Download or read book Experimental Investigation of the Response of Turbulent Premixed Flames to Acoustic Oscillations written by R. Balachandran and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of the Response of Flames with Different Degrees of Premixedness to Acoustic Oscillations written by Anna-Maria Kypraiou and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Theoretical and Experimental Investigation of Turbulent Premixed Flames written by Medhat T. F. Azzazy 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 Stabilization and Dynamic of Premixed Swirling Flames written by Paul Palies and published by Academic Press. This book was released on 2020-07-03 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stabilization and Dynamic of Premixed Swirling Flames: Prevaporized, Stratified, Partially, and Fully Premixed Regimes focuses on swirling flames in various premixed modes (stratified, partially, fully, prevaporized) for the combustor, and development and design of current and future swirl-stabilized combustion systems. This includes predicting capabilities, modeling of turbulent combustion, liquid fuel modeling, and a complete overview of stabilization of these flames in aeroengines. The book also discusses the effects of the operating envelope on upstream fresh gases and the subsequent impact of flame speed, combustion, and mixing, the theoretical framework for flame stabilization, and fully lean premixed injector design. Specific attention is paid to ground gas turbine applications, and a comprehensive review of stabilization mechanisms for premixed, partially-premixed, and stratified premixed flames. The last chapter covers the design of a fully premixed injector for future jet engine applications. Features a complete view of the challenges at the intersection of swirling flame combustors, their requirements, and the physics of fluids at work Addresses the challenges of turbulent combustion modeling with numerical simulations Includes the presentation of the very latest numerical results and analyses of flashback, lean blowout, and combustion instabilities Covers the design of a fully premixed injector for future jet engine applications
Download or read book Experimental Investigation and Analysis of the Nonlinear Response of Turbulent Swirl stabilized Flames written by Sebastian Schimek and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of Turbulent Scalar Flux in Premixed Flames written by Peter Anthony Markus Kalt and published by . This book was released on 1998 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation and Spectral Modeling of Turbulent Combustion Noise from Premixed and Non Premixed Flames written by Christoph Jörg and published by . This book was released on 2015 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermoacoustic Combustion Instability Control written by Dan Zhao and published by Academic Press. This book was released on 2023-02-13 with total page 1145 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoacoustic Combustion Instability Control: Engineering Applications and Computer Codes provides a unique opportunity for researchers, students and engineers to access recent developments from technical, theoretical and engineering perspectives. The book is a compendium of the most recent advances in theoretical and computational modeling and the thermoacoustic instability phenomena associated with multi-dimensional computing methods and recent developments in signal-processing techniques. These include, but are not restricted to a real-time observer, proper orthogonal decomposition (POD), dynamic mode decomposition, Galerkin expansion, empirical mode decomposition, the Lattice Boltzmann method, and associated numerical and analytical approaches. The fundamental physics of thermoacoustic instability occurs in both macro- and micro-scale combustors. Practical methods for alleviating common problems are presented in the book with an analytical approach to arm readers with the tools they need to apply in their own industrial or research setting. Readers will benefit from practicing the worked examples and the training provided on computer coding for combustion technology to achieve useful results and simulations that advance their knowledge and research. Focuses on applications of theoretical and numerical modes with computer codes relevant to combustion technology Includes the most recent modeling and analytical developments motivated by empirical experimental observations in a highly visual way Provides self-contained chapters that include a comprehensive, introductory section that ensures any readers new to this topic are equipped with required technical terms
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: This book deals with unsteady combustor issues, which have posed key challenges associated with development of clean, high-efficiency combustion systems.
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 Experimental Study of Premixed Flames in a Taylor Couette Combustor written by Vahid Vaezi and published by . This book was released on 2000 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Study of Turbulent Premixed Combustion in V shaped Flames written by Sina Kheirkhah and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Characteristics of turbulent premixed flames were investigated experimentally. The investigations were performed using Mie scattering, Particle Image Velocimetry, Rayleigh scattering, and broad-band luminosity imaging techniques. Methane-air flames associated with a relatively wide range of turbulence intensities, fuel-air equivalence ratios, and mean bulk flow velocities were investigated. For a relatively moderate value of turbulence intensity, a new concept is introduced and utilized to provide a detailed description associated with interaction of turbulent flow and flame front. The concept pertains to reactants velocity estimated at the vicinity of the flame front and is referred to as the edge velocity. Specifically, it is shown that fluctuations of the flame front position are induced by fluctuations of the edge velocity. For a relatively wide range of turbulence intensity, several characteristics of turbulent premixed flames, namely, front topology, brush thickness, surface density, and consumption speeds are investigated. For the first time, several flame front structures are identified and studied. It is shown that, due to formation of these front structures, the regime of turbulent premixed combustion transitions from the regime of counter-gradient diffusion to that of the gradient diffusion. In addition to these, a comprehensive study is performed to investigate influence of flame configuration on several flame front characteristics. It is obtained that, although changing the flame configuration influences several flame characteristics, the trends associated with the effects of governing parameters on the characteristics are nearly independent of the flame configuration.
Download or read book Unsteady Supersonic Combustion written by Mingbo Sun and published by Springer Nature. This book was released on 2020-04-14 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the unsteady phenomena needed to understand supersonic combustion. Following an initial chapter that introduces readers to the basic concepts in and classical studies on unsteady supersonic combustion, the book highlights recent studies on unsteady phenomena, which offer insights on e.g. interactions between acoustic waves and flames, flow dominating instability, ignition instability, flame flashback, and near-blowout-limit combustion. In turn, the book discusses in detail the fundamental mechanisms of these phenomena, and puts forward practical suggestions for future scramjet design.
Download or read book Thermoacoustic Instability written by R. I. Sujith and published by Springer Nature. This book was released on 2021-12-14 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book systematically presents the consolidated findings of the phenomenon of self-organization observed during the onset of thermoacoustic instability using approaches from dynamical systems and complex systems theory. Over the last decade, several complex dynamical states beyond limit cycle oscillations such as quasiperiodicity, frequency-locking, period-n, chaos, strange non-chaos, and intermittency have been discovered in thermoacoustic systems operated in laminar and turbulent flow regimes. During the onset of thermoacoustic instability in turbulent systems, an ordered acoustic field and large coherent vortices emerge from the background of turbulent combustion. This emergence of order from disorder in both temporal and spatiotemporal dynamics is explored in the contexts of synchronization, pattern formation, collective interaction, multifractality, and complex networks. For the past six decades, the spontaneous emergence of large amplitude, self-sustained, tonal oscillations in confined combustion systems, characterized as thermoacoustic instability, has remained one of the most challenging areas of research. The presence of such instabilities continues to hinder the development and deployment of high-performance combustion systems used in power generation and propulsion applications. Even with the advent of sophisticated measurement techniques to aid experimental investigations and vast improvements in computational power necessary to capture flow physics in high fidelity simulations, conventional reductionist approaches have not succeeded in explaining the plethora of dynamical behaviors and the associated complexities that arise in practical combustion systems. As a result, models and theories based on such approaches are limited in their application to mitigate or evade thermoacoustic instabilities, which continue to be among the biggest concerns for engine manufacturers today. This book helps to overcome these limitations by providing appropriate methodologies to deal with nonlinear thermoacoustic oscillations, and by developing control strategies that can mitigate and forewarn thermoacoustic instabilities. The book is also beneficial to scientists and engineers studying the occurrence of several other instabilities, such as flow-induced vibrations, compressor surge, aeroacoustics and aeroelastic instabilities in diverse fluid-mechanical environments, to graduate students who intend to apply dynamical systems and complex systems approach to their areas of research, and to physicists who look for experimental applications of their theoretical findings on nonlinear and complex systems.
Download or read book Experimental Investigation of Flow Turbulence Effects on Premixed Methane air Flames written by Kenneth Owen Smith and published by . This book was released on 1978 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interactions Between Coherent and Turbulent Oscillations and Their Impact on the Dynamics of Flames and Flow Fields written by Ashwini Karmarkar and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This primary focus of this dissertation is to investigate the coupling mechanisms by which flow field fluctuations can interact with heat release oscillations and how the coupling mechanisms are impacted by the addition of turbulent fluctuations. This work is particularly motivated by the problem of combustion instability in gas turbine engines. Combustion instability is a type of thermoacoustic instability that occurs due to coupling between the coherent oscillations in heat release rate and the acoustic modes of the combustor. The modulation of heat release rate due to the interaction of the flame front with coherent structures in the flow can be a driver of combustion instability. While there have multiple studies analysing the interaction between flames and coherent structures, many of the experimental studies focus on the low-turbulence regime, which is not representative of realistic engine conditions. More recent studies have analysed flame response and limiting phenomena at high turbulence intensities, although the interaction between competing phenomena of turbulent and coherent oscillations have not been comprehensively studied so far and is therefore a focus contribution of this work. In this dissertation, two configurations are studied -- the canonical rod-stabilized V-flame and a more realistic partially-premixed swirl flame. The canonical configuration allows for more control over individual flow parameters so that the coherent and turbulent fluctuations can be independently controlled and systematically varied. High-speed stereoscopic particle image velocimetry (sPIV) is the primary diagnostic used in this configuration. The coherent oscillations in the flow field are excited by longitudinal acoustic excitation and different configurations of perforated plates in the burner provide varying turbulence intensities. The results from this work conclusively show that the magnitude of turbulence intensity in the flow can significantly impact the flow dynamics, the symmetry of the flow response to external excitation, and the coupling between the flow field and flame fluctuations. The realistic swirling flame configuration is used to characterize the interaction between the precessing vortex core (PVC), which is the consequence of a global hydrodynamic instability, and thermoacoustic instabilities, which are the result of a coupling between combustor acoustics and the unsteady heat release rate of combustion. This study is performed using experimental data obtained from a model gas turbine combustor system to simulate realistic conditions. High-speed stereoscopic particle image velocimetry, OH planar laser-induced fluorescence, and acetone planar laser-induced fluorescence are used to obtain information about the velocity fields, flame, and fuel flow behavior, respectively. The results from this work show that in the cases where the frequency of the PVC overlaps with the frequency of a thermoacoustic mode, the thermoacoustic mode is subsequently suppressed. Further, the thermoacoustic coupling process is driven by both velocity and mixture variations, but the PVC oscillations do not significantly drive variations in the mixture, only the velocity field. Put together, the findings from both configurations provide important insight into the coupling mechanisms that govern the interactions between the various flow field fluctuations and their impact on the unsteady heat release from the flame.
