Machine learning techniques to predict the flame state, temperature and species concentrations in counter-flow diffusion flames operated with CH4/CO/H2-air mixtures
Conception of a pilot plant scaled optically accessible combustion chamber for determining the combustion properties of process, mixed and natural gases under the influence of external recirculation and changing wall conditions
Experimental study and proposed power correlation for laminar burning velocity of hydrogen-diluted methane with respect to pressure and temperature variation
Machine learning is a popular way to find patterns and relationships in high complex datasets. Wi... more Machine learning is a popular way to find patterns and relationships in high complex datasets. With the nowadays advancements in storage and computational capabilities, some machine-learning techniques are becoming suitable for real-world applications. The aim of this work is to conduct a comparative analysis of machine learning algorithms and conventional statistical techniques. These methods have long been used for clustering large amounts of data and extracting knowledge in a wide variety of science fields. However, the central knowledge of the different methods and their specific requirements for the data set, as well as the limitations of the individual methods, are an obstacle for the correct use of these methods. New machine learning algorithms could be integrated even more strongly into the current evaluation if the right choice of methods were easier to make. In the present work, some different algorithms of machine learning are listed. Four methods (artificial neural netwo...
Insight into fuel isomeric effects on laminar flame propagation of pentanones
Proceedings of the Combustion Institute
Abstract Laminar flame propagation was investigated for pentanone isomers/air mixtures (3-pentano... more Abstract Laminar flame propagation was investigated for pentanone isomers/air mixtures (3-pentanone, 2-pentanone and 3-methyl-2-butanone) in a high-pressure constant-volume cylindrical combustion vessel at 393–423 K, 1–10 atm and equivalence ratios of 0.6–1.5, and in a heat flux burner at 393 K, 1 atm and equivalence ratios of 0.6–1.5. Two kinds of methods generally show good agreement, both of which indicate that the laminar burning velocity increases in the order of 3-methyl-2-butanone, 2-pentanone and 3-pentanone. A kinetic model of pentanone isomers was developed and validated against experimental data in this work and in literature. Modeling analysis was performed to provide insight into the flame chemistry of the three pentanone isomers. H-abstraction reactions are concluded to dominate fuel consumption, and further decomposition of fuel radicals eventually produces fuel-specific small radicals. The differences in radical pools are concluded to be responsible for the observed fuel isomeric effects on laminar burning velocity. Among the three pentanone isomers, 3-pentanone tends to produce ethyl and does not prefer to produce methyl and allyl in flames, thus it has the highest reactivity and fastest laminar flame propagation. On the contrary, 3-methyl-2-butanone tends to produce allyl and methyl instead of ethyl, and consequently has the lowest reactivity and slowest laminar flame propagation.
Laminar burning velocities, CO, and NOx emissions of premixed polyoxymethylene dimethyl ether flames
Fuel
Abstract Polyoxymethylene dimethyl ethers (OMEn) with the chemical structure of CH 3 O ( CH 2 O )... more Abstract Polyoxymethylene dimethyl ethers (OMEn) with the chemical structure of CH 3 O ( CH 2 O ) n CH 3 are a promising synthetic e-fuel class that can be produced from renewable electricity and improves the emission characteristics of internal combustion engines. However, knowledge of their fundamental combustion properties, such as the laminar burning velocity, is limited in the literature, preventing the full assessment of their application potential in combustion devices. Thus, a heat flux burner is applied in this study to measure the laminar burning velocities of OME1 and OME2 over a wide range of equivalence ratios of 0.6–1.9 and at initial temperatures of 383–401 K under atmospheric pressure for the first time. The obtained data are compared with computed results using a recently developed reaction mechanism for OME1–4. Good agreement is observed. The experimental results are also discussed in the context of a comparison to literature data of dimethyl ether and OME3, demonstrating the minor impact of chain length of (OMEn) on their burning velocities, which is further analyzed in terms of sensitivity analysis on reaction kinetics. Furthermore, the exhaust gas composition of NO x and CO is determined experimentally for flames of OME1 and OME2 using a probe method and compared to the numerical results, observing mostly good agreement, where the remaining differences could be explained on the basis of combined experimental and model uncertainties. This provides unique knowledge on the emission performance of the combustion of (OMEn).
Experimental and numerical investigations on extinction strain rates in non-premixed counterflow methane and propane flames in an oxygen reduced environment
Fuel
Abstract The aim of this work is to contribute to the better understanding of the oxidation proce... more Abstract The aim of this work is to contribute to the better understanding of the oxidation process of light hydrocarbons, low calorific value gas and components of natural gas in the presence of inert gases and the influence of oxygen reduction in exhaust gas recirculation situations. The extinction behavior of laminar counterflow diffusion flames of methane (CH4), ethene (C2H4) and propane (C3H8) under nitrogen diluted condition has been investigated experimentally and numerically. In the experimental set-up, a counterflow burner was employed to investigate the extinction behavior under atmospheric conditions (1 bar and 298 K). The present study highlights the non-linear influence on the decrease in the extinction strain rate (ESR) that were found with decreasing fuel content and decreasing oxygen content. The oxygen content on the oxide side was stepwise diluted with nitrogen in order to distinctly show the possible oxygen-depleted influence in the recirculation areas. Additionally, it has been shown that the distance between the nozzles has an impact on the ESR but not on the general rising trend with the increasing fuel content in the non-premixed flames. Moreover, to clarify the influence, the flame zones were visualized using a system of high-speed OH* chemiluminescence camera. It was possible to investigate the width, intensity and position of the flame front from the radical detection. This provided a comprehensive data base for the subsequent numerical validation. In order to complement the experimental investigations, extensive uncertainty analyses were conducted and a new laser-based approach for the detection of flame extinction were demonstrated for the low-visible flames. Besides the experimental study, ESRs of CH4 and C3H8 combustion obtained from the experimental measurements were compared with those predicted by the numerical simulations. The San Diego-2014 reaction mechanism was used to represent the detailed chemical reaction, in which the predicted ESRs agree well with the experimental data was shown. Additionally, the effects of radiative heat loss, molecular transport model and chemical reactions on the ESRs were studied numerically. The present results suggest that the radiative heat loss plays a minor role on the ESRs, the molecular transport model is more significant and the ESRs are quite sensitive to several key reactions.
Determining the laminar burning velocity of nitrogen diluted dimethoxymethane ( OME 1 ) using the heat‐flux burner method: Numerical and experimental investigations
Machine learning techniques to predict the flame state, temperature and species concentrations in counter-flow diffusion flames operated with CH4/CO/H2-air mixtures
Conception of a pilot plant scaled optically accessible combustion chamber for determining the combustion properties of process, mixed and natural gases under the influence of external recirculation and changing wall conditions
Experimental study and proposed power correlation for laminar burning velocity of hydrogen-diluted methane with respect to pressure and temperature variation
Machine learning is a popular way to find patterns and relationships in high complex datasets. Wi... more Machine learning is a popular way to find patterns and relationships in high complex datasets. With the nowadays advancements in storage and computational capabilities, some machine-learning techniques are becoming suitable for real-world applications. The aim of this work is to conduct a comparative analysis of machine learning algorithms and conventional statistical techniques. These methods have long been used for clustering large amounts of data and extracting knowledge in a wide variety of science fields. However, the central knowledge of the different methods and their specific requirements for the data set, as well as the limitations of the individual methods, are an obstacle for the correct use of these methods. New machine learning algorithms could be integrated even more strongly into the current evaluation if the right choice of methods were easier to make. In the present work, some different algorithms of machine learning are listed. Four methods (artificial neural netwo...
Insight into fuel isomeric effects on laminar flame propagation of pentanones
Proceedings of the Combustion Institute
Abstract Laminar flame propagation was investigated for pentanone isomers/air mixtures (3-pentano... more Abstract Laminar flame propagation was investigated for pentanone isomers/air mixtures (3-pentanone, 2-pentanone and 3-methyl-2-butanone) in a high-pressure constant-volume cylindrical combustion vessel at 393–423 K, 1–10 atm and equivalence ratios of 0.6–1.5, and in a heat flux burner at 393 K, 1 atm and equivalence ratios of 0.6–1.5. Two kinds of methods generally show good agreement, both of which indicate that the laminar burning velocity increases in the order of 3-methyl-2-butanone, 2-pentanone and 3-pentanone. A kinetic model of pentanone isomers was developed and validated against experimental data in this work and in literature. Modeling analysis was performed to provide insight into the flame chemistry of the three pentanone isomers. H-abstraction reactions are concluded to dominate fuel consumption, and further decomposition of fuel radicals eventually produces fuel-specific small radicals. The differences in radical pools are concluded to be responsible for the observed fuel isomeric effects on laminar burning velocity. Among the three pentanone isomers, 3-pentanone tends to produce ethyl and does not prefer to produce methyl and allyl in flames, thus it has the highest reactivity and fastest laminar flame propagation. On the contrary, 3-methyl-2-butanone tends to produce allyl and methyl instead of ethyl, and consequently has the lowest reactivity and slowest laminar flame propagation.
Laminar burning velocities, CO, and NOx emissions of premixed polyoxymethylene dimethyl ether flames
Fuel
Abstract Polyoxymethylene dimethyl ethers (OMEn) with the chemical structure of CH 3 O ( CH 2 O )... more Abstract Polyoxymethylene dimethyl ethers (OMEn) with the chemical structure of CH 3 O ( CH 2 O ) n CH 3 are a promising synthetic e-fuel class that can be produced from renewable electricity and improves the emission characteristics of internal combustion engines. However, knowledge of their fundamental combustion properties, such as the laminar burning velocity, is limited in the literature, preventing the full assessment of their application potential in combustion devices. Thus, a heat flux burner is applied in this study to measure the laminar burning velocities of OME1 and OME2 over a wide range of equivalence ratios of 0.6–1.9 and at initial temperatures of 383–401 K under atmospheric pressure for the first time. The obtained data are compared with computed results using a recently developed reaction mechanism for OME1–4. Good agreement is observed. The experimental results are also discussed in the context of a comparison to literature data of dimethyl ether and OME3, demonstrating the minor impact of chain length of (OMEn) on their burning velocities, which is further analyzed in terms of sensitivity analysis on reaction kinetics. Furthermore, the exhaust gas composition of NO x and CO is determined experimentally for flames of OME1 and OME2 using a probe method and compared to the numerical results, observing mostly good agreement, where the remaining differences could be explained on the basis of combined experimental and model uncertainties. This provides unique knowledge on the emission performance of the combustion of (OMEn).
Experimental and numerical investigations on extinction strain rates in non-premixed counterflow methane and propane flames in an oxygen reduced environment
Fuel
Abstract The aim of this work is to contribute to the better understanding of the oxidation proce... more Abstract The aim of this work is to contribute to the better understanding of the oxidation process of light hydrocarbons, low calorific value gas and components of natural gas in the presence of inert gases and the influence of oxygen reduction in exhaust gas recirculation situations. The extinction behavior of laminar counterflow diffusion flames of methane (CH4), ethene (C2H4) and propane (C3H8) under nitrogen diluted condition has been investigated experimentally and numerically. In the experimental set-up, a counterflow burner was employed to investigate the extinction behavior under atmospheric conditions (1 bar and 298 K). The present study highlights the non-linear influence on the decrease in the extinction strain rate (ESR) that were found with decreasing fuel content and decreasing oxygen content. The oxygen content on the oxide side was stepwise diluted with nitrogen in order to distinctly show the possible oxygen-depleted influence in the recirculation areas. Additionally, it has been shown that the distance between the nozzles has an impact on the ESR but not on the general rising trend with the increasing fuel content in the non-premixed flames. Moreover, to clarify the influence, the flame zones were visualized using a system of high-speed OH* chemiluminescence camera. It was possible to investigate the width, intensity and position of the flame front from the radical detection. This provided a comprehensive data base for the subsequent numerical validation. In order to complement the experimental investigations, extensive uncertainty analyses were conducted and a new laser-based approach for the detection of flame extinction were demonstrated for the low-visible flames. Besides the experimental study, ESRs of CH4 and C3H8 combustion obtained from the experimental measurements were compared with those predicted by the numerical simulations. The San Diego-2014 reaction mechanism was used to represent the detailed chemical reaction, in which the predicted ESRs agree well with the experimental data was shown. Additionally, the effects of radiative heat loss, molecular transport model and chemical reactions on the ESRs were studied numerically. The present results suggest that the radiative heat loss plays a minor role on the ESRs, the molecular transport model is more significant and the ESRs are quite sensitive to several key reactions.
Determining the laminar burning velocity of nitrogen diluted dimethoxymethane ( OME 1 ) using the heat‐flux burner method: Numerical and experimental investigations
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Papers by Sven Eckart