Download or read book Chemical Kinetic Modeling of Jet Fuel Surrogates written by Krithika Narayanaswamy and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Jet fuels, like typical transportation fuels, are mixtures of several hundreds of compounds belonging to different hydrocarbon classes. Their composition varies from one source to another, and only average fuel properties are known at best. In order to understand the combustion characteristics of the real fuels, and to address the problem of combustion control, computational studies using a detailed kinetic model to represent the real fuel, serves as a highly useful tool. However, the complexity of the real fuels makes it infeasible to simulate their combustion characteristics directly, requiring a simplified fuel representation to circumvent this difficulty. Typically, the real fuels are modeled using a representative surrogate mixture, i.e. a well-defined mixture comprised of a few components chosen to mimic the desired physical and chemical properties of the real fuel under consideration. Surrogates have been proposed for transportation fuels, including aviation fuels, and several kinetic modeling attempts for the proposed surrogates have also been made. However, (i) the fundamental kinetics of individual fuels, which make up the surrogate mixtures is not understood well, (ii) their combustion behavior at low through high temperatures has not been comprehensively validated, and this directly impacts the (iii) reliability of the multi-component reaction mechanism for a surrogate made up of these individual components. The present work is aimed at addressing the afore-mentioned concerns. The objective of this work is to develop a single, reliable kinetic model that can describe the oxidation of a few representative fuels, which are important components of transportation fuel surrogates, and thereby capture the specificities of the simpler, but still multi-component surrogates. The reaction mechanism is intended to well-represent the individual components as well as a multi-component surrogate for jet fuel made up of these fuel components. Further, this reaction mechanism is desired to be applicable at low through high temperatures, and be compact enough that chemical kinetic analysis is feasible. First, a representative compound for each of the major hydrocarbon classes found in the real jet fuel is identified. A surrogate for jet fuels is chosen to be comprised of n-dodecane (to represent normal alkanes), methylcyclohexane (to represent cyclic alkanes), and m-xylene (to represent aromatics). A Component Library approach is invoked for the development of a single, consistent, and reliable chemical scheme to accurately model this multi-component surrogate mixture. The chemical model is assembled in stages, starting with a base model and adding to it sub-mechanisms for the individual components of the surrogate, namely m- xylene, n-dodecane, and methylcyclohexane. The chemical model is validated comprehensively every time the oxidation pathways of a new component are incorporated into it and the experimental data is well captured by the simulations. In addition to the jet fuel surrogate, with the number of fuels described in the proposed reaction mechanism, a surrogate for the alternative Fischer-Tropsch fuels is also considered. Surrogates are defined for jet fuels and Fischer-Tropsch fuels by matching target properties important for combustion applications between the surrogate and the real fuel. The simulations performed using the proposed reaction mechanism, with the surrogates defined as fuels, are compared against global targets, such as ignition delays, flow reactor profiles, and flame speed measurements for representative jet fuels and Fischer-Tropsch fuels. The computations show promising agreement with these experimental data sets. The proposed reaction mechanism is well-suited to be used in real flow simulations of jet fuels. The proposed reaction mechanism has the ability to describe the kinetics of n- heptane, iso-octane, substituted aromatics, n-dodecane, and methylcyclohexane, all of which are important components of transportation fuel surrogates. Considering the large number of hydrocarbons whose kinetics are well described by this reaction mechanism, there are avenues for this reaction mechanism to be used to model other transportation fuels, such as gasoline, diesel, and alternative fuels, in addition to the jet and Fischer-Tropsch fuels discussed in the present study.

Download or read book Detailed and Simplified Chemical Kinetics of Aviation Fuels and Surrogates written by Valentini Markaki and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemistries of aviation fuels are invariably complex due to largehydrocarbon molecules. There are also large variations for a given fuel type. Furthermore, flow timescales encountered in high performance propulsion devicesincreasingly lead to difficulties associated with kinetically controlled or influencedphenomena such as flame stability, extinction and re-light. Current indications alsosuggest that fuel sources will become significantly more diverse in the future andmay, for example, encompass Fischer-Tropsch and/or bio-derived components. Thecombustion properties of such fuels can vary significantly from those in current useand this work outlines a route towards surrogate fuel mechanisms of sufficientaccuracy and generality to support the development of practical devices. A reaction class based route to the derivation of detailed chemical kineticmechanisms for alkyl-substituted aromatics is outlined and applied to thecyclopentadiene/indene, benzene/naphthalene, toluene/1-methyl naphthalenesystems. Work has also been extended to the n-propyl benzene system as well. These reaction classes were applied to model the oxidation of the above fuels withencouraging results. Important reaction channels during oxidation were identifiedand specifically, the methyl groups on aromatic rings have been identified asimportant in the context of radical scavenging. Furthermore, 1-methyl naphthalenemay also be used to modulate sooting tendencies in aviation and Diesel surrogates. Results obtained from chemical kinetic modelling of cyclopentadiene, toluene, npropylbenzene, naphthalene and 1-methyl naphthalene oxidation in shock tubes, jet-stirred and plug-flow reactors at various sets of representative stoichiometriesand temperatures are reported.

Download or read book Detailed Chemical Kinetic Modeling of Surrogate Fuels for Gasoline and Application to an HCCI Engine written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gasoline consists of many different classes of hydrocarbons, such as paraffins, olefins, aromatics, and cycloalkanes. In this study, a surrogate gasoline reaction mechanism is developed, and it has one representative fuel constituent from each of these classes. These selected constituents are iso-octane, n-heptane, 1-pentene, toluene, and methyl-cyclohexane. The mechanism was developed in a step-wise fashion, adding submechanisms to treat each fuel component. Reactions important for low temperature oxidation (

Download or read book Progress in Chemical Kinetic Modeling for Surrogate Fuels written by and published by . This book was released on 2008 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gasoline, diesel, and other alternative transportation fuels contain hundreds to thousands of compounds. It is currently not possible to represent all these compounds in detailed chemical kinetic models. Instead, these fuels are represented by surrogate fuel models which contain a limited number of representative compounds. We have been extending the list of compounds for detailed chemical models that are available for use in fuel surrogate models. Detailed models for components with larger and more complicated fuel molecular structures are now available. These advancements are allowing a more accurate representation of practical and alternative fuels. We have developed detailed chemical kinetic models for fuels with higher molecular weight fuel molecules such as n-hexadecane (C16). Also, we can consider more complicated fuel molecular structures like cyclic alkanes and aromatics that are found in practical fuels. For alternative fuels, the capability to model large biodiesel fuels that have ester structures is becoming available. These newly addressed cyclic and ester structures in fuels profoundly affect the reaction rate of the fuel predicted by the model. Finally, these surrogate fuel models contain large numbers of species and reactions and must be reduced for use in multi-dimensional models for spark-ignition, HCCI and diesel engines.

Download or read book Chemical Kinetic Modeling of Component Mixtures Relevant to Gasoline written by and published by . This book was released on 2009 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, a recently revised version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multi-component gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines. Simulation results are discussed focusing attention on the mixing effects of the fuel components.

Download or read book Detailed and Simplified Chemical Kinetics of Aviation Fuels and Surrogates written by and published by . This book was released on 2006 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The removal of the high Damkohler number assumption from modeling approaches is essential for the computational simulation of combusting flows where strong direct kinetic effects are present. Examples of relevant physical phenomena include flame extinction and re-light as well as pollutant emissions. Calculation methods (e.g. LES/FMDF) aimed at including such effects are computationally demanding and simplified reaction mechanisms that represent the desired chemical features with sufficient accuracy are required. Difficulties are augmented for aviation fuels due to the wide range of fuel components and sufficiently accurate detailed surrogate mechanisms are required for the subsequent derivation of further simplifications under actual operating conditions prior to the implementation into calculation methods for turbulent flows. The present paper addresses the issue of substituted aromatics and outlines a reaction class based route to the derivation of detailed chemical kinetic mechanisms. The example given considers the toluene/1-methyl naphthalene system.

Download or read book Recent Progress in the Development of Diesel Surrogate Fuels written by and published by . This book was released on 2009 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been much recent progress in the area of surrogate fuels for diesel. In the last few years, experiments and modeling have been performed on higher molecular weight components of relevance to diesel fuel such as n-hexadecane (n-cetane) and 2,2,4,4,6,8,8-heptamethylnonane (iso-cetane). Chemical kinetic models have been developed for all the n-alkanes up to 16 carbon atoms. Also, there has been much experimental and modeling work on lower molecular weight surrogate components such as n-decane and n-dodecane that are most relevant to jet fuel surrogates, but are also relevant to diesel surrogates where simulation of the full boiling point range is desired. For two-ring compounds, experimental work on decalin and tetralin recently has been published. For multi-component surrogate fuel mixtures, recent work on modeling of these mixtures and comparisons to real diesel fuel is reviewed. Detailed chemical kinetic models for surrogate fuels are very large in size. Significant progress also has been made in improving the mechanism reduction tools that are needed to make these large models practicable in multi-dimensional reacting flow simulations of diesel combustion. Nevertheless, major research gaps remain. In the case of iso-alkanes, there are experiments and modeling work on only one of relevance to diesel: iso-cetane. Also, the iso-alkanes in diesel are lightly branched and no detailed chemical kinetic models or experimental investigations are available for such compounds. More components are needed to fill out the iso-alkane boiling point range. For the aromatic class of compounds, there has been no new work for compounds in the boiling point range of diesel. Most of the new work has been on alkyl aromatics that are of the range C7 to C8, below the C10 to C20 range that is needed. For the chemical class of cycloalkanes, experiments and modeling on higher molecular weight components are warranted. Finally for multi-component surrogates needed to treat real diesel, the inclusion of higher molecular weight components is needed in models and experimental investigations.

Download or read book Use of Measured Species Class Concentrations with Chemical Kinetic Modeling for the Prediction of Autoxidation and Deposition of Jet Fuels Postprint written by and published by . This book was released on 2007 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: The production of detrimental carbonaceous deposits in jet aircraft fuel systems results from the involvement of trace heteroatomic species in the autoxidation chain that occurs upon fuel heating. Although it has been known for many years that these sulfur-, nitrogen-, and oxygen-containing species contribute to the tendency of a fuel to form deposits, simple correlations have been unable to predict the oxidation rates or the deposit forming tendencies over a range of fuel samples. In the present work, a chemical kinetic mechanism developed previously is refined to include the roles of key fuel species classes, such as phenols, reactive sulfur species, dissolved metals, and hydroperoxides. The concentrations of these fuel species classes in the unreacted fuel samples are measured experimentally and used as an input to the mechanism. The resulting model is used to simulate autoxidation behavior observed over a range of fuel samples.

Download or read book Detailed Kinetic Modeling of Gasoline Surrogate Mixtures written by and published by . This book was released on 2009 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, a recently revised version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multi-component gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines. Simulation results are discussed focusing attention on the mixing effects of the fuel components.

Download or read book Laminar Flame Speed of Jet Fuel Surrogates and Second Generation Biojet Fuel Blends written by Jeffrey Munzar and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "An understanding of the fundamental combustion properties of alternative fuels is essential for their adoption as replacements for non-renewable sources. In the aviation industry, a promising candidate is hydrotreated renewable jet fuel (HRJF). HRJF can be synthesized in a sustainable and economically viable manner from long chain fatty-acid methyl esters found in jatropha and camelina seed, and the laboratory-scale characterization of the combustion properties of HRJF is an active area of research. Such research is motivated, in part, by the chemical complexity of biojet fuels which are composed of hundreds of hydrocarbon species, similar to conventional aviation grade fuels. The laminar flame speed has been identified as an important combustion parameter for many combustion applications, and is especially relevant to the aviation community. The laminar flame speed is also an important parameter in the validation of chemical kinetic mechanisms, as it is representative of the chemical reactivity of the fuel. In this study, laminar, atmospheric pressure, premixed stagnation flames were used to determine the laminar flame speed of HRJF blended in varying ratios with Jet A-1 aviation fuel, requiring a combination of experimental and numerical methods. Jet A-1 was also studied to allow for comparative benchmarking of the biojet blends. Experiments were carried out in a jet-wall stagnation flame geometry at a pre-heated temperature of 400 K. Centerline velocity profiles were obtained using particle image velocimetry, from which the strained reference flame speeds were determined. Simulations of each experiment were carried out using the CHEMKIN-PRO software package together with a detailed chemical kinetic mechanism, with the specification of necessary boundary conditions taken entirely from experimental measurements. A direct comparison method was used to infer the true laminar flame speed from the experimental and numerical strained reference flame speeds. In order to model the chemical kinetics of Jet A-1 and the biojet blends, it was necessary to identify a surrogate blend that emulates the reactivity of the biojet fuels, while consisting of a much smaller number of pure compounds. Published data shows significant discrepancies for many jet fuel surrogate components, motivating their inclusion in this study. Thus, laminar flame speeds were also obtained for three candidate jet fuel surrogate components: n-decane, methylcyclohexane and toluene, which are representative of the alkane, cycloalkane and aromatic components of conventional aviation fuel, respectively. Results for the pure surrogate components were used to generate a suitable surrogate blend for the biojet blends. The results form this work resolve conflicting laminar flame speed data for the surrogate components, which is essential for the further development of chemical kinetic mechanisms and contributes to the surrogate modelling of jet fuel combustion. The laminar flame speeds of the biojet blends are compared to the Jet A-1 benchmark over a wide range of equivalence ratios. The biojet blends are found to behave similarly to Jet A-1 for low to moderate levels of blending, but show a marked disagreement otherwise." --

Download or read book Combustion and Chemical Kinetics Study of Jet Fuel Biogas and Solid Fuel in Diffusion Flames written by Saeid Jahangirian and published by . This book was released on 2009 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Kinetic Modeling of Gasoline Surrogate Components and Mixtures Under Engine Conditions written by and published by . This book was released on 2010 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, an improved version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multicomponent gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines (3-50 atm, 650-1200K, stoichiometric fuel/air mixtures). Simulation results are discussed focusing attention on the mixing effects of the fuel components.

