Lars Seidel - Academia.edu (original) (raw)

Papers by Lars Seidel

Research paper thumbnail of Diesel-PPC engine: Predictive Full Cycle Modeling with Reduced and Detailed Chemistry

SAE Technical Paper Series, 2011

ABSTRACT Partially Premixed Combustion (PPC) engines have demonstrated a potential for high effic... more ABSTRACT Partially Premixed Combustion (PPC) engines have demonstrated a potential for high efficiency and low emissions operation. To be able to study the combustion in detail but also to perform parametric studies on the potential of the PPC concept a one dimensional (1D) engine simulation tool was used with 1; a prescribed burn rate 2; predictive combustion tool with reduced chemical model and 3; predictive combustion tool with detailed chemical models. Results indicate that fast executing reduced chemistry work reasonably well in predicting PPC performance and that n-decane is possibly a suitable diesel substitute in PPC modeling while n-heptane is not.

Research paper thumbnail of Evaluation of the influence of thermodynamic data for propane and propene ignition delay times

The influence of thermodynamic data on auto ignition chemistry for propane and propene has been i... more The influence of thermodynamic data on auto ignition chemistry for propane and propene has been investigated. Thermodynamic data with high sensitivity on simulation results have been evaluated thoroughly. It was found that a small change in the heat of formation of C3H6 has high impact on calculated ignition delay times for propene and propane / oxygen mixtures. The new thermodynamic data was calculated through statistical methods from quantum chemical results of the benchmarked quantum chemical method G3B3. This resulted in a very small decrease of the standard heat of formation at 298 K of C3H6 from 20.57 kJ/mol to 19.97 kJ/mol, which resulted in a 36% increase in the calculated ignition delay times. Additionally the calculated heat of formation of C3H5 was 33.6 kJ/mol higher than in the previously used data set. This major change of the heat of formation of allyl results in a 91% increase in calculated ignition delay time for propene as fuel at 1440 K. Allyl (C3H5) shows to be a sensitive specie to the change of the thermodynamic data on the ignition delay times. The differences established through the comparison of these quantities shows a positive influence on the prediction of the propene and propane ignition delay times.

Research paper thumbnail of Prompt NO formation in flames: The influence of NCN thermochemistry

Proceedings of the Combustion Institute, 2013

The influence of the route via the NCN radical on NO formation in flames was examined from a ther... more The influence of the route via the NCN radical on NO formation in flames was examined from a thermochemistry and reaction kinetics perspective. A detailed analysis of available experimental and theoretical thermochemical data combined with an Active Thermochemical Tables analysis suggests a heat of formation of 457.8 ± 2.0 kJ/mol for NCN, consistent with carefully executed theoretical work of Harding et al. (2008) [5]. This value is significantly different from other previously reported experimental and theoretical values. A combination of an extensively validated comprehensive hydrocarbon oxidation model extended by the GDFkin3.0_NCN-NO x sub-mechanism reproduced NCN and NO mole fraction profiles in a recently characterized fuel-rich methane flame only when heat of formation values in the range of 445 -453 kJ/mol are applied. Sensitivity analysis revealed that the sensitivities of contributing steps to NO and NCN formation are strongly dependent on the absolute value of the heat of formation of NCN being used. In all flames under study the applied NCN thermochemistry highly influences simulated NO and NCN mole fractions.

Research paper thumbnail of Combustion Chemistry of the Butane Isomers in Premixed Low-Pressure Flames

Zeitschrift für Physikalische Chemie, 2011

ABSTRACT The combustion chemistry of the two butane isomers represents a subset in a comprehensiv... more ABSTRACT The combustion chemistry of the two butane isomers represents a subset in a comprehensive description of C1–C4 hydrocarbon and oxygenated fuels. A critical examination of combustion models and their capability to predict emissions from this class of fuels must rely on high-quality experimental data that address the respective chemical decomposition and oxidation pathways, including quantitative intermediate species mole fractions. Premixed flat low-pressure (40 mbar) flames of the two butane isomers were thus studied under identical, fuel-rich (ϕ=1.71) conditions. Two independent molecular-beam mass spectrometer (MBMS) set-ups were used to provide quantitative species profiles. Both data sets, one from electron ionization (EI)-MBMS with high mass resolution and one from photoionization (PI)-MBMS with high energy resolution, are in overall good agreement. Simulations with a flame model were used to analyze the respective reaction pathways, and differences in the combustion behavior of the two isomers are discussed. Read More: http://www.oldenbourg-link.com/doi/abs/10.1524/zpch.2011.0148

Research paper thumbnail of Detailed mass spectrometric and modeling study of isomeric butene flames

Combustion and Flame, 2013

Höinghaus, Detailed mass spectrometric and modeling study of isomeric butene flames, Combust. Fla... more Höinghaus, Detailed mass spectrometric and modeling study of isomeric butene flames, Combust. Flame 160 (2013) [487][488][489][490][491][492][493][494][495][496][497][498][499][500][501][502][503] The original publication is available at www.elsevier.com http://dx.

Research paper thumbnail of A Fast Tool for Predictive IC Engine In-Cylinder Modelling with Detailed Chemistry

SAE Technical Paper Series, 2012

Attention: This paper is not yet published. If you are interested in purchasing it-via Mail, Fax ... more Attention: This paper is not yet published. If you are interested in purchasing it-via Mail, Fax or Download-please click on the" Mail" shopping cart icon below and proceed through the checkout process once you are finished browsing our web site. When this paper becomes ...

Research paper thumbnail of Diesel-PPC engine: Predictive Full Cycle Modeling with Reduced and Detailed Chemistry

SAE Technical Paper Series, 2011

ABSTRACT Partially Premixed Combustion (PPC) engines have demonstrated a potential for high effic... more ABSTRACT Partially Premixed Combustion (PPC) engines have demonstrated a potential for high efficiency and low emissions operation. To be able to study the combustion in detail but also to perform parametric studies on the potential of the PPC concept a one dimensional (1D) engine simulation tool was used with 1; a prescribed burn rate 2; predictive combustion tool with reduced chemical model and 3; predictive combustion tool with detailed chemical models. Results indicate that fast executing reduced chemistry work reasonably well in predicting PPC performance and that n-decane is possibly a suitable diesel substitute in PPC modeling while n-heptane is not.

Research paper thumbnail of Evaluation of the influence of thermodynamic data for propane and propene ignition delay times

The influence of thermodynamic data on auto ignition chemistry for propane and propene has been i... more The influence of thermodynamic data on auto ignition chemistry for propane and propene has been investigated. Thermodynamic data with high sensitivity on simulation results have been evaluated thoroughly. It was found that a small change in the heat of formation of C3H6 has high impact on calculated ignition delay times for propene and propane / oxygen mixtures. The new thermodynamic data was calculated through statistical methods from quantum chemical results of the benchmarked quantum chemical method G3B3. This resulted in a very small decrease of the standard heat of formation at 298 K of C3H6 from 20.57 kJ/mol to 19.97 kJ/mol, which resulted in a 36% increase in the calculated ignition delay times. Additionally the calculated heat of formation of C3H5 was 33.6 kJ/mol higher than in the previously used data set. This major change of the heat of formation of allyl results in a 91% increase in calculated ignition delay time for propene as fuel at 1440 K. Allyl (C3H5) shows to be a sensitive specie to the change of the thermodynamic data on the ignition delay times. The differences established through the comparison of these quantities shows a positive influence on the prediction of the propene and propane ignition delay times.

Research paper thumbnail of Prompt NO formation in flames: The influence of NCN thermochemistry

Proceedings of the Combustion Institute, 2013

The influence of the route via the NCN radical on NO formation in flames was examined from a ther... more The influence of the route via the NCN radical on NO formation in flames was examined from a thermochemistry and reaction kinetics perspective. A detailed analysis of available experimental and theoretical thermochemical data combined with an Active Thermochemical Tables analysis suggests a heat of formation of 457.8 ± 2.0 kJ/mol for NCN, consistent with carefully executed theoretical work of Harding et al. (2008) [5]. This value is significantly different from other previously reported experimental and theoretical values. A combination of an extensively validated comprehensive hydrocarbon oxidation model extended by the GDFkin3.0_NCN-NO x sub-mechanism reproduced NCN and NO mole fraction profiles in a recently characterized fuel-rich methane flame only when heat of formation values in the range of 445 -453 kJ/mol are applied. Sensitivity analysis revealed that the sensitivities of contributing steps to NO and NCN formation are strongly dependent on the absolute value of the heat of formation of NCN being used. In all flames under study the applied NCN thermochemistry highly influences simulated NO and NCN mole fractions.

Research paper thumbnail of Combustion Chemistry of the Butane Isomers in Premixed Low-Pressure Flames

Zeitschrift für Physikalische Chemie, 2011

ABSTRACT The combustion chemistry of the two butane isomers represents a subset in a comprehensiv... more ABSTRACT The combustion chemistry of the two butane isomers represents a subset in a comprehensive description of C1–C4 hydrocarbon and oxygenated fuels. A critical examination of combustion models and their capability to predict emissions from this class of fuels must rely on high-quality experimental data that address the respective chemical decomposition and oxidation pathways, including quantitative intermediate species mole fractions. Premixed flat low-pressure (40 mbar) flames of the two butane isomers were thus studied under identical, fuel-rich (ϕ=1.71) conditions. Two independent molecular-beam mass spectrometer (MBMS) set-ups were used to provide quantitative species profiles. Both data sets, one from electron ionization (EI)-MBMS with high mass resolution and one from photoionization (PI)-MBMS with high energy resolution, are in overall good agreement. Simulations with a flame model were used to analyze the respective reaction pathways, and differences in the combustion behavior of the two isomers are discussed. Read More: http://www.oldenbourg-link.com/doi/abs/10.1524/zpch.2011.0148

Research paper thumbnail of Detailed mass spectrometric and modeling study of isomeric butene flames

Combustion and Flame, 2013

Höinghaus, Detailed mass spectrometric and modeling study of isomeric butene flames, Combust. Fla... more Höinghaus, Detailed mass spectrometric and modeling study of isomeric butene flames, Combust. Flame 160 (2013) [487][488][489][490][491][492][493][494][495][496][497][498][499][500][501][502][503] The original publication is available at www.elsevier.com http://dx.

Research paper thumbnail of A Fast Tool for Predictive IC Engine In-Cylinder Modelling with Detailed Chemistry

SAE Technical Paper Series, 2012

Attention: This paper is not yet published. If you are interested in purchasing it-via Mail, Fax ... more Attention: This paper is not yet published. If you are interested in purchasing it-via Mail, Fax or Download-please click on the" Mail" shopping cart icon below and proceed through the checkout process once you are finished browsing our web site. When this paper becomes ...