Download or read book Examination of Mechanisms and Fuel Molecular Effects on Soot Formation written by Meredith B Colket (III.) and published by . This book was released on 1985 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acetylene, vinlyacetylene, and benzene have been pyrolyzed in a single-pulse shock tube over the temperature range of 1000 to 2400K and for dwell times of approximately 700 microseconds. Gas samples of reactant, intermediate, and final products were collected and analyzed using gas chromatography. Experimental data were used in conjunction with a computer model to develop (or confirm existing) detailed chemical kinetic models for several of the hydrocarbons that were pyrolyzed. Model results agreed well with experimental data not only for the decomposition of the parent compound and formation and decomposition of single-ring aromatic species. The formation processes are believed to lead to the production of polycyclic aromatic hydrocarbons, soot precursors, and eventually soot.
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:
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 Fuel Structure and Pressure Effects on the Formation of Soot Particles in Diffusion Flames written by Robert J. Santoro and published by . This book was released on 1988 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the first year of the present grant, efforts have concentrated on examining the effects of fuel molecular structure on soot formation in diffusion flames. Studies involving alkane, alkene, alkyne and aromatic fuel species have been studied with specific attention given to the surface growth process. Analysis of these studies has demonstrated a strong fuel structure dependence for the amount of soot formed, the conversion percentage of fuel carbon to soot, and the soot particle surface area present in these diffusion flames. However, when surface area taken into account, similar specific surface growth rate coefficients are observed for all the fuels studied. These results point to a similar surface growth process for all the fuels. Consistent with premixed flame results, the present studies show a continual decrease in this specific surface growth rate coefficient with time. Other effects of fuel structure observed include an acceleration of the inception of soot particles to lower locations and, thus, earlier times in the flame as soot conversion percentage increases. These results also point to the importance of the initial particle inception process which appears to control subsequent soot particle evolution. Keywords: Soot formation; Soot particles; Diffusion flames.
Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1987-05 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1988 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Ionic Mechanisms of Soot Formation in Flames written by H. F. Calcote and published by . This book was released on 1984 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemi-ion, ion-molecule mechanism of soot nucleation has been further examined by studies in premixed flames with Langmuir probes, molecular beam ion sampling mass spectrometry, and by flame temperature measurements. Langmuir probes were used to obtain absolute total ion concentrations in acetylene-oxygen flames over a range of equivalence ratios extending from stoichiometric mixtures to very sooty flames. These data were used in a preliminary calibration of the mass spectrometer. Two peaks in both total and individual positive ion concentration profiles were identified preceding the appearance of soot--the second peak occurred only at equivalence ratios very near the soot point or in sooty flames. The peak ion concentration decreased with increasing equivalence ratio well beyond the threshold equivalence ratio for soot formation. This refutes one of the arguments that has been used against the proposed mechanism, namely that ion concentrations increase at the equivalence ratio for soot formation. Means of treating particle electronics involved in sooty flames have been organized and applied to explain the effect of chemical additives on soot production. The effect of flame temperature (1700 to 2400 K) on soot threshold and soot yield was determined for a series of fuels. Increasing flame temperatures increased the soot threshold equivalence ratio with small temperature dependence, and decreased the soot volume fraction with a large temperature dependence. The results continue to support the chemi-ion, ion-molecule mechanism of soot nucleation. Originator furnished keywords include: Soot formation, Smoke, Ions in flames, Ion-molecule reactions, Flames, Combustion.
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 Soot Formation in Combustion written by Henning Bockhorn and published by . This book was released on 1995-01-01 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 Combustion Physics written by Chung K. Law and published by Cambridge University Press. This book was released on 2010-08-23 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: This graduate-level text incorporates these advances in a comprehensive treatment of the fundamental principles of combustion physics. The presentation emphasises analytical proficiency and physical insight, with the former achieved through complete, though abbreviated, derivations at different levels of rigor, and the latter through physical interpretations of analytical solutions, experimental observations, and computational simulations. Exercises are mostly derivative in nature in order to further strengthen the student's mastery of the theory. Implications of the fundamental knowledge gained herein on practical phenomena are discussed whenever appropriate. These distinguishing features provide a solid foundation for an academic program in combustion science and engineering.
Download or read book Molecular Weight Growth Pathways in Fuel rich Combustion written by David Franklin Kronholm and published by . This book was released on 2000 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Effects of Fuel Molecular Structure and Composition on Soot Formation in Direct injection Spray Flames written by Kenth Ingemar Svensson and published by . This book was released on 2005 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extinction and two-color soot measurement results were compared. The two-color KL values were seen to level off at around 0.5, but continue to increase monotonically as soot increased. The broad band method is therefore not good for absolute soot measurements. Natural luminosity measurements were sensitive to the first appearance of soot, but were non-linear.
Download or read book A Preliminary Analysis of the Effects of Mixing on Soot Formation written by Kevin L. Hoag and published by . This book was released on 1982 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