Download or read book Chemical Kinetic Modeling of Combustion of Automotive Fuels written by W. J. Pitz and published by . This book was released on 2006 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this report are to: (1) Develop detailed chemical kinetic reaction models for components of fuels, including olefins and cycloalkanes used in diesel, spark-ignition and HCCI engines; (2) Develop surrogate mixtures of hydrocarbon components to represent real fuels and lead to efficient reduced combustion models; and (3) Characterize the role of fuel composition on production of emissions from practical automotive engines.

Download or read book Mathematical Modelling of Gas Phase Complex Reaction Systems Pyrolysis and Combustion written by and published by Elsevier. This book was released on 2019-06-21 with total page 1034 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical Modelling of Gas-Phase Complex Reaction Systems: Pyrolysis and Combustion, Volume 45, gives an overview of the different steps involved in the development and application of detailed kinetic mechanisms, mainly relating to pyrolysis and combustion processes. The book is divided into two parts that cover the chemistry and kinetic models and then the numerical and statistical methods. It offers a comprehensive coverage of the theory and tools needed, along with the steps necessary for practical and industrial applications. Details thermochemical properties and "ab initio" calculations of elementary reaction rates Details kinetic mechanisms of pyrolysis and combustion processes Explains experimental data for improving reaction models and for kinetic mechanisms assessment Describes surrogate fuels and molecular reconstruction of hydrocarbon liquid mixtures Describes pollutant formation in combustion systems Solves and validates the kinetic mechanisms using numerical and statistical methods Outlines optimal design of industrial burners and optimization and dynamic control of pyrolysis furnaces Outlines large eddy simulation of turbulent reacting flows

Download or read book Cleaner Combustion written by Frédérique Battin-Leclerc and published by Springer Science & Business Media. This book was released on 2013-09-06 with total page 657 pages. Available in PDF, EPUB and Kindle. Book excerpt: This overview compiles the on-going research in Europe to enlarge and deepen the understanding of the reaction mechanisms and pathways associated with the combustion of an increased range of fuels. Focus is given to the formation of a large number of hazardous minor pollutants and the inability of current combustion models to predict the formation of minor products such as alkenes, dienes, aromatics, aldehydes and soot nano-particles which have a deleterious impact on both the environment and on human health. Cleaner Combustion describes, at a fundamental level, the reactive chemistry of minor pollutants within extensively validated detailed mechanisms for traditional fuels, but also innovative surrogates, describing the complex chemistry of new environmentally important bio-fuels. Divided into five sections, a broad yet detailed coverage of related research is provided. Beginning with the development of detailed kinetic mechanisms, chapters go on to explore techniques to obtain reliable experimental data, soot and polycyclic aromatic hydrocarbons, mechanism reduction and uncertainty analysis, and elementary reactions. This comprehensive coverage of current research provides a solid foundation for researchers, managers, policy makers and industry operators working in or developing this innovative and globally relevant field.

Download or read book Experimental and Kinetic Modeling Study of Cyclohexane and Its Mono alkylated Derivatives Combustion written by Zhandong Wang and published by Springer. This book was released on 2018-01-23 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the combustion chemistry of cyclohexane, methylcyclohexane, and ethylcyclohexane on the basis of state-of-the-art synchrotron radiation photoionization mass spectrometry experiments, quantum chemistry calculations, and extensive kinetic modeling. It explores the initial decomposition mechanism and distribution of the intermediates, proposes a novel formation mechanism of aromatics, and develops a detailed kinetic model to predict the three cycloalkanes’ combustion properties under a wide range of conditions. Accordingly, the thesis provides an essential basis for studying much more complex cycloalkanes in transport fuels and has applications in engine and fuel design, as well as emission control.

Download or read book KINETIC MODELING OF FUEL EFFECTS OVER A WIDE RANGE OF CHEMISTRY PROPERTIES AND SOURCES written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Kinetic modeling is an important tool for engine design and can also be used for engine tuning and to study response to fuel chemistry and properties before an engine configuration is physically built and tested. Methodologies needed for studying fuel effects include development of fuel kinetic mechanisms for pure compounds, tools for designing surrogate blends of pure compounds that mimic a desired market fuel, and tools for reducing kinetic mechanisms to a size that allows inclusion in complex CFD engine models. In this paper, we demonstrate the use of these tools to reproduce engine results for a series of research diesel fuels using surrogate fuels in an engine and then modeling results with a simple 2 component surrogate blend with physical properties adjusted to vary fuel volatility. Results indicate that we were reasonably successful in mimicking engine performance of real fuels with blends of pure compounds. We were also successful in spanning the range of the experimental data using CFD and kinetic modeling, but further tuning and matching will be needed to exactly match engine performance of the real and surrogate fuels.