Laminar Flame Speeds and Ignition Delay Times of Gasoline/Air and Gasoline/Alcohol/Air Mixtures: The Effects of Heavy Alcohol Compared to Light Alcohol

Abstract Global concerns about CO2 levels in the atmosphere, energy security, and the depletion of fossil fuel supply have been the key motivation to develop bio-based fuel resources, which leads to promising and potential strategies of renewable and carbon-neutral biofuels. Among biofuels being strongly developed, 2,5-dimethylfuran (DMF) is a new alternative biofuel candidate since DMF could be synthesized from available and durable lignocellulosic biomass, as well as DMF's physicochemical properties were found to be similar to those of fossil fuels. Therefore, the comprehensive investigation on DMF is very essential before putting DMF into the commercial scale and the engine application. In this current work, the temporal evolutions of laminar flame characteristics including laminar burning velocities, unstretched flame propagation speed, and Schlieren images were critically reviewed based on the comparison of DMF with other fuels. Besides, flame instabilities were also evaluated in detail. Finally, ignition delay times were thoroughly analyzed with the variation of the initial parameters such as temperature, pressure, and equivalent ratio, suggesting that DMF could become the potential fuel for the spark ignition engine. In the future, the experimental studies on the real engines fueled with DMF should be carefully and completely performed to have a comprehensive evaluation of this promising biofuel class.

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Laminar Flame Speed and Ignition Delay Time Data for the Kinetic Modeling of Hydrogen and Syngas Fuel Blends

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4007737 ◽

2013 ◽

Vol 135 (2) ◽

Cited By ~ 102

Author(s):

Michael C. Krejci ◽

Olivier Mathieu ◽

Andrew J. Vissotski ◽

Sankaranarayanan Ravi ◽

Travis G. Sikes ◽

...

Keyword(s):

Carbon Monoxide ◽

Chemical Kinetics ◽

Ignition Delay ◽

Laminar Flame ◽

Flame Speed ◽

Laminar Flame Speed ◽

Elevated Pressures ◽

Ignition Delay Times ◽

Wide Range ◽

Delay Times

Laminar flame speeds and ignition delay times have been measured for hydrogen and various compositions of H2/CO (syngas) at elevated pressures and elevated temperatures. Two constant-volume cylindrical vessels were used to visualize the spherical growth of the flame through the use of a schlieren optical setup to measure the laminar flame speed of the mixture. Hydrogen experiments were performed at initial pressures up to 10 atm and initial temperatures up to 443 K. A syngas composition of 50/50 by volume was chosen to demonstrate the effect of carbon monoxide on H2-O2 chemical kinetics at standard temperature and pressures up to 10 atm. All atmospheric mixtures were diluted with standard air, while all elevated-pressure experiments were diluted with a He:O2 ratio of 7:1 to minimize instabilities. The laminar flame speed measurements of hydrogen and syngas are compared to available literature data over a wide range of equivalence ratios, where good agreement can be seen with several data sets. Additionally, an improved chemical kinetics model is shown for all conditions within the current study. The model and the data presented herein agree well, which demonstrates the continual, improved accuracy of the chemical kinetics model. A high-pressure shock tube was used to measure ignition delay times for several baseline compositions of syngas at three pressures across a wide range of temperatures. The compositions of syngas (H2/CO) by volume presented in this study included 80/20, 50/50, 40/60, 20/80, and 10/90, all of which are compared to previously published ignition delay times from a hydrogen-oxygen mixture to demonstrate the effect of carbon monoxide addition. Generally, an increase in carbon monoxide increases the ignition delay time, but there does seem to be a pressure dependency. At low temperatures and pressures higher than about 12 atm, the ignition delay times appear to be indistinguishable with an increase in carbon monoxide. However, at high temperatures the relative composition of H2 and CO has a strong influence on ignition delay times. Model agreement is good across the range of the study, particularly at the elevated pressures.

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Ignition and Flame Speed Kinetics of Two Natural Gas Blends With High Levels of Heavier Hydrocarbons

Volume 3: Combustion, Fuels and Emissions, Parts A and B ◽

10.1115/gt2008-51344 ◽

2008 ◽

Cited By ~ 11

Author(s):

Gilles Bourque ◽

Darren Healy ◽

Henry Curran ◽

Christopher Zinner ◽

Danielle Kalitan ◽

...

Keyword(s):

High Pressure ◽

Chemical Kinetics ◽

Ignition Delay ◽

Laminar Flame ◽

Flame Speed ◽

Data Set ◽

Chemical Kinetic Model ◽

Fuel Blends ◽

Ignition Delay Times ◽

Delay Times

High-pressure experiments and chemical kinetics modeling were performed to generate a database and a chemical kinetic model that can characterize the combustion chemistry of methane-based fuel blends containing significant levels of heavy hydrocarbons (up to 37.5% by volume). Ignition delay times were measured in two different shock tubes and in a rapid compression machine at pressures up to 34 atm and temperatures from 740 to 1660 K. Laminar flame speeds were also measured at pressures up to 4 atm using a high-pressure vessel with optical access. Two different fuel blends containing ethane, propane, n-butane, and n-pentane added to methane were studied at equivalence ratios varying from lean (0.3) to rich (2.0). This paper represents the most comprehensive set of experimental ignition and laminar flame speed data available in the open literature for CH4/C2H6/C3H8/C4H10/C5H12 fuel blends with significant levels of C2+ hydrocarbons. Using these data, a detailed chemical kinetics model, based on current and recent work by the authors, was compiled and refined. The predictions of the model are very good over the entire range of ignition delay times, considering the fact that the data set is so thorough. Nonetheless, some improvements to the model can still be made with respect to ignition times at the lowest temperatures and for the laminar flame speeds at pressures above 1 atm and rich conditions.

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On the Rational Interpretation of Data on Laminar Flame Speeds and Ignition Delay Times

Combustion Science and Technology ◽

10.1080/00102202.2014.970686 ◽

2014 ◽

Vol 187 (1-2) ◽

pp. 27-36 ◽

Cited By ~ 9

Author(s):

Chung K. Law ◽

Fujia Wu ◽

Fokion N. Egolfopoulos ◽

Vyaas Gururajan ◽

Hai Wang

Keyword(s):

Ignition Delay ◽

Laminar Flame ◽

Ignition Delay Times ◽

Delay Times

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An Investigation of Combustion Properties of Butanol and its Potential for Power Generation

Volume 3: Coal, Biomass and Alternative Fuels; Cycle Innovations; Electric Power; Industrial and Cogeneration Applications; Organic Rankine Cycle Power Systems ◽

10.1115/gt2017-64551 ◽

2017 ◽

Author(s):

Torsten Methling ◽

Sandra Richter ◽

Trupti Kathrotia ◽

Marina Braun-Unkhoff ◽

Clemens Naumann ◽

...

Keyword(s):

Ignition Delay ◽

Laminar Flame ◽

Cone Angle ◽

Transformation Method ◽

Chemical Kinetic ◽

Reaction Model ◽

Ignition Delay Times ◽

Combustion Properties ◽

Delay Times ◽

Reaction Models

Over the last years, global concerns about energy security and climate change have resulted in many efforts focusing on the potential utilization of non-petroleum-based, i.e. bio-derived, fuels. In this context, n-butanol has recently received high attention because it can be produced sustainably. A comprehensive knowledge about its combustion properties is inevitable to ensure an efficient and smart use of n-butanol if selected as a future energy carrier. In the present work, two major combustion characteristics, here laminar flame speeds applying the cone-angle method and ignition delay times applying the shock tube technique, have been studied, experimentally and by modeling exploiting detailed chemical kinetic reaction models, at ambient and elevated pressures. The in-house reaction model was constructed applying the RMG-method. A linear transformation method recently developed, linTM, was exploited to generate a reduced reaction model needed for an efficient, comprehensive parametric study of the combustion behavior of n-butanol/hydrocarbon mixtures. All experimental data were found to agree with the model predictions of the in-house reaction model, for all temperatures, pressures, and fuel-air ratios. On the other hand, calculations using reaction models from the open literature mostly overpredict the measured ignition delay times by about a factor of two. The results are compared to those of ethanol, with ignition delay times very similar and laminar flame speeds of n-butanol slightly lower, at atmospheric pressure.

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Ignition delay times, laminar flame speeds, and species time-histories in the H2S/CH4 system at atmospheric pressure

Proceedings of the Combustion Institute ◽

10.1016/j.proci.2018.06.034 ◽

2019 ◽

Vol 37 (1) ◽

pp. 735-742 ◽

Cited By ~ 10

Author(s):

Clayton R. Mulvihill ◽

Charles L. Keesee ◽

Travis Sikes ◽

Rodolfo S. Teixeira ◽

Olivier Mathieu ◽

...

Keyword(s):

Ignition Delay ◽

Atmospheric Pressure ◽

Laminar Flame ◽

Ignition Delay Times ◽

Delay Times ◽

Time Histories

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A Study on Fundamental Combustion Properties of Oxymethylene Ether-2

10.1115/gt2021-60078 ◽

2021 ◽

Author(s):

John N. Ngugi ◽

Sandra Richter ◽

Marina Braun-Unkhoff ◽

Clemens Naumann ◽

Markus Köhler ◽

...

Keyword(s):

Experimental Data ◽

Reaction Mechanisms ◽

Ignition Delay ◽

Laminar Flame ◽

Cone Angle ◽

Sensitivity Analyses ◽

Chain Reactions ◽

Ignition Delay Times ◽

Combustion Properties ◽

Delay Times

Abstract Oxymethylene ethers (OMEn, n = 1–5) are a promising class of synthetic fuels that have the potential to be used as additives or substitutes to diesel in compression ignition engines. A comprehensive understanding of their combustion properties is required for their safe and efficient utilization. In this study, the results of a combined experimental and modeling work on oxidation of OME2 are reported: (i) Ignition delay time measurements of stoichiometric OME2 / synthetic air mixtures diluted 1:5 with nitrogen using the shock tube method at pressures of 1, 4, and 16 bar, and (ii) laminar flame speeds of OME2 / air mixtures using the cone angle method at ambient and elevated pressures of 3 and 6 bar. The experimental data sets obtained have been used for validation of a detailed reaction mechanisms of OME2. The results of ignition delay times showed that OME2 exhibits a two-stage ignition in the lower temperature region. There is a good match of the measured data compared to the predicted ones using three reaction mechanisms from the literature. The mechanism from Cai et al. (2020) best predicted the temperature and pressure dependence of ignition delay times. For laminar flame speeds, the experimental data were well matched by the mechanism from Ren et al. (2019) at p = 1, 3, and 6 bar and for all equivalence ratios considered. From sensitivity analyses calculations, it was observed that chain reactions involving small radicals, i.e., H, O, OH, HO2, and CH3 control the oxidation of OME2. The comparison of the results of this work and our previous work (Ngugi et al. (2021)) on OME1 show that these two fuels have similar oxidation pathways. The results obtained in this work will contribute to a better understanding of the combustion of oxymethylene ethers, and thus, to the design and optimization of burners and engines as well.

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Numerical Study on the Effect of Real Syngas Compositions on Ignition Delay Times and Laminar Flame Speeds at Gas Turbine Conditions

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4025248 ◽

2013 ◽

Vol 136 (1) ◽

Cited By ~ 9

Author(s):

Olivier Mathieu ◽

Eric L. Petersen ◽

Alexander Heufer ◽

Nicola Donohoe ◽

Wayne Metcalfe ◽

...

Keyword(s):

Ignition Delay ◽

Delay Time ◽

Gas Turbines ◽

Ignition Delay Time ◽

Laminar Flame ◽

Flame Speed ◽

Operating Conditions ◽

Laminar Flame Speed ◽

Ignition Delay Times ◽

Delay Times

Depending on the feedstock and the production method, the composition of syngas can include (in addition to H2 and CO) small hydrocarbons, diluents (CO2, water, and N2), and impurities (H2S, NH3, NOx, etc.). Despite this fact, most of the studies on syngas combustion do not include hydrocarbons or impurities and in some cases not even diluents in the fuel mixture composition. Hence, studies with realistic syngas composition are necessary to help in designing gas turbines. The aim of this work was to investigate numerically the effect of the variation in the syngas composition on some fundamental combustion properties of premixed systems such as laminar flame speed and ignition delay time at realistic engine operating conditions. Several pressures, temperatures, and equivalence ratios were investigated for the ignition delay times, namely 1, 10, and 35 atm, 900–1400 K, and ϕ = 0.5 and 1.0. For laminar flame speed, temperatures of 300 and 500 K were studied at pressures of 1 atm and 15 atm. Results showed that the addition of hydrocarbons generally reduces the reactivity of the mixture (longer ignition delay time, slower flame speed) due to chemical kinetic effects. The amplitude of this effect is, however, dependent on the nature and concentration of the hydrocarbon as well as the initial condition (pressure, temperature, and equivalence ratio).

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