Download or read book Turbulent Premixed Flames written by Nedunchezhian Swaminathan and published by Cambridge University Press. This book was released on 2011-04-25 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: A work on turbulent premixed combustion is important because of increased concern about the environmental impact of combustion and the search for new combustion concepts and technologies. An improved understanding of lean fuel turbulent premixed flames must play a central role in the fundamental science of these new concepts. Lean premixed flames have the potential to offer ultra-low emission levels, but they are notoriously susceptible to combustion oscillations. Thus, sophisticated control measures are inevitably required. The editors' intent is to set out the modeling aspects in the field of turbulent premixed combustion. Good progress has been made on this topic, and this cohesive volume contains contributions from international experts on various subtopics of the lean premixed flame problem.

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 Premixed Turbulent Flame Propagation written by D. A. Santavicca and published by . This book was released on 1987 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: A pulsed flame flow reactor has been developed for the study of one-dimensional, freely propagating, premixed turbulent flames over a broad range of turbulence Reynolds and Damkohler numbers. Laser Doppler velocimetry is used to characterize the turbulent flow field ahead of the flame in terms of its intensity, length scale and energy spectrum. Two-dimensional imaging is used to characterize the turbulent flame structure. Preliminary results indicate that the method of fractal analysis may be useful for quantifying turbulent flame structure in order to evaluate the effect of turbulence on flame propagation through changes in the flame structure. Keywords: Premixed turbulent combustion; Catalytic combustion; Catalytic ignition.

Download or read book Premixed Turbulent Flame Propagation written by D. A. Santavicca and published by . This book was released on 1990 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of an experimental study of turbulence-flame interactions and their effect on turbulent flame propagation are reported. Experiments are conducted in a new turbulent flow system which is capable of producing relative turbulence intensities as high as 100 percent. Using a freely propagating, one-dimensional flame configuration, measurements are made using LDV of the mean velocity, turbulence intensity, integral time scale, energy spectrum, Reynolds stress, and integral length scale, at a fixed location both before and after flame arrival. A complete set os such measurements has been made at one operating condition which characterize both the magnitude of flame generated turbulence and its anisotropic nature. The freely propagating, one dimensional flame configuration has also been used to study the effect of turbulence on turbulent flame structure. Two dimensional Mie scattering is used to obtain a two-dimensional slice of the turbulent flame surface. Such measurements have been made at 15 different conditions over very broad range of turbulence Reynolds and Damkohler numbers and have been analyzed to determine the fractal nature of the turbulent flame surface. The results of these measurements show that premixed turbulent flame surfaces are fractal throughout the reaction sheet regime. Keywords: Premixed turbulent combustion; Turbulent flame interactions; Turbulent flame propagation; Turbulent flame structure. (JHD).

Download or read book Recent Advances in the Aerospace Sciences written by Corrado Casci and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume, published in honor of Prof. Luigi Crocco, appears when Luigi Crocco celebrates his 75th birthday of a life devoted to study, research, and teaching. The events in his life and World War II forced Luigi Crocco, as well as other Italian scientists, to look to foreign countries for the calm haven so vital to study. This notwithstanding, his scientific activity was never inter rupted, and this volume is an acknowledgment of scientists and researchers to his work and life. Prefazione Questo volume in onore del prof. ing. Luigi Crocco vede la luce quando Luigi Crocco compie i 75 anni di una vita dedicata allo studio, alia ricerca e all'insegnamento. a Le vicende della vita, ed anche della 2 guerra mondiale, hanno costretto Luigi Crocco, come altri scienziati italiani, a dover cercare in altri Paesi quella serenita necessaria per dedicarsi allo studio. Ma la sua attivita scientifica non ha avuto interruzioni e questo volume essere la testimonianza di studiosi e di ricercatori alia sua opera e alia sua vita."

Download or read book Flashback Mechanisms in Lean Premixed Gas Turbine Combustion written by Ali Cemal Benim and published by Academic Press. This book was released on 2014-12-01 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Blending fuels with hydrogen offers the potential to reduce NOx and CO2 emissions in gas turbines, but doing so introduces potential new problems such as flashback. Flashback can lead to thermal overload and destruction of hardware in the turbine engine, with potentially expensive consequences. The little research on flashback that is available is fragmented. Flashback Mechanisms in Lean Premixed Gas Turbine Combustion by Ali Cemal Benim will address not only the overall issue of the flashback phenomenon, but also the issue of fragmented and incomplete research. Presents a coherent review of flame flashback (a classic problem in premixed combustion) and its connection with the growing trend of popularity of more-efficient hydrogen-blend fuels Begins with a brief review of industrial gas turbine combustion technology Covers current environmental and economic motivations for replacing natural gas with hydrogen-blend fuels

Download or read book Turbulent Reactive Flows written by R. Borghi and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 958 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent reactive flows are of common occurrance in combustion engineering, chemical reactor technology and various types of engines producing power and thrust utilizing chemical and nuclear fuels. Pollutant formation and dispersion in the atmospheric environment and in rivers, lakes and ocean also involve interactions between turbulence, chemical reactivity and heat and mass transfer processes. Considerable advances have occurred over the past twenty years in the understanding, analysis, measurement, prediction and control of turbulent reactive flows. Two main contributors to such advances are improvements in instrumentation and spectacular growth in computation: hardware, sciences and skills and data processing software, each leading to developments in others. Turbulence presents several features that are situation-specific. Both for that reason and a number of others, it is yet difficult to visualize a so-called solution of the turbulence problem or even a generalized approach to the problem. It appears that recognition of patterns and structures in turbulent flow and their study based on considerations of stability, interactions, chaos and fractal character may be opening up an avenue of research that may be leading to a generalized approach to classification and analysis and, possibly, prediction of specific processes in the flowfield. Predictions for engineering use, on the other hand, can be foreseen for sometime to come to depend upon modeling of selected features of turbulence at various levels of sophistication dictated by perceived need and available capability.

Download or read book Fundamentals of Premixed Turbulent Combustion written by Andrei Lipatnikov and published by CRC Press. This book was released on 2012-10-24 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lean burning of premixed gases is considered to be a promising combustion technology for future clean and highly efficient gas turbine combustors. Yet researchers face several challenges in dealing with premixed turbulent combustion, from its nonlinear multiscale nature and the impact of local phenomena to the multitude of competing models. Filling

Download or read book Unsteady Combustor Physics written by Tim C. Lieuwen and published by Cambridge University Press. This book was released on 2012-08-27 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing clean, sustainable energy systems is a pre-eminent issue of our time. Most projections indicate that combustion-based energy conversion systems will continue to be the predominant approach for the majority of our energy usage. Unsteady combustor issues present the key challenge associated with the development of clean, high-efficiency combustion systems such as those used for power generation, heating or propulsion applications. This comprehensive study is unique, treating the subject in a systematic manner. Although this book focuses on unsteady combusting flows, it places particular emphasis on the system dynamics that occur at the intersection of the combustion, fluid mechanics and acoustic disciplines. Individuals with a background in fluid mechanics and combustion will find this book to be an incomparable study that synthesises these fields into a coherent understanding of the intrinsically unsteady processes in combustors.

Download or read book Encyclopedic Dictionary of Polymers written by Jan W. Gooch and published by Springer Science & Business Media. This book was released on 2010-11-08 with total page 1048 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference, in its second edition, contains more than 7,500 polymeric material terms, including the names of chemicals, processes, formulae, and analytical methods that are used frequently in the polymer and engineering fields. In view of the evolving partnership between physical and life sciences, this title includes an appendix of biochemical and microbiological terms (thus offering previously unpublished material, distinct from all competitors.) Each succinct entry offers a broadly accessible definition as well as cross-references to related terms. Where appropriate to enhance clarity further, the volume's definitions may also offer equations, chemical structures, and other figures. The new interactive software facilitates easy access to a large database of chemical structures (2D/3D-view), audio files for pronunciation, polymer science equations and many more.

Download or read book Propagation of Large Scale Premixed Turbulent Flames written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Combustion Phenomena written by Jozef Jarosinski and published by CRC Press. This book was released on 2009-02-12 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extensively using experimental and numerical illustrations, CombustionPhenomena: Selected Mechanisms of Flame Formation, Propagation, and Extinction provides a comprehensive survey of the fundamental processes of flame formation, propagation, and extinction. Taking you through the stages of combustion, leading experts visually display, mathematically explain, and clearly theorize on important physical topics of combustion. After a historical introduction to the field, they discuss combustion chemistry, flammability limits, and spark ignition. They also study counterflow twin-flame configuration, flame in a vortex core, the propagation characteristics of edge flames, instabilities, and tulip flames. In addition, the book describes flame extinction in narrow channels, global quenching of premixed flames by turbulence, counterflow premixed flame extinction limits, the interaction of flames with fluids in rotating vessels, and turbulent flames. The final chapter explores diffusion flames as well as combustion in spark- and compression-ignition engines. It also examines the transition from deflagration to detonation, along with the detonation wave structure. With downloadable resources of images that beautifully illustrate a range of combustion phenomena, this book facilitates a practical understanding of the processes occurring in the conception, spread, and extinguishment of a flame. It will help you on your way to finding solutions to real issues encountered in transportation, power generation, industrial processes, chemical engineering, and fire and explosion hazards.

Download or read book A Two eddy Theory of Premixed Turbulent Flame Propagation written by R. G. Abdel-Gayed and published by . This book was released on 1981 with total page 25 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 THE SURFACE STRUCTURE OF TURBULENT PREMIXED HYDROGEN AIR RIM STABILIZED FLAMES AT HIGH REYNOLDS NUMBER PREMIXED TURBULENT FLAMES FLAMES written by MING-SHIN WU and published by . This book was released on 1991 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: three-dimensional simulation, to remove 2-D deficiencies, appears to be computationally feasible for high Reynolds number conditions of interest for practical applications.

Download or read book A Two eddy Theory of Premixed Turbulent Flame Propagation written by R. G. Abdel-Gayed and published by . This book was released on 1981 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experiments in Laminar and Turbulent Premixed Counter flow Flames at Variable Lewis Number written by Sean Salusbury and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "This thesis examines preferential diffusion effects in laminar and turbulent premixed combustion. Stretched, fuel-lean, laminar flames of methane, propane and hydrogen are studied experimentally in a counter-flow flame configuration to investigate the effect of Lewis number on stretched flames. Laminar flame results show that a maximum reference flame speed exists for mixtures with Le >= 1 at lower flame-stretch values than the extinction stretch rate. A continually-increasing reference flame speed is measured for Le “ 1 mixtures until extinction occurs when the flame is constrained by the stagnation point.Turbulent counter-flow flame experiments are then performed for these mixtures, using high-blockage turbulence-generating plates to produce turbulence intensities on the order of u'/sLo = 1 to 10. Measurements of average and instantaneous velocity within the turbulent flame are performed by time-resolved particle image velocimetry measurements. Average and instantaneous flame front position is also measured by Rayleigh spectroscopy.Measurements of average turbulent burning velocity demonstrate the ambiguity in definitions of the burning velocity and the difficulty of examining turbulent flame chemistry using averaged measurements. Instantaneous statistics are shown to be superior tools for studying turbulent combustion. The probability-density functions (PDF) of the local flamelet burning velocities for Le >= 1 mixtures show that the instantaneous flamelet burning velocities increase with increasing turbulence intensity and flame stretch. The PDF for the Le ~= 1 mixture has a sharply skewed shape at high turbulence intensity and has a sharp drop-off in probability at a velocity that corresponds with the experimentally-measured maximum reference flame speed from the laminar flame experiments. In contrast, in the Le “ 1 turbulent flames, the most-probable instantaneous flamelet burning velocities increase with increasing turbulence intensity and can significantly exceed the maximum reference flame speed measured in counter-flow laminar flames at extinction.These results are reinforced by instantaneous flame position measurements. Flame front location PDFs show the most probable flame location to be linked to velocity PDFs. Furthermore, hydrogen PDFs are recognizably skewed as u'/sLo increases, indicating a tendency for the Le “ 1 mixture to propagate farther into the unburned reactants. These results support the leading edge theory of premixed turbulent flame propagation for flames in which preferential diffusion effects are expected.In the study of turbulent flames, this work promotes the use of local, instantaneous statistics as a tool for describing experimental results and studying fuel chemistry." --