Download or read book Fuel Molecular Structure and Flame Temperature Effects on Soot Formation in Gas Turbine Combustors written by and published by . This book was released on 1989 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Soot and Radiation in a Gas Turbine Combustor written by A. H. Lefebvre and published by . This book was released on 1987 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of pressure, inlet air temperature, and fuel type on the soot threshold or critical equivalence ratio, are presented. Higher pressures yield lower soot thresholds, while no dependence on fuel type, as described by either the fuel hydrogen-to-carbon ratio, fuel molecular weight, number of carbon atoms, or number of carbon-carbon bonds, is observed. Variations in inlet air temperature have a complex effect; however, the results clearly show that the experimentally measured flame temperature is central to a description of the incipient soot formation process. The critical equivalence ratio dependence on pressure and temperature is shown to agree with a two-step semi-global model for soot precursor evolution for pressures form 0.1 to 0.8 MPa, and measured flame temperatures between 1600 and 2400K. The effects of equivalence ratio, pressure, and fuel chemistry on total non-luminous flame radiation were also studied. Radiant intensity was highest for an equivalence ratio of unity and increased linearly with pressure from 0.4 to 0.8 MPa. Keywords: Incipient soot formation, Flame radiation and emissivity, Premixed flames, Pressure dependence.
Download or read book Particulate Carbon written by Donald Siegla and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of the symposium, "Particulate Carbon: Formation During Combustion", held at the General Motors Research Laboratories on October 15 and 16, 1980, was to discuss fundamental aspects of soot formation and oxidation in combustion systems and to stimulate new research by extensive interactions among the participants. This book contains lhe papers and discussions of that symposium, the 26th in an annual series covering many different disciplines which are timely and of interest to both General Motors and the technical community at large. The subject of this symposium has considerable relevance for man in his effort to control and preserve his environment. Emission of particulate carbon into the atmos phere from combustion sources is of concern to scientists and laymen alike. The hope of reducing this emission clearly requires an understanding of its formation during the combustion process, itself an area of considerable long-term research interest. It is our hope that this symposium has served to summarize what is known so that what remains to be learned can be pursued with greater vigor.
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 Effects of Fuel Molecular Structure on Emissions in a Jet Flame and a Model Gas Turbine Combustor written by Anandkumar Makwana and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Stricter environmental requirements, worldwide air traffic growth, and unsteady fuel prices all has led to an increased interest in alternative jet fuels. Additionally, several nations are investing resources identifying local fuel sources to make the fuel supply more resilient against disruptions and flexible to use of multiple, reliable fuel stocks. The alternative jet fuels that are being defined have unusual molecular distributions relative to current fuels. These differences in molecular structure affect the gas-phase kinetics during combustion, and hence the use of alternative fuels can impact emissions differently than conventional fuels. The differences in the emission characteristics between a newly developed alternative fuel and conventional fuel highlight the need to focus the research efforts on understanding how the fundamental properties of the fuel can affect emissions. The current work focuses on investigating the chemical effects of fuel molecular structure on the emission behavior of the fuels. In particular, the study explores how the fuel composition and premixing affect the production of polycyclic aromatic hydrocarbons (PAH), hazardous air pollutants (HAPs), and soot in a combustion environment. The study uses two experimental configurations: a jet flame and a model gas turbine combustor. Laser induced incandescence (LII) and laser extinction (LE) are used to obtain two-dimensional soot volume fraction in the flames. Laser induced fluorescence (LIF) is used to obtain the two-dimensional aromatic species distribution in the flames. Additionally, numerical analysis is used to investigate the effects of premixing on the soot formation processes in the jet flames for a high molecular weight fuel.
Download or read book Advanced Combustion Science written by Tsuneo Someya and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-uniform combustion, as encountered in diesel and gas turbine engines, furnaces, and boilers, is responsible for the conversion of fossil fuel to energy and also for the corresponding formation of pollutants. In spite of great research efforts in the past, the mechanism of non-uniform combustion has remained less explored than that of other combustion types, since it consists of many, mostly transient processes which influence each other. In view of this background, a group research project, "Exploration of Combustion Mechanism", was established to explore the mechanism of combustion, especially that of diffusive combustion, and also to find efficient ways to control the combustion process for better utilization of fuel and the reduction of pollutant emission. The group research was started, after preparatory activity of 2 years, in April 1988, for a period of 3 years, as a project with a Grant-in-Aid for Scientific Research of Priority Area subsidized by the Ministry of Education, Science and Culture of Japan. The entire group of 43 members was set up as an organizing committee of 13 members, and five research groups, consisting of 36 members. The research groups were: (1) Steady combustion, (2) Unsteady spray combustion, (3) Control of combustion, (4) Chemistry of combustion, and (5) Effects of fuels. At the beginning of the project it was agreed that we should pursue the mechanism of combustion from a scientific viewpoint, namely, the target of the project was to obtain the fundamentals, or "know why", rather than "know how" of combustion.
Download or read book Soot in Combustion Systems and Its Toxic Properties written by J. Lahaye and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our interest in Mulhouse for carbon black and soot began some 30 years ago when J.B. Donnet developed the concept of surface chemistry of carbon and its involvement in interactions with gas, liquid and solid phases. In the late sixties, we began to study soot formation in pyrolytic systems and later on in flames. The idea of organ1z1ng a meeting on soot formation originated some four or five years ago, through discussions among Professor J.B. Howard, Dr. A. D'Alessio and ourselves. At that time the scientific community was becoming aware of the necessity to strictly control soot formation and emission. Being involved in the study of surface properties of carbon black as well as of formation of soot, we realized that the combustion community was not always fully aware of the progress made by the physical-chemists on carbon black. Reciprocally, the carbon specialists were often ignoring the research carried out on soot in flames. One objective of this workshop was to stimulate discussions between these two scientific communities. During the preparation of the meeting, and especially during the review process by the Material Science Committee of the Scientific Affairs Division of N.A.T.O. the toxicological aspect emerged as being an important component to be addressed during the workshop. To reflect these preoccupations we invited biologists, physical chemists and engineers, all leaders in their field. The final programme is a compromise of the different aspects of the subject and was divided in five sessions.
Download or read book Correlation of Soot Formation in Turbojet Engines and in Laboratory Flames written by Robert K. Gould and published by . This book was released on 1981 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data obtained from aviation gas turbine combustor tests have been examined to determine the effects of fuel properties on soot-related measurements such as engine smoke number, combustor flame radiation, and/or combustor linear temperature. Some tests of smaller laboratory combustors used to simulate these large combustors were also examined. From the existing data it is clear that soot production is a strong function of the fuel chemical composition. Variations in the physical properties of the fuel do not correlate well with soot-related effects. In studies in which a broad range of fuel properties was examined, correlation of soot-related effects with basic fuel compositional parameters including (1) the hydrogen content of the fuel, (2) the aromatic content of the fuel, and (3) the amount of multiple-ring aromatics in the fuel show that typically only the first of these correlates well. However, it has also been shown that fuel compositions can be chosen for which this correlating parameter fails.
Download or read book Effect of Fuel Molecular Structure on Soot Formation in Gas Turbine Engines written by D. W. Naegeli and published by . This book was released on 1980 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fuel Effects on Gas Turbine Combustors and Engines An Annotated Bibliography written by COORDINATING RESEARCH COUNCIL INC ATLANTA GA. and published by . This book was released on 1981 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Partial Contents Include: (1) Flame Radiation, Combustion Liner Temperature, and Combustor Liner Durability; (2) Exhaust Smoke and Soot Formation; (3) Gaseous Emissions and Combustion Efficiency; (4) Flame Ignition and Stability, Reaction Rates, and Spray Characteristics; and (5) Carbon Deposition.
Download or read book Soot Formation in Laminar Diffusion Flames written by eO L. Geulder and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxygen Enhanced Combustion written by Charles E. Baukal Jr. and published by CRC Press. This book was released on 2013-03-15 with total page 779 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion technology has traditionally been dominated by air/fuel combustion. However, two developments have increased the significance of oxygen-enhanced combustion-new technologies that produce oxygen less expensively and the increased importance of environmental regulations. Advantages of oxygen-enhanced combustion include less pollutant emissi
Download or read book Effects of Fuel Specification and Additives on Soot Formation written by G. S. Samuelsen and published by . This book was released on 1983 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this program was to develop an employ the method necessary to identify the causal effects of fuel properties, additive properties, and combustor operating conditions on soot formation and to provide information needed to evaluate and develop models destined for gas turbine design. Present knowledge of these effects is limited to systems which are either too simple to adequately represent gas turbine combustion or too complex to permit access to detailed optical diagnostics. The projected use by Air Force aircraft of relax-detailed optical diagnostics. The projected use by Air Force aircraft of relaxed specification fuels having an increased tendency to produce soot portends greater difficulty meeting the future USAF aircraft smoke emission goals and makes this information essential. To answer these technical questions, a multifaceted study was undertaken to test candidate model laboratory combustors in the conduct of fuel effects measurement of local soot size and number density, develop and assess the effect of extractive probe perturbation to local values of soot size and number density, employ an extractive probe and sampling system to assess the effect of fuel molecular structure and additives on the physical and chemical properties of soot, and determine the effectiveness of the ASTM smoke point in predicting sooting behavior in complex flows.
Download or read book Effects of Gas Turbine Combustion on Soot Deposition written by D. J. White and published by . This book was released on 1979 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of premixing the reaction air and fuel of a gas turbine combustor on soot formation were investigated. Other parameters such as pressure, temperature and reaction zone fuel-air ratio were also evaluated. Soot formation was found to be dominated by fuel-air premixing and could be suppressed readily through a partial premix process. (Author).
Download or read book Fuel Component Effects on Combuster Soot Formation written by and published by . This book was released on 1990 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: The principal objective of this program was to obtain information on the effect of fuel composition and combustor operating conditions on soot formation in a model laboratory combustor which is representative of aircraft gas turbine engines (GTEs). Work included the development of a laboratory scale combustor that reflects the characteristics of practical GTEs and the blending of a fuel surrogate from pure hydrocarbons to stimulate JP-4. The results show that the soot yield is affected by fuel molecular structure, loading, engine aerodynamics, and pattern of fuel injection. The performance of the combustor was shown to be highly sensitive to the atomizing air conditions of the fuel nozzle.
Download or read book Fossil Fuel Combustion written by William Bartok and published by Wiley-Interscience. This book was released on 1991-05-10 with total page 888 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive handbook presents recent research results on combustion theory. Contributors from both industry and academia present the state of knowledge on flame properties. Includes a review of combustion chemistry and measurement techniques; discusses heterogeneous and homogeneous combustion.
Download or read book Soot Formation in Combustion written by Henning Bockhorn and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 595 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soot Formation in Combustion represents an up-to-date overview. The contributions trace back to the 1991 Heidelberg symposium entitled "Mechanism and Models of Soot Formation" and have all been reedited by Prof. Bockhorn in close contact with the original authors. The book gives an easy introduction to the field for newcomers, and provides detailed treatments for the specialists. The following list of contents illustrates the topics under review:
