Download or read book A Study on the Sooting Tendency of Jet Fuel Surrogates Using the Threshold Soot Index written by Amy Mensch and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fuel Effects on Soot Formation in Turbojet Engines written by D. B. Olson and published by . This book was released on 1984 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The sooting tendencies of sixteen Navy jet fuels and eight fuel blending components have been studied in laboratory flames to compare with results obtained in other programs using these fuels in turbojet engines and combustors. The average molecular weight, density, ASTM smoke point, and diffusion flame and premixed flame threshold sooting index of each fuel have been measured. An apparatus has been assembled to measure premixed flame soot yields using a multi-wavelength laser extinction technique. Experiments have been performed on a six-component test fuel blended using pure hydrocarbon components. The diffusion flame soot threshold of this fuel can be predicted using the pure component values but the predicted premixed flame soot threshold is larger than measured. Experiments are planned to measure soot yields of the jet fuels and to correlate the laboratory measurements with engine test results. (Author).

Download or read book Correlations of Soot Formation in Turbojet Engines and in Laboratory Flames written by Robert J. Gill and published by . This book was released on 1983 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: Test data for F101, J79, and TF-41 jet engines were abstracted from the literature and analyzed to determine the correlation between smoke-related engine performance data and laboratory measurements of fuel sooting tendencies. The smoke-related data included smoke number, linear temperature rise, radiation flux, and Smoke Emission Index measurements. The engine data were correlated with the following laboratory measurements of fuel sooting tendencies: fuel hydrogen percent, total fuel aromatic content, polycyclic aromatic content, smoke point, H/c ratio, C/O ratio, and several types of threshold sooting indices (TSIs). Rules for estimating TSI values for multicomponent mixtures, such as jet fuels, were developed in order to utilize the existing laboratory data for pure fuels (i.e., single chemical compounds). It was determined that no single laboratory measurement of fuel sooting tendency could be used to correlate all the selected engine test data. Improved results can probably be obtained with more accurate and complete fuel analyses as well as improvements in the procedures for estimating jet fuel TSIs.

Download or read book Multi Scale Investigations in Soot Formation and Chemical Vapor Deposition written by Abhishek Jain and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress is made in this thesis in understanding the complex multi-scale chemical and physical processes governing the formation of condensed phase material from gaseous species. The formation of soot through combustion and the synthesis of functional nanomaterial through chemical vapor deposition (CVD) are examined. We first attempt to characterize the sooting tendencies of alternative fuels using different techniques. A new numerical model based on modified flamelet equations is used along with a modified chemical mechanism to predict the effect of fuel molecular structure on soot yield in gasoline surrogates. These simulations provide trends on sooting behavior and are one-dimensional calculations that neglect other phenomenon that govern soot yield and distribution. To determine how other factors influence sooting behavior in laminar flames we carry out experimental and numerical studies to understand how the addition of oxygen to the oxidizer changes soot yield and distribution. Finite-rate chemistry based Direct Numerical Simulations (DNS) are carried out for a series of methane/air flames with increasing Oxygen Index (OI) using an extensively validated, semi-detailed chemical kinetic mechanism, along with an aggregate-based soot model and the results are compared with experimental measurements. It is seen that the effect of variable OI is well captured for major flame characteristics including flame heights, soot yield, and distribution by the numerical simulations when compared to the experimental data. This study is however confined to a small fuel that may not represent behavior seen in real fuels or the constituents that make up these gasoline fuels or their surrogates. Thus, we examine the effects of premixing on soot processes in an iso-octane coflow laminar flame at atmospheric pressure. Iso-octane is chosen as a higher molecular weight fuel as it is an important component of gasoline and its surrogates. Flames at different levels of premixing are investigated ranging from jet equivalence ratios of 1 (non-premixed), 24, 12, and 6. Numerical simulations are compared against experimental measurements and good agreement is seen in soot yield and soot spatial distributions with increasing levels of premixing. While the above studies for soot were carried out for laminar flames combustion devices frequently operate at conditions that lead to turbulent flow. Therefore, to understand how soot is affected by turbulence we computationally study the effects large Polycyclic Atromatic Hydrocarbons species (PAH) have on soot yield and distribution in turbulent non-premixed sooting jet flames using ethylene and and jet fuel surrogate (JP-8). The effects of large PAH on soot are highlighted by comparing the PAH profiles, soot nucleation rate, and soot volume fraction distributions obtained from both simulations for each test flame. Comparisons are also made with experiments when available and further analysis is performed to determine the cause of the observed behavior. Finally, a new multi-scale model is proposed for the computational modeling of the synthesis of functional nanomaterials using CVD. The proposed model is applied to a W(CO)6/H2Se system that has been used by researchers at Penn State to perform WSe2 crystal growth. A force-field for W/C/O/H/Se is developed and favorable agreement is seen when compared to QM data. A reaction mechanism leading from W(CO)6 and H2Se to the crystal precursor is then developed and used in a reacting flow simulation of the custom CVD chamber at Penn State. The bulk reacting flow numerical predictions show promising results for the gas-phase and precursor species, while additional work is still being performed to make the method more robust.

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 Comparison of Sooting Behavior Amongst Various Liquid Fuels written by Aman Ved Kalia and published by . This book was released on 2015 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrocarbon combustion at fuel - air equivalence ratio (scientific symbol) greater than 1 results in incomplete combustion and formation of black flaky substance, soot. Soot is found responsible for health ailments, global warming and degradation of combustor performance in aircrafts. The study aims at determining the sooting threshold for various fuel samples and correlation of fuel chemical composition with sooting threshold. Premixed laminar combustion of fuel samples is observed on the Meker burner setup for varying fuel - air equivalence ratio (scientific symbol). The air flow rate and pressure are kept constant while the flow rate of liquid fuel through the plane jet atomizer assembly is varied with a flow control in - line rotameter and a constant feed pressure. By varying the fuel flow rate, [scientific symbol] is varied which causes changes in the flame. At rich [scientific symbol] , a bright yellow streak of soot is observed which vanishes when the fuel supply is reduced. This allows in determining the exact value of [scientific symbol] at which the sooting begins, called incipient sooting or sooting threshold. Aromatic compounds show a lower soot threshold due to their ease of forming poly - aromatic hydrocarbons which are the base constituent of soot particulate matter. In succession to aromatic compounds, dicyclic paraffins also lead to lower sooting thresholds. Iso - paraffins, cyclo - paraffins and n - paraffins have a comparatively higher sooting threshold. Experimental results show HRJ - tallow to have the highest sooting threshold with a [scientific symbol] of ~ 1.61 and Gevo jet blend a close second with [scientific symbol] ~ 1.53.

Download or read book Development of Surrogates for Aviation Jet Fuels written by Seyed Ali Nasseri and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Predicting Sooting Tendencies from Chemical Structure with Experimental and Theoretical Insight written by and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particulate matter (PM) emissions from internal combustion engines negatively impact public health and global climate. These problems are exacerbated by newer gasoline direct injection engines, which are more fuel-efficient, but also produce more soot than traditional spark ignited engines. Reducing soot formation is therefore of paramount importance in the development of new fuels. A fuel's sooting tendency is a quantitative parameter that describes the sooting behavior of a pure compound or fuel mixture. The yield sooting index (YSI), developed by McEnally and Pfefferle, accurately measures sooting tendencies using small sample quantities. Using an experimental sooting tendency database, we have developed a predictive model for sooting behavior from a quantitative structure-activity relationship (QSAR). It was developed so that input molecules are first decomposed into individual carbon-type fragments for which the sooting tendency contribution can be assigned based on a Bayesian linear regression against the experimental database. The model's predictive accuracy is comparable to its training performance using leave-one-out cross-validation. We have used this model to provide quantitative insights into the effects of chemical structure on soot formation, but excitingly, we have also been able to readily identify the presence of more complicated kinetic sooting mechanisms for structures which are extreme outliers. Oxygenated aromatics can be produced readily from biomass as renewable sources and oxygenated aromatics with very similar structures tend to have a much lower sooting tendency, for example methoxybenzene (anisole, 107), 2-methylphenol (m-cresol, 103), 2-ethylphenol (120), 3-ethylphenol (138) and 1-phenylethanol (142). Thus, the presence of just one oxygen atom in an aromatic compound can drastically alter the reaction pathways leading to soot precursors. We have applied density functional theory (DFT) calculations and flow reactor experiments to examine how oxygenation alters reaction pathways in a combustion environment. This study has allowed us to gain understanding on how the location of an oxygenated functional group influences soot formation. Our work provides a blueprint for the design of oxygenated fuels from biomass, which minimize the production of soot in low oxygen environments.

Download or read book Experimental and Numerical Studies for Soot Formation in Laminar Coflow Diffusion Flames of Jet A 1 and Synthetic Jet Fuels written by Meghdad Saffaripour and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Combustion Generated Fine Carbonaceous Particles written by Andrea D'Anna and published by KIT Scientific Publishing. This book was released on 2014-08-13 with total page 754 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soot is of importance for its contribution to atmospheric particles with their adverse health impacts and for its contributions to heat transfer in furnaces and combustors, to luminosity from candles, and to smoke that hinders escape from buildings during fires and that impacts global warming or cooling. The different chapters of the book adress comprehensively the different aspects from fundamental approaches to applications in technical combustion devices.

Download or read book Handbook of Algal Biofuels written by Mostafa El-Sheekh and published by Elsevier. This book was released on 2021-12-02 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Algal Biofuels: Aspects of Cultivation, Conversion and Biorefinery comprehensively covers the cultivation, harvesting, conversion, and utilization of microalgae and seaweeds for different kinds of biofuels. The book addresses four main topics in the algal biofuel value-chain. First, it explores algal diversity and composition, covering micro- and macroalgal diversity, classification, and composition, their cultivation, biotechnological applications, current use within industry for biofuels and value-added products, and their application in CO2 sequestration, wastewater treatment, and water desalination. Next, the book addresses algal biofuel production, presenting detailed guidelines and protocols for different production routes of biodiesel, biogas, bioethanol, biobutanol, biohydrogen, jet fuel, and thermochemical conversation methods. Then, the authors discuss integrated approaches for enhanced biofuel production. This includes updates on the recent advances, breakthroughs, and challenges of algal biomass utilization as a feedstock for alternative biofuels, process intensification techniques, life cycle analysis, and integrated approaches such as wastewater treatment with CO2 sequestration using cost-effective and eco-friendly techniques. In addition, different routes for waste recycling for enhanced biofuel production are discussed alongside economic analyses. Finally, this book presents case studies for algal biomass and biofuel production including BIQ algae house, Renewable Energy Laboratory project, Aquatic Species Program, and the current status of algal industry for biofuel production. Handbook of Algal Biofuels offers an all-in-one resource for researchers, graduate students, and industry professionals working in the areas of biofuels and phycology and will be of interest to engineers working in renewable energy, bioenergy, alternative fuels, biotechnology, and chemical engineering. Furthermore, this book includes structured foundational content on algae and algal biofuels for undergraduate and graduate students working in biology and life sciences. Provides complete coverage of the biofuel production process, from cultivation to biorefinery Includes a detailed discussion of process intensification, lifecycle analysis and biofuel byproducts Describes key aspects of algal diversity and composition, including their cultivation, harvesting and advantages over conventional biomass

Download or read book Numerical Study on the Sooting Tendencies of Bio derived Fuels for Spark ignition Engines written by Yuan Xuan and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: While more efficient vehicles have been developed over the decades, their performance is limited by the properties of existing fuels. In response, the Co-Optimization of Fuels and Engines Initiative (Co-Optima) under the U.S. Department of Energy (DOE) has developed a rigorous screening approach to identify the most promising biomass-derived blendstocks that are suitable for advanced spark-ignition (SI) engines. A detailed kinetic model has also been developed to predict the combustion properties of the selected blendstocks. This kinetic model has been designed mainly targeting ignition and flame propagation properties, and it has not previously been validated for soot formation. In this work, we numerically predicted the sooting tendency of 20 Co-Optima SI blendstocks using the Co-Optima kinetic model. The sooting tendencies are determined quantitatively using the Yield Sooting Index (YSI) methodology. As shown in Fig. 1, the predicted YSIs show good agreement with measurements, except for 2,5-dimethylfuran. We also quantify the sensitivity of the YSI predictions to aromatic growth reactions and fuel decomposition reactions of the test fuels. It is found that PAH growth reactions have little impact on YSIs for all 20 fuels under investigation. On the other hand, fuel decomposition reactions have a significant influence on the YSI of 2,5-dimethylfuran. Perturbing their reaction rates by a factor of two is shown to lead to 11 % YSI prediction uncertainty.

Download or read book Fuel Effects on Operability of Aircraft Gas Turbine Combustors written by Meredith Colket and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In summarizing the results obtained in the first five years of the National Jet Fuel Combustion Program (NJFCP), this book demonstrates that there is still much to be learned about the combustion of alternative jet fuels.

Download or read book A Study on the Effect of Temperature on Soot Formation in a Jet Stirred Combustor written by Hiroki Satō and published by . This book was released on 1989 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Novel Application of Topological Indices 2 Prediction of the Threshold Soot Index for Hydrocarbon Fuels written by Milton P. Hanson and published by . This book was released on 1987 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The propensity of hydrocarbons to form soot in a diffusion flame is correlated here for the first time againt various topological indices. Two of the indices, the hydrogen deficiency index and the Balaban distance sum connectivity index, were found to be especially valuable for correlational purposes. For a total of 98 hydrocarbon fuel molecules, of differing types, regression analyses yielded good correlations between the threshold soot indices (TSIs) for diffusion flames and these two indices. An equation which can be used to estimate TSI values in fuel molecules is presented. Keywords include: Topological indices, Soot formation, Soot fuels.

Download or read book Soot Nanostructure Evolution from Gas Turbine Engine Premixed and Diffusion Flame written by Chung-hsuan Huang and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion generated soot impacts human health and climate. Particulate emissions from combustors on jet aircraft are relevant to each area, occurring at ground level and at altitude. One of the advantages of alternative fuels is their potential for reducing emission levels. Comparative field-testing of alternative fuels for their emissions was conducted in the Alternative Aviation Fuel Experiment II (AAFEX II), a NASA-led ground-based field campaign. In this study, particulate emissions from a CFM-56-2C1 engine aboard a DC-9 aircraft were characterized by HRTEM and XPS for nanostructure, carbon speciation and surface chemistry. Fuels studied included JP-8, a 50:50 (JP-8 & HRJ) blend, Hydrotreated Renewable Jet (HRJ), and a Fischer-Tropsch (FT) synthetic fuel. Soot nanostructure and surface chemistry are examined across engine power levels from 4% to 100%. Nanostructure ranged from amorphous (reflecting organic carbon) to graphitic (reflecting elemental carbon) as characterized by lamellae length analysis. With JP-8 fuel, soot particle bonding chemistry, as inferred from the XPS ratio for sp2/sp3 carbon is compared to soot nanostructure evolution. Increasing lamellae length is found to strongly correlate with increasing sp2/sp3 ratio with increasing engine power -- suggesting a change in species identity contributing to the soot growth process. Comparisons between fuels for the same power levels yielded insights into differences in soot processes as dependent upon initial fuel. Soots from the renewable HRJ and FT fuels exhibit significant nanostructure at each power level, rather than the progression as observed for JP-8. This difference is associated with differences in the soot formation environments as dependent upon fuel. To further examine the correlation between chemical environment and soot structure as manifested on different physical length scales, primary particle size versus lamellae length was compared. For JP-8 and its blend with HRJ, there is correlation with engine power, i.e. each spatial metric increases with increasing power, suggesting common underlying cause(s) for both observations. For the HRJ and FT fuels, there is no discernable trend. These results are interpreted in terms of the aromatic content of the JP-8 and blended fuels and their different pyrolysis kinetics compared to paraffinic components of the fuels. Observations of fullerenic nanostructure, particularly evident in soots from the pure paraffinic fuels were interpreted as reflecting partial premixing in order to produce the C5 membered rings for lamellae curvature. This led to the hypothesis defining this study: Partially premixed combustion produces soot with fullerenic nanostructure. Curvature is that one special feature of nanostructure that can be related back to particular gas phase specie(s), namely cyclopentadiene and PAHs containing 5-membered rings.This hypothesis was tested in the following two laboratory flame studies. Partial premixing within simple gas jet diffusion flames has a very long history -- stemming back to the Bunsen flame. Yet HRTEM data of soot from such flames appears absent. In the first study cyclopentane was used as fuel to test lamellae curvature dependence upon C5 species. Modest curvature was observed -- given competing fuel pyrolysis and ring dehydrogenation to yield cyclopentadiene, referred to as C5. Using benzene as the primary fuel with partial premixing tested the chemical path for C5 production -- proceeding through partial benzene oxidation yielding the phenoxy radical followed by CO loss to produce C5. A strong variation of lamellae curvature with oxygen content in the primary fuel stream was observed -- reflecting the increasing C5 production rate. Generality of the nanostructure dependence upon partial premixing and associated change in gas phase chemistry (compared to pure thermal pyrolysis) was demonstrated using an ordinary laboratory Bunsen burner with ethylene as fuel. In absence of partial premixing, soot production is well described by the HACA mechanism, C6 PAHs with observed flat lamellae, without curvature, dissimilar to observations here accompanying partial premixing.In the third study, the main goal was to test two main parameters -- adiabatic flame temperature (2000K) and fuel/air equivalence ratio ([phi] = 2.0) -- for their relative impact on soot nanostructure formation. The soots were collected from a burner-stabilized flat flame burning the petroleum-based JP-8, synthetic FT, and surrogate -- iso-Octane/n-Dodecane, m-Xylene/n-Dodecane, and n-Dodecane -- fuels on a McKenna burner. Images from high-resolution transmission microscopy (HRTEM) show that for the same equivalence ratio of [phi] = 2.0 with temperature maintained constant, soot from the FT fuel has significant curvature compared to soot from the JP-8 fuel, as also found in FT-derived soot from the jet engine. This comparative observation indicates two major findings. First is that the soot nanostructure depends upon initial fuel composition -- and by extension molecular structure. Similar findings from diesel engine studies have also been documented by Yehliu (2010) 1. Second is that fuel pyrolysis pathways and products also depend upon the fuel components. Adjustment of flame adiabatic temperature suggests a temperature threshold for realization of such differences. Soot nanostructure comparisons with a surrogate fuel mixture of n-dodecane/m-xylene (75:25 wt.%) further illustrate pyrolysis processes and intermediates as dependent upon fuel molecular structure and components present. To further compare the experimental results, CHEMKIN with the SERDP mechanism using the burner-stabilized flame model was carried out and processed for the three surrogate fuels, iso-Octane, n-Dodecane, and m-Xylene at various reaction temperatures and fuel/air equivalence ratios. Both the C5H5/C6H6 ratio and C3H3 profiles were distinctly different between the pure n-dodecane and m-xylene/n-dodecane mixture. That the C3H3 profile is also the main difference between the iso-octane and surrogate fuel mix suggests that C3H3 participation in 5-membered ring formation is also key to introduction of 2-D curvature in lamella -- especially given that the highest curvature is observed for FT fuel soot. Moreover, by these results the higher C5H5 observed for the surrogate mixture is an inferred consequence of the different C3H3 profile. Presently these calculated values are only used to interpret the observed curvature differences, as threshold values or the concentration dependency of curvature upon particular species are currently unknown.The goal of this study was to build a bridge between molecular gas phase species and the soot nanostructure. Initial observations of nanostructure curvature in jet engine soot prompted interest. Current chemical kinetic models can address fuel breakdown, thermal and oxidatively assisted, PAH formation and growth all via detailed kinetics, followed by soot inception via their physical and chemical coalescence. Thereafter soot models are particle based and use measured growth rates and aerosol dynamics to account for increasing soot mass and aggregate formation. No modeling studies have yet addressed the link between gas phase species with any aspect of soot nanostructure. As shown here soot nanostructure can reflect its origin, specifically the species forming the soot lamellae. The novelty of two-dimensional curvature is that it can be related uniquely to C5 species, via known chemical pathways -- involving oxygen directly or indirectly. The oxygen concentration in the primary fuel stream defines the level of partial premixing. Therein lies the origin of the hypothesis that partial premixing leads to (recognizable) curvature in soot lamellae. Definition of the operative range of [phi] and temperature will constitute future work for C5 production and its manifestation as curvature in nanostructure.

Download or read book Impact of Oxygenated Fuels on Sooting Tendency and Soot Oxidative Reactivity with Application to Biofuels written by Eduardo Jose Barrientos Betancourt and published by . This book was released on 2014 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: