shows that benzene formation via the fulvene intermediate is a very important pathway for 1-hexene.
Nawdiyal, A., Hansen, N., Zeuch, T., Seidel, L., Mauß, F., "Experimental and modelling study of speciation and benzene formation pathways in premixed 1-hexene flames", Proc. Comb. Inst., Vol 35, pp. 325-332, 2015.
Files:
- All 1-Hexene Files (zip archive)
- Mole fraction profiles for the flame with phi=1.0
- Mole fraction profiles for the flame with phi=1.7
- Mole fraction profiles for the flame with phi=2.0
- Temperature profile for the flame with phi=1.0
- Temperature profile for the flame with phi=1.7
- Temperature profile for the flame with phi=2.0
- Mechanism
- Thermodynamic data
- Thermodynamic data (for Open Smoke)
- Transport data
Butene isomers:
A reaction mechanism for C4 isomers (butane and butene). The mechanism was developed in
collaboration with the university Bielefeld and Göttingen.
Premixed low-pressure (40 mbar) flat argon-diluted (25%) flames of the three butene isomers (1-butene, trans-2-butene and i-butene) were studied under fuel-rich (phi = 1.7) conditions using a newly developed analytical combination of high-resolution in situ molecular-beam mass spectrometry (MBMS) and in situ gas chromatography (GC). The time-of-flight MBMS with its high mass resolution enables the detection of both stable and reactive species, while the gas chromatograph permits the separation of isomers from the same sampling volume. The isomer-specific species information and the quantitative mole fraction profiles of more than 30 stable and radical species measured for each fuel were used to extend and validate the C4 subset of a comprehensive flame simulation model. The experimental data shows different destruction pathways for the butene isomers, as expected, and the model is well capable to predict the different combustion behavior of the isomeric flames. The detailed analysis of the reaction pathways in the flame and the respective model predictions are discussed.
Premixed low-pressure (40 mbar) flat argon-diluted (25%) flames of the three butene isomers (1-butene, trans-2-butene and i-butene) were studied under fuel-rich (phi = 1.7) conditions using a newly developed analytical combination of high-resolution in situ molecular-beam mass spectrometry (MBMS) and in situ gas chromatography (GC). The time-of-flight MBMS with its high mass resolution enables the detection of both stable and reactive species, while the gas chromatograph permits the separation of isomers from the same sampling volume. The isomer-specific species information and the quantitative mole fraction profiles of more than 30 stable and radical species measured for each fuel were used to extend and validate the C4 subset of a comprehensive flame simulation model. The experimental data shows different destruction pathways for the butene isomers, as expected, and the model is well capable to predict the different combustion behavior of the isomeric flames. The detailed analysis of the reaction pathways in the flame and the respective model predictions are discussed.
Schenk, M., León, L., Moshammer, K., Oßwald, P., Kohse-Höinghaus, K., Zeuch, T., Seidel, L., and Mauss, F., "Detailed mass spectrometric and modeling study of isomeric butene flames", Combust. Flame, Vol. 160, pp. 487-503, 2013.
Files:
Butane isomers:
Detailed investigation of butane isomers in burner stabilised flames. This work was done in
collaboration with the university Göttingen and Bielefeld. It is recommend to use the
mechanism for butene isomers since it is a consistent further development of the mechanism
from this study.
The combustion chemistry of the two butane isomers represents a subset in a comprehensive description of C1–C4 hydrocarbon and oxygenated fuels. A critical examination of combustion models and their capability to predict emissions from this class of fuels must rely on high-quality experimental data that address the respective chemical decomposition and oxidation pathways, including quantitative intermediate species mole fractions. Premixed flat low-pressure (40 mbar) flames of the two butane isomers were thus studied under identical, fuel-rich (phi=1.71) conditions. Two independent molecular-beam mass spectrometer (MBMS) set-ups were used to provide quantitative species profiles. Both data sets, one from electron ionization (EI)-MBMS with high mass resolution and one from photoionization (PI)-MBMS with high energy resolution, are in overall good agreement. Simulations with a flame model were used to analyze the respective reaction pathways, and differences in the combustion behavior of the two isomers are discussed.
The combustion chemistry of the two butane isomers represents a subset in a comprehensive description of C1–C4 hydrocarbon and oxygenated fuels. A critical examination of combustion models and their capability to predict emissions from this class of fuels must rely on high-quality experimental data that address the respective chemical decomposition and oxidation pathways, including quantitative intermediate species mole fractions. Premixed flat low-pressure (40 mbar) flames of the two butane isomers were thus studied under identical, fuel-rich (phi=1.71) conditions. Two independent molecular-beam mass spectrometer (MBMS) set-ups were used to provide quantitative species profiles. Both data sets, one from electron ionization (EI)-MBMS with high mass resolution and one from photoionization (PI)-MBMS with high energy resolution, are in overall good agreement. Simulations with a flame model were used to analyze the respective reaction pathways, and differences in the combustion behavior of the two isomers are discussed.
Osswald, P., Kohse-Hoinghaus, K., Struckmeier, U., Zeuch, T., Seidel, L., Leon, L., Mauss, F., "Combustion chemistry of the butane isomers in premixed low-pressure flames.", Zeitschrift Fuer Physikalische Chemie, 225(9-10), 1029–1054 (2011).
Files:
Skeletal n-Heptane Mechanism with PAH and NOx model:
The reaction scheme is compiled of the skeletal n-heptane oxidation scheme from Zeuch et
al. with an additional PAH growth model from Mauss. Further a sub mechanism for thermal NOx
was included. The mechanism consists of 121 species.
Zeuch, T., Moréac, G., Ahmed, S. S., Mauss, F. , "A comprehensive skeletal mechanism for the oxidation of n-heptane generated by chemistry-guided reduction", Combustion and Flame, 155(4), 651–674, 2008.
Mauss, F. "Entwicklung eines kinetischen Modells der Rußbildung mit schneller Polymerisation", PhD Thesis, RWTH Aachen, 1997
Mauss, F. "Entwicklung eines kinetischen Modells der Rußbildung mit schneller Polymerisation", PhD Thesis, RWTH Aachen, 1997
Files:
C1-C4 chemistry:
On the basis of existing detailed kinetic schemes a general and consistent mechanism of the
oxidation of hydrocarbons and the formation of higher hydrocarbons was compiled for
computational studies covering the characteristic properties of a wide range of combustion
processes. Computed ignition delay times of hydrocarbon–oxygen mixtures (CH4-, C2H6-, C3H8-,
n-C4H10-, CH4 + C2H6-, C2H4, C3H6-O2) match the experimental values. The calculated absolute
flame velocities of laminar premixed flames (CH4-, C2H6-, C3H8-, n-C4H10-, C2H4-, C3H6-, and
C2H2-air) and the dependence on mixture strength agree with the latest experimental
investigations reported in the literature. With the same model concentration profiles for
major and intermediate species in fuel-rich, non-sooting, premixed C2H2-, C3H6- air flames
and a mixed C2H2/C3H6 (1:1)-air flame at 50 mbar are predicted in good agreement with
experimental data. An analysis of reaction pathways shows for all three flames that benzene
formation can be described by propargyl combination.
Hoyermann, K., Mauss, F., Zeuch, T. "A detailed chemical reaction mechanism for the oxidation of hydrocarbons and its application to the analysis of benzene formation in fuel-rich premixed laminar acetylene and propene flames." Phys. Chem. Chem. Phys., 6(14), 3824–3835, 2004.
Files: