TY - GEN A1 - Oßwald, Patrick A1 - Kohse-Höinghaus, Katharina A1 - Struckmeier, Ulf A1 - Zeuch, Thomas A1 - Seidel, Lars A1 - Leon, Larisa A1 - Mauß, Fabian T1 - Combustion chemistry of the butane isomers in premixed low-pressure flames T2 - Zeitschrift für Physikalische Chemie Y1 - 2011 SN - 0942-9352 VL - 225 IS - 9-10 SP - 1029 EP - 1054 ER - TY - CHAP A1 - Mauß, Fabian A1 - Tuner, Martin A1 - Fröjd, Karin A1 - Seidel, Lars T1 - "Diesel-PPC engine: Predictive Full Cycle Modeling with Reduced and Detailed Chemistry" Y1 - 2011 ER - TY - GEN A1 - Goos, Elke A1 - Sickfeld, Christina A1 - Mauß, Fabian A1 - Seidel, Lars A1 - Ruscic, Branko A1 - Burcat, Alexander A1 - Zeuch, Thomas T1 - Prompt NO formation in flames: The influence of NCN thermochemistry T2 - Proceedings of the Combustion Institute Y1 - 2013 SN - 1540-7489 VL - Vol. 34 SP - 657 EP - 666 ER - TY - GEN A1 - Seidel, Lars A1 - Hoyermann, Karlheinz A1 - Mauß, Fabian A1 - Nothdurft, Jörg A1 - Zeuch, Thomas T1 - Pressure Dependent Product Formation in the Photochemically Initiated allyl + allyl reaction T2 - Molecules Y1 - 2013 SN - 1420-3049 VL - 18 IS - 11 SP - 13608 EP - 13622 ER - TY - GEN A1 - Seidel, Lars A1 - Moshammer, Kai A1 - Wang, Xiaoxiao A1 - Zeuch, Thomas A1 - Kohse-Höinghaus, Katharina A1 - Mauß, Fabian T1 - Comprehensive kinetic modeling and experimental study of a fuel-rich, premixed n-heptane flame T2 - Combustion and Flame N2 - 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 (ϕ=1.69) n-heptane flame at 40mbar 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 (500-2000K) and pressures (1-40bar). 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. KW - Hydrocarbon Oxidation Mechanism, Low Pressure Flame, Molecular-beam Spectrometry, n-Heptane, Soot Precursors Y1 - 2015 U6 - https://doi.org/10.1016/j.combustflame.2015.01.002 SN - 0010-2180 VL - 162 IS - 5 SP - 2045 EP - 2058 ER - TY - CHAP A1 - Dudziak, Ines A1 - Niproschke, Saskia A1 - Bilz, Ludwig A1 - Fischer, Saskia M. A1 - Oertel, Lars A1 - Schubarth, Wilfried A1 - Seidel, Andreas A1 - Ulbricht, Juliane A1 - Wachs, Sebastian ED - Bilz, Ludwig ED - Schubarth, Wilfried ED - Dudziak, Ines ED - Fischer, Saskia M. ED - Niproschke, Saskia ED - Ulbricht, Juliane T1 - Häufigkeiten, Formen und Erfolg von Lehrerinterventionen aus Lehrer- und Schülersicht T2 - Gewalt und Mobbing an Schulen. Wie sich Gewalt und Mobbing entwickelt haben, wie Lehrer intervenieren und welche Kompetenzen sie brauchen Y1 - 2017 SN - 978-3-7815-2095-0 SP - 103 EP - 127 PB - Klinkhardt CY - Bad Heilbrunn ER - TY - CHAP A1 - Leon de Syniawa, Larisa A1 - Nawdiyal, A. A1 - Seidel, Lars A1 - Mauß, Fabian T1 - Formation of C5 Species from iso-Butene T2 - Book of Abstracts, SMARTCATs 2nd General Meeting & Workshop on Smart Energy Carriers in Industry Lisbon, 14-16 November - 2016 KW - Formation of C5 Species Y1 - 2016 UR - http://media.wix.com/ugd/504c46_ad5e1606ba5c444aaa48e7a6f8a95288.pdf SP - 42 EP - 43 ER - TY - CHAP A1 - Shrestha, Krishna Prasad A1 - Seidel, Lars A1 - Mauß, Fabian A1 - Zeuch, Thomas ED - Bockhorn, Henning ED - Scala, F. ED - Commodo, M. ED - Tregrossi, A. T1 - Development of a kinetic mechanism for NOx fuel interaction T2 - Proceedings, Joint Meeting of the German and Italian Sections of the Combustion Institute, 41st Meeting on Combustion, Sorrento, May 2018 N2 - This work introduces a newly developed reaction mechanism to predict fuel/NOx interaction in freely propagating, burner stabilized premixed flames, shock tubes, jet stirred reactors and plug flow reactors experiments. The study focuses on pure ammonia as fuel as well as H₂,H₂/CO, CH₄ doped with NO, NO₂ and N₂O. The kinetic scheme also focuses on the formation and consumption of nitrogen oxides at different experimental conditions. It is found that the doping with N₂O has almost no sensitivity on the H₂ chemistry, while small amount of NO₂ is enough to change the pressure dependence of H₂ auto ignition. The experiments with N₂O still show the significant influence of the chain breaking reaction H+O₂(+M)⇋HO₂(+M) on the H₂ ignition delay times, resulting in the crossing lines for the ignition delay times, which are moved at higher pressure to higher temperature. The concentration of HO₂ is decisive for the active reaction pathway in shock tube oxidation as well as in jet stirred and flow reactor. Reaction NO+HO₂⇋NO₂+OH and NO₂+H⇋NO+OH are very important because they strongly influence the inter conversion process of NO and NO₂ in jet stirred reactor and flow reactor for cases studied herein. The formation of NO in burner stabilized premixed flames is shown to demonstrate the capability of the mechanism to be integrated into mechanisms for hydrocarbon oxidation. KW - Development of a Kinetic Y1 - 2018 UR - http://www.combustion-institute.it/proceedings/XXXXI-ASICI/proceedings2018.pdf SN - 978-88-88104-22-5 PB - Associazione Sezione Italiana del Combustion Institute CY - Napoli ER - TY - CHAP A1 - Netzer, Corinna A1 - Seidel, Lars A1 - Lehtiniemi, Harry A1 - Ravet, Frédéric A1 - Mauß, Fabian T1 - Impact of gasoline surrogates with different fuel sensitivity (RON-MON) on knock prediction T2 - Proceedings of the 6th European Conference on Computational Mechanics (Solids, Structures and Coupled Problems) ECCM 6 and 7th European Conference on Computational Fluid Dynamics ECFD 7, Glasgow, Scotland, UK June 11 – 15, 2018 KW - Impact of gasoline surrogates Y1 - 2018 UR - http://www.eccm-ecfd2018.org/frontal/docs/Ebook-Glasgow-2018-ECCM-VI-ECFD-VII.pdf SP - 906 EP - 917 ER - TY - CHAP A1 - Franken, Tim A1 - Netzer, Corinna A1 - Pasternak, Michal A1 - Mauß, Fabian A1 - Seidel, Lars A1 - Matrisciano, Andrea A1 - Borg, Anders A1 - Lehtiniemi, Harry A1 - Kulzer, André Casal T1 - Assessment of Water Injection in a SI Engine using a Fast Running Detailed Chemistry Based Combustion Model T2 - Symposium of Combustion Control 2018, Aachen KW - Assessment of Water Injection Y1 - 2018 UR - https://www.researchgate.net/publication/326059620 UR - http://logesoft.com/loge-16/wp-content/uploads/2018/07/2018-06-19-SCC_-1.pdf CY - Aachen ER - TY - CHAP A1 - Netzer, Corinna A1 - Seidel, Lars A1 - Lehtiniemi, Harry A1 - Ravet, Frédéric A1 - Mauß, Fabian T1 - Impact of Formulation of Fuel Surrogates on Engine Knock Prediction T2 - International Multidimensional Engine Modeling User's Group Meeting at the SAE Congress, April 9th , 2018, Detroit, USA KW - Impact of Formulation of Fuel Surrogates Y1 - 2018 UR - http://www.erc.wisc.edu/imem/2018/Paper%234-Netzer%20et%20al.pdf ER - TY - CHAP A1 - Shrestha, Krishna Prasad A1 - Seidel, Lars A1 - Mauß, Fabian T1 - Kinetic study of methanol and ethanol oxidation in presence of NOx T2 - Workshop on Gas-phase reaction kinetics of biofuels oxygenated molecules KW - Gas-phase Reaction Y1 - 2018 UR - https://www.researchgate.net/publication/324731559 ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Giri, Binod Raj A1 - Elbaz, Ayman M. A1 - Issayev, Gani A1 - Roberts, William L. A1 - Seidel, Lars A1 - Mauß, Fabian A1 - Farooq, Aamir T1 - A detailed chemical insights into the kinetics of diethyl ether enhancing ammonia combustion and the importance of NOx recycling mechanism T2 - Fuel Communications N2 - In this work, we investigated the combustion characteristics of ammonia (NH3) by blending it with various proportions of diethyl ether (DEE). We measured laminar flame speed of various NH3/DEE blends (DEE, 10–40% by mole) using a constant volume spherical vessel at Ti = 298 K and Pi = 3 and 5 bar and Φ = 0.8–1.3. We developed a detailed kinetic model to describe the trends of the current and previously published experimental data. For the robustness of the model, we first developed a comprehensive diethyl ether kinetic mechanism to accurately characterize neat DEE oxidation behavior. We validated the kinetic model using a large pool of experimental data comprising shock tube, rapid compression machine, jet-stirred and flow reactors, freely propagating, and burner-stabilized premixed flames. The developed kinetic model performs remarkably in capturing the combustion behavior of pure DEE and NH3. Importantly, our model captures the experimental data of laminar flame speed and ignition delay times of various NH3/DEE blends over a wide range of conditions. We found that DEE is a promising candidate to promote the combustion characteristics of NH3. A small portion of DEE (10%) enhances the laminar flame speed of NH3 by a factor of 2 at Pi = 1 bar, Ti = 298 K, and Φ = 1.0. A further doubling of the DEE mole fraction to 20% did not enhance the laminar flame speed of NH3 with the same propensity. At low temperatures, adding 5% DEE in NH3 blend has significantly expedited the system reactivity by lowering the autoignition temperature. A further 5% increment of DEE (i.e., 10% DEE in NH3) lowers the autoignition temperature by ∼120 K to achieve the same ignition delay time. The “NOsingle bondNO2” looping mechanism predominantly drives such reactivity accelerating effect. Here, the reactions, NO + HO2 = NO2 + OH and NO2 + H = NO + OH, appear to enhance the reactive radical pool by generating OH radicals. We observed that the HNO path is favored more with increasing DEE content which eventually liberates NO. Other key reactions in “NOsingle bondNO2” looping mechanism are: CH3 + NO2 = CH3O + NO, CH3O2 + NO = CH3O + NO2, C2H5 + NO2 = C2H5O + NO, C2H5O2 + NO = C2H5O + NO2. In addition, CH3 + NH2(+M) = CH3NH2(+M) reaction is also one of the important cross-reactions which leads to the formation of HCN. Therefore, cross-reactions between the nitrogen and carbon family are crucial in accurately predicting autoignition timing. This work provides a detailed chemical insight into the NH3 and DEE interaction, which could be applied to other fuel blends of NH3. The kinetic model is also validated for several C1single bondC3 fuels including their interaction with NOx. KW - DEE KW - Ammonia KW - Kinetic Model KW - Laminar flame speed KW - Ignition delay time Y1 - 2022 U6 - https://doi.org/10.1016/j.jfueco.2022.100051 SN - 2666-0520 VL - 10 ER - TY - GEN A1 - Franken, Tim A1 - Srivastava, Vivek A1 - Lee, Sung-Yong A1 - Heuser, Benedikt A1 - Shrestha, Krishna Prasad A1 - Seidel, Lars A1 - Mauß, Fabian ED - Xandra, Margot ED - Payri, Raúl ED - Serrano, José Ramón T1 - Numerical Analysis of the Combustion of Diesel, Dimethyl Ether, and Polyoxymethylene Dimethyl Ethers (OMEn, n=1-3) Using Detailed Chemistry T2 - THIESEL 2022 : Conference on Thermo- and Fluid-Dynamics of Clean Propulsion Powerplants, 13th-16th September 2022 : conference proceedings N2 - New types of synthetic fuels are introduced in internal combustion engine applications to achieve carbon-neutral and ultra-low emission combustion. Dimethyl Ether (DME) and Polyoxymethylene Dimethyl Ethers (OMEn) belong to such kind of synthetic fuels. Recently, Shrestha et al. (2022) have developed a novel detailed chemistry model for OMEn (n=1-3) to predict the ignition delay time, laminar flame speed and species formation for various thermodynamic conditions. The detailed chemistry model is applied in the zero dimensional (0D) stochastic reactor model (DI-SRM) to investigate the non-premixed combustion in a 2-liter diesel engine. Further insights in the formation of unburned hydrocarbons (HC), carbon monoxide and nitrogen oxides during the combustion of OMEn fuels are obtained in this work. The combustion and emission formation of DME and OMEn (n=1-3) are investigated and compared to conventional Diesel combustion. The mixture formation is governed by an earlier vaporization of the DME and OMEn fuels, faster homogenization of the respective air-fuel mixture and higher reactivity. At the same injection pressure, the OMEn fuels obtain higher NOx but lower CO and HC emissions. High amounts of aromatics, ethene, methane formaldehyde and formic acid are found within the Diesel exhaust gas. The DME and OMEn exhaust gas contains higher fractions of formaldehyde and formic acid, and fractions of methane, methyl formate and nitromethane. KW - Polyoxymethylene Dimethyl Ethers KW - Stochastic Reactor Model KW - Detailed Chemistry KW - Modelling KW - Emissions Y1 - 2022 UR - https://www.lalibreria.upv.es/portalEd/UpvGEStore/products/p_6328-1-1 SN - 978-84-1396-055-5 U6 - https://doi.org/10.4995/Thiesel.2022.632801 PB - Editorial Universitat Politècnica de València CY - València ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Giri, Binod Raj A1 - Seidel, Lars A1 - Farooq, Aamir A1 - Mauß, Fabian T1 - A Kinetic Modeling Study for the Effect of NOx on Oxymethylene ethers (OMEn, n = 0 and 1) oxidation T2 - 10th European Combustion Meeting, Neapel N2 - We present a detailed kinetic model for the oxidation of dimethyl ether (OME0) and dimethoxymethane (OME1) in presence of NOx. We further explored the effect of NOx chemistry on the oxidation kinetics of the two OMEs. Our kinetic model is validated against the recent flow reactor data from Zhang et al. (Combust. Flame. 224 (2021) 94– 107). The results indicated that NO doping severely alters the oxidation kinetics of both fuels. The onset temperature for total fuel consumption is significantly shifted to lower temperatures for both fuels, which is in line with the experimental observation. We found that the addition of NO significantly inhibited the NTC behaviour of dimethyl ether. This inhibiting effect appears to stem from the competition between CH3OCH2O2 radical consumption by NO directly and the isomerization/dissociation reactions of CH3OCH2O2. Unlike dimethyl ether, dimethoxymethane does not exhibit a strong NTC behavior, and NO addition completely inhibited its weak NTC behavior. KW - DME KW - DMM KW - Oxymethylene ethers KW - NOx KW - Kinetic Modeling Y1 - 2021 UR - https://www.researchgate.net/publication/353620538_A_Kinetic_Modeling_Study_for_the_Effect_of_NOx_on_Oxymethylene_ethers_OMEn_n_0_and_1_oxidation CY - Neapel ER - TY - GEN A1 - Franken, Tim A1 - Shrestha, Krishna Prasad A1 - Seidel, Lars A1 - Mauß, Fabian ED - Sens, Marc T1 - Effect of Gasoline–Ethanol–Water Mixtures on Auto-Ignition in a Spark Ignition Engine T2 - International Conference on Knocking in Gasoline Engines N2 - The climate protection plan of the European Union requires a significant reduction of CO2 emissions from the transportation sector by 2030. Today ethanol is already blended by 10vol-% in gasoline and further increase of the ethanol content to 20vol-% is discussed. During the ethanol production process, distillation and molecular sieving is required to remove the water concentration to achieve high-purity ethanol. However, hydrous ethanol can be beneficial to suppress knock of spark ignition engines. The hygroscopic nature of ethanol can allow to increase the water content in gasoline – water emulsions even more, without adding additional surfactants, and improve the thermal efficiency by optimized combustion phasing, while keeping the system complexity low. Hence, the effect of gasoline – ethanol – water mixtures on the auto-ignition in a single-cylinder spark ignition engine is investigated by using multi-dimensional simulation and detailed chemistry. The gasoline – ethanol mixtures are defined to keep the Research Octane Number constant, while the Motored Octane Number is decreasing. In total five surrogates are defined and investigated: E10 (10vol-% ethanol-in-gasoline), E20, E30, E70 and E100. The water content is determined according to experimentally defined ternary diagrams that evaluated stable gasoline – ethanol – water emulsion at different gasoline – ethanol blending ratios. The auto-ignition modes of the surrogates are analyzed using the diagram, which determines if hotspots are within harmless deflagration or harmful developing detonation regime. The strongest auto-ignition is observed for the E10 surrogate, while increasing ethanol content reduces the surrogate reactivity and increases the resonance parameter. No auto-ignition of the unburnt mixture is observed for the E70 and E100 surrogates. The addition of hydrous ethanol decreased the excitation time of the surrogates, especially at low ethanol content, wherefor the reactivity parameter is significantly increased. The hotspots for E10, E20 and E30 surrogates with hydrous ethanol are found within the developing detonation regime, while hotspots of the E70 surrogate with hydrous ethanol are found in the transition regime. For the hydrous E100 surrogate no auto-ignition is predicted because of reduced temperature of the unburnt mixture due to water vaporization, which outweighs the increased reactivity due to water vapor addition. KW - Knock KW - Gasoline KW - Ethanol KW - Simulation KW - Detailed Chemistry KW - Spark Ignition Y1 - 2022 SN - 978-3-8169-3544-5 U6 - https://doi.org/10.24053/9783816985440 SP - 175 EP - 222 PB - expert CY - Tübingen ER - TY - GEN A1 - Franken, Tim A1 - Seidel, Lars A1 - Shrestha, Krishna Prasad A1 - Gonzalez Mestre, Laura Catalina A1 - Mauß, Fabian T1 - Multi-objective Optimization of Gasoline, Ethanol, and Methanol in Spark Ignition Engines N2 - In this study, an engine and fuel co-optimization is performed to improve the efficiency and emissions of a spark ignition engine utilizing detailed reaction mechanisms and stochastic combustion modelling. The reaction mechanism for gasoline surrogates (Seidel 2017), ethanol, and methanol (Shrestha et al. 2019) is validated for experiments at different thermodynamic conditions. Liquid thermophysical properties of the RON95E10 surrogate (iso-octane, n-heptane, toluene, and ethanol mixture), ethanol, and methanol are determined using the NIST standard reference database (NIST 2018) and Yaws database (Yaws 2014). The combustion chemistry, laminar flame speed, and thermophysical data are pre-compiled in look-up tables to speed up the simulations (tabulated chemistry). The auto-ignition in the stochastic reactor model is predicted by the detailed chemistry and subsequently evaluated using the Bradley Detonation Diagram (Bradley et al. 2002, Gu et al. 2003, Neter 2019), which assigns two dimensionless parameters (resonance parameter and reactivity parameter). According to the defined developing detonation limits, the auto-ignition is either in deflagration, sub-sonic auto-ignition, or developing detonation mode. Ethanol and methanol show a knock-reducing characteristic, which is mainly due to the high heat of vaporization. The multi-objective optimization process includes mathematical algorithms for design space exploration with Uniform Latin Hypercube, pareto front convergence with Non-dominated Sorting Genetic Algorithm II (NSGA-II), and multi-criteria decision making (Deb et al. 2002). The optimization input parameter ranges are selected according to the previous sensitivity analysis, and the objectives are to minimize specific CO2 and specific CO and maximize indicated efficiency. The performance study of different optimization algorithms shows that the incorporation of metamodels is beneficial to improve the design space exploration, while keeping the optimization duration low. The comparison of different reaction mechanisms, which are applied in the optimization process, shows a strong impact on the pareto front solutions. This is due to differences in the emission formation and auto-ignition between the different reaction schemes. Overall, the engine efficiency is increased by 3.5 % points, and specific CO2 emissions are reduced by 99 g/kWh for ethanol and 142 g/kWh for methanol combustion compared to the base case. This is achieved by advanced spark timing, lean combustion, and reduced C:H ratio of ethanol and methanol in relation to RON95E10. KW - Optimization KW - Methanol KW - Ethanol KW - Spark Ignition Engine KW - Gasoline KW - Simulation Y1 - 2021 UR - https://www.researchgate.net/publication/351688526_Multi-objective_Optimization_of_Gasoline_Ethanol_and_Methanol_in_Spark_Ignition_Engines ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Seidel, Lars A1 - Zeuch, Thomas A1 - Moréac, Gladys A1 - Dagaut, Philippe A1 - Mauß, Fabian T1 - On the implications of nitromethane – NOx chemistry interactions for combustion processes T2 - Fuel N2 - 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. KW - Nitromethane KW - NOx KW - Fuel-NOx KW - Kinetic modeling KW - EGR Y1 - 2021 UR - https://www.sciencedirect.com/science/article/pii/S001623612032857X#! U6 - https://doi.org/10.1016/j.fuel.2020.119861 SN - 0016-2361 VL - 289 ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Giri, Binod Raj A1 - Adil, Mohammad A1 - Seidel, Lars A1 - Zeuch, Thomas A1 - Farooq, Aamir A1 - Mauß, Fabian T1 - Detailed Chemical Kinetic Study of Acetaldehyde Oxidation and Its Interaction with NOx T2 - Energy & fuels N2 - This work entails a detailed modeling and experimental study for the oxidation kinetics of acetaldehyde (CH3CHO) and its interaction with NOx. The ignition behavior of CH3CHO/O2/Ar has been investigated in a shock tube over the temperature range of 1149 to 1542 K, with equivalence ratios of 0.5 and 1.0 and pressures near 1.2 bar. Absorbance−time profiles of acetaldehyde were recorded using a mid-IR laser during the autoignition measurements. A comprehensive kinetic model has been developed to quantitatively predict the oxidation of acetaldehyde and its interaction with NOx. The kinetic model has been validated using experimental data of this work and available literature data from shock tube, plug flow, and jet-stirred reactors, freely propagating, and burner-stabilized premixed flames. For better accuracy of the kinetic model, the thermochemistry of 14 important species in the acetaldehyde submechanism was calculated using ab initio methods. The heat of formation of these species was computed using atomization and isodesmic reaction schemes. For the first time, this modeling study examines the effect of NO on acetaldehyde oxidation behavior over a wide range of experimental conditions. In most cases, the proposed kinetic model captures the experimental trends remarkably well. Interestingly, the doping of NO in CH3CHO did not perturb the NTC behavior of CH3CHO in contrast to other fuels, such as n-heptane and dimethyl ether. However, for flow reactor conditions at 1 atm, doping with 504 ppm of NO was found to promote the reactivity of acetaldehyde by lowering the onset temperature for CH3CHO oxidation by ∼140 K. The hydroxyl radical is the main cause of this shift, which originates from the NO + HO2 = OH + NO2 reaction. Further evolution of hydroxyl radicals occurs via the “NO−NO2” looping mechanism and expedites the reactivity of the system. This experimental and modeling work sheds new light on acetaldehyde oxidation behavior and its interaction with NOx under combustion-relevant conditions. KW - NOx KW - Kinetic modeling KW - Acetaldehyde KW - Ignition delay time Y1 - 2021 UR - https://pubs.acs.org/doi/10.1021/acs.energyfuels.1c01948?ref=pdf U6 - https://doi.org/10.1021/acs.energyfuels.1c01948 SN - 1520-5029 SN - 0887-0624 VL - 35 IS - 18 SP - 14963 EP - 14983 ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Vin, Nicolas A1 - Herbinet, Olivier A1 - Seidel, Lars A1 - Battin-Leclerc, Frédérique A1 - Zeuch, Thomas A1 - Mauß, Fabian T1 - Insights into nitromethane combustion from detailed kinetic modeling – Pyrolysis experiments in jet-stirred and flow reactors T2 - Fuel N2 - 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. Mole fraction profiles of major products and of intermediates were identified with gas chromatography and Fourier transform infrared spectroscopy. Using these experimental data, as well as published ones, 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 present 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. However, for pyrolysis conditions, future work is desirable to improve predictions of intermediate species. This work extends the kinetic database and helps to improve the understanding of nitromethane chemistry. The kinetic model presented in this work can serve as a base model for hydrocarbons and oxygenated fuels higher than C2 and nitrogen-containing compounds higher than C1 as well as for pure nitrogen compounds. Y1 - 2020 UR - https://www.sciencedirect.com/science/article/pii/S001623611931703X#! U6 - https://doi.org/https://doi.org/10.1016/j.fuel.2019.116349 SN - 0016-2361 VL - 261 ER - TY - GEN A1 - Netzer, Corinna A1 - Pasternak, Michal A1 - Seidel, Lars A1 - Ravet, Frédéric A1 - Mauß, Fabian T1 - Computationally efficient prediction of cycle-to-cycle variations in spark-ignition engines T2 - International Journal of Engine Research N2 - Cycle-to-cycle variations are important to consider in the development of spark-ignition engines to further increase fuel conversion efficiency. Direct numerical simulation and large eddy simulation can predict the stochastics of flows and therefore cycle-to-cycle variations. However, the computational costs are too high for engineering purposes if detailed chemistry is applied. Detailed chemistry can predict the fuels’ tendency to auto-ignite for different octane ratings as well as locally changing thermodynamic and chemical conditions which is a prerequisite for the analysis of knocking combustion. In this work, the joint use of unsteady Reynolds-averaged Navier–Stokes simulations for the analysis of the average engine cycle and the spark-ignition stochastic reactor model for the analysis of cycle-to-cycle variations is proposed. Thanks to the stochastic approach for the modeling of mixing and heat transfer, the spark-ignition stochastic reactor model can mimic the randomness of turbulent flows that is missing in the Reynolds-averaged Navier–Stokes modeling framework. The capability to predict cycle-to-cycle variations by the spark-ignition stochastic reactor model is extended by imposing two probability density functions. The probability density function for the scalar mixing time constant introduces a variation in the turbulent mixing time that is extracted from the unsteady Reynolds-averaged Navier–Stokes simulations and leads to variations in the overall mixing process. The probability density function for the inflammation time accounts for the delay or advancement of the early flame development. The combination of unsteady Reynolds-averaged Navier–Stokes and spark-ignition stochastic reactor model enables one to predict cycle-to-cycle variations using detailed chemistry in a fraction of computational time needed for a single large eddy simulation cycle. Y1 - 2020 U6 - https://doi.org/10.1177/1468087419856493 SN - 2041-3149 SN - 1468-0874 VL - 21 IS - 4 SP - 649 EP - 663 ER - TY - GEN A1 - Netzer, Corinna A1 - Seidel, Lars A1 - Ravet, Frédéric A1 - Mauß, Fabian T1 - Assessment of the validity of RANS knock prediction using the resonance theory T2 - International Journal of Engine Research N2 - Following the resonance theory by Bradley and co-workers, engine knock is a consequence of an auto-ignition in the developing detonation regime. Their detonation diagram was developed using direct numerical simulations and was applied in the literature to engine knock assessment using large eddy simulations. In this work, it is analyzed if the detonation diagram can be applied for post-processing and evaluation of predicted auto-ignitions in Reynolds-averaged Navier–Stokes simulations even though the Reynolds-averaged Navier–Stokes approach cannot resolve the fine structures resolved in direct numerical simulations and large eddy simulations that lead to the prediction of a developing detonation. For this purpose, an engine operating point at the knock limit spark advance is simulated using Reynolds-averaged Navier–Stokes and large eddy simulations. The combustion is predicted using the G-equation and the well-stirred reactor model in the unburnt gases based on a detailed gasoline surrogate reaction scheme. All the predicted ignition kernels are evaluated using the resonance theory in a post-processing step. According to the different turbulence models, the predicted pressure rise rates and gradients differ. However, the predicted ignition kernel sizes and imposed gas velocities by the auto-ignition event are similar, which suggests that the auto-ignitions predicted by Reynolds-averaged Navier–Stokes simulations can be given a meaningful interpretation within the detonation diagram. Y1 - 2020 U6 - https://doi.org/10.1177/1468087419846032 SN - 2041-3149 SN - 1468-0874 VL - 21 IS - 4 SP - 610 EP - 621 ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Eckart, Sven A1 - Elbaz, Ayman M. A1 - Giri, Binod Raj A1 - Fritsche, Chris A1 - Seidel, Lars A1 - Roberts, William L. A1 - Krause, Hartmut A1 - Mauß, Fabian T1 - A comprehensive kinetic model for dimethyl ether and dimethoxymethane oxidation and NOx interaction utilizing experimental laminar flame speed measurements at elevated pressure and temperature T2 - Combustion and Flame N2 - 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. This study is the first to report dimethoxymethane laminar flame speeds at a pressure higher than 1 bar. Using these 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. KW - Dimethyl ether KW - Dimethoxymethane KW - Laminar flame speed KW - Kinetic modeling KW - NOx Y1 - 2020 U6 - https://doi.org/10.1016/j.combustflame.2020.04.016 SN - 1556-2921 VL - 218 SP - 57 EP - 74 ER - TY - GEN A1 - Franken, Tim A1 - Mauß, Fabian A1 - Seidel, Lars A1 - Gern, Maike Sophie A1 - Kauf, Malte A1 - Matrisciano, Andrea A1 - Kulzer, Andre Casal T1 - Gasoline engine performance simulation of water injection and low-pressure exhaust gas recirculation using tabulated chemistry T2 - International Journal of Engine Research N2 - This work presents the assessment of direct water injection in spark-ignition engines using single cylinder experiments and tabulated chemistry-based simulations. In addition, direct water injection is compared with cooled low-pressure exhaust gas recirculation at full load operation. The analysis of the two knock suppressing and exhaust gas cooling methods is performed using the quasi-dimensional stochastic reactor model with a novel dual fuel tabulated chemistry model. To evaluate the characteristics of the autoignition in the end gas, the detonation diagram developed by Bradley and coworkers is applied. The single cylinder experiments with direct water injection outline the decreasing carbon monoxide emissions with increasing water content, while the nitrogen oxide emissions indicate only a minor decrease. The simulation results show that the engine can be operated at l = 1 at full load using water–fuel ratios of up to 60% or cooled low-pressure exhaust gas recirculation rates of up to 30%. Both technologies enable the reduction of the knock probability and the decrease in the catalyst inlet temperature to protect the aftertreatment system components. The strongest exhaust temperature reduction is found with cooled low-pressure exhaust gas recirculation. With stoichiometric air–fuel ratio and water injection, the indicated efficiency is improved to 40% and the carbon monoxide emissions are reduced. The nitrogen oxide concentrations are increased compared to the fuel-rich base operating conditions and the nitrogen oxide emissions decrease with higher water content. With stoichiometric air–fuel ratio and exhaust gas recirculation, the indicated efficiency is improved to 43% and the carbon monoxide emissions are decreased. Increasing the exhaust gas recirculation rate to 30% drops the nitrogen oxide emissions below the concentrations of the fuel-rich base operating conditions. KW - Water Injection KW - Exhaust Gas Recirculation KW - Efficiency KW - Spark Ignition Engine KW - Stochastic Reactor Model KW - Emissions Y1 - 2020 UR - https://journals.sagepub.com/doi/abs/10.1177/1468087420933124 U6 - https://doi.org/10.1177/1468087420933124 SN - 2041-3149 SN - 1468-0874 VL - 21 IS - 10 SP - 1857 EP - 1877 ER - TY - GEN A1 - Franken, Tim A1 - Seidel, Lars A1 - Matrisciano, Andrea A1 - Mauß, Fabian A1 - Kulzer, Andre Casal A1 - Schuerg, Frank T1 - Analysis of the Water Addition Efficiency on Knock Suppression for Different Octane Ratings T2 - SAE World Congress N2 - Water injection can be applied to spark ignited gasoline engines to increase the Knock Limit Spark Advance and improve the thermal efficiency. The Knock Limit Spark Advance potential of 6 °CA to 11 °CA is shown by many research groups for EN228 gasoline fuel using experimental and simulation methods. The influence of water is multi-layered since it reduces the in-cylinder temperature by vaporization and higher heat capacity of the fresh gas, it changes the chemical equilibrium in the end gas and increases the ignition delay and decreases the laminar flame speed. The aim of this work is to extend the analysis of water addition to different octane ratings. The simulation method used for the analysis consists of a detailed reaction scheme for gasoline fuels, the Quasi-Dimensional Stochastic Reactor Model and the Detonation Diagram. The detailed reaction scheme is used to create the dual fuel laminar flame speed and combustion chemistry look-up tables. The Detonation Diagram is used as a novel approach in the Quasi-Dimensional Stochastic Reactor Model to evaluate the auto-ignition characteristic in the end gas and determine if it is a harmless deflagration or developing detonation. First, the Quasi-Dimensional Stochastic Reactor Model is trained for three engine operating points and a RON95 E10 fuel. Its performance is evaluated based on experimental results of a single cylinder research engine. Subsequently, different spark timings and water-fuel ratios are investigated for different Primary Reference Fuels. The results outline that water addition can effectively reduce the strength of auto-ignition in the end gas for different Primary Reference Fuels. Thereby, it can be stated that the reduction of the auto-ignition strength through water addition by 50 – 80 % water-fuel ratio for high octane number fuels corresponds to the spark timing delay of 6 °CA or an increase of research octane number by 10 points. KW - Gasoline KW - Knock KW - Water KW - Engines KW - Combustion KW - Simulation Y1 - 2020 U6 - https://doi.org/10.4271/2020-01-0551 SN - 2688-3627 SN - 0148-7191 ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Lhuillier, Charles A1 - Barbosa, Amanda Alves A1 - Brequigny, Pierre A1 - Contino, Francesco A1 - Mounaïm-Rousselle, Christine A1 - Seidel, Lars A1 - Mauß, Fabian T1 - An experimental and modeling study of ammonia with enriched oxygen content and ammonia/hydrogen laminar flame speed at elevated pressure and temperature T2 - Proceedings of the Combustion Institute N2 - 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. Moreover, ammonia laminar flame speeds with helium as an inert were measured for the first time. Using these experimental data along with published ones, 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. The most important reactions under rich conditions are: NH2+NH=N2H2+H, NH2+NH2=N2H2+H2, N2H2+H=NNH+H2 and N2H2+M=NNH+H+M. These reactions were also found to be among the most sensitive reactions for predicting the laminar flame speed for all the cases investigated. KW - Ammonia KW - Laminar flame speed KW - Kinetic modeling KW - Ammonia-hydrogen KW - NOx Y1 - 2020 UR - https://www.sciencedirect.com/science/article/pii/S1540748920302881#! U6 - https://doi.org/10.1016/j.proci.2020.06.197 SN - 1540-7489 VL - 2020 SP - 1 EP - 12 ER - TY - GEN A1 - Netzer, Corinna A1 - Li, Tian A1 - Seidel, Lars A1 - Mauß, Fabian A1 - Løvås, Terese T1 - Stochastic Reactor-Based Fuel Bed Model for Grate Furnaces T2 - Energy & Fuels N2 - Biomass devolatilization and incineration in grate-fired plants are characterized by heterogeneous fuel mixtures, often incompletely mixed, dynamical processes in the fuel bed and on the particle scale, as well as heterogeneous and homogeneous chemistry. This makes modeling using detailed kinetics favorable but computationally expensive. Therefore, a computationally efficient model based on zero-dimensional stochastic reactors and reduced chemistry schemes, consisting of 83 gas-phase species and 18 species for surface reactions, is developed. Each reactor is enabled to account for the three phases: the solid phase, pore gas surrounding the solid, and the bulk gas. The stochastic reactors are connected to build a reactor network that represents the fuel bed in grate-fired furnaces. The use of stochastic reactors allows us to account for incompletely mixed fuel feeds, distributions of local temperature and local equivalence ratio within each reactor and the fuel bed. This allows us to predict the released gases and emission precursors more accurately than if a homogeneous reactor network approach was employed. The model approach is demonstrated by predicting pyrolysis conditions and two fuel beds of grate-fired plants from the literature. The developed approach can predict global operating parameters, such as the fuel bed length, species release to the freeboard, and species distributions within the fuel bed to a high degree of accuracy when compared to experiments. Y1 - 2020 UR - https://pubs.acs.org/doi/full/10.1021/acs.energyfuels.0c02868 U6 - https://doi.org/10.1021/acs.energyfuels.0c02868 SN - 1520-5029 VL - 34 IS - 12 SP - 16599 EP - 16612 ER - TY - GEN A1 - Netzer, Corinna A1 - Seidel, Lars A1 - Ravet, Frédéric A1 - Mauß, Fabian T1 - Impact of the surrogate formulation on 3D CFD engine knock prediction using detailed chemistry T2 - Fuel N2 - For engine knock prediction, surrogate fuels are often composed of iso-octane and n-heptane since they are the components of the Primary Reference Fuel (PRF). By definition, a PRF has no octane sensitivity (S = RON-MON). However, for a commercial gasoline fuel holds RON > MON and therefor S > 0. More complex surrogates are Toluene Reference Fuels (TRF) and Ethanol containing Toluene Reference Fuels (ETRF). In this work, the impact of the surrogate formulation on the prediction of flame propagation and auto-ignition in the unburnt gases are investigated. The surrogates are composed such that the Research Octane Number is the same. The auto-ignition events ahead of the flame front are predicted using 3D CFD and a combustion model based on the ETRF mechanism by Seidel (2017). The strength of the auto-ignition is determined using the detonation diagram by Bradley and co-workers (2002, 2003). Applying the different surrogates, ignition kernels of different size and reactivity are predicted. The results indicate a dependency on the local temperature history and the low temperature chemistry of the fuel species. The comparison of homogenous constant volume reactor and transient simulations show that the analysis of ignition delay time and octane rating solely from homogenous simulations is not sufficient if the knock tendency of a surrogate in engine simulations needs to be characterized. Y1 - 2019 U6 - https://doi.org/10.1016/j.fuel.2019.115678 SN - 1873-7153 VL - Volume 254 ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Seidel, Lars A1 - Zeuch, Thomas A1 - Mauß, Fabian T1 - Kinetic Modeling of NOx Formation and Consumption during Methanol and Ethanol Oxidation T2 - Combustion Science and Technology KW - Kinetic Modeling of NOx Formation Y1 - 2019 U6 - https://doi.org/10.1080/00102202.2019.1606804 SN - 1563-521X VL - 191 IS - 9 SP - 1628 EP - 1660 ER - TY - GEN A1 - Franken, Tim A1 - Netzer, Corinna A1 - Mauß, Fabian A1 - Pasternak, Michal A1 - Seidel, Lars A1 - Borg, Anders A1 - Lehtiniemi, Harry A1 - Matrisciano, Andrea A1 - Kulzer, André Casal T1 - Multi-objective optimization of water injection in spark-ignition engines using the stochastic reactor model with tabulated chemistry T2 - International Journal of Engine Research N2 - Water injection is investigated for turbocharged spark-ignition engines to reduce knock probability and enable higher engine efficiency. The novel approach of this work is the development of a simulation-based optimization process combining the advantages of detailed chemistry, the stochastic reactor model and genetic optimization to assess water injection. The fast running quasi-dimensional stochastic reactor model with tabulated chemistry accounts for water effects on laminar flame speed and combustion chemistry. The stochastic reactor model is coupled with the Non-dominated Sorting Genetic Algorithm to find an optimum set of operating conditions for high engine efficiency. Subsequently, the feasibility of the simulation-based optimization process is tested for a three-dimensional computational fluid dynamic numerical test case. The newly proposed optimization method predicts a trade-off between fuel efficiency and low knock probability, which highlights the present target conflict for spark-ignition engine development. Overall, the optimization shows that water injection is beneficial to decrease fuel consumption and knock probability at the same time. The application of the fast running quasi-dimensional stochastic reactor model allows to run large optimization problems with low computational costs. The incorporation with the Non-dominated Sorting Genetic Algorithm shows a well performing multi-objective optimization and an optimized set of engine operating parameters with water injection and high compression ratio is found. KW - Water Injection KW - Genetic Optimization KW - Spark Ignition Engine KW - Stochastic Reactor Model KW - Detailed Chemistry Y1 - 2019 UR - https://journals.sagepub.com/doi/full/10.1177/1468087419857602 U6 - https://doi.org/10.1177/1468087419857602 SN - 2041-3149 VL - 20 IS - 10 SP - 1089 EP - 1100 ER - TY - GEN A1 - León, Larisa A1 - Ruwe, Lena A1 - Moshammer, Kai A1 - Seidel, Lars A1 - Shrestha, Krishna Prasad A1 - Wang, Xiaoxiao A1 - Mauß, Fabian A1 - Kohse-Höinghaus, Katharina A1 - Hansen, Nils T1 - Chemical insights into the larger sooting tendency of 2-methyl-2-butene compared to n-pentane T2 - Combustion and Flame N2 - A comprehensive, chemically detailed mechanism for the combustion of 2-methyl-2-butene and n-pentane is presented to provide insights into the different sooting tendencies of these two structurally different C5 hydrocarbons. 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 partially isomer-resolved chemical composition of this flame was determined using flame-sampling molecular-beam mass spectrometry with single-photon ionization by tunable, synchrotron-generated vacuum-ultraviolet radiation. 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. KW - 2-Methyl-2-butene KW - n-Pentane KW - Laminar premixed flames KW - Molecular-beam mass spectrometry KW - Kinetic modeling KW - PAH formation Y1 - 2019 UR - https://www.sciencedirect.com/science/article/abs/pii/S0010218019302883#! U6 - https://doi.org/10.1016/j.combustflame.2019.06.029 SN - 0010-2180 VL - 208 SP - 182 EP - 197 ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Seidel, Lars A1 - Zeuch, Thomas A1 - Mauß, Fabian T1 - Modeling for Nitromethane oxidation T2 - 1st International Conference on Smart Energy Carriers Napoli, 2019 N2 - The diminishing availability of conventional fuels and stricter regulations on pollution control and CO2 emission targets have led scientist and engineers to look for alternative fuels. Recently nitromethane has slowly gained interest as alternative fuel over conventional fuel for internal combustion engines. In the past, it was mostly used as rocket propellant or as an explosives [1,2]. Nitromethane is an energetic compound with a wide variety of applications, including its use as a monopropellant, a liquid explosive, a solvent for chemical processing and analysis, and a highperformance fuel additive for internal combustion engines and pulsed detonation engines [3]. The chemical formula of nitromethane is CH3NO2. As the name suggests, the molecule is essentially methane with one of the four hydrogens replaced by a nitro group. In essence, it is the simplest of possible energetic CHON molecules that contain nitro groups, which is why it is often used in reaction studies as a prototype for more complex energetic materials. There is no reliable kinetic model for nitromethane combustion, which is validated over a wide range of experimental conditions. There are a few published studies [4–8] both numerically and experimentally focusing often on a single reactor at very specific conditions. The aim of the present work is to extend our recently published mechanism [9] for syngas, methane and ammonia oxidation to include CH3NO2 as fuel and validate against the available experimental data from the literature. The development and compilation strategy for our mechanism is described in our recent work [9] and this study is conducted in a similar manner. Rates are taken mainly from [7,10–16]. This makes the kinetic model more robust and reliable for combustion modelling. Y1 - 2019 UR - http://logesoft.com/loge-16/wp-content/uploads/2019/01/Abstract_1stICSEC_SMARTCATs_Napoli_Shrestha-et-al_2018-11-28.pdf ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Seidel, Lars A1 - Zeuch, Thomas A1 - Mauß, Fabian T1 - Modeling of NOx Formation and Consumption during Oxidation of Small Alcohols T2 - 9th European Combustion Meeting, Proceedings of the European Combustion Meeting N2 - This work presents a newly developed kinetic mechanism extending our recent work (Shrestha et al. [1]) for the oxidation of methanol and ethanol and their fuel interaction with NO x chemistry in jet-stirred reactors, flow reactors, and burner-stabilized premixed flames. The work mainly focuses on fuel interaction with nitrogen chemistry and NO formation in laminar premixed flames. It is found that for methanol oxidation in jet-stirred reactor doping of the fuel blends with NO increase the reactivity of the system by increasing the net production of OH radicals. The increased amount of OH is formed via NO/NO 2 interconversion reaction channels NO+HO 2 ⇋NO 2 +OH, NO 2 +H⇋NO+OH, NO 2 +HO 2 ⇋HONO+O 2, followed by the thermal decomposition of HONO producing NO and OH. In burner-stabilized premixed flames studied here for methanol/air and ethanol/air, NO is mainly formed via the NCN route (CH+N 2 ⇋NCN+H) and minor contribution comes from the NNH route (NNN⇋N 2 +H). Y1 - 2019 UR - https://hal.archives-ouvertes.fr/hal-02334906 ER - TY - GEN A1 - Netzer, Corinna A1 - Franken, Tim A1 - Lehtiniemi, Harry A1 - Mauß, Fabian A1 - Seidel, Lars T1 - Numerical Analysis of the Impact of Water Injection on Combustion and Thermodynamics in a Gasoline Engine using Detailed Chemistry T2 - SAE technical papers Y1 - 2018 U6 - https://doi.org/10.4271/2018-01-0200 SN - 0148-7191 SN - 0096-5170 IS - 2018-01-0200 ER - TY - GEN A1 - Franken, Tim A1 - Netzer, Corinna A1 - Pasternak, Michal A1 - Mauß, Fabian A1 - Seidel, Lars A1 - Matrisciano, Andrea A1 - Borg, Anders A1 - Lehtiniemi, Harry A1 - Kulzer, André Casal T1 - Simulation of Spark-Ignited Engines with Water Injection using the Stochastic Reactor Model, 37th International Symposium on Combustion Y1 - 2018 UR - https://www.researchgate.net/publication/328265636 ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Seidel, Lars A1 - Zeuch, Thomas A1 - Mauß, Fabian T1 - Detailed Kinetic Mechanism for the Oxidation of Ammonia Including the Formation and Reduction of Nitrogen Oxides T2 - Energy & Fuels N2 - This work introduces a newly developed reaction mechanism for the oxidation of ammonia in freely propagating and burner-stabilized premixed flames as well as shock-tube, jet-stirred reactor, and plug-flow reactor experiments. The paper mainly focuses on pure ammonia and ammonia–hydrogen fuel blends. The reaction mechanism also considers the formation of nitrogen oxides as well as the reduction of nitrogen oxides depending upon the conditions of the surrounding gas phase. Doping of the fuel blend with NO2 can result in acceleration of H2 autoignition via the reaction NO2 + HO2 ⇋ HONO + O2, followed by the thermal decomposition of HONO, or deceleration of H2 oxidation via NO2 + OH ⇋ NO + HO2. The concentration of HO2 is decisive for the active reaction pathway. The formation of NO in burner-stabilized premixed flames is shown to demonstrate the capability of the mechanism to be integrated … KW - Energy & Fuels Y1 - 2018 U6 - https://doi.org/10.1021/acs.energyfuels.8b01056 SN - 1520-5029 SN - 0887-0624 VL - 32 IS - 10 SP - 10202 EP - 10217 ER - TY - GEN A1 - Netzer, Corinna A1 - Seidel, Lars A1 - Pasternak, Michal A1 - Lehtiniemi, Harry A1 - Perlman, Cathleen A1 - Ravet, Frédéric A1 - Mauß, Fabian T1 - Three-dimensional computational fluid dynamics engine knock prediction and evaluation based on detailed chemistry and detonation theory T2 - International Journal of Engine Research N2 - Engine knock is an important phenomenon that needs consideration in the development of gasoline-fueled engines. In our days, this development is supported using numerical simulation tools to further understand and predict in-cylinder processes. In this work, a model tool chain which uses a detailed chemical reaction scheme is proposed to predict the auto-ignition behavior of fuels with different octane ratings and to evaluate the transition from harmless auto-ignitive deflagration to knocking combustion. In our method, the auto-ignition characteristics and the emissions are calculated using a gasoline surrogate reaction scheme containing pathways for oxidation of ethanol, toluene, n-heptane, iso-octane and their mixtures. The combustion is predicted using a combination of the G-equation based flame propagation model utilizing tabulated laminar flame speeds and well-stirred reactors in the burned and … KW - Engine knock is an important phenomenon Y1 - 2018 U6 - https://doi.org/10.1177/1468087417740271 SN - 1468-0874 SN - 2041-3149 VL - 19 IS - 1 SP - 33 EP - 44 ER - TY - GEN A1 - Werner, Adina A1 - Netzer, Corinna A1 - Lehtiniemi, Harry A1 - Borg, Anders A1 - Matrisciano, Andrea A1 - Seidel, Lars A1 - Mauß, Fabian T1 - A Computationally Efficient Combustion Progress Variable (CPV) Approach for Engine Applications KW - (CPV) Approach for Engine Applications Y1 - 2018 U6 - https://doi.org/10.13140/RG.2.2.15334.27209 ER - TY - GEN A1 - Werner, Adina A1 - Matrisciano, Andrea A1 - Netzer, Corinna A1 - Lehtiniemi, Harry A1 - Borg, Anders A1 - Seidel, Lars A1 - Mauß, Fabian T1 - Further Application of the Fast Tabulated CPV Approach Y1 - 2018 UR - https://www.researchgate.net/publication/330737537 U6 - https://doi.org/10.13140/RG.2.2.18689.71529 N1 - 1st International Conference on Smart Energy Carriers ER - TY - GEN A1 - Weber, Kathrin A1 - Li, T. A1 - Løvås, Terese A1 - Perlman, Cathleen A1 - Seidel, Lars A1 - Mauß, Fabian T1 - Stochastic reactor modeling of biomass pyrolysis and gasification T2 - Journal of analytical and applied pyrolysis N2 - Abstract In this paper, a partially stirred stochastic reactor model is presented as an alternative for the modeling of biomass pyrolysis and gasification. Instead of solving transport equations in all spatial dimensions as in CFD simulations, the description of state variables and mixing processes is based on a probability density function, making this approach computationally efficient. The virtual stochastic particles, an ensemble of flow elements consisting of porous solid biomass particles and surrounding gas, mimic the turbulent exchange of heat and mass in practical systems without the computationally expensive resolution of spatial dimensions. Each stochastic particle includes solid phase, pore gas and bulk gas interaction. The reactor model is coupled with a chemical mechanism for both surface and gas phase reactions. A Monte Carlo algorithm with operator splitting … KW - Pyrolysis KW - gasification KW - Stochastic reactor modeling Y1 - 2017 U6 - https://doi.org/10.1016/j.jaap.2017.01.003 SN - 0165-2370 VL - 124 SP - 592 EP - 601 ER - TY - GEN A1 - Seidel, Lars A1 - Netzer, Corinna A1 - Hilbig, Martin A1 - Mauß, Fabian A1 - Klauer, Christian A1 - Pasternak, Michal A1 - Matrisciano, Andrea T1 - Systematic reduction of detailed chemical reaction mechanisms for engine applications T2 - Journal of Engineering for Gas Turbines and Power N2 - 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 computational fluid dynamics 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. KW - Reaction Mechanism Reduction KW - Engine Modelling Y1 - 2017 U6 - https://doi.org/10.1115/1.4036093 SN - 1528-8919 SN - 0742-4795 VL - 139 IS - 9 SP - 091701-1 EP - 091701-9 ER - TY - GEN A1 - Netzer, Corinna A1 - Seidel, Lars A1 - Pasternak, Michal A1 - Klauer, Christian A1 - Perlman, Cathleen A1 - Ravet, Frédéric A1 - Mauß, Fabian T1 - Engine Knock Prediction and Evaluation Based on Detonation Theory Using a Quasi-Dimensional Stochastic Reactor Mode T2 - SAE technical paper KW - Engine Knock Prediction and Evaluation Based Y1 - 2017 U6 - https://doi.org/10.4271/2017-01-0538 SN - 0096-5170 SN - 0148-7191 IS - 2017-01-0538 SP - 11 Seiten ER - TY - CHAP A1 - Netzer, Corinna A1 - Seidel, Lars A1 - Pasternak, Michal A1 - Mauß, Fabian A1 - Lehtiniemi, Harry A1 - Perlman, Cathleen A1 - Ravet, Frédéric ED - Leipertz, Alfred ED - Fröba, Andreas Paul T1 - 3D CFD Engine Knock Predication and Evaluation Based on Detailed Chemistry and Detonation Theory T2 - Motorische Verbrennung : aktuelle Probleme und moderne Lösungsansätze, XIII. Tagung im Haus der Technik Ludwigsburg, 16.-17. März 2017 KW - 3D CFD Engine Knock Y1 - 2017 SN - 978-3-945806-08-1 PB - ESYTEC Energie- und Systemtechnik GmbH CY - Erlangen ER - TY - CHAP A1 - Netzer, Corinna A1 - Seidel, Lars A1 - Pasternak, Michal A1 - Klauer, Christian A1 - Perlman, Cathleen A1 - Ravet, Frédéric A1 - Mauß, Fabian T1 - Impact of Gasoline Octane Rating on Engine Knock using Detailed Chemistry and a Quasi-dimensional Stochastic Reaktior Model T2 - Digital Proceedings of the 8th European Combustion Meeting (ECM 2017), Dubrovnik, Croatia Y1 - 2017 UR - https://www.researchgate.net/publication/319059022 SP - 493 EP - 498 ER - TY - CHAP A1 - Netzer, Corinna A1 - Seidel, Lars A1 - Lehtiniemi, Harry A1 - Ravet, Frédéric A1 - Mauß, Fabian T1 - Efficient tracking of knock onset for a wide range of fuel surrogates T2 - International Multidimensional Engine Modeling User's Group Meeting at the SAE Congress KW - Efficient tracking of knock Y1 - 2017 UR - https://www.researchgate.net/publication/319137036 ER - TY - GEN A1 - Moshammer, Kai A1 - Seidel, Lars A1 - Wang, Yu A1 - Selim, Hatem A1 - Sarathy, S. Mani A1 - Mauß, Fabian A1 - Hansen, Nils T1 - Aromatic ring formation in opposed-flow diffusive 1, 3-butadiene flames T2 - Proceedings of the Combustion Institute N2 - This paper is concerned with the formation of one-and two-ring aromatic species in near atmospheric-pressure opposed-flow diffusion flames of 1, 3-butadiene (1, 3-C 4 H 6). The chemical structures of two different 1, 3-C 4 H 6/Ar–O 2/Ar flames were explored using flame-sampling molecular-beam mass spectrometry with both electron and single-photon ionization. We provide mole fraction profiles 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 … KW - formation of one-and two-ring aromatic species Y1 - 2017 U6 - https://doi.org/10.1016/j.proci.2016.09.010 SN - 1540-7489 VL - 36 IS - 1 SP - 947 EP - 955 ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Seidel, Lars A1 - Mauß, Fabian A1 - Zeuch, Thomas T1 - Kinetic Modeling for NOx prediction with improved base Chemistry T2 - COST 1404, SMARTCATs, Chemistry of smart energy carriers and technologies, 3rd General Meeting and Workshop on SECs in Industry of SMARTCATs Action KW - COST 1404, SMARTCATs, Chemistry of smart energy carriers and technologies, 3rd General Meeting and Workshop on SECs in Industry of SMARTCATs Action Y1 - 2017 UR - http://www.smartcats.eu/wp-content/uploads/2017/10/AM3_02_01.pdf ER - TY - CHAP A1 - Seidel, Lars A1 - Netzer, Corinna A1 - Hilbig, Martin A1 - Mauß, Fabian A1 - Klauer, Christian A1 - Pasternak, Michal A1 - Matrisciano, Andrea T1 - Systematic Reduction of Detailed Chemical Reaction Mechanisms for Engine Applications T2 - ASME 2016 Internal Combustion Engine Division Fall Technical Conference Greenville, South Carolina, USA, October 9–12, 2016 N2 - 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 (SRM) 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. KW - Systematic Reduction KW - Chemical Reaction Mechanismus for Engine Applications Y1 - 2016 SN - 978-0-7918-5050-3 N1 - Paper No. ICEF2016-9304 PB - The American Society of Mechanical Engineers CY - New York, N.Y. ER - TY - CHAP A1 - Matrisciano, Andrea A1 - Borg, Anders A1 - Perlman, Cathleen A1 - Pasternak, Michal A1 - Seidel, Lars A1 - Netzer, Corinna A1 - Mauß, Fabian A1 - Lehtiniemi, Harry T1 - Simulation of DI-Diesel combustion using tabulated chemistry approach T2 - 1st Conference on Combustion Processes in Marine and Automotive Engines, 7th - 8th June 2016, Lund, Schweden KW - Simulation of DI-Diesel Y1 - 2016 UR - http://ecco-mate.eu/images/Training%20events/LUND/ECCO-MATE_C1_Proceedings.pdf SP - 44 EP - 47 ER - TY - CHAP A1 - Matrisciano, Andrea A1 - Seidel, Lars A1 - Klauer, Christian A1 - Lehtiniemi, Harry A1 - Mauß, Fabian T1 - An a priori thermodynamic data analysis based chemical lumping method for the reduction of large and multi-component chemical kinetic mechanisms T2 - 5th International Workshop on Model Reduction in Reacting Flows, Lübbenau, 2015 N2 - A chemical species lumping approach for reduction of large hydrocarbons and oxygenated fuels is presented. The methodology is based on an a priori analysis of the Gibbs free energy of the isomer species which is then used as main criteria for the evaluation of lumped group. Isomers with similar Gibbs free energy are lumped assuming they present equal concentrations when applied to standard reactor conditions. Unlike several lumping approaches found in literature, no calculation results from the primary mechanism have been employed prior to the application of our chemical lumping strategy. KW - Combustion, Mechanism Reduction Y1 - 2015 UR - www.modelreduction.net UR - http://modelreduction.net/wp-content/uploads/2015/07/5th_IWMRRF_2015.pdf ER - TY - CHAP A1 - Seidel, Lars A1 - Klauer, Christian A1 - Pasternak, Michal A1 - Matrisciano, Andrea A1 - Netzer, Corinna A1 - Hilbig, Martin A1 - Mauß, Fabian T1 - Systematic Mechanism Reduction for Engine Applications T2 - 5th International Workshop on Model Reduction in Reacting Flows, Lübbenau, 2015 N2 - In this work we apply various concepts of mechanism reduction with a PDF based method for species profile conservation. The reduction process is kept time efficient by only using 0D and 1D reactors. To account for the expansion phase in internal combustion engines a stochastic engine tool is used to validate the reduction steps. KW - Combustion, Mechanism Reduction Y1 - 2015 UR - www.modelreduction.net UR - http://modelreduction.net/wp-content/uploads/2015/07/5th_IWMRRF_2015.pdf ER - TY - CHAP A1 - Matrisciano, Andrea A1 - Seidel, Lars A1 - Klauer, Christian A1 - Mauß, Fabian A1 - Lehtiniemi, Harry T1 - An a priori thermodynamic data analysis based on chemical lumping method for the reduction of large and multi-component chemical kinetic mechanisms T2 - 5th Annual Internation Workshop on Model Reduction in Reaction Flows (IWMRRF) Lübbenau, 28.06-01.07.2015, proceedings Y1 - 2015 ER - TY - CHAP A1 - Rodriguez Henriquez, Jose Juan A1 - Seidel, Lars A1 - Mauß, Fabian T1 - Plug Flow Reactor Set-up evaluation with methane decomposition at mild conditions and overpressure T2 - Abstract book, 7th European Combustion Meeting (ECM), Budapest, Hungary, March 30-April 2 Y1 - 2015 SN - 978-963-12-1257-0 ER - TY - CHAP A1 - Seidel, Lars A1 - Perlman, Cathleen A1 - Fröjd, Karin A1 - Klaus, Anna-Katharina A1 - Laska, Timothy A1 - Jalving, J. A1 - Mauß, Fabian ED - Seidel, Lars T1 - CPU Efficient Modelling of Biomass Gasification Using a Stochastic Reactor Approach and Chemistry Guided Reduction T2 - 22nd European Biomass Conference and Exhibition KW - Biomass Y1 - 2014 ER - TY - GEN A1 - Seidel, Lars A1 - Perlman, Cathleen A1 - Fröjd, Karin A1 - Klaus, Anna-Katharina A1 - Laska, Timothy A1 - Jalving, T. A1 - Mauß, Fabian T1 - CPU Efficient Modelling of Biomass Gasification Using a Stochastic Reactor Approach and Chemistry Guided Reduction KW - CPU Efficient Modelling Y1 - 2014 UR - http://www.loge.se/pdf/poster_BiomassConferenceBCE2014.pdf N1 - 1st International Workshop on Computational Fluid Dynamics (CFD) and biomass thermochemical Conversion SP - 1 ER - TY - GEN A1 - Schenk, Marina A1 - Leon, Larisa A1 - Moshammer, Kai A1 - Oßwald, Patrick A1 - Kohse-Höinghaus, Katharina A1 - Zeuch, Thomas A1 - Seidel, Lars A1 - Mauß, Fabian T1 - Detailed mass spectrometric and modeling study of isomeric butene flames T2 - Combustion and Flame Y1 - 2013 SN - 1556-2921 VL - 160 IS - 3 SP - 487 EP - 503 ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Elbaz, Ayman M. A1 - Giri, Binod Raj A1 - Arab, Omar Z. A1 - Adil, Mohammad A1 - Seidel, Lars A1 - Roberts, William L. A1 - Farooq, Aamir A1 - Mauß, Fabian T1 - Experimental and Kinetic Modeling Study of 1, 3-Dioxolane Oxidation and Comparison with Dimethoxymethane T2 - Energy & Fuels N2 - This work reports laminar flame speeds and ignition delay times of 1,3-dioxolane/O2/inert gases over a wide range of conditions. Laminar flame speeds were determined experimentally at pressures of 1 and 3 bar, the temperature of 300 K, and equivalence ratios ranging from 0.7 to 1.4 using a constant-volume spherical chamber, whereas ignition delay times were measured in a shock tube at a pressure of 1 bar, the temperature range of 1000–1265 K, and equivalence ratios of 0.5 and 1.0. A detailed kinetic model is developed to predict the oxidation of 1,3-dioxolane utilizing our new experimental data and published datasets on the oxidation of 1,3-dioxolane in freely propagating flames, autoignition in rapid compression machines and shock tubes, and speciation in a jet-stirred reactor. Model predictions are in reasonable agreement with the experimental data. Laminar flame speeds and ignition delay times of 1,3-dioxolane (cyclic ether) are compared with those of dimethoxymethane (acyclic ether). It is found that 1,3-dioxolane has a higher laminar flame speed than that of dimethoxymethane, which may be attributed to the formation of C2H4, C2H2, and the H atom from 1,3-dioxolane. On the contrary, ignition delay times of 1,3-dioxolane are longer than those of dimethoxymethane below 1000 K and shorter above 1000 K for the same dilution level. The reaction ȮCHO = CO2 + H is critical for accurately predicting 1,3-dioxolane oxidation, and it significantly influences model predictions under low-pressure conditions. The model developed in this work will serve as the base mechanism for higher cyclic and acyclic ethers. Y1 - 2022 U6 - https://doi.org/10.1021/acs.energyfuels.2c01132 SN - 1520-5029 SN - 0887-0624 VL - 36 IS - 14 SP - 7744 EP - 7754 ER - TY - GEN A1 - Shrestha, Krishna Prasad A1 - Eckart, Sven A1 - Drost, Simon A1 - Fritsche, Chris A1 - Schießl, Robert A1 - Seidel, Lars A1 - Maas, Ulrich A1 - Krause, Hartmut A1 - Mauß, Fabian T1 - A comprehensive kinetic modeling of oxymethylene ethers (OMEn, n= 1–3) oxidation-laminar flame speed and ignition delay time measurements T2 - Combustion and Flame N2 - This work reports on the development and experimental validation of a detailed reaction mechanism for the oxidation of polyoxymethylene dimethyl ethers (OMEn, n = 1–3). The validation is done by constant-volume chamber laminar flame speeds (393 K and 443 K, 1 to 5 bar, and equivalence ratio 0.8 to 1.6) and Rapid Compression Machine ignition delay times (550–680 K, 10 and 15 bar, equivalence ratios of 0.5–2.0) in OMEn/air mixtures. Using our new experimental and published data, the validation basis for the new kinetic model comprises the pyrolysis and oxidation of OMEn (n = 1–3) in freely propagating flames, auto-ignition in rapid compression machines and shock tubes, and speciation in jet-stirred and flow reactors as well as burner-stabilized premixed flames. The model provides a reasonable agreement with the experimental data for a broad range of conditions investigated. The performance of the developed model is compared against the recent literature models. OMEn (n = 1–3) all have the same laminar flame speed. The model suggests that the chemistry of OME0 (DME) and CH3OCHO (methyl formate) is the one that dictates the flame chemistry. Under the same pressure and equivalence ratio conditions, ignition delay times of OME2 and OME3 are similar for the investigated temperature range. This work helps to improve the understanding of OMEs chemistry. The model developed in this work will serve as the base mechanism for higher chain length OMEs (n>3). Y1 - 2022 U6 - https://doi.org/10.1016/j.combustflame.2022.112426 SN - 1556-2921 SN - 0010-2180 VL - 246 ER - TY - GEN A1 - Mante, Till A1 - Prehn, Sascha A1 - Theile, Martin A1 - Seidel, Lars A1 - Mestre, Laura A1 - Buchholz, Bert A1 - Mauß, Fabian ED - Heintzel, Alexander T1 - Investigation of An Ammonia Diesel Dual-Fuel Combustion Process on a Heavy-Duty Single Cylinder Research Engine for the Development of Suitable Simulation Tools for Maritime Applications T2 - Heavy-Duty-, On- und Off-Highway-Motoren 2022 : Stand der Energiewende im Heavy-Duty-Bereich N2 - This paper discusses the adaption of a single cylinder research engine for a retrofit application with an ammonia diesel dual-fuel combustion process and the build of an ammonia fuel system. The gaseous ammonia will be injected in the air intake pipe and the premixed ammonia air mixture will enter the combustion chamber. The diesel injection is carried out via a high-pressure common rail system. All relevant parameters can be freely adjusted via a freely programmable control unit. With the help of experimental data from a single cylinder research engine at the chair of piston machines and internal combustion engines of the University of Rostock (LKV), a dual-fuel combustion model based on detailed chemistry will be developed and optimized. This model will be integrated in a full research engine model, which ensures the best possible representation of the real engine. The combustion model is being developed by LOGE Deutschland GmbH. The full research engine model is developed by FVTR GmbH. The analysis of the combustion process starts with pure diesel operating points and is successively substituted by ammonia in the course of the measurement campaigns. Both the combustion characteristics are relevant, as they significantly influence the resulting performance and engine operation, as well as the exhaust emissions, as the carbon emissions can be reduced, but the nitrogen oxides and ammonia slip increase significantly in relevance due to the ammonia. The results obtained will be used to derive initial recommendations for action and to estimate the potential for application in the inland waterway shipping. In addition, the development of the systematic simulation tools covers a broad spectrum of research questions and aims to increase the efficiency of the necessary R&D. Y1 - 2022 SN - 978-3-658-41477-1 SN - 978-3-658-41476-4 U6 - https://doi.org/10.1007/978-3-658-41477-1_3 SP - 24 EP - 39 PB - Springer Vieweg CY - Wiesbaden ER - TY - GEN A1 - Hilbig, Martin A1 - Malliotakis, Zisis A1 - Seidel, Lars A1 - Vourliotakis, George A1 - Keramiotis, Christos A1 - Mauß, Fabian A1 - Founti, Maria T1 - The effect of base chemistry choice in a generated n‐hexane oxidation model using an automated mechanism generator T2 - International Journal of Chemical Kinetics N2 - The present study describes the utilization of a reaction mechanism generator for the development of chemical kinetic models. The aim of the investigation is twofold. The in-house developed mechanism generator is updated with reaction classes reported in the literature, and the effect of the lower hydrocarbon chemistry, that is, base chemistry, on the generation process is assessed. For this purpose, the algorithm is implemented on two different base chemistry mechanisms, that have previously been validated against a different range of hydrocarbons, that is, the mechanisms of the groups coauthoring the study. n-Hexane has been used as a modeling target due to its important role in combustion studies as a surrogate for engine and aviation applications. The steps of the generation process are given in detail as this is the first time the current algorithm is utilized. The two generated mechanisms are compared against speciation data, ignition delay times, and flame velocities from the literature. The overall agreement of the generated mechanisms is satisfying; discrepancies exist in the negative temperature coefficient regime. Reaction path analysis and sensitivity analysis were performed, revealing the reactions that cause the different mechanism performance. Among others, the study reveals that the generated schemes pose a fast and adequate alternative to literature mechanisms; it is however evident that the latter may include more detailed reaction paths and are therefore superior in terms of validation. Y1 - 2019 U6 - https://doi.org/10.1002/kin.21309 SN - 1097-4601 SN - 0538-8066 VL - 51 IS - 10 SP - 786 EP - 798 ER - TY - GEN A1 - Van Treek, Lisa A1 - Lubrano Lavadera, Marco A1 - Seidel, Lars A1 - Mauß, Fabian A1 - Konnov, Alexander A. T1 - Experimental and modelling study of laminar burning velocity of aqueous ethanol T2 - Fuel N2 - Laminar burning velocities of ethanol-water-air mixtures have been determined using the heat flux method. Aqueous ethanol contained 0–40% of water by mole fraction. Laminar premixed flat flames were stabilized on a perforated burner under adiabatic conditions for the equivalence ratio range from 0.7 to 1.4. Burning velocity measurements were performed for the initial gas temperature of 358 K and at atmospheric pressure. The results for ethanol-air flames are in good agreement with the previous data obtained using the same heat flux method. The present and literature experimental data were compared against predictions using four different kinetic models. All models show uniform behaviour over the range of ethanol dilution by water covered in the present study. However, model predictions significantly diverge from the experimental data obtained in spherical flames. To quantify the effect of dilution on the laminar burning velocity, an empirical dimensionless correlation has been derived from the experimental data and predictions of the models tested. Further numerical analyses were performed to identify the effects of water addition on laminar burning velocities. Results suggested that water strongly interacts with the H2/O2 and C1 oxidation/recombination routes. Y1 - 2019 U6 - https://doi.org/10.1016/j.fuel.2019.116069 SN - 1873-7153 VL - 257 ER - TY - GEN A1 - Van Treek, Lisa A1 - Roth, Norbert A1 - Seidel, Lars A1 - Mauß, Fabian T1 - Measurements of the laminar burning velocities of rich ethylene/air mixtures T2 - Fuel N2 - Laminar burning velocities of premixed ethylene/air flames were investigated under fuel lean and rich conditions. The laminar burning velocities were measured with the heat flux method at atmospheric pressure and unburnt gas temperatures of 298 K. The measurements have been performed for the equivalence ratio range of Φ = 0.7–2.5 using stabilized and flat flames on a perforated burner plate under adiabatic conditions. This is the first time that experimental measurements with the heat flux method of the ethylene/air flames under super fuel rich conditions are performed. The experimental data were compared against predictions using three different kinetic models and published flame speed. The measured flame speeds agree with other published data within the error margin. The experimental and predicted laminar flames do agree at fuel lean conditions, but there are some notable discrepancies under fuel rich conditions. KW - ethylene KW - laminar burning velocity KW - heat flux burner Y1 - 2020 UR - https://www.sciencedirect.com/science/article/pii/S0016236120309340 U6 - https://doi.org/10.1016/j.fuel.2020.117938 SN - 0016-2361 VL - 275 ER - TY - GEN A1 - Van Treek, Lisa A1 - Roth, Norbert A1 - Seidel, Lars A1 - Mauß, Fabian T1 - Laminar burning velocities of rich ethylene / air flames N2 - The laminar burning velocity SL of a given mixture of fuel and oxidizer is an important parameter to characterize premixed flames. SL is not only a fundamental parameter to calculate properties of turbulent flames, it is also an important target for the development of chemical kinetic mechanisms. Under fuel rich conditions it has relevance when simulating soot formation in burner stabilized flames. Many experiments on soot formation have been conducted in fuel-rich burner stabilized ethylene flames. Therefore an interest exists in experimental data for laminar burning velocity, in particular in fuel-rich ethylene flames. In the present work, ethylene / air flames were measured in the heat flux setup. Subsequently, the experimental data were compared against existing data and modelled using two kinetic models. KW - laminar burning velocity KW - ethylene / air flames KW - rich flames Y1 - 2017 UR - https://www.researchgate.net/publication/320802733_Laminar_burning_velocities_of_rich_ethylene_air_flames N1 - 3rd General Meeting and Workshop on Smart Energy Carriers in Industry – Prague, October 25 - 27, 2017 ER - TY - GEN A1 - Van Treek, Lisa A1 - Lubrano Lavadera, Marco A1 - Konnov, Alexander A. A1 - Seidel, Lars A1 - Mauß, Fabian T1 - Measurements of the laminar burning velocities of ethanol-water-air flames N2 - The laminar burning velocity of ethanol-water-air flames at atmospheric pressure and initial gas temperatures of T = 358 K was measured with the heat flux method. The mixture of ethanol-water-air contained 0%, 10%, 20%, 30% and 40% water by mole and the equivalence ratio (ϕ) range was varied from 0.7 to 1.4. The experiments were compared against predictions using three different kinetic models. Y1 - 2019 UR - https://www.researchgate.net/publication/330635016_Measurements_of_the_laminar_burning_velocities_of_ethanol-water-air_flames N1 - 1st International Conference on Smart Energy Carriers ER - TY - GEN A1 - Matrisciano, Andrea A1 - Netzer, Corinna A1 - Werner, Adina A1 - Borg, Anders A1 - Seidel, Lars A1 - Mauß, Fabian T1 - A Computationally Efficient Progress Variable Approach for In-Cylinder Combustion and Emissions Simulations T2 - SAE Technical Paper N2 - The use of complex reaction schemes is accompanied by high computational cost in 3D CFD simulations but is particularly important to predict pollutant emissions in internal combustion engine simulations. One solution to tackle this problem is to solve the chemistry prior the CFD run and store the chemistry information in look-up tables. The approach presented combines pre-tabulated progress variable-based source terms for auto-ignition as well as soot and NOx source terms for emission predictions. The method is coupled to the 3D CFD code CONVERGE v2.4 via user-coding and tested over various speed and load passenger-car Diesel engine conditions. This work includes the comparison between the combustion progress variable (CPV) model and the online chemistry solver in CONVERGE 2.4. Both models are compared by means of combustion and emission parameters. A detailed n-decane/α-methyl-naphthalene mechanism, comprising 189 species, is used for both online and tabulated chemistry simulations. The two chemistry solvers show very good agreement between each other and equally predict trends derived experimentally by means of engine performance parameters as well as soot and NOx engine-out emissions. The CPV model shows a factor 8 speed-up in run-time compared to the online chemistry solver without compromising the accuracy of the solution. Y1 - 2019 U6 - https://doi.org/10.4271/2019-24-0011 SN - 0148-7191 SN - 2688-3627 ER - TY - GEN A1 - Kurapati, Vinaykumar Reddy A1 - Borg, Anders A1 - Seidel, Lars A1 - Mauß, Fabian T1 - SprayLet: One-Dimensional Interactive Cross-Sectionally Averaged Spray Model T2 - SAE Technical Paper N2 - Spray modeling is among the main aspects of mixture formation and combustion in internal combustion engines. It plays a major role in pollutant formation and energy efficiency although adequate modeling is still under development. Strong grid dependence is observed in the droplet-based stochastic spray model commonly used. As an alternative, an interactive model called 'SprayLet' is being developed for spray simulations based on one-dimensional integrated equations for the gas and liquid phases, resulting from cross-sectionally averaging of multi-dimensional transport equations to improve statistical convergence. The formulated one-dimensional cross-section averaged system is solved independently of the CFD program to provide source terms for mass, momentum and heat transfer between the gas and liquid phases. The transport processes take place in a given spray cone where the nozzle exit is automatically resolved. In the 1D program, the conservation equations are for droplet diameter, droplet temperature, as well as for continuity and momentum of the liquid and the gaseous phase are solved. The source terms between the phases are conservatively embedded into the spray region of the CFD program. In CFD program, the transport equations are solved for gas phase only. The SprayLet model is validated using standard Sandia sprays by comparing penetration lengths and fuel mixture fractions with experimental data. Y1 - 2023 U6 - https://doi.org/10.4271/2023-24-0083 SN - 0148-7191 SN - 2688-3627 ER - TY - GEN A1 - Turquand d'Auzay, Charles A1 - Shapiro, Evgeniy A1 - Prouvier, Matthieu A1 - Winkler, Axel A1 - Seidel, Lars A1 - Borg, Anders A1 - Mauß, Fabian T1 - Evaluation of Fast Detailed Kinetics Calibration Methodology for 3D CFD Simulations of Spray Combustion T2 - SAE Technical Paper N2 - Meeting strict current and future emissions legislation necessitates development of computational tools capable of predicting the behaviour of combustion and emissions with an accuracy sufficient to make correct design decisions while keeping computational cost of the simulations amenable for large-scale design space exploration. While detailed kinetics modelling is increasingly seen as a necessity for accurate simulations, the computational cost can be often prohibitive, prompting interest in simplified approaches allowing fast simulation of reduced mechanisms at coarse grid resolutions appropriate for internal combustion engine simulations in design context. In this study we present a simplified Well-stirred Reactor (WSR) implementation coupled with 3D CFD Ricardo VECTIS solver. A detailed evaluation of benchmark ECN spray problem is presented demonstrating that a single point calibration of such a model using a bulk reaction multiplier approach can provide correct representation of the solution across a wide range of temperatures on grid sizes typically employed for RANS internal combustion engine simulations with tabulated kinetics or zonal combustion models. Y1 - 2022 U6 - https://doi.org/10.4271/2022-01-1042 SN - 0148-7191 SN - 0096-5170 IS - 2022-01-1042 ER - TY - GEN A1 - Manna, Maria Virginia A1 - Sabia, Pino A1 - Shrestha, Krishna Prasad A1 - Seidel, Lars A1 - Ragucci, Raffaele A1 - Mauß, Fabian A1 - De Joannon, Mara T1 - NH3NO interaction at low-temperatures: an experimental and modeling study T2 - Proceedings of the Combustion Institute N2 - The present work provides new insight into NH3single bondNO interaction under low-temperature conditions. The oxidation process of neat NH3 and NH3 doped with NO (450, 800 ppm) was experimentally investigated in a Jet Stirred Flow Reactor at atmospheric pressure for the temperature range 900–1350 K. Results showed NO concentration is entirely controlled by DeNOx reactions in the temperature range 1100–1250 K, while NH3single bondNO interaction does not develop through a sensitizing NO effect, for these operating conditions. A detailed kinetic model was developed by systematically updating rate constants of controlling reactions and declaring new reactions for N2H2 isomers (cis and trans). The proposed mechanism well captures target species as NO and H2 profiles. For NH3single bondNO mixtures, NO profiles were properly reproduced through updated DeNOx chemistry, while NH2 recombination reactions were found to be essential for predicting the formation of H2. The role of ammonia as a third-body species is implemented in the updated mechanism, with remarkable effects on species predictions. For neat NH3 mixture, the reaction H+O2(+M)=HO2(+M) was crucial to predict NO formation via the reaction NH2+HO2double bondH2NO+OH. Y1 - 2023 U6 - https://doi.org/10.1016/j.proci.2022.09.027 SN - 1873-2704 VL - 39 IS - 1 SP - 775 EP - 784 ER - TY - GEN A1 - Kurapati, Vinaykumar Reddy A1 - Borg, Anders A1 - Seidel, Lars A1 - Mauß, Fabian T1 - Fast CFD Diesel engine modelling using the 1-Dimentional SprayLet approach T2 - SAE Technical Paper N2 - In the SAE article 2023-24-0083: SprayLet: One-dimensional interactive cross-sectionally averaged spray model, we formulatet a one-dimensional Spray model in interaction with the surrounding gas phase. We could demonstrate, that the model predicted liquid and gaseous penetration length in good aggreement with ECN spray experiments. In this paper we use this model in engine CFD (CONVERGE CFD) and demonstrate a strong reduction in CPU time (50%). We can show a strong decrease in grid dependency, which allows a further reduction of CPU time (90%). We will present engine CFD simulations, comparing detailed spray with SpayLet simulations. This includes pressure traces, heat release, and emissions. Y1 - 2024 UR - https://www.sae.org/publications/technical-papers/content/2024-01-2684/ SN - 0148-7191 SN - 2688-3627 IS - 2024-01-2684 ER - TY - GEN A1 - Franken, Tim A1 - Seidel, Lars A1 - Gonzalez Mestre, Laura Catalina A1 - Shrestha, Krishna Prasad A1 - Matrisciano, Andrea A1 - Mauss, Fabian T1 - Assessment of Auto-Ignition Tendency of Gasoline, Methanol, Toluene and Hydrogen Fuel Blends in Spark Ignition Engines T2 - THIESEL 2020 Conference on Thermo-and Fluid Dynamic Processes in Direct Injection Engines N2 - State of the art spark ignited gasoline engines achieve thermal efficiencies above 46 % e.g. due to friction optimized crank trains, high in-cylinder tumble flow and direct fuel injection. Further improvements of thermal efficiency are expected from lean combustion, higher compression ratio and new knock-resistant fuel blends. One of the limitations to these improvements are set by the autoignition in the end gas, which can develop to knocking combustion and severely damage the internal combustion engine. The auto-ignition is enhanced by high cylinder gas temperatures and reactive species in the end gas composition. Quasi-dimensional Stochastic Reactor Model simulations with detailed chemistry allow to consider the thermochemistry properties of surrogates and complex end gas compositions. Based on the detailed reaction scheme and surrogate model, an innovative tabulated chemistry approach is utilized to generate dual-fuel laminar flame speed and combustion chemistry look-up tables. This reduces the simulation duration to seconds per cycle, while the loss in accuracy compared to solving the chemistry “online” is marginal. The auto-ignition events predicted by the tabulated chemistry simulation are evaluated using the Detonation Diagram developed by Bradley and co-workers. This advanced methodology for quasi-dimensional models evaluates the resonance between the shock wave and reactionfront velocity from auto-ignition in the end gas and determines if it is a harmful developing detonation or normal deflagration. The aim of this work is to evaluate the auto-ignition characteristics of different fuel blends. The Stochastic Reactor Model with tabulated chemistry is applied to perform a numerical analysis of the autoignition of the fuel blends and operating conditions. Experimental measurements of a single cylinder research engine operated with RON95 E10 fuel are used to train and validate the simulation model. The RON95 E10 fuel is blended with Methanol, Hydrogen and Toluene. The knock tendency based on the evaluation of auto-ignition events of the different fuel blends are analysed for three operating points at 1500 rpm 15 bar IMEP, 2000 rpm 20 bar IMEP and 2500 rpm 15 bar IMEP with advanced spark timings. Y1 - 2020 UR - https://hal.science/hal-03573870 ER -