Download or read book Modeling of Chemical Reactions and Soot Formation in Turbulent Flows by Means of Stochastic Particle Methods written by Dirk Großschmidt and published by . This book was released on 2007 with total page 163 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 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of soot formation in turbulent jet flames burning ethylene in air were studied for Reynolds numbers ranging from 4,000 to 23,000. Laser-based techniques were used to measure the soot volume fraction, particle size and number density as well as the temperature and relative concentration of hydroxyl radicals and polycyclic aromatic hydrocarbons. Measurements of the characteristics length scales for the soot and hydroxyl radical fields throughout the turbulent flames were obtained. The maximum soot eddy size was observed to be 7 mm or about three times the size of the diameter of the fuel jet (d= 2.18 mm). The soot eddy size increased linearly along the centerline of the turbulent flame until the mid-point, where it leveled off and finally decreased in the oxidation zone. In contrast, the hydroxyl radical eddy size always increased along the flame with a maximum eddy size of 12 mm for the higher Reynolds number flames. Analysis of the radial dependence of the eddy size was also determined. Relatively little radial dependence in the eddy size was observed for the soot particles indicating that the soot eddies moved off the axis very fast as compared to the mixing rate. However for the hydroxyl radicals, the eddy size was always larger off the axis of the flame except near the flame tip. With respect to the temperature field, temperature probability density functions indicated bimodality at all axially locations. With respect to soot formation, the highest soot formation location and the peak mean temperature were observed on the fuel-rich side of the stoichiometric flame location while the peak hydroxyl radical concentration was on the fuel-lean side.
Download or read book Modeling and Simulation of Turbulent Combustion written by Santanu De and published by Springer. This book was released on 2017-12-12 with total page 663 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive review of state-of-the-art models for turbulent combustion, with special emphasis on the theory, development and applications of combustion models in practical combustion systems. It simplifies the complex multi-scale and nonlinear interaction between chemistry and turbulence to allow a broader audience to understand the modeling and numerical simulations of turbulent combustion, which remains at the forefront of research due to its industrial relevance. Further, the book provides a holistic view by covering a diverse range of basic and advanced topics—from the fundamentals of turbulence–chemistry interactions, role of high-performance computing in combustion simulations, and optimization and reduction techniques for chemical kinetics, to state-of-the-art modeling strategies for turbulent premixed and nonpremixed combustion and their applications in engineering contexts.
Download or read book Numerical Simulations of Soot Formation in Turbulent Flows written by Massimiliano Di Domenico and published by . This book was released on 2008 with total page 0 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 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 Fundamentals of Turbulent and Multiphase Combustion written by Kenneth Kuan-yun Kuo and published by John Wiley & Sons. This book was released on 2012-07-03 with total page 914 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed coverage of advanced combustion topics from the author of Principles of combustion, Second Edition Turbulence, turbulent combustion, and multiphase reacting flows have become major research topics in recent decades due to their application across diverse fields, including energy, environment, propulsion, transportation, industrial safety, and nanotechnology. Most of the knowledge accumulated from this research has never been published in book form—until now. Fundamentals of Turbulent and Multiphase Combustion presents up-to-date, integrated coverage of the fundamentals of turbulence, combustion, and multiphase phenomena along with useful experimental techniques, including non-intrusive, laser-based measurement techniques, providing a firm background in both contemporary and classical approaches. Beginning with two full chapters on laminar premixed and non-premixed flames, this book takes a multiphase approach, beginning with more common topics and moving on to higher-level applications. In addition, Fundamentals of Turbulent and Multiphase Combustion: Addresses seven basic topical areas in combustion and multiphase flows, including laminar premixed and non-premixed flames, theory of turbulence, turbulent premixed and non-premixed flames, and multiphase flows Covers spray atomization and combustion, solid-propellant combustion, homogeneous propellants, nitramines, reacting boundary-layer flows, single energetic particle combustion, and granular bed combustion Provides experimental setups and results whenever appropriate Supported with a large number of examples and problems as well as a solutions manual, Fundamentals of Turbulent and Multiphase Combustion is an important resource for professional engineers and researchers as well as graduate students in mechanical, chemical, and aerospace engineering.
Download or read book Soot Formation in Ultra rich Turbulent Combustion of Natural Gas at Elevated Pressure written by Marc Hendrikus Franciscus Woolderink and published by . This book was released on 2014 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theories of Turbulent Combustion in High Speed Flows written by Paul A. Libby and published by . This book was released on 1995 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flow Field and Soot Formation Characteristics in Swirl stabilized Non premixed Turbulent Flames written by Lu-Yin Wang and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soot formation and evolution in relation with the flow fields were investigated experimentally in turbulent swirl-stabilized non-premixed flames using three different fuels: methane, ethanol and aviation Jet A-1. The studied flames were confined and stabilized in a model gas turbine combustor with a swirl number of ~0.55. Soot volume fraction, fv, and primary soot particle size, dp, were measured using auto-compensating laser-induced incandescence, and planar three-component velocity fields were measured using stereoscopic particle image velocimetry. Measurements of planar laser-induced fluorescence of OH and OH* chemiluminescence were also made for methane and ethanol flames. The OH* field was further Abel-inverted to qualitatively locate the heat release zone. The flow field for all flames featured pronounced inner and outer recirculation zones (IRZ, ORZ), each bounded by their corresponding inner and outer shear layers (ISL, OSL). Abel-inverted OH* intensity maps showed that primary reaction zones occurred in the vicinity of ISL. The central fuel jet penetrating into the IRZ accompanied by a stagnation zone was observed in all methane flames. Soot measurements showed that the overall dp for methane and Jet A-1 flames ranged between 30 nm and 60 nm without discernible trends. In methane flames, peak time-averaged fv occurred between the central jet penetration and the ISL. The decrease and the final disappearance of time-averaged fv were strongly correlated with elevated OH, demonstrating a dominant oxidative attack of OH on soot. With a ~7% increase in air flow rate, the level of soot volume fraction dropped by nearly threefold due to enhanced turbulence intermittency. The appearance of ethanol spray flames, which lacked a bright yellow color, largely differed from others. The absence of soot was confirmed in the laser-induced incandescence measurements. The isothermal flow field of ethanol flames exhibited a large-scale structure of precessing vortex core which was then suppressed under reacting conditions. In Jet A-1 flames, spray pattern changed from V-shaped hollow cone to semi-solid cone when air flow rate increased by 20%, resulting in a 60% reduction in peak time-averaged fv. In contrast to results obtained from the methane flame, soot was found primarily outside the ISL where fuel existed in abundance.
Download or read book Turbulent Combustion written by Norbert Peters and published by Cambridge University Press. This book was released on 2000-08-15 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: The combustion of fossil fuels remains a key technology for the foreseeable future. It is therefore important that we understand the mechanisms of combustion and, in particular, the role of turbulence within this process. Combustion always takes place within a turbulent flow field for two reasons: turbulence increases the mixing process and enhances combustion, but at the same time combustion releases heat which generates flow instability through buoyancy, thus enhancing the transition to turbulence. The four chapters of this book present a thorough introduction to the field of turbulent combustion. After an overview of modeling approaches, the three remaining chapters consider the three distinct cases of premixed, non-premixed, and partially premixed combustion, respectively. This book will be of value to researchers and students of engineering and applied mathematics by demonstrating the current theories of turbulent combustion within a unified presentation of the field.
Download or read book Physical and Chemical Aspects of Combustion written by F Dryer and published by CRC Press. This book was released on 1997-08-20 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains a collection of papers prepared by leading experts on selected areas of particular importance to researchers in combustion science. The editors have gathered writings on fundamental physical and chemical aspects of combustion, including combustion chemistry, soot formation, and condensed phase and turbulent combustion intended to be a source of current understanding on the topics covered. The materials were originally presented as part of a Colloquium on Combustion held in honor of Professor Irvin Glassman.
Download or read book Modeling of Soot Formation in Turbulent Diffusion Flames Impinging on a Cold Surface written by Roytor Charoensin-O-larn and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heat and Mass Transfer in Boundary Layers written by Suhas V. Patankar and published by . This book was released on 1970 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Combustion Modeling written by Tarek Echekki and published by Springer Science & Business Media. This book was released on 2010-12-25 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent combustion sits at the interface of two important nonlinear, multiscale phenomena: chemistry and turbulence. Its study is extremely timely in view of the need to develop new combustion technologies in order to address challenges associated with climate change, energy source uncertainty, and air pollution. Despite the fact that modeling of turbulent combustion is a subject that has been researched for a number of years, its complexity implies that key issues are still eluding, and a theoretical description that is accurate enough to make turbulent combustion models rigorous and quantitative for industrial use is still lacking. In this book, prominent experts review most of the available approaches in modeling turbulent combustion, with particular focus on the exploding increase in computational resources that has allowed the simulation of increasingly detailed phenomena. The relevant algorithms are presented, the theoretical methods are explained, and various application examples are given. The book is intended for a relatively broad audience, including seasoned researchers and graduate students in engineering, applied mathematics and computational science, engine designers and computational fluid dynamics (CFD) practitioners, scientists at funding agencies, and anyone wishing to understand the state-of-the-art and the future directions of this scientifically challenging and practically important field.
Download or read book CFD Prediction of Coupled Radiation Heat Transfer and Soot Production in Turbulent Flames written by and published by . This book was released on 1906 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The mechanisms governing the formation and destruction of soot in turbulent combustion are intimately coupled to thermal radiation due to the strong dependence of sooting processes and radiative loss on temperature. Detailed computational fluid dynamics (CFD) predictions of the radiative and soot output from turbulent non-premixed flames are normally performed by parabolic algorithms. However, the modelling of combustion systems, such as furnaces and unwanted enclosure fires, often require a fully elliptic description of the flow field and its related physical phenomena. Thus, this thesis investigates the intimate coupling between radiative energy exchange and the mechanisms governing soot formation and destruction within a three-dimensional, general curvilinear CFD code. Thermal radiation is modelled by the discrete transfer radiation model (DTRM). Special emphasis is given to approximate solutions to the radiative transfer equation encompassing various models for the radiative properties of gases and soot. A new algorithm is presented, entitled the differential total absorptivity (DTA) solution, which, unlike alternative solutions, incorporates the source temperature dependence of absorption. Additionally, a weighted sum of gray gases (WSGG) solution is described which includes the treatment of gray boundaries. Whilst the DTA solution is particularly recommended for systems comprising large temperature differences, the WSGG solution is deemed most appropriate for numerical simulation of lower temperature diffusion flames, due to its significant time advantage. The coupling between radiative loss and soot concentration is investigated via a multiple laminar flamelet concept applied within the CFD simulation of confined turbulent diffusion flames burning methane in air at 1 and 3 atm. Flamelet families are employed relating individual sooting mechanisms to the level of radiative loss, which is evaluated by the DTRM formulated for emitting-absorbing mixtures of soot,
Download or read book Large Eddy Simulation of Soot Evolution in Turbulent Reacting Flows written by Michael Edward Mueller and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Soot particles are nanoparticles consisting primarily of carbon that are formed during the combustion of fuel-rich mixtures. Due to environmental and health concerns, soot emissions from combustion systems are tightly regulated, and this regulation will only become stricter in the future. To enable the design of the next generation of low-emission combustion systems, predictive numerical simulations will be required. However, soot is a particularly difficult modeling problem due to the needs for high-fidelity models for soot itself in addition to chemistry and turbulence. This dissertation seeks to develop an integrated modeling framework based on Large Eddy Simulation (LES) for soot evolution in turbulent reacting flows. The final objective is the demonstration and evaluation of the model in an actual aircraft combustor. In order to enable these high-fidelity simulations, three component models have been developed. First, a detailed soot model is developed within the framework of the Method of Moments. New models for soot aggregation and fragmentation are proposed, and closure of the moment source terms is achieved with the Hybrid Method of Moments (HMOM), an accurate yet computationally efficient method. Second, a new turbulent combustion model is developed based on the Radiation Flamelet/Progress Variable (RFPV) model that can account for the removal of precursors from the gas-phase to form soot particles. Third, a subfilter PDF model is developed to account for the unresolved small-scale interactions between soot, turbulence, and chemistry. The subfilter PDF approach is validated a priori against a recent DNS database of soot evolution in a turbulent nonpremixed flame. The integrated modeling approach is then validated against experimental measurements in two laboratory-scale turbulent nonpremixed flames: a natural gas piloted jet flame and an ethylene bluff body flame. Differences in soot evolution due to the differences in the large-scale mixing in the two flames are discussed. The validated model is then applied to the simulation of a Pratt & Whitney aircraft combustor. Two operating points are simulated to assess the ability of the integrated model to reproduce quantitative trends in soot emissions.
