Laminar Flame Speed Of Jet Fuel Surrogates And Second Generation Biojet Fuel Blends

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Laminar Flame Speed of Jet Fuel Surrogates and Second Generation Biojet Fuel Blends

Author : Jeffrey Munzar
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (922 download)

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Book Synopsis Laminar Flame Speed of Jet Fuel Surrogates and Second Generation Biojet Fuel Blends by : Jeffrey Munzar

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." --

Flame Propagation of Jet A-1 Fuel and Its Surrogates

Author : Bradley Denman
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (922 download)

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Book Synopsis Flame Propagation of Jet A-1 Fuel and Its Surrogates by : Bradley Denman

Download or read book Flame Propagation of Jet A-1 Fuel and Its Surrogates written by Bradley Denman and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The laminar flame speed is an essential flame parameter for both chemical kinetic mechanism validation and turbulent combustion studies. Kerosene-derived jet fuel flame speeds, however, are largely unknown and due to complex composition of the fuels themselves they cannot be modelled numerically. To overcome this limitation surrogate fuels and blends are used to reproduce the same flame speed of amore complex mixture. To accomplish this for aviation fuel, a database is created of four potential jet fuel surrogate components for laminar flame speed. The neat hydrocarbon surrogates investigated are n-dodecane and n-decane, methylcyclohex-ane, and toluene, which represent the alkane, cycloalkane, and aromatic components of conventional aviation fuel, respectively. Several blends of these surrogate fuels are tested experimentally and numerically to validate the effect of blend composition on flame speed. The database is then used to develop a blend to match the flame speeds of a commercial aviation fuel, Jet A-1. Unlike previous investigations of flame propagation, in this study, numerical simulations are directly compared to velocity profile measurements in laminar stagnation flames to extrapolate to a condition of zero flame stretch. Numerical simulations of each experiment are obtained using the CHEMKIN-PRO software package and the JetSurF 2.0 mechanism with accurate specification of all necessary boundary conditions from experimental measurements. The advantage of this technique is that the extrapolation to the unstretched condition is independent of the how well the mechanism predicts reactivity. Therefore, JetSurF 2.0 was simultaneously validated for each of the surrogate fuels and blends in a previously unused manner. The mechanism showed relatively good agreement for the n-alkane and cycloalkane fuels for which it was optimized for, while consistently under predicted the reactivity of toluene. The compiled database of jet fuel surrogate components allowed for five different potential surrogate mixtures to be developed. Experimental results of these blends suggest that although jet fuel is a very complex mixture a simple surrogate mixture consisting of 73% n-decane and 27% toluene byvolume appropriately matches the flame speed of Jet A-1. Numerical results using JetSurF 2.0 suggest that a 63% n-decane and 37% toluene by volume blend is the most appropriate surrogate and this was used to extrapolate the experimental JetA-1 results and determine its laminar flame speed." --

Flame Studies on Conventional, Alternative, and Surrogate Jet Fuels, and Their Reference Hydrocarbons

Author : Xin Hui
Publisher :
ISBN 13 :
Total Pages : 161 pages
Book Rating : 4.:/5 (934 download)

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Book Synopsis Flame Studies on Conventional, Alternative, and Surrogate Jet Fuels, and Their Reference Hydrocarbons by : Xin Hui

Download or read book Flame Studies on Conventional, Alternative, and Surrogate Jet Fuels, and Their Reference Hydrocarbons written by Xin Hui and published by . This book was released on 2013 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents work on the flame propagation and extinction of various liquid hydrocarbon fuels, including conventional and alternative jet fuels, surrogate fuels, and their reference hydrocarbon components. The laminar flame speeds and extinction stretch rates are experimentally determined by using a twin-flame counterflow setup integrated with a Digital Particle Image Velocimetry system for the flow field measurement. The experimental results are also compared with computed values obtained by using various published kinetic models for different fuels. In general, most of the simulation results agree with the experimental data with an average deviation less than 10%, which are reasonable considering the uncertainties in both experiments and kinetic models. The results of this work show that the conventional Jet-A and alternative jet fuels share very similar flame speeds and extinction limits despite of their differences in the molecular composition. The results of two surrogate mixtures for Jet-A show that they are both able to reproduce very well the flame speeds and extinction limits of the target jet fuel. Additional studies on aromatic species relevant to the conventional jet fuels illustrate that the degree and position of alkyl substitution on the benzene ring have a strong effect on the reactivity of the aromatic components studied. By extending the flame propagation studies to elevated pressures up to 3 atm, it is found that the flame speed results at elevated pressures are consistent in the trend with atmospheric results. Further attempts are made to identify and quantify the effects of preheat temperature and pressure on burning rate. This dissertation provides experimental flame speed and extinction data of high fidelity for jet fuels and relevant hydrocarbons. The fundamental data provided herein can serve as the benchmark database, and can be used in development and validation of combustion kinetic models.

Biojet Fuel in Aviation Applications

Author : Cheng Tung Chong
Publisher : Elsevier
ISBN 13 : 012823072X
Total Pages : 360 pages
Book Rating : 4.1/5 (282 download)

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Book Synopsis Biojet Fuel in Aviation Applications by : Cheng Tung Chong

Download or read book Biojet Fuel in Aviation Applications written by Cheng Tung Chong and published by Elsevier. This book was released on 2021-06-27 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biojet fuels have the potential to make an important contribution towards decarbonising the aviation sector. Biojet Fuel in Aviation Applications: Production, Usage and Impact of Biofuels covers all aspects of this sustainable aviation fuel including aviation biofuel public policies, production technologies, physico-chemical properties, combustion performances, techno-economics of sustainable fuel production, sustainability and energywater-food (EWF) nexus. This must-have book also charts the current state of the industry by discussing the relevant industry players who are currently producing alternative aviation fuels and flight tests, while also providing a glimpse of the future of the industry. This comprehensive book is written for undergraduate students, postgraduate students, researchers, engineers and policy makers wanting to build up knowledge in the specific area of biojet fuel or the broader fields of sustainable energy and aeronautics. Reviews major aviation and biojet fuel policies, legislations, initiatives and roadmaps around the world Features existing and emerging biojet fuel production pathways from various feedstocks Highlights the key properties of biojet fuels that ensures inter-operability with conventional jet aviation fuel Discusses the economic aspects of the biojet fuel industry and the barriers preventing its commercialisation Examines the sustainability of biojet fuel from a life cycle assessment, energy balance and EWF nexus point of views

Production Processes of Renewable Aviation Fuel

Author : Claudia Gutierrez-Antonio
Publisher : Elsevier
ISBN 13 : 0128231718
Total Pages : 272 pages
Book Rating : 4.1/5 (282 download)

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Book Synopsis Production Processes of Renewable Aviation Fuel by : Claudia Gutierrez-Antonio

Download or read book Production Processes of Renewable Aviation Fuel written by Claudia Gutierrez-Antonio and published by Elsevier. This book was released on 2021-01-22 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Production Processes of Renewable Aviation Fuel: Present Technologies and Future Trends presents the available production processes for renewable aviation fuel, including the application of intensification and energy integration strategies. Despite biofuels have gained a lot of interest in the last years, renewable aviation fuel is one of the less studied. In the last ten years, there has been an incredible growth in the number of patents and articles related with its production processes. Several transformation pathways have been proposed, and new ones have been outlined. The book contains the main information about the production processes of renewable aviation fuel, considering international standards, available technologies, and recent scientific contributions. It also outlines the motivation for the development of renewable aviation fuel, and its main processing pathways from the different renewable raw materials. In addition, the application of intensification and energy integration strategies is presented, along with the identified future trends in this area Includes the motivation for the development of renewable aviation fuel and applicable standards Describes the processing pathways from biomass to produce renewable aviation fuel Presents the application of intensification and energy integration strategies for the production of renewable aviation fuel The future trends in the production processes of renewable aviation fuel are discussed

Laminar Burning Velocities and Laminar Flame Speeds of Multi-component Fuel Blends at Elevated Temperatures and Pressures

Author : Jung Joo Byun
Publisher :
ISBN 13 :
Total Pages : 332 pages
Book Rating : 4.:/5 (731 download)

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Book Synopsis Laminar Burning Velocities and Laminar Flame Speeds of Multi-component Fuel Blends at Elevated Temperatures and Pressures by : Jung Joo Byun

Download or read book Laminar Burning Velocities and Laminar Flame Speeds of Multi-component Fuel Blends at Elevated Temperatures and Pressures written by Jung Joo Byun and published by . This book was released on 2011 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Iso-octane, n-heptane, ethanol and their blends were tested in a constant volume combustion chamber to measure laminar burning velocities. The experimental apparatus was modified from the previous version to an automatically-controlled system. Accuracy and speed of data acquisition were improved by this modification. The laminar burning velocity analysis code was also improved for minimized error and fast calculation. A large database of laminar burning velocities at elevated temperatures and pressures was established using this improved experimental apparatus and analysis code. From this large database of laminar burning velocities, laminar flame speeds were extracted. Laminar flame speeds of iso-octane, n-heptane and blends were investigated and analysed to derive new correlations to predict laminar flame speeds of any blending ratio. Ethanol and ethanol blends with iso-octane and/or n-heptane were also examined to see the role of ethanol in the blends. Generally, the results for iso-octane and n-heptane agree with published data. Additionally, blends of iso-octane and n-heptane exhibited flame speeds that followed linear blending relationships. A new flame speed model was successfully applied to these fuels. Ethanol and ethanol blends with iso-octane and/or n-heptane exhibited a strongly non-linear blending relationship and the new flame speed model was not applied to these fuels. It was shown that the addition of ethanol into iso-octane and/or n-heptane accelerated the flame speeds.

Sustainable Jet Fuel for Aviation

Author : Erik C. Wormslev
Publisher : Nordic Council of Ministers
ISBN 13 : 9289346612
Total Pages : 253 pages
Book Rating : 4.2/5 (893 download)

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Book Synopsis Sustainable Jet Fuel for Aviation by : Erik C. Wormslev

Download or read book Sustainable Jet Fuel for Aviation written by Erik C. Wormslev and published by Nordic Council of Ministers. This book was released on 2016 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study assesses to what extent the production and use of advanced sustainable jet fuel may contribute to GHG reduction and mitigation, and identifies the commercial potential for initiating and scaling up advanced sustainable jet fuel production at a Nordic level. The report explores as well on how to most efficiently use the available Nordic know-how, feedstock and production facilities. The report draws on the latest available reports and statistics, as well as interviews with stakeholders and experts across the Nordic countries, concludes on identifying the most matured technologies, the Nordic opportunities and challenges, and ideas to mitigate the barriers within the Nordic private and public sectors.

The Study of Laminar Flame Speed of Conventional and Sustainable Aviation Fuel at Elevated Pressure

Author :
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (141 download)

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Book Synopsis The Study of Laminar Flame Speed of Conventional and Sustainable Aviation Fuel at Elevated Pressure by :

Download or read book The Study of Laminar Flame Speed of Conventional and Sustainable Aviation Fuel at Elevated Pressure written by and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Laminar Flame Speed Measurments of Synthetic Gas Blends with Hydrocarbon Impurities

Author : Charles Lewis Keesee
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (942 download)

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Book Synopsis Laminar Flame Speed Measurments of Synthetic Gas Blends with Hydrocarbon Impurities by : Charles Lewis Keesee

Download or read book Laminar Flame Speed Measurments of Synthetic Gas Blends with Hydrocarbon Impurities written by Charles Lewis Keesee and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: New laminar flame speed measurements have been taken for a wide range of synthetic gas, or syngas, mixtures. These experiments began with two baseline mixtures. The first of these baseline mixtures was a bio-syngas surrogate with a 50/50 H2/CO split, and the second baseline mixture was a coal syngas blend with a 40/60 H2/CO split. Experiments were conducted over a range of equivalence ratios from [phi] = 0.5 to 3 at initial conditions of 1 atm and 296 K. Upon completion of the baseline experiments, two different hydrocarbons were added to the fuel mixtures at levels ranging from 0.8 to 15% by volume, keeping the H2/CO ratio locked for the bio-syngas and coal syngas mixtures. The addition of these light hydrocarbons, namely CH4 and C2H6, had been shown in a previous numerical study to have significant impacts on the laminar flame speed, and the present experiments validated the suspected trends. For example, a 7% addition of methane to the coal-syngas blend decreased the peak flame speed by about 25% and shifted it from [phi] = 2.2 to a leaner value near [phi] = 1.5. Also, the addition of ethane at 1.7% reduced the mixture flame speed more than a similar addition of methane (1.6%). Images taken during the experiments show the addition of hydrocarbons increasing the stability of the flame. The analysis also looked at the effects of hydrocarbon addition on the Markstein lengths and Lewis numbers of the mixtures. Markstein lengths were relatively consistent throughout all mixtures investigated. The Lewis numbers were found to move closer to unity for both lean and rich mixtures as hydrocarbons were added. Compared to the experimental results the model predicts the shape of the flame speed curve and places the peak at the correct equivalence ratio. However the model predicts a slower flame speed when hydrocarbons are added. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155067

Experimental Study of Laminar Burning Speed and Plasma-stabilized Flame

Author : Saeid Zare
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)

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Book Synopsis Experimental Study of Laminar Burning Speed and Plasma-stabilized Flame by : Saeid Zare

Download or read book Experimental Study of Laminar Burning Speed and Plasma-stabilized Flame written by Saeid Zare and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since being discovered, combustion of fuels, especially fossil fuels in the last centuries, has been the dominant source of energy for human life. However, over the years, the adverse effects and shortcomings caused by the vast utilization of these energy sources have been observed; the three most important of which are unreliable resources, unfavorable natural outcomes, and limited performance. Using biofuels is one of the well-established proposed solutions to the scarcity and environmental issues of fossils as they are sustainable sources of energy with acceptable and even superior combustion characteristics. As a second-generation biofuel, anisole has shown promising results with high flame speed and high knock resistance. Therefore, the first chapter of this thesis is focused on experimental investigation of anisole laminar burning speed and stability properties so that it can be used as a benchmark for future kinetic mechanism validations. Stability is another important parameter in combustion systems, especially in diffusion jet flame combustion as used in many applications like thrusters or burners. Different methods are applied to improve the stability of such diffusion flames in propulsion systems, e.g., changing geometrical or flow characteristics of the burner. Most of these efforts have not been practically successful, due to the cost and compatibility issues. Another technique which minimizes such problems is to use electron impact excitation, dissociation and ionization and generate highly concentrated charged/excited species and active radicals. These methods include microwave, dielectric barrier, and repetitive nanosecond pulsed (RNP) discharge and the latter has shown promising results as one of the most effective low-temperature plasma (LTP) methods. In chapters 3 to 5, the benefits and issues associated with using RNP discharge in a single-element concentric methane-air inverse diffusion jet flame are discussed. It has been shown that RNP discharge with adequate discharge properties (voltage and repetition) can increase the stability of the flame and expand the flammability of the jet toward leaner compositions. However, the effectiveness is significant in a certain voltage-frequency ranges which results a non-thermal spark discharge mode. Hence, different modes of discharge were investigated and a parametric study on the transition between these modes were done.

Fuel Structure Effects on Surrogate Alternative Jet Fuel Emission

Author : Giacomo Flora
Publisher :
ISBN 13 :
Total Pages : 259 pages
Book Rating : 4.:/5 (939 download)

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Book Synopsis Fuel Structure Effects on Surrogate Alternative Jet Fuel Emission by : Giacomo Flora

Download or read book Fuel Structure Effects on Surrogate Alternative Jet Fuel Emission written by Giacomo Flora and published by . This book was released on 2015 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emergence of alternative jet fuels has opened new challenges for the selection of practical alternatives that minimize the emissions and are suitable for existing gas turbine engines. Alternative jet fuels are in the early stages of development, and little fundamental emissions data are currently available. An accurate knowledge of their combustion behavior is highly important for a proper fuel selection based on emissions.This dissertation work investigated the oxidation of different alternative fuel surrogates composed of binary mixtures in order to correlate fuel composition with emissions. The proposed surrogate mixtures included n-dodecane/n-heptane (47.5/52.5 by liq. vol.), n-dodecane/iso-octane (47.9/52.1 by liq, vol.), n-dodecane/methylcyclohexane (49/51 by liq. vol.) and n-dodecane/m-xylene (75/25 by liq. vol.) mixtures. Experiments were carried out at the UDRI heated shock tube facility, and covered a pre-ignition temperature range of 950--1550 K at a pre-ignition pressure of ~16 atm, an equivalence ratio of 3, an argon concentration of 93% (by mol), and under homogeneous gas-phase conditions. Experimental data were modeled using the 2014 SERDP mechanism for jet fuel surrogates (525 species and 3199 reactions). Similar ignition delay times were measured for the tested surrogate blends, confirming previous observations regarding the controlling role of normal alkanes during the induction period. The experimental observation was also compared with modeling results reporting reasonably good agreements. A kinetic analysis of the SERDP 2014 mechanism was also performed, highlighting the major chemical pathways relevant to the pre-ignition chemistry, especially the role of the hydroperoxyl radical at the low temperatures. A wide speciation of combustion products was also carried out under the test conditions. All the aliphatic blends reported similar emissions, whereas the presence of m-xylene produced lower emissions than the aliphatic surrogate blends at lower temperatures. For certain species (light gases) this experimental observation was also supported by the kinetic mechanism predictions. However, aromatic species formed from combustion of n-dodecane/m-xylene surrogate blend were always overestimated by the model and in poor agreement with experimental observations. The results also confirmed the role of acetylene as assisting growth of large PAHs and formation of soot.

Computational and Experimental Studies of Jet Fuel Combustion

Author :
Publisher :
ISBN 13 :
Total Pages : 14 pages
Book Rating : 4.:/5 (574 download)

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Book Synopsis Computational and Experimental Studies of Jet Fuel Combustion by :

Download or read book Computational and Experimental Studies of Jet Fuel Combustion written by and published by . This book was released on 2009 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental and computational study was completed on the structure of two sets of flames: a nonsooting CH4 counterflow diffusion flame doped with 1000 ppm of either jet fuel or a 6-component surrogate and a well-defined baseline C2H4 flame under incipient sooting conditions perturbed with the addition of 2000 ppm by mole of either jet fuel or two surrogates, a 6-component Utah/Yale blend and a two-component Aachen surrogate. Gas samples were extracted from the flame with quartz microprobes for subsequent GC/MS analysis. Profiles of critical fuel decomposition products and soot precursors, such as benzene and toluene, were compared. The data for C7-C12 alkanes were consistent with typical decomposition of large alkanes with both surrogates showing good qualitative agreement with jet fuel in their pyrolysis trends. Olefins were formed as the fuel alkanes decomposed, with agreement between the surrogates and jet fuel improved for small alkenes. Good agreement between jet fuel and the surrogates was found with respect to critical soot precursors such as benzene and toluene. Although the 6-component Utah/Yale surrogate performed better than the Aachen surrogate, the latter performed adequately and retained the advantage of simplicity, since it consisted of only two components. Additional work focused on the development of a domain decomposition parallel solution methodology for coflow diffusion flames.

Combustion of Surrogate Jet Fuel Components in Premixed Stagnation Flames

Author : Bryan Fishbein
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (72 download)

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Book Synopsis Combustion of Surrogate Jet Fuel Components in Premixed Stagnation Flames by : Bryan Fishbein

Download or read book Combustion of Surrogate Jet Fuel Components in Premixed Stagnation Flames written by Bryan Fishbein and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Experimental and Numerical Investigation of Laminar Flame Speeds of H2/co/co2/n2 Mixtures

Author : Jayaprakash Natarajan
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (268 download)

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Book Synopsis Experimental and Numerical Investigation of Laminar Flame Speeds of H2/co/co2/n2 Mixtures by : Jayaprakash Natarajan

