TY - GEN A1 - Agbro, Edirin A1 - Tomlin, Alison S. A1 - Zhang, Wankang A1 - Burluka, Alexey A1 - Mauß, Fabian A1 - Alfazazi, Adamu A1 - Sarathy, S. Mani T1 - Chemical Kinetic Modeling Study on the Influence of n-Butanol Blending on the Combustion, Autoignition, and Knock Properties of Gasoline and Its Surrogate in a Spark-Ignition Engine T2 - American Chemical Society N2 - The ability of a mechanism describing the oxidation kinetics of toluene reference fuel (TRF)/n-butanol mixtures to predict the impact of n-butanol blending at 20% by volume on the autoignition and knock properties of gasoline has been investigated under conditions of a strongly supercharged spark-ignition (SI) engine. Simulations were performed using the LOGEengine code for stoichiometric fuel/air mixtures at intake temperature and pressure conditions of 320 K and 1.6 bar, respectively, for a range of spark timings. At the later spark timing of 6° crank angle (CA) before top dead center (BTDC), the predicted knock onsets for a gasoline surrogate (TRF) and the TRF/n-butanol blend are higher compared to the measurements, which is consistent with an earlier study of ignition delay times predicted in a rapid compression machine (RCM; Agbro, E.; Tomlin, A. S.; Lawes, M.; Park, S.; Sarathy, S. M. The influence of n … KW - The ability of a mechanism describing the oxidation kinetics Y1 - 2018 U6 - https://doi.org/10.1021/acs.energyfuels.8b00962 SN - 1520-5029 SN - 0887-0624 VL - 32 IS - 10 SP - 10065 EP - 10077 ER - TY - CHAP A1 - Ahmed, Syed Sayeed A1 - Moréac, Gladys A1 - Zeuch, Thomas A1 - Mauß, Fabian T1 - Reduced Mechanism for the Oxidation of the Mixtures of n-Heptane and iso-Octane T2 - Proceedings of the European Combustion Meeting, Louvain-la-Neuve, Belgium, April 3 - 6, 2005 Y1 - 2005 N1 - CD-ROM PB - Combustion Inst. CY - Louvain-la-Neuve ER - TY - CHAP A1 - Ahmed, Syed Sayeed A1 - Moréac, Gladys A1 - Zeuch, Thomas A1 - Mauß, Fabian T1 - Efficient lumping technique for the automatic generation of n-heptane and iso-octane oxidation mechanism T2 - 227th ACS National meeting, Anaheim, CA, March 28-April 1, 2004 N2 - The aim of this work is to generate a semi-detailed mechanism for the oxidation of n-heptane and iso-octane mixture with 241 species and 1905 reactions and to optimize it for the different engine operating conditions to cover the full range of temperature. A step wise efficient lumping strategy for different reaction types combine with necessity analysis has been used for the simplification and reduction of mechanism in order to make it faster and less complex in terms of both number of reactions and species. Its validation has been done against the shock tube experimental data from Fieweger et al. for both low and high temperature regions, lean and rich fuel conditions, a range of octane numbers and pressures from 13 bar to 40 bar. In addition, the mechanism was tested using a zero dimensional Homogenous Charge Compression Ignition engine model against experiments under a range of different octane numbers and initial temperatures. Y1 - 2004 SP - 265 EP - 266 PB - American Chemical Society CY - Washington, DC ER - TY - CHAP A1 - Amnéus, Per A1 - Tunér, Martin A1 - Mauß, Fabian A1 - Collin, Robert A1 - Nygren, Jenny A1 - Richter, Mattias A1 - Aldén, Marcus A1 - Kraft, Markus A1 - Bhave, Amit A1 - Hildingsson, Leif A1 - Johansson, Bengt T1 - "Formaldehyd and Hydroxyl Radicals in an HCCI Engine - Calculations and Measurements" Y1 - 2007 U6 - https://doi.org/10.4271/2007-01-0049 ER - TY - GEN A1 - Asgarzade, Rufat A1 - Franken, Tim A1 - Mauss, Fabian T1 - Experimental investigation of CH4/O2/CO2 mixtures in a single-cylinder spark ignition engine N2 - The Power-to-X-to-Power (P2X2P) technology involves producing synthetic methane from renewable hydrogen and captured CO2, which is then used for cogeneration of electricity and heat through oxyfuel combustion. With the P2X2P energy system demonstrator, NOx-free and carbon neutral heat and electricity generation as well as storage of excess renewable energy are realized. This work presents the experimental investigation of combustion characteristics for CH4/O2/CO2 mixtures in a single cylinder spark ignition engine that is a part of the P2X2P system. Y1 - 2025 ER - TY - GEN A1 - Asgarzade, Rufat A1 - Franken, Tim A1 - Mauss, Fabian T1 - Development of an oxyfuel engine test bench for power-to-X-to-power application T2 - 12th European Combustion Meeting N2 - This work presents the development of an oxyfuel engine test bench which is integrated into a Power-to-X-to-Power energy storage system demonstrator. These storage systems are considered carbon-free because they recirculate carbon without emitting it into the atmosphere. Y1 - 2025 ER - TY - GEN A1 - Asgarzade, Rufat A1 - Franken, Tim A1 - Mauss, Fabian T1 - Oxyfuel combustion process development for an SI engine in a power-to-X-to-power energy system N2 - This work presents the development of an oxyfuel engine test bench which is to be integrated to a Power-to-X-to-Power energy storage system demonstrator. Such storage systems are considered carbon-neutral because they recirculate carbon without emitting it into the atmosphere. Y1 - 2025 ER - TY - GEN A1 - Asgarzade, Rufat A1 - Franken, Tim A1 - Mauss, Fabian ED - Hemaizia, Abdelkader T1 - Multi-objective optimization of oxyfuel gas engine using stochastic engine model and detailed chemistry T2 - SAE technical papers N2 - The energy transition initiatives in Germany’s renown coal mining region Lusatia have driven research into Power-to-X-to-Power technologies, where synthetic fuel is produced from renewably sourced hydrogen and captured CO2, and converted to electricity and heat through oxyfuel combustion. This work investigates the multi-objective optimization of oxyfuel gas engine using a stochastic engine model and detailed chemistry. Exhaust gas recirculation (EGR) rate, initial cylinder temperature and pressure, spark timing, piston bowl radius and depth are selected as design parameters to minimize the exhaust temperature at exhaust valve opening and indicated specific fuel consumption (ISFC) corresponding to oxyfuel operation with different dry and wet EGR rates. The optimization problem is solved for a dry EGR and four wet EGR cases with various CO2/H2O fractions, aiming to achieve comparable performance as in conventional natural gas / air operation, and energy-efficient carbon capture. The case with the lowest humidity (T10deg) had the lowest temperature of 1537 K, while the one with the highest vapor fraction (T70deg) attained the minimum 260 g/kWh ISFC. The superiority of the T10deg case is offset by much higher cooling demand (3.06 kW) for CO2 separation than that for T70deg case (0.81 kW). The constraint for combustion efficiency (>65%) limited the solution space towards high ISFC values, while the constraint for low indicated mean effective pressure (IMEP) (>7 bar) and the constraint for high IMEP (<8 bar) limited the solution space in between the two distinct clusters of feasible designs, and towards high exhaust temperature, respectively. The optimized designs from all the cases could outperform the reference case in terms of IMEP, nevertheless they fell below 31% indicated efficiency, which is associated with stoichiometric combustion. KW - Gas engines KW - Greenhouse gas emissions KW - Exhaust gas recirculation (EGR) KW - Ignition timing KW - Synthetic fuels KW - Fuel consumption KW - Carbon dioxide KW - Combustion and combustion processes KW - Natural gas KW - Engines Y1 - 2025 U6 - https://doi.org/10.4271/2025-01-0529 SN - 0148-7191 PB - SAE International CY - Warrendale, PA, United States ER - TY - CHAP A1 - Aslanjan, Jana A1 - Klauer, Christian A1 - Guenther, Vivien A1 - Mauß, Fabian T1 - Simulation of a three-way catalyst using a transient multi-channel model T2 - Digital Proceedings of the 8th European Combustion Meeting (ECM 2017), Dubrovnik, Croatia N2 - The conversion effects of a three-way catalyst (TWC) are simulated in previous works using single-channel approaches and detailed kinetic models. In addition to the single-channel model multiple representative catalyst channels are used in this work to take heat transfer between the channels into account. Furthermore, different inlet temperature distributions are considered and tested. An experimental four-stroke engine setup with emission outputs fed into a TWC is used to validate the model. Furthermore, the temperature progress is simulated to reflect the catalyst’s light off temperature. Heat conduction between the channels is modeled to provide proper heat dissipation during the catalytic process. A good agreement to the experimental data can be achieved with low computational cost. Y1 - 2017 UR - https://www.researchgate.net/profile/Jana_Aslanjan/publication/319136860_Simulation_of_a_three-way_catalyst_using_a_transient_multi-channel_model/links/59941a8caca272ec9087c553/Simulation-of-a-three-way-catalyst-using-a-transient-multi-channel-model.pdf SP - 570 EP - 574 CY - Dubrovnik ER - TY - CHAP A1 - Aslanjan, Jana A1 - Klauer, Christian A1 - Günther, Vivien A1 - Mauß, Fabian T1 - On the Influence of Inlet Gas Variations and Gas Phase Chemistry in a Three-Way Catalyst T2 - COMODIA - The Ninth International Conference on Modeling and Diagnostics for Advanced, July 25, 2017 - July 28, 2017 N2 - The conversion effects of a three-way catalyst are simulated in previous works using single and multiple representative channel approaches with detailed surface kinetic models. In addition, this article introduces global gas phase chemistry to the model. This allows reflecting ongoing reactions due to incomplete combustion products in low temperature regime. The 1D single-channel model representative for the catalyst is used here. Next to the comparison of the catalyst outlet emissions with and without gas phase chemistry, the transient temperature increase is simulated in order to model the catalysts light off temperature. Additionally, the transient inlet emissions are enhanced to show the influence of water and hydrogen on the modeling results. The heat transfer is modeled by wall heat losses to provide proper heat dissipation out of the catalyst. The modeling results show a good agreement to the experimental data with low computational cost. Y1 - 2017 U6 - https://doi.org/10.1299/jmsesdm.2017.9.A308 ER - TY - GEN A1 - Aslanjan, Jana A1 - Klauer, Christian A1 - Günther, Vivien A1 - Mauß, Fabian T1 - Simulation of a three-way-catalyst using a transient multi-channel model N2 - The importance to reduce automotive exhaust gas emissions is constantly increasing. Not only the country-specific laws are getting more stringent also the global increase of automobiles is requiring a responsible handling of the issue. The three-way-catalytic converter (TWC) is one of the most common catalysts for the engine exhaust gas after treatment. The reduction of CO, NO and unburned hydrocarbons is fulfilled via oxidation of carbon monoxide and hydrocarbons, and reduction of nitrogen oxides. These conversion effects were simulated in previous works using single channel approaches [e.g. Fröjd/Mauss, SAE International 2011-01-1306] and detailed kinetic models [e.g Chatterjee et al., Faraday Discussions 119 (2001) 371-384 and Koop et al., Appl. Catal.B: Environmental 91 (2009), 47-58]. In this work multiple representative catalyst channels are used to take heat variations in between the catalyst into account. Each channel is split into a user given number of cells and each cell is treated like a perfectly stirred reactor (PSR). The simulation is validated against an experimental four-stroke engine setup with emission outputs fed into a TWC. Next to the emissions the transient temperature increase is simulated in order to model the catalyst light off temperature. The heat transfer is modelled by wall heat losses to provide a proper heat dissipation out of the catalyst. The simulation results show a good agreement to the experimental data with low computational cost. Y1 - 2017 UR - https://unitedscientificgroup.com/conferences/catalysis/2017/pdfs/CCE-2017_Proceedings.pdf N1 - CCE-2017 International Conference on Catalysis and Chemical Engineering Baltimore, USA, February 22 - 24, 2017 SP - S. 103 ER - TY - GEN A1 - Aslanjan, Jana A1 - Klauer, Christian A1 - Günther, Vivien A1 - Mauß, Fabian T1 - Development of a Physical Parameter Optimizer for 1D Catalyst Modeling on the Example of a Transient Three-Way Catalyst Experiment, 37th International Symposium on Combustion 2018, Dublin N2 - The importance of catalytic after-treatment for automotive emissions is not neglectable concerning current environmental protection discussions. A reasonable and time efficient catalyst model can help to reduce the necessity of time consuming experimental investigations on physical parameters for catalytic converter construction. It can further support the preparation of necessary experimental setups to analyze physical and chemical phenomena in catalysts. Physical parameter and/or chemical kinetic optimizers can be an advanced tool to support computational models in terms of adjustment to an experiment. In this work a physical parameter optimizer is developed and validated against a transient three-way catalyst experiment. The modeling results are compared to the measured data in terms of temperature and emission conversion behavior and show a good agreement. KW - Three-Way Catalyst KW - 1D-Simulation KW - Emissions KW - After Treatment KW - Optimization Y1 - 2018 UR - https://www.researchgate.net/publication/328998399 ER - TY - GEN A1 - Aslanjan, Jana A1 - Klauer, Christian A1 - Perlman, Cathleen A1 - Günther, Vivien A1 - Mauß, Fabian T1 - Simulation of a Three-Way Catalyst Using Transient Single and Multi-Channel Models T2 - SAE technical paper KW - Simulation of a Three-Way Catalyst Using Y1 - 2017 U6 - https://doi.org/10.4271/2017-01-0966 SN - 0148-7191 SN - 0096-5170 IS - 2017-01-0966 ER - TY - GEN A1 - Bai, X. S. A1 - Fuchs, L. A1 - Balthasar, M. A1 - Mauß, Fabian T1 - Detailed Kinetic Soot Modeling in Turbulent Jet Diffusion Flames T2 - Symposium (International) on Combustion Y1 - 1998 SN - 0082-0784 VL - 27 IS - 2 SP - 1623 EP - 1630 ER - TY - GEN A1 - Balthasar, M. A1 - Heyl, A. A1 - Mauß, Fabian A1 - Schmitt, Frank A1 - Bockhorn, Henning T1 - Flamelet Modeling of Soot Formation in Laminar Ethylene Air Diffusion Flames T2 - Symposium (International) on Combustion Y1 - 1996 SN - 0082-0784 VL - 26 IS - 2 SP - 2369 EP - 2377 ER - TY - GEN A1 - Balthasar, M. A1 - Mauß, Fabian A1 - Wang, H. T1 - A computational study of the thermal ionization of soot particles and its effect on their growth in laminar premixed flames T2 - Combustion and Flame Y1 - 2002 U6 - https://doi.org/10.1016/S0010-2180(02)00344-9 SN - 1556-2921 VL - 129 IS - 1-2 SP - 204 EP - 216 ER - TY - GEN A1 - Banyon, Colin A1 - Rodriguez Henriquez, Jose Juan A1 - Paterakis, George A1 - Malliotakis, Zisis A1 - Souflas, Konstantinos A1 - Keramiotis, Christos A1 - Vourliotakis, George A1 - Mauß, Fabian A1 - Curran, Henry J. A1 - Skevis, George A1 - Koutmos, Panagiotis A1 - Founti, Maria T1 - A comparative study of the effect of varied reaction environments on a swirl stabilized flame geometry via optical measurements T2 - Fuel : the science and technology of fuel and energy N2 - The present work is a part of a larger experimental campaign which examines the behaviour of various fuels on a swirl stabilized flame burner configuration. Overall, detailed speciation measurements and temperature measurements were combined with optical measurements. The work presented here concerns the part of the experimental campaign which deals with the optical characteristics of the examined flames. The work adds to the growing database of experimental measurements assessing engine-relevant reaction environments which shift from traditional ones in order to meet pollutant emission regulations and efficiency standards. Here, the oxidation of several commonly used fuel and fuel surrogates that are subjected to the addition of a bio-derived fuel additive (dimethyl ether) and emulated exhaust gas recirculation (EGR) is studied in a laboratory-scale swirl … KW - swirl burner KW - speciation measurements KW - temperature measurements Y1 - 2018 U6 - https://doi.org/10.1016/j.fuel.2017.09.105 SN - 0016-2361 VL - 216 SP - 826 EP - 834 ER - TY - CHAP A1 - Bellanca, R. A1 - Mauß, Fabian A1 - Wang, H. T1 - Automatic optimization of detailed kinetic mechanism for HCCI-engine simulation T2 - The 227th ACS National Meeting, Anaheim, CA, March 28-April 1, 2004 N2 - In recent years detailed kinetic models have been developed and validated for both auto ignition and laminar combustion processes. The range of validity of these models is limited by the range of physical parameters covered by the available experimental data. Often, a re-optimization of the models is necessary. Optimization of reaction models has been automated in the past for example for the development of the GRI-Mech. In this work a similar procedure has been applied to optimize a gasoline fuel reference model as developed by Curran and Westbrook for HCCI engine cases. The HCCI-process was simulated using a compressed homogeneous reactor. Computations have been carried out on a PC in a graphical user interface environment. Experimental data were collected at Lund Institute of Technology on a Volvo engine with variable compression ratio and port injection mixes of iso-octane/n-heptane. Results show that, after optimization, HCCI experiments can be predicted for the given conditions. Y1 - 2004 SP - 267 EP - 268 PB - American Chemical Society CY - Washington, DC ER - TY - CHAP A1 - Bensler, H. A1 - Montefrancesco, Emanuela A1 - Willand, J. A1 - Bo, T. A1 - Risi, A. A1 - Mauß, Fabian A1 - Netzell, Karl T1 - Prediction on non-premixed combustion and soot formation using and interactive flamelet approach T2 - Conference proceedings, Conference on Thermo- and Fluid Dynamic Processes in Diesel Engines, September 12th - 15th 2006, Valencia, Spain Y1 - 2006 SN - 84-9705-982-4 SP - 339 EP - 352 PB - Univ. Politécnica CY - Valencia ER - TY - CHAP A1 - Blurock, Edward S. A1 - Lovas, Terese A1 - Mauß, Fabian T1 - Steady State Reduced Mechanisms based on Domain Splitting T2 - Proceedings of the 19th International Conference on the Dynamics of Explosions and Reactive Systems, Hakone, July 27 - August 1, 2003 Y1 - 2003 N1 - CD-ROM CY - Hakone ER - TY - GEN A1 - Breitbach, H. A1 - Göttgens, J. A1 - Mauß, Fabian A1 - Pitsch, H. A1 - Peters, Norbert T1 - Laminar Counterflow Mixing of Acetylene into Hot Combustion Products T2 - Symposium (International) on Combustion Y1 - 1994 SN - 0082-0784 VL - 25 IS - 1 SP - 1357 EP - 1364 ER - TY - GEN A1 - David, William I. F. A1 - Agnew, Gerry D. A1 - Bañares-Alcántara, René A1 - Barth, James A1 - Hansen, John Bogild A1 - Bréquigny, Pierre A1 - De Joannon, Mara A1 - Fürstenberg Stott, Sofia A1 - Fürstenberg Stott, Conor A1 - Guati-Rojo, Andrea A1 - Hatzell, Marta A1 - MacFarlane, Douglas R. A1 - Makepeace, Joshua W. A1 - Mastorakos, Epaminondas A1 - Mauß, Fabian A1 - Medford, Andrew A1 - Mounaim-Rousselle, Christine A1 - Nowicki, Duncan A. A1 - Picciani, Mark A. A1 - Postma, Rolf S. A1 - Rouwenhorst, Kevin H. R. A1 - Sabia, Pino A1 - Salmon, Nicholas A1 - Simonov, Alexandr N. A1 - Smith, Collin A1 - Torrente-Murciano, Laura A1 - Valera-Medina, Augustin T1 - 2023 Roadmap on ammonia as a carbon-free fuel T2 - Journal of Physics: Energy N2 - The 15 short chapters that form this 2023 ammonia-for-energy roadmap provide a comprehensive assessment of the current worldwide ammonia landscape and the future opportunities and associated challenges facing the use of ammonia, not only in the part that it can play in terms of the future displacement of fossil-fuel reserves towards massive, long-term, carbon-free energy storage and heat and power provision, but also in its broader holistic impacts that touch all three components of the future global food-water-energy nexus. Y1 - 2024 U6 - https://doi.org/10.1088/2515-7655/ad0a3a SN - 2515-7655 VL - 6 IS - 2 ER - TY - GEN A1 - Dong, Shijun A1 - Aul, Christopher A1 - Gregoire, Claire A1 - Cooper, Sean P. A1 - Mathieu, Olivier A1 - Petersen, Eric L. A1 - Rodriguez, Jose A1 - Mauß, Fabian A1 - Wagnon, Scott W. A1 - Kukkadapu, Goutham A1 - Pitz, William J. A1 - Curran, Henry J. T1 - A comprehensive experimental and kinetic modeling study of 1-hexene T2 - Combustion and Flame N2 - It is important to understand the low-temperature chemistry of 1-hexene as it is used as a representative alkene component in gasoline surrogate fuels. Ignition delay times (IDTs) of 1-hexene measured in rapid compression machines (RCMs) can be used to validate its low-temperature chemistry. However, volume history profiles are not available for published RCM IDT data. This has restricted the validation of the low-temperature chemistry of 1-hexene at engine-relevant conditions (i.e. at low temperatures and high pressures). Thus, new RCM IDT data with associated volume history profiles are needed. In this study, both an RCM and a high-pressure shock tube (ST) are employed to measure IDTs of 1-hexene at equivalence ratios of 0.5, 1.0 and 2.0 in ‘air’ and at pressures of 15 and 30 atm. A cool-flame (first stage) and total (second stage) ignition was observed in the RCM experiments. Moreover, carbon monoxide and water versus time histories produced during 1-hexene oxidation at highly diluted conditions were measured in a ST. A new detailed chemical kinetic model describing 1-hexene oxidation is proposed and validated using these new measured data together with various experimental data available in the literature. The kinetic model can predict well the auto-ignition behavior and oxidation processes of 1-hexene at various conditions. The rate constants and branching ratio for hydroxyl radical addition to the double bond of 1-hexene are particularly important and discussed based on the experimental and theoretically calculated results from previous studies as well as validation results from jet-stirred reactor (JSR) species profiles. Flux and sensitivity analyses are performed to determine the important reaction classes for 1-hexene oxidation and show that the reactions associated with hydroxy radical addition to the double bond contribute most to the low-temperature reactivity of 1-hexene. In the negative temperature coefficient (NTC) regime, the isomerization of hexenyl-peroxy radicals promotes fuel reactivity due to its associated chain branching pathways. Y1 - 2021 U6 - https://doi.org/10.1016/j.combustflame.2021.111516 SN - 1556-2921 SN - 0010-2180 VL - 232 ER - TY - CHAP A1 - Ebenezer, N. A1 - Mauß, Fabian T1 - A robust and adaptive method for model chemical kinetics based on PRISM and ISAT philosophies T2 - Proceedings - 3rd European Combustion Meeting, ECM 2007, Mediterranean Agronomic Institute of Chania, Crete, Greece, 11 - 13 April 2007 Y1 - 2007 N1 - CD-ROM PB - The Combustion Institute, Greek Section CY - Chania ER - TY - GEN A1 - Eckart, Sven A1 - Shrestha, Krishna P A1 - Giri, Binod R A1 - Fang, Qilong A1 - Chen, Chen A1 - Li, Wei A1 - Krause, Hartmut A1 - Mauss, Fabian A1 - Liu, Dong A1 - Li, Yuyang T1 - Chemical insights into ethyl acetate flames from experiment and kinetic modeling: Laminar burning velocity, speciation and NOx emission T2 - Proceedings of the Combustion Institute N2 - Oxygenated fuels, such as alcohols, ethers, and esters, are promising alternatives to conventional fuels. These fuels can help reduce detrimental emissions like carbon monoxide and unburned hydrocarbons and enhance octane ratings. Among these oxygenates, ethyl acetate (EA), a small alkyl ester sourced from biomass, emerges as a clean, promising energy carrier. It serves as a surrogate fuel to facilitate investigations into the combustion behaviours of biodiesel. Despite its importance, the literature knowledge of EA combustion characteristics is limited. Therefore, this study aims to broaden the knowledge of the combustion behaviour of this type of oxygenated fuel compound. In this study, we measured the laminar burning velocities of EA by employing a heat flux burner and a closed combustion vessel over the equivalence ratios of 0.7 – 1.7, pressures of 1 – 10 bar and temperatures ranging from 353 – 423 K. Further, we also measured the NOx emissions in exhaust gas of the premixed flames fueled by EA/air for the first time over the equivalence ratio of 0.8 – 1.2. Additionally, we employed a non-premixed counterflow flame setup for extensive characterisation of species and their concentration under diverse conditions encompassing various strain rates and oxygen concentrations. Finally, we utilized these newly measured data to construct and validate a detailed kinetic model developed as part of this work. The newly developed model will help characterize the combustion properties of EA. Y1 - 2024 UR - https://www.sciencedirect.com/science/article/pii/S1540748924002955 U6 - https://doi.org/10.1016/j.proci.2024.105487 VL - 40 (2024) SP - 1 EP - 7 PB - Elsevier ER - TY - GEN A1 - Eckart, Sven A1 - Shrestha, Krishna P A1 - Giri, Binod R A1 - Fang, Qilong A1 - Li, Wei A1 - Mauss, Fabian A1 - Krause, Hartmut A1 - Li, Yuyang T1 - Insight into premixed diethoxymethane flames: Laminar burning velocities, temperatures, and emissions behaviour T2 - Proceedings of the Combustion Institute N2 - Diethoxymethane ((CH3CH2O)2CH2, DEM) is a promising carbon-neutral fuel. DEM is a diether or acetal with a molecular structure similar to oxymethylene ethers (CH3O–(CH2O)n–CH3, OMEn). Thus, DEM can be expected to have a similar combustion behavior to OMEs, reducing harmful emissions such as NOx and particulate matter (PM) in internal combustion engines. From both experimental and kinetic modeling, fundamental studies on DEM are scarce in the literature. More studies are required to gain a detailed insight into the oxidation kinetics of DEM. Laminar burning velocity (LBV) is a critical property that allows a detailed assessment of the potential application of DEM in combustion devices. Unfortunately, the literature on the LBV of DEM is limited. Therefore, in this study we have investigated the LBV of DEM using two reactors for the first time, namely a heat flux burner and a combustion chamber. The experimental data is reported for equivalence ratio between 0.7 and 1.7, initial temperatures of 368–423 K, and initial pressure of 1–5 bar. In addition, we developed a detailed kinetic model extending our recent work of Shrestha et al. (Combust. Flame. 246 (2022) 112,426) to characterize the combustion behavior of DEM utilizing the new experimental data from this work and the literature data. Our model performs remarkably well in capturing the newly measured LBV experimental data over various experimental conditions. We found that DEM and dimethoxy methane (DMM) have similar values of LBVs (within ±1.5 cm/s) for a given condition, which indicates that intermediate chemistry governs the flame chemistry. Despite DEM being a larger molecule that is expected to have slightly lower LBVs than DMM, its effect on the measured values of LBVs is negligible. Finally, we experimentally measured NOx formation in DEM flame for the first time. The stochiometric flame has the highest NOx formation. The proposed model predicted the equivalence ratio dependence of NOx nicely. However, it overestimates the NOx formation for stoichiometric DEM/air mixtures by ∼30 %. The model suggests that the thermal NO formation route is favored at lean and stochiometric conditions. In contrast, the prompt NO formation route is enhanced for rich mixtures. Y1 - 2024 UR - https://www.sciencedirect.com/science/article/pii/S1540748924003870 U6 - https://doi.org/10.1016/j.proci.2024.105579 VL - 40 SP - 1 EP - 7 PB - Elsevier ER - TY - GEN A1 - El Harrab, Hayat A1 - Askar, Enis A1 - Franken, Tim A1 - Mauss, Fabian T1 - Experimental and reaction kinetic study of hydrogen ignition behavior at ignition limits T2 - Proceedings of the Combustion Institute N2 - The paper presents the results of an experimental and reaction kinetic investigation of hydrogen ignition at different pressures in a closed vessel, highlighting its non-linear behavior and the effects of radical wall termination. The reaction kinetic simulation predicts the three characteristic ignition limits of hydrogen caused by radical and thermal auto-ignition and is in close agreement with the experimental measurements. The first ignition limit is determined by the chain branching reaction . This limit shows strong sensitivity towards the wall termination of O, H and OH radicals. The second ignition limit is influenced by the wall termination of O, H, OH, HO2 and H2O2 radicals. The third ignition limit is dominated by the reaction paths and , which is why it shows strong sensitivity towards wall termination of HO₂ and H₂O₂ radicals. Increasing the radical wall termination rate by increasing the sticking coefficient of the radicals at the wall or the surface-to-volume-ratio leads to an increase of the auto-ignition temperature at the same pressure. The introduction of radical wall termination reactions improved the prediction of ignition limits and highlighted the profound effect of the autoclave wall and vessel size on the hydrogen ignition behavior. KW - Hydrogen KW - Auto-ignition temperature KW - Ignition limit KW - Radical wall termination reaction Y1 - 2025 U6 - https://doi.org/10.1016/j.proci.2025.105980 SN - 1540-7489 VL - 41 SP - 1 EP - 7 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Elbaz, Ayman M. A1 - Giri, Binod Raj A1 - Issayev, Gani A1 - Shrestha, Krishna Prasad A1 - Mauß, Fabian A1 - Farooq, Aamir A1 - Roberts, William L. T1 - Experimental and Kinetic Modeling Study of Laminar Flame Speed of Dimethoxymethane and Ammonia Blends T2 - Energy & Fuels N2 - Ammonia (NH3) is considered a promising carbon-neutral fuel, with a high hydrogen content, that can diversify the global energy system. Blending ammonia with a highly reactive fuel is one possible strategy to enhance its combustion characteristics. Here, an investigation of blends of NH3 and dimethoxymethane (DMM), a biofuel with high fuel-born oxygen content and no carbon–carbon bonds, is reported. Unstretched laminar burning velocity (SL) and Markstein length of different NH3/DMM blends were experimentally determined using spherically propagating premixed flames. The DMM mole fraction was varied from 0.2 to 0.6 while measuring SL at 298 K, 0.1 MPa, and equivalence ratios (Φ) over the range of 0.8–1.3. The addition of DMM was found to immensely enhance the combustion characteristics of ammonia. DMM 20% (by mole fraction) in the NH3/DMM blend increased SL by more than a factor of 3 over neat ammonia; such enhancement was found to be comparable to 60% CH4 in NH3 (Φ = 0.9–1.1) blends. Increasing Φ was found to significantly decrease the burned gas Markstein length for lean cases, whereas a negligible effect was observed for rich mixtures. A composite chemical kinetic model of DMM/NH3, aimed at interpreting the high-temperature combustion chemistry, was able to reliably predict SL for neat NH3 and DMM flames. Also, the predictive capability of the kinetic model to describe SL for DMM/NH3 blends is reasonably good. Sensitivity analysis and reaction path analysis indicated that the NH3/DMM blends could be understood as dual oxidation processes of the individual fuels that are competing for the same radical pool. KW - Ammonia KW - Dimethoxymethane KW - Laminar flame speed KW - Kinetic modeling Y1 - 2020 UR - https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.0c02269 U6 - https://doi.org/10.1021/acs.energyfuels.0c02269 SN - 1520-5029 VL - 34 IS - 11 SP - 14727 EP - 14740 ER - TY - GEN A1 - Elbaz, Ayman M. A1 - Giri, Binod Raj A1 - Shrestha, Krishna Prasad A1 - Arab, Omar Z. A1 - Farooq, Aamir A1 - Mauß, Fabian A1 - Roberts, William L. T1 - A comprehensive experimental and kinetic modeling study of laminar flame propagation of ammonia blended with propene T2 - Combustion and Flame N2 - Enhancement of ammonia reactivity is crucial for potential applications of ammonia as an engine and gas turbine fuel. A common strategy for improving ammonia's poor reactivity is blending it with more reactive fuels like hydrogen and methane. However, fundamental studies of ammonia combustion with higher hydrocarbons and key intermediate oxidation species of higher alkanes such as propene do not exist. Thus, this work presents an effort to study the laminar flame propagation of ammonia blended with propene. Laminar burning velocity (SL) of NH3/C3H6/air mixtures was measured at 298 K, pressures up to 5 bar, equivalence ratios of 0.7 to 1.3, and various propene to ammonia ratios (i.e.,% propene to ammonia mole fraction, xC3H6 = 10 to 50) in a high-pressure spherical propagating flame vessel. A kinetic model was developed based on our previous work to characterize the combustion behavior of NH3/C3H6/air mixture. The model reasonably agrees with the experimental data and follows the observed trends very well. The results showed that blending NH3 with C3H6 positively enhanced SL of NH3 by promoting the formation of key radicals e.g., O, OH, and H. Relative to a neat ammonia/air mixture, co-firing ammonia with propene leads to a reduced pressure dependence of the laminar burning velocity. However, the reaction H + O2(+M)=HO2(+M) leads to strong pressure dependency of lean NH3/C3H6 mixtures compared to rich mixtures. The model reveals that besides fuel-NO coming from NH3, prompt NO also actively contributes to NO formation. It is seen that N2O formation is significantly suppressed with increasing pressure or increasing C3H6 content in the fuel blend. In contrast to NO and N2O, NO2 concentration increases slightly with an increase in pressure. The reported experimental data and model will be useful in understanding the interaction between NH3 and alkenes. Y1 - 2023 U6 - https://doi.org/10.1016/j.combustflame.2023.112791 SN - 0010-2180 VL - 253 ER - TY - CHAP A1 - Fischer, Michael A1 - Günther, Michael A1 - Berger, Carsten A1 - Troeger, Ralf A1 - Pasternak, Michal A1 - Mauß, Fabian ED - Günther, Michael ED - Sens, Marc T1 - Suppressing Knocking by Using CleanEGR – Better Fuel Economy and Lower Raw Emissions Simultaneously T2 - Knocking in Gasoline Engines, 5th International Conference, December 12-13, 2017, Berlin, Germany KW - Suppressing Knocking Y1 - 2018 SN - 978-3-319-69760-4 U6 - https://doi.org/10.1007/978-3-319-69760-4_21 SP - 384 PB - Springer International Publishing CY - Cham ER - TY - GEN A1 - Fotiadis, Kyriakos A1 - Asimakopoulou, Akrivi A1 - Baltzopoulou, Penelope A1 - Kastrinaki, Georgia A1 - Koutsonikolas, Dimitrios A1 - Karagiannakis, George A1 - Skevis, George A1 - Richter, Jana A1 - Mauß, Fabian T1 - Experimental Characterization of a Novel Foam Burner Design for the Low-Excess-Enthalpy Combustion of Very Lean Syngas Mixtures T2 - Energies N2 - In the present work, a novel foam burner design is proposed and experimentally evaluated for operation with highly diluted syngas mixtures. The lab-scale burner consists of a purpose-built, square-shaped, high-temperature-grade stainless steel tubular reactor filled with square-sectioned siliconized silico carbide (SiSiC) foams. The assembly was installed in an electrical furnace. Spatially resolved temperature measurements were obtained along the reactor axis, while simultaneous measurements of CO, CO2, H2, O2, and N2 were taken at the burner exit and the water levels were recorded upstream and downstream of the reactor. The results clearly show that flames can be stabilized along the reactor for a range of foam characteristics and operating conditions. Hydrogen conversion efficiencies in excess of 98%, and overall thermal efficiencies close to 95% were achieved for the selected operating conditions. Overall, the denser 10 ppi foam demonstrated superior combustion characteristics in terms of stability, lower enthalpy rises, and a wider operating range at the expense of a very modest pressure drop penalty. Finally, scanning electron microscopy, coupled with energy dispersion spectroscopy (SEM/EDS) and Raman spectroscopy analyses, was used to determine the morphological and compositional characteristics of the pristine and aged foams. After more than 100 h of operation, no significant performance degradation was observed, even though the burner design was subjected to considerable thermal stress. Y1 - 2023 U6 - https://doi.org//10.3390/en16197014 SN - 1996-1073 VL - 16 IS - 19 SP - 7014 ER - TY - GEN A1 - Franken, Tim A1 - Duggan, Alexander A1 - Feng, Tao A1 - Borg, Anders A1 - Lehtiniemi, Harry A1 - Matrisciano, Andrea A1 - Mauß, Fabian T1 - Multi-Objective Optimization of Fuel Consumption and NOx Emissions using a Stochastic Reactor Model, THIESEL 2018 Conference on Thermo- and Fluid Dynamic Processes in Direct Injection Engines KW - Multi-Objective Optimization Y1 - 2018 UR - https://www.researchgate.net/publication/328265385 ER - TY - CHAP A1 - Franken, Tim A1 - Duggan, Alexander A1 - Feng, Tao A1 - Mauß, Fabian T1 - Multi-Objective Optimization of Fuel Consumption and NOx Emissions for a Heavy-Duty Direct Injection Diesel Engine T2 - European ESTECO User Meeting 2018, Trieste, Italy KW - Multi-Objective Optimization of Fuel Consumption Y1 - 2018 UR - https://www.researchgate.net/publication/325477898 ER - TY - GEN A1 - Franken, Tim A1 - Duggan, Alexander A1 - Matrisciano, Andrea A1 - Lehtiniemi, Harry A1 - Borg, Anders A1 - Mauß, Fabian T1 - Multi-Objective Optimization of Fuel Consumption and NO x Emissions with Reliability Analysis Using a Stochastic Reactor Model T2 - SAE Technical Paper N2 - The introduction of a physics-based zero-dimensional stochastic reactor model combined with tabulated chemistry enables the simulation-supported development of future compression-ignited engines. The stochastic reactor model mimics mixture and temperature inhomogeneities induced by turbulence, direct injection and heat transfer. Thus, it is possible to improve the prediction of NOx emissions compared to common mean-value models. To reduce the number of designs to be evaluated during the simulation-based multi-objective optimization, genetic algorithms are proven to be an effective tool. Based on an initial set of designs, the algorithm aims to evolve the designs to find the best parameters for the given constraints and objectives. The extension by response surface models improves the prediction of the best possible Pareto Front, while the time of optimization is kept low. This work presents a novel methodology to couple the stochastic reactor model and the Non-dominated Sorting Genetic Algorithm. First, the stochastic reactor model is calibrated for 10 low, medium and high load operating points at various engine speeds. Second, each operating point is optimized to find the lowest fuel consumption and specific NOx emissions. The optimization input parameters are the temperature at intake valve closure, the compression ratio, the start of injection, the injection pressure and exhaust gas recirculation rate. Additionally, it is ensured that the maximum peak cylinder pressure and turbine inlet temperature are not exceeded. This enables a safe operation of the engine and exhaust aftertreatment system under the optimized conditions. Subsequently, a reliability analysis is performed to estimate the effect of off-nominal conditions on the objectives and constraints. The novel multi-objective optimization methodology has proven to deliver reasonable results. The zero-dimensional stochastic reactor model with tabulated chemistry is a fast running physics-based model that allow to run large optimization problems in a short amount of time. The combination with the reliability analysis also strengthens the confidence in the simulation-based optimized engine operation parameters. Y1 - 2019 U6 - https://doi.org/10.4271/2019-01-1173 SN - 0148-7191 SN - 2688-3627 ER - TY - GEN A1 - Franken, Tim A1 - Duggan, Alexander A1 - Tao, Feng A1 - Matrisciano, Andrea A1 - Lehtiniemi, Harry A1 - Borg, Anders A1 - Mauß, Fabian T1 - Multi-Objective Optimization of Fuel Consumption and NOx Emissions of a heavy-duty Diesel engine using a Stochastic Reactor Model T2 - SAE technical paper N2 - Highly fuel-efficient Diesel engines, combined with effective exhaust aftertreatment systems, enable an economic and low-emission operation of heavy-duty vehicles. The challenge of its development arises from the present engine complexity, which is expected to increase even more in the future. The approved method of test bench measurements is stretched to its limits, because of the high demand for large parameter variations. The introduction of a physics-based quasi-dimensional stochastic reactor model combined with tabulated chemistry enables the simulation-supported development of these Diesel engines. The stochastic reactor model mimics mixture and temperature inhomogeneities induced by turbulence, direct injection and heat transfer. Thus, it is possible to improve the prediction of NOx emissions compared to common mean-value models. To reduce the number of designs to be evaluated during … KW - Highly fuel-efficient Diesel engines Y1 - 2019 SN - 0096-5170 SN - 0148-7191 IS - 2019-01-1173 ER - TY - GEN A1 - Franken, Tim A1 - Klauer, Christian A1 - Kienberg, Martin A1 - Matrisciano, Andrea A1 - Mauß, Fabian T1 - Prediction of thermal stratification in an engine-like geometry using a zero-dimensional stochastic reactor model T2 - International Journal of Engine Research KW - Prediction of thermal stratification Y1 - 2019 UR - https://journals.sagepub.com/eprint/5AKgEhAVA8RDS2tQWdGK/full SN - 2041-3149 U6 - https://doi.org/10.1177/1468087418824217 SN - 1468-0874 ER - TY - GEN A1 - Franken, Tim A1 - Matrisciano, Andrea A1 - Sari, Rafael A1 - Robles, Alvaro Fogue A1 - Monsalve-Serrano, Javier A1 - Pintor, Dario Lopez A1 - Pasternak, Michal A1 - Garcia, Antonio A1 - Mauß, Fabian T1 - Modeling of Reactivity Controlled Compression Ignition Combustion Using a Stochastic Reactor Model Coupled with Detailed Chemistry T2 - SAE technical papers : 15th International Conference on Engines & Vehicles N2 - Advanced combustion concepts such as reactivity controlled compression ignition (RCCI) have been proven to be capable of fundamentally improve the conventional Diesel combustion by mitigating or avoiding the soot-NOx trade-off, while delivering comparable or better thermal efficiency. To further facilitate the development of the RCCI technology, a robust and possibly computationally efficient simulation framework is needed. While many successful studies have been published using 3D-CFD coupled with detailed combustion chemistry solvers, the maturity level of the 0D/1D based software solution offerings is relatively limited. The close interaction between physical and chemical processes challenges the development of predictive numerical tools, particularly when spatial information is not available. The present work discusses a novel stochastic reactor model (SRM) based modeling framework capable of predicting the combustion process and the emission formation in a heavy-duty engine running under RCCI combustion mode. The combination of physical turbulence models, detailed emission formation sub-models and stateof-the-art chemical kinetic mechanisms enables the model to be computationally inexpensive compared to the 3D-CFD approaches. A chemical kinetic mechanism composed of 248 species and 1428 reactions was used to describe the oxidation of gasoline and diesel using a primary reference fuel (PRF)mixture and n-heptane, respectively. The model is compared to operating conditions from a single-cylinder research engine featuring different loads, speeds, EGR and gasoline fuel fractions. The model was found to be capable of reproducing the combustion phasing as well as the emission trends measured on the test bench, at some extent. The proposed modeling approach represents a promising basis towards establishing a comprehensive modeling framework capable of simulating transient operation as well as fuel property sweeps with acceptable accuracy. KW - Stochastic Reactor Models KW - RCCI KW - Chemical Kinetics KW - Low Temperature Combustion Y1 - 2021 UR - https://www.sae.org/publications/technical-papers/content/2021-24-0014/ U6 - https://doi.org/10.4271/2021-24-0014 SN - 0148-7191 SN - 2688-3627 ER - TY - GEN A1 - Franken, Tim A1 - Mauss, Fabian A1 - Sharma, Saurabh A1 - Brueger, Arnim A1 - Lepka, Marco T1 - Optimization of oxyfuel biogas combustion in combined heat and power plants : a multi-criteria study T2 - 32. Deutscher Flammentag – Paderborn, Germany: 15th – 17th September 2025 N2 - This paper investigates the influence of oxygen addition on the combustion of biogas and biomethane in a combined heat and power plant using numerical methods. A multi-objective optimization platform was established, employing a stochastic engine model with detailed chemistry to predict oxyfuel combustion and emission formation. Additionally, a hybrid optimization algorithm, combining NSGA-II and metamodels, was utilized to conduct the optimization. The optimization results indicate that the lowest indicated specific fuel consumption was achieved with biomethane, while the lowest NOx emissions were attained with biogas. An increase in oxygen addition proved beneficial for reducing specific fuel consumption. However, higher oxygen addition rates resulted in increased NOx emissions. KW - Biogas KW - Optimization KW - Oxyfuel Y1 - 2025 ER - TY - GEN A1 - Franken, Tim A1 - Mauß, Fabian T1 - Development of Methodology for Predictive Diesel Combustion Simulation Using 0D Stochastic Reactor Model T2 - SAE Technical Papers N2 - Stringent exhaust emission limits and new vehicle test cycles require sophisticated operating strategies for future diesel engines. Therefore, a methodology for predictive combustion simulation, focused on multiple injection operating points is proposed in this paper. The model is designated for engine performance map simulations, to improve prediction of NOx, CO and HC emissions.The combustion process is calculated using a zero dimensional direct injection stochastic reactor model based on a probability density function approach. Further, the formation of exhaust emissions is described using a detailed reaction mechanism for n-heptane, which involves 56 Species and 206 reactions. The model includes the interaction between turbulence and chemistry effects by using a variable mixing time profile. Thus, one is able to capture the effects of mixture inhomogeneities on NOx, CO and HC emission formation.The mixing time model is parameterized using transfer functions for engine operating parameters, e.g., injection mass, injection duration, air fuel ratio, start of injection and speed. These functions are calibrated for nine operating points using multi objective simulated annealing optimization combined with fast running metamodels that speed up the optimization process. The calibrated transfer functions are validated for nine additional operating points. The results for the calibration and validation points show a good match of the combustion heat release rate. Especially the main injection heat release rate is well predicted by the model. The NOx and CO emissions reflect the experimental trends and are in close range to the measurements. Finally, the model is tested for triple injection operating points. The results match the measurements, which show the applicability of the stochastic reactor model in conjunction with the mixing time transfer functions for engine performance map simulations. KW - Mathematical analysis KW - Diesel / Compression Ignition engines Y1 - 2016 U6 - https://doi.org/10.4271/2016-01-0566 SN - 0148-7191 SN - 0096-5170 IS - 2016-01-0566 SP - 14 Seiten 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 - Netzer, Corinna A1 - Mauß, Fabian T1 - Water Injection in Spark-Ignition Engines, FVV Autumn Conference 2018 Y1 - 2018 UR - https://www.researchgate.net/publication/328265540 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 - 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 - 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 - Franken, Tim A1 - Rachow, Fabian A1 - Charlafti, Evgenia A1 - Flege, Jan Ingo A1 - Jenssen, Martin A1 - Verma, Rakhi A1 - Günther, Vivien A1 - Mauss, Fabian T1 - Numerical investigation of oxy-methane combustion for stationary engines T2 - 40th International Symposium on Combustion N2 - This work presents a numerical investigation of turbulent oxyfuel combustion of methane in a gas engine with passive pre-chamber. The experimental data of a motored operating point at 1600 rpm and natural gas fired operating point at 2450 rpm, 6 bar IMEP and λ=1.5 are provided by TU Freiberg to validate the simulation model. The performance of the detailed chemistry model of Shrestha et al. predicting laminar burning velocity of premixed methane-oxygen flames is evaluated using the experiments of Mouze-Mornettas et al. The detailed chemistry model predicts the laminar flame speed within an accuracy range of ±10% for elevated pressure, temperature, and different equivalence ratios. For predicting the turbulent combustion in the gas engine, a three-dimensional (3D) Large Eddy Simulation (LES) with G Equation model and laminar flame speed look-up tables is used. The chemistry in the unburnt and burnt gas is solved using a constant volume detailed chemistry solver. The 3D LES model shows a good match of the motored and natural gas fired in-cylinder pressure profile. Subsequently the fuel is switched to methane and oxygen is used as oxidizer. The 3D LES results show an increase of maximum cylinder pressure up to 100 bar for λ=1.5, and the turbulent flame regime is shifted towards high Damköhler numbers compared to combustion with air. Diluting the cylinder gas with 50 mole-% CO2 or 65 mole-% H2O shows a significant reduction of peak cylinder pressure, and lower Damköhler and higher Karlovitz numbers compared to methane-oxygen combustion. KW - Oxyfuel KW - Simulation KW - Engines Y1 - 2024 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 - 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 - 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 - 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 - Sommerhoff, Arnd A1 - Willems, Werner A1 - Matrisciano, Andrea A1 - Lehtiniemi, Harry A1 - Borg, Anders A1 - Netzer, Corinna A1 - Mauß, Fabian T1 - Advanced Predictive Diesel Combustion Simulation Using Turbulence Model and Stochastic Reactor Model T2 - SAE technical paper KW - Advanced Predictive Y1 - 2017 UR - http://papers.sae.org/2017-01-0516 U6 - https://doi.org/10.4271/2017-01-0516 SN - 0148-7191 SN - 0096-5170 N1 - WCX™ 17: SAE World Congress Experience 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 - Franken, Tim A1 - Verma, Rakhi A1 - Sharma, Saurabh A1 - Gloesslein, Tobias A1 - Brueger, Arnim A1 - Mauss, Fabian T1 - Modeling of synthetic methane production using Gaussian processes regression T2 - CYPHER Workshop on "Digital Twins for the Decarbonization of hard-to-abate industries" N2 - The production of green gases using Power-to-gas in industry and the energy sector is essential for reducing the carbon footprint. In this process, green hydrogen and carbon dioxide are converted into synthetic methane using nickel catalysts. The carbon dioxide can be obtained from the environment or from point sources such as waste-to-energy plants, combined heat and power plants or industrial furnaces. A one-dimensional model of methane synthesis in the Sabatier reactor enables the simulation of transport processes in the porous medium and the reaction kinetics on the active surface of the nickel catalyst. Despite the low dimensionality, the reactor model is still computationally intensive, as it must solve the reaction mechanism of heterogeneous surface reactions and the mass and heat transport. The introduction of Gaussian processes regression can help to significantly reduce the computational effort for the prediction of species and temperature in the Sabatier reactor under different thermodynamic conditions. This allows for faster turnaround times, enables the application of advanced methods like optimization and more. The accuracy of a Gaussian processes regression is investigated in this work. KW - Gaussian Processes KW - Machine Learning KW - Reactor Y1 - 2024 UR - https://www.researchgate.net/publication/384441411_Modeling_of_synthetic_methane_production_using_Gaussian_processes_regression ER - TY - GEN A1 - Fritsche, Chris A1 - Eckart, Sven A1 - Shrestha, Krishna Prasad A1 - Mauß, Fabian A1 - Krause, Hartmut T1 - Methane flames with a substitution of 50 to 100 percent hydrogen: Experimental and numerical investigation of the temperature and pressure dependence of the laminar burning velocities T2 - 10th European Combustion Meeting, Proceedings of the European Combustion Meeting N2 - This work reports the laminar burning velocities for CH4/H2 blends in mixtures with air utilizing the constant volume chamber at temperatures from 300 to 423 K, pressures from 2 to 10 bar and equivalence ratios from 0.7 to 2.4. A detailed chemical kinetic model based on our previous work is used to reproduce the experimental data. The chemical kinetic model can reproduce the experimental data better at lean conditions compared to rich conditions. It is observed that with an increase in H2 fraction in fuel blend, laminar burning velocities increase. Model reveals that with increasing H2 fraction in the fuel blend, formation of key radicals H, OH and O are promoted leading to higher laminar burning velocities. The most sensitive reactions are O2+H=OH+O, CO+OH=CO2+H, CH4+H=CH3+H2 and CH4+OH=CH3+H2O. It is found that as initial mixture temperature increases, the laminar burning velocity increases and shows a linear trend whereas this trend is reversed as the initial pressure increases. KW - Methane KW - Hydrogen KW - Kinetic Model KW - Laminar burning velocity KW - Constant Volume chamber Y1 - 2021 UR - https://www.researchgate.net/publication/358415279_Methane_flames_with_a_substitution_of_50_to_100_percent_hydrogen_Experimental_and_numerical_investigation_of_the_temperature_and_pressure_dependence_of_the_laminar_burning_velocities ER - TY - GEN A1 - Fritsche, Chris A1 - Shrestha, Krishna Prasad A1 - Eckart, Sven A1 - Mauß, Fabian A1 - Krause, Hartmut T1 - Temperature and pressure dependency of the burning velocity in laminar premixed methanol and polyoxymethylene dimethyl ether (OME1, OME2, and OME3) flames T2 - 10th European Combustion Meeting, Proceedings of the European Combustion Meeting N2 - This work reports the laminar burning velocities (LBV) for the liquid fuels methanol, and polyoxymethylene dimethyl ethers (OMEn, n = 1-3) in mixtures with air utilizing the heat flux burner and constant volume chamber at temperature 393 to 443 K, pressure 1 to 10 bar, and equivalence ratio 0.6 to 1.9. Laminar burning velocities for OME2 and OME3 higher than 1 bar are reported for the first time. A detailed chemical kinetic model for OME2 and OME3 was developed based on our previous work utilizing experimental data from this work. Overall, model predictions are in good agreement with the experimental data. It is previously shown that with increases in unburned gas temperature laminar burning velocity increases and shows a linear trend with respect to temperature. Further, laminar burning velocity decreases with an increase of initial pressure. The dependence of burning velocity is not linear for all the fuels investigated. For comparable temperature and pressure conditions, it was found that with an additional CH2O group the laminar burning velocities increase marginally and there is no shift of maximum laminar burning velocity with respect to equivalence ratio. KW - Oxymethylene ethers KW - Lamianr burning velocity KW - Kinetic Modeling KW - heat flux burne KW - constant volume chamber Y1 - 2021 UR - https://www.researchgate.net/publication/358415681_Temperature_and_pressure_dependency_of_the_burning_velocity_in_laminar_premixed_methanol_and_polyoxymethylene_dimethyl_ether_OME1_OME2_and_OME3_flames ER - TY - GEN A1 - Giri, Binod Raj A1 - Mai, Tam V.‐T. A1 - Shrestha, Krishna Prasad A1 - Giri, Sushant A1 - Naik, R. Thirumaleswara A1 - Verma, Rakhi A1 - Mauss, Fabian A1 - Huynh, Lam K. T1 - Theoretical kinetic study of NH₂ reactions with dimethyl ether and diethyl ether : implications for kinetic modeling T2 - International journal of chemical kinetics N2 - Ammonia (NH₃) and hydrogen (H₂) have emerged as promising carbon‐free fuels to help mitigate global warming by reducing greenhouse gas emissions. Our ongoing research currently focuses on understanding the combustion characteristics of NH₃ blends with oxygenates and hydrocarbons, uncovering the critical role of carbon–nitrogen cross‐reactions in accurately modeling their combustion behavior. Amino (NH₂) radicals, which are abundant in ammonia and nitrogen‐rich environments, strongly influence the low‐temperature reactivity of NH₃‐hydrocarbon/oxygenate mixtures, affecting overall reactivity and emission characteristics. Recognizing the importance of NH₂ radicals, we investigated the reaction kinetics of NH₂ with dimethyl ether (DME, CH₃OCH₃) and diethyl ether (DEE, CH₃CH₂OCH₂CH₃) using appropriate high‐level ab initio and statistical rate theory methods. We computed the potential energy profiles at the CCSD(T)/cc‐pV(T, Q)Z//M06‐2X/aug‐cc‐pVTZ level of theory, analyzing the reactivity of NH₂ radicals at various C─H sites of these diethers. Incorporating these newly derived rate parameters, our updated kinetic model successfully captures previous experimental data, addressing the modeling challenges encountered in our earlier studies. Our findings, including insights into the impact of NH₂ radicals, contribute to an understanding of ammonia combustion and its potential in achieving carbon‐neutral energy systems. KW - Diethyl ether KW - Dimethyl ether KW - Kinetic modeling KW - NH Y1 - 2025 U6 - https://doi.org/10.1002/kin.21779 SN - 0538-8066 SN - 1097-4601 VL - 57 IS - 6 SP - 353 EP - 363 PB - Wiley CY - Hoboken, NJ ER - TY - GEN A1 - Giri, Binod Raj A1 - Palacios, Manuel Monge A1 - Thangaraj, Ravikumar A1 - Shrestha, Krishna Prasad A1 - Viskolcz, Béla A1 - Mauss, Fabian A1 - Szőri, Milán T1 - An Ab initio based OH initiated oxidation kinetics of glycerol carbonate: A promising biofuel component T2 - Proceedings of the Combustion Institute N2 - The global energy demand is steadily increasing because of the population explosion and economic growth. Fossil fuels supply around 85 % of global primary energy demand. On one hand, fulfilling the increasing energy demands is a big challenge for the next few decades. On the other hand, the continued burning of fossil fuels leads to higher CO2 emissions, severely impacting global warming. Therefore, the policymakers vow to shift from conventional fuels to renewable resources for economic, environmental, and future energy security reasons. In this context, biofuels from lignocellulosic biomass and/or carbon-neutral fuels produced in the sustainable carbon cycle can close the carbon cycle and reach net zero-carbon emission. Recently, glycerol carbonate has been proposed as a promising fuel or fuel additive for future sustainability. Therefore, we investigated the hydrogen abstraction reactions of glycerol carbonate (GC) by OH radicals using high-level ab initio and variational transition state theory calculations. We mapped out the potential energy surface using the CCSD(T)/cc-pV(D, T)Z//MP2/cc-pVTZ level of theory. We used the ab initio parameters to obtain the site-specific rate coefficients by employing the variational transition state theory. We observed that every hydrogen atom in GC displays a unique reactivity with OH radicals. We derived branching ratio of each channel that are difficult to access experimentally. The overall rate coefficients exhibit a strong non-Arrhenius behaviour, which can be represented as: This is the first reported rate data for the glycerol carbonate and OH radicals reaction. Y1 - 2024 UR - https://www.sciencedirect.com/science/article/abs/pii/S1540748924004760 U6 - https://doi.org/10.1016/j.proci.2024.105668 VL - 40 SP - 1 EP - 8 PB - Elsevier ER - TY - GEN A1 - Giri, Binod Raj A1 - Shrestha, Krishna Prasad A1 - Mai, Tam V.-T. A1 - Giri, Sushant A1 - Adil, Mohammad A1 - Naik, R. Thirumaleswara A1 - Mauß, Fabian A1 - Huynh, Lam Kim T1 - A Theoretical Study of NH2 Radical Reactions with Propane and Its Kinetic Implications in NH3-Propane Blends’ Oxidation T2 - Energies N2 - The reaction of NH2 radicals with C3H8 is crucial for understanding the combustion behavior of NH3/C3H8 blends. In this study, we investigated the temperature dependence of the rate coefficients for the hydrogen abstraction reactions of C3H8 by NH2 radicals using high-level theoretical approaches. The potential energy surface was constructed at the CCSD(T)/cc-pV(T, Q)//M06-2X/aug-cc-pVTZ level of theory, and the rate coefficients were computed using conventional transition state theory, incorporating the corrections for quantum tunneling and hindered internal rotors (HIR). The computed rate coefficients showed a strong curvature in the Arrhenius behavior, capturing the experimental literature data well at low temperatures. However, at T > 1500 K, the theory severely overpredicted the experimental data. The available theoretical studies did not align with the experiment at high temperatures, and the possible reasons for this discrepancy are discussed. At 300 K, the reaction of NH2 with C3H8 predominantly occurs at the secondary C-H site, which accounts for approximately 95% of the total reaction flux. However, the hydrogen abstraction reaction at the primary C-H site becomes the dominant reaction above 1700 K. A composite kinetic model was built, which incorporated the computed rate coefficients for NH2 + C3H8 reactions. The importance of NH2 + C3H8 reactions in predicting the combustion behavior of NH3/C3H8 blends was demonstrated by kinetic modeling. Y1 - 2023 U6 - https://doi.org/10.3390/en16165943 SN - 1996-1073 VL - 16 IS - 16 ER -