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 - 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 - 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 - 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 - 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 - 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 -