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

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

Author : Jeffrey Munzar

Publisher :

Page : pages

File Size : 49,3 MB

Release : 2013

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"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 :

Page : pages

File Size : 16,77 MB

Release : 2013

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"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 :

Page : 161 pages

File Size : 49,50 MB

Release : 2013

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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

Page : 360 pages

File Size : 29,27 MB

Release : 2021-06-27

Category : Business & Economics

ISBN : 012823072X

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Book Description

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

Page : 272 pages

File Size : 49,54 MB

Release : 2021-01-22

Category : Technology & Engineering

ISBN : 0128231718

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Book Description

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 :

Page : 332 pages

File Size : 14,33 MB

Release : 2011

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ISBN :

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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

Page : 253 pages

File Size : 38,4 MB

Release : 2016

Category : Denmark

ISBN : 9289346612

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Book Description

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.





Laminar Flame Speed Measurments of Synthetic Gas Blends with Hydrocarbon Impurities

Author : Charles Lewis Keesee

Publisher :

Page : pages

File Size : 15,99 MB

Release : 2015

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ISBN :

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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 :

Page : 0 pages

File Size : 24,4 MB

Release : 2021

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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.