Download or read book Experimental and Numerical Investigation of Laminar Flame Speeds of H2/co/co2/n2 Mixtures written by Jayaprakash Natarajan and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Coal derived synthetic gas (syngas) fuel is a promising solution for today s increasing demand for clean and reliable power. Syngas fuels are primarily mixtures of H2 and CO, often with large amounts of diluents such as N2, CO2, and H2O. The specific composition depends upon the fuel source and gasification technique. This requires gas turbine designers to develop fuel flexible combustors capable of operating with high conversion efficiency while maintaining low emissions for a wide range of syngas fuel mixtures. Design tools often used in combustor development require data on various fundamental gas combustion properties. For example, laminar flame speed is often an input as it has a significant impact upon the size and static stability of the combustor. Moreover it serves as a good validation parameter for leading kinetic models used for detailed combustion simulations. Thus the primary objective of this thesis is measurement of laminar flame speeds of syngas fuel mixtures at conditions relevant to ground-power gas turbines. To accomplish this goal, two flame speed measurement approaches were developed: a Bunsen flame approach modified to use the reaction zone area in order to reduce the influence of flame curvature on the measured flame speed and a stagnation flame approach employing a rounded bluff body. The modified Bunsen flame approach was validated against stretch-corrected approaches over a range of fuels and test conditions; the agreement is very good (less than 10% difference). Using the two measurement approaches, extensive flame speed information were obtained for lean syngas mixtures at a range of conditions: 1) 5 to 100% H2 in the H2/CO fuel mixture; 2) 300-700 K preheat temperature; 3) 1 to 15 atm pressure, and 4) 0-70% dilution with CO2 or N2. The second objective of this thesis is to use the flame speed data to validate leading kinetic mechanisms for syngas combustion. Comparisons of the experimental flame speeds to those predicted using detailed numerical simulations of strained and unstrained laminar flames indicate that all the current kinetic mechanisms tend to over predict the increase in flame speed with preheat temperature for medium and high H2 content fuel mixtures. A sensitivity analysis that includes reported uncertainties in rate constants reveals that the errors in the rate constants of the reactions involving HO2 seem to be the most likely cause for the observed higher preheat temperature dependence of the flame speeds. To enhance the accuracy of the current models, a more detailed sensitivity analysis based on temperature dependent reaction rate parameters should be considered as the problem seems to be in the intermediate temperature range (~800-1200 K).

Development of a Spherical Combustion Chamber for Measuring Laminar Flame Speeds in Navy Bulk Fuels and Biofuel Blends

Author : Omari D. Buckley
Publisher :
ISBN 13 :
Total Pages : 65 pages
Book Rating : 4.:/5 (773 download)

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Book Synopsis Development of a Spherical Combustion Chamber for Measuring Laminar Flame Speeds in Navy Bulk Fuels and Biofuel Blends by : Omari D. Buckley

Download or read book Development of a Spherical Combustion Chamber for Measuring Laminar Flame Speeds in Navy Bulk Fuels and Biofuel Blends written by Omari D. Buckley and published by . This book was released on 2011 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the results of an experimental study to determine laminar flame speeds using the spherical flame method. An experimental combustion chamber, based on the constant-volume bomb method, was designed, built, and instrumented to conduct these experiments. Premixed Ethylene/air mixtures at a pressure of 2 atm, temperature of 298± 5K and equivalence ratios ranging from 0.8 to 1.5 were ignited and using a high speed video Schlieren system images were taken to measure the laminar flame speed in the expanding spherical flame front. The results were compared against published data for ethylene/air mixtures which yielded agreement within 5%. An attempt was made to measure the laminar flame speed for F-76 at a pressure of 5 atm and temperature of 500K; however, premixed conditions were unable to be met due to auto-ignition and vapor characteristics of F-76. Suggestions for future work provide a potential solution and improvement to the current design.

Effect of Blending on High-pressure Laminar Flame Speed Measurements, Markstein Lengths, and Flame Stability of Hydrocarbons

Author : William Baugh Lowry
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (781 download)

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Book Synopsis Effect of Blending on High-pressure Laminar Flame Speed Measurements, Markstein Lengths, and Flame Stability of Hydrocarbons by : William Baugh Lowry

Download or read book Effect of Blending on High-pressure Laminar Flame Speed Measurements, Markstein Lengths, and Flame Stability of Hydrocarbons written by William Baugh Lowry and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Natural gas is the primary fuel used in industrial gas turbines for power generation. Hydrocarbon blends of methane, ethane, and propane make up a large portion of natural gas and it has been shown that dimethyl ether can be used as a supplement or in its pure form for gas turbine combustion. Because of this, a fundamental understanding of the physical characteristics such as the laminar flame speed is necessary, especially at elevated pressures to have the most relevance to the gas turbine industry. This thesis discusses the equations governing premixed laminar flames, historical methods used to measure the laminar flame speed, the experimental device used in this study, the procedure for converting the measured data into the flame speed, the results of the measurements, and a discussion of the results. The results presented in this thesis include the flame speeds for binary blends of methane, ethane, propane, and dimethyl ether performed at elevated pressures, up to 10-atm initial pressure, using a spherically expanding flame in a constant-volume vessel. Also included in this thesis is a comparison between the experimental measurements and four chemical kinetic models. The C4 mechanism, developed in part through collaboration between the National University of Ireland Galway and Texas A & M, was improved using the data presented herein, showing good agreement for all cases. The effect of blending ethane, propane, and dimethyl ether with methane in binary form is emphasized in this study, with the resulting Markstein length, Lewis number (Le), and flame stability characterized and discussed. It was noticed in this study, as well as in other studies, that the critical radius of the flame typically decreased as the Le decreased, and that the critical radius of the flame increased as the Le increased. Also, a rigorous uncertainty analysis has been performed, showing a range of 0.3 cm/s to 3.5 cm/s depending on equivalence ratio and initial pressure.

Enhancements of a Combustion Vessel to Determine Laminar Flame Speeds of Hydrocarbon Blends with Helium Dilution at Elevated Temperatures and Pressures

Download Enhancements of a Combustion Vessel to Determine Laminar Flame Speeds of Hydrocarbon Blends with Helium Dilution at Elevated Temperatures and Pressures PDF Online Free

Author : Drew Plichta
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (868 download)

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Book Synopsis Enhancements of a Combustion Vessel to Determine Laminar Flame Speeds of Hydrocarbon Blends with Helium Dilution at Elevated Temperatures and Pressures by : Drew Plichta

Download or read book Enhancements of a Combustion Vessel to Determine Laminar Flame Speeds of Hydrocarbon Blends with Helium Dilution at Elevated Temperatures and Pressures written by Drew Plichta and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel flexibility in gas turbines is of particular importance because of the main fuel source, natural gas. Blends of methane, ethane, and propane are big constituents in natural gas and consequently are of particular interest. With this level of importance comes the need for baseline data such as laminar flame speed of said fuels. While flame speeds at standard temperature and pressure have been extensively studied in the literature, experimental data at turbine-like conditions are still lacking currently. This thesis discusses the theory behind laminar flames; new data acquisition techniques; temperature and pressure capability improvements; measured flame speeds; and a discussion of the results including stability analysis. The measured flame speeds were those of methane, ethane, and propane fuel blends, as well as pure methane, at an elevated pressure of 5 atm and temperatures of 298 and 473 K, using a constant-volume, cylindrical combustion vessel. The current Aramco mechanism developed in conjunction with National University of Ireland Galway compared favorably with the data, while the literature data showed discrepancies at stoichiometric to rich conditions. An in-depth flame speed uncertainty analysis yielded a wide range of values from 0.5 cm/s to 21.5 cm/s. It is well known that high-pressure experiments develop flame instabilities when air is used as the oxidizer. In this study, the hydrodynamic instabilities were restrained by using a high diluent-to-oxygen ratio. The thermal-diffusive instabilities were inhibited by using helium as the diluent. To characterize this flame stability, the Markstein length and Lewis number were calculated for the presented conditions. The resultant positive Markstein lengths showed a low propensity of flame speed to flame stretch, while the larger-than-unity Lewis numbers showed the relatively higher diffusivity of helium to that of nitrogen. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/149407