Download or read book Effects of Temperature and Hydroxyl Concentration on Incipient Soot Formation in Premixed Flames written by Mark Miller Harris and published by . This book was released on 1985 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurements of Soot Formation and Hydroxyl Concentration in Near Critical Equivalence Ratio Premixed Ethylene Flame written by Michael Andrew Inbody and published by . This book was released on 1993 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurements of Soot Formation and Hydroxyl Concentration in Near Critical Equivalence Ratio Premixed Ethylene Flame written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-27 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: The testing and development of existing global and detailed chemical kinetic models for soot formation requires measurements of soot and radical concentrations in flames. A clearer understanding of soot particle inception relies upon the evaluation and refinement of these models in comparison with such measurements. We present measurements of soot formation and hydroxyl (OH) concentration in sequences of flat premixed atmospheric-pressure C2H4/O2/N2 flames and 80-torr C2H4/O2 flames for a unique range of equivalence ratios bracketting the critical equivalence ratio (phi(sub c)) and extending to more heavily sooting conditions. Soot volume fraction and number density profiles are measured using a laser scattering-extinction apparatus capable of resolving a 0.1 percent absorption. Hydroxyl number density profiles are measured using laser-induced fluorescence (LIF) with broadband detection. Temperature profiles are obtained from Rayleigh scattering measurements. The relative volume fraction and number density profiles of the richer sooting flames exhibit the expected trends in soot formation. In near-phi(sub c) visibility sooting flames, particle scattering and extinction are not detected, but an LIF signal due to polycyclic aromatic hydrocarbons (PAH's) can be detected upon excitation with an argon-ion laser. A linear correlation between the argon-ion LIF and the soot volume fraction implies a common mechanistic source for the growth of PAH's and soot particles. The peak OH number density in both the atmospheric and 80-torr flames declines with increasing equivalence ratio, but the profile shape remains unchanged in the transition to sooting, implying that the primary reaction pathways for OH remain unchanged over this transition. Chemical kinetic modeling is demonstrated by comparing predictions using two current reaction mechanisms with the atmospheric flame data. The measured and predicted OH number density profiles show good agreement. The predicted benzene number...

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 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 A Fundamental Study of Soot Formation in Diffusion Flames written by Richard L. Axelbaum and published by . This book was released on 1988 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Masters Theses in the Pure and Applied Sciences written by Wade H. Shafer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses in the Pure and Applied Sciences was first conceived, published, SIld disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna and broader dissemination. tional publishing house to assure improved service Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 30 (thesis year 1985) a total of 12,400 theses titles from 26 Canadian and 186 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work.

Download or read book Fossil Energy Update written by and published by . This book was released on 1986 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ionic Mechanisms of Carbon Formation in Flames written by H. F. Calcote and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soot Formation in a Jet Stirred Combustor written by Joseph Terence Hodges and published by . This book was released on 1989 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Detailed Studies of Soot Formation in Laminar Diffusion Flames for Application to Modeling Studies written by and published by . This book was released on 1993 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation of soot formation in laminar diffusion flames has shown that soot particle surface growth under laminar diffusion flame conditions ceases because of the depletion of hydrocarbon species, in particular acetylene and benzene, and not due soot particle reactivity loss due to thermal aging of the particles. This results has been obtained through direct species concentration measurements under well controlled conditions while the particle reactivity effects were calculated based on premixed flame results along with particle temperature/time information available from earlier laminar diffusion flame studies. Comparisons with a soot formation model which incorporated detailed chemistry effects showed good agreement in terms of predicted and measured species concentration and soot particle field evolution. In addition, a novel technique for measuring soot volume fraction has been developed based on laser-induced incandescence and applied to similar laminar diffusion flame, studies with good success. This technique represents a major development in terms of its ability to make soot volume fraction measurements in unsteady inhomogeneous combusting flows. Soot formation, Soot particles, Diffusion flames.

Download or read book Hydrodynamic Effects on Soot Formation in Laminar Hydrocarbon fueled Diffusion Flames written by Guozheng Lin and published by . This book was released on 1996 with total page 568 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 Soot Formation in Turbulent Combusting Flows written by and published by . This book was released on 2001 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study investigated the effects of turbulence on the spatial distribution of the soot particle and OH fields in turbulent C2H4 air/jet diffusion flames. Measurements obtained using planar laser-induced incandescence (LII) for soot volume fraction and laser-induced fluorescence (LIF) for both OH, and polycyclic aromatic hydrocarbons (PAH) formed the basis for investigating soot formation and destruction processes in these flames. These laser-based techniques were applied to the flame independently as well as simultaneously. Extensive information on the structure of the soot and OH fields was obtained from two-dimensional imaging experiments. Imaging results for soot, OH and PAH indicated three distinct soot formation/oxidation regions; a rapid soot growth region, in which OH and soot particles lie in distinctly different radial locations; a mixing dominated region controlled by large-scale fluid motion; and, finally, a soot oxidation region in which the OH and soot fields overlap spatially, resulting in the rapid oxidation of soot particles. Detailed quantitative analyses including soot volume fraction, OH and soot zone thickness variations, and probabilities distributions for soot and OH were performed. The measurements of soot and OH zone thickness showed that the soot zone thickness varied nearly linearly in the formation region, while approximately a doubling of thickness of the OH zone was evident over the studied Reynolds number range (4000-23000). The probability density function results tor soot, OH, and PAH indicated that OH and PAH are spatially interrelated with respect to soot formation and oxidation processes

Download or read book Soot and Pah Formation in Counterflow Non premixed Flames Atmospheric Butane and Butanol Isomers and Elevated pressure Ethylene written by Pradeep K Singh and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the complexity of the fluid dynamics and non-linear reactions in the combustion zone, a simplified approach to study this process is required. Given these complexities, it is practically very challenging to take measurements in very high temperature and pressure zones in practical combustion systems, and if by any means those measurements can be made, it is equally challenging to analyze those measurements. Hence, in order to more comprehensively understand these processes, the problem needs to be resolved into the smaller and controllable sub-category of experiments, by creating laminar flamelets. One approach used in creating these flamelets is by establishing simplified non-premixed flames in the counterflow configuration. Alongwith all the fundamental properties of combustion, it is important to study the health hazard and environmentally detrimental emissions, such as soot and polycyclic aromatic hydrocarbons (PAHs). Such combustion studies need to be carried out using the non-intrusive in-situ optical diagnostics measurement techniques, such as the Laser Induced Incandescence (LII), Planar Laser Induced Fluorescence (PLIF) and Light Extinction (LE). These measurements for renewable biofuels aid in better understanding of the soot formation process, as well as in developing the fuel specific knowledge to bring them into commercial use. Furthermore since the most practical combustion systems operate at elevated pressures, it is also important to understand the soot formation process under elevated pressure conditions. Considering these, in the current study, the soot and PAH formation processes for butane and butanol isomers (C4 fuels) at atmospheric pressure; and for ethylene at elevated pressure have been experimentally investigated and compared in a counterflow non-premixed flame configuration. Under the investigated conditions, butane isomers were observed to form more soot than butanol isomers, thereby showing the effect of the hydroxyl group. The effects of isomeric structural differences on sooting propensity were also observed within the butane and butanol isomers. In addition, while soot volume fraction was seen to increase with increasing fuel mole fraction, the ranking of sooting propensity for these C4 fuels remained unchanged. For the conditions studied, the sooting tendency ranking generally follows n-butane > iso-butane > tert-butanol > n-butanol > iso-butanol > sec-butanol. . The counterflow non-premixed flames were also simulated using the gas-phase chemical kinetic models, USC Mech II [1], Sarathy et al. [2] and Merchant et al. [3] available in the literature to compute the spatially-resolved profiles of soot precursors, including acetylene and propargyl. For these C4 fuels, the PAHs of various aromatic ring size groups (2, 3, 4, and larger aromatic rings) have been characterized and compared in non-premixed combustion configuration. In particular, the formation and growth of the PAHs of different aromatic ring sizes in these counterflow flames was examined by tracking the PAH-PLIF signals at various detection wavelengths. PAH-PLIF experiments were conducted, by blending each of the branched-chain isomers with the baseline straight-chain isomer, in order to study the synergistic effects. The fuel structure effects on the PAH formation and growth processes were also analyzed by comparing the PAH growth pathways for these C4 fuels. A chemical kinetic model, POLIMI mechanism [4-7], available in the literature that includes both the fuel oxidation and the PAH chemistry was also used to simulate and compare the PAH species up to A4 rings. Counterflow non-premixed sooting ethylene‒air flames with fuel mole fractions of 0.20‒0.40 in the pressure range of 1‒6 atm were investigated experimentally with the laser diagnostic techniques of LII, PLIF and LE. A better understating of the quantitative soot formation process has been developed for ethylene counterflow flames under elevated pressure conditions. The effect of pressure on the formation of PAHs with different aromatic ring sizes has also been determined qualitatively. With increase in pressure, the increase in soot volume fraction and PAH-PLIF signals were observed. A chemical kinetic model available in the literature, that includes both the fuel oxidation and the PAH chemistry, was also used to simulate and compare the PAH species up to A4 rings. At the incipient stage of the PAH formation, the simulated results exhibited similar behavior to the experimental observations. A chemical kinetic model, WF-PAH mechanism [8], available in the literature was also used to compute the PAHs up to four aromatic rings. This chemical kinetic model predicted enhancing PAHs formation with an increase in pressure, consistent with the experimental trend.

Download or read book International Journal of Fluid Mechanics Research written by and published by . This book was released on 1999 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: