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Book Effects of the Fuel Air Mixing on Combustion Instabilities and NOx Emissions in Lean Premixed Combustion

Download or read book Effects of the Fuel Air Mixing on Combustion Instabilities and NOx Emissions in Lean Premixed Combustion written by Wessam Estefanos and published by . This book was released on 2016 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was conducted to investigate the effects of the fuel-air mixing on combustion instabilities and NO x emissions in lean premixed combustion. High speed PIV measurements in water were conducted to capture the mean and dynamic behavior of the cold flow generated by a 3X model of the tested premixer. High speed PLIF in water measurements were conducted to quantify the mean and unsteady fuel-air mixing at different momentum flux ratios. Atmospheric combustion tests using the original premixer, were conducted using natural gas and propane at the same momentum flux ratios of the PLIF mixing tests. An emissions analyzer was used to measure the emissions from combustion tests. Dynamic pressure transducers were used to measure the amplitude and the frequency of the dynamic pressure oscillations associated with the combustion instabilities. CHEMKIN-PRO was used to model the atmospheric combustion and predict NO x emissions at different conditions. Results showed that unsteady fuel-air mixing was concentrated at the center and near the outer edges of the premixer. These regions were characterized by high fuel concentration gradients. With the increase in the momentum flux ratio, the concentration gradient and the level of unsteady mixing increased, indicating that the fuel-air spatial unmixedness was the source of the unsteady mixing. It was found that local flow turbulence tended to decrease the concentration gradient through enhancing the fuel-air mixing, which resulted in decreasing the level of unsteady mixing. NO x emissions from atmospheric combustion increased with the increase in the momentum flux ratio due to the increase in the flame temperature and the fuel-air spatial and temporal unmixedness. The intensity of the combustion dynamics increased with the increase in the level of unsteady mixing. Axial injection of the fuel into the regions of strong unsteady mixing eliminated the combustion dynamics through damping the unsteady mixing. Results of CHEMKIN-PRO agreed very well with the experimental results and showed that the spatial and temporal unmixedness have a significant effect on NO x emissions for very lean combustion (F = 0.4). With the increase in the equivalence ratio, their relative contribution decreased.

Book Lean Combustion

Download or read book Lean Combustion written by Derek Dunn-Rankin and published by Academic Press. This book was released on 2011-07-28 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion under sufficiently fuel-lean conditions can have the desirable attributes of high efficiency and low emissions, this being particularly important in light of recent and rapid increases in the cost of fossil fuels and concerns over the links between combustion and global climate change. Lean Combustion is an eminently authoritative, reference work on the latest advances in lean combustion technology and systems. It will offer engineers working on combustion equipment and systems both the fundamentals and the latest developments in more efficient fuel usage and in much-sought-after reductions of undesirable emissions, while still achieving desired power output and performance. This volume brings together research and design of lean combustion systems across the technology spectrum in order to explore the state-of-the-art in lean combustion and its role in meeting current and future demands on combustion systems. Readers will learn about advances in the understanding of ultra lean fuel mixtures and how new types of burners and approaches to managing heat flow can reduce problems often found with lean combustion such as slow, difficult ignition and frequent flame extinction. The book will also offer abundant references and examples of recent real-world applications. Covers all major recent developments in lean combustion science and technology, with new applications in both traditional combustion schemes as well as such novel uses as highly preheated and hydrogen-fueled systems Offers techniques for overcoming difficult ignition problems and flame extinction with lean fuel mixtures Covers new developments in lean combustion using high levels of pre-heat and heat re-circulating burners, as well as the active control of lean combustion instabilities

Book Flashback Mechanisms in Lean Premixed Gas Turbine Combustion

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

Book The John Zink Hamworthy Combustion Handbook Second Edition

Download or read book The John Zink Hamworthy Combustion Handbook Second Edition written by Charles E. Baukal, Jr. and published by CRC Press. This book was released on 2013-08-23 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the length of time it has been around, its importance, and vast amounts of research, combustion is still far from being completely understood. Issues regarding the environment, cost, and fuel consumption add further complexity, particularly in the process and power generation industries. Dedicated to advancing the art and science of industrial combustion, The John Zink Hamworthy Combustion Handbook, Second Edition: Volume 3 – Applications offers comprehensive, up-to-date coverage of equipment used in the process and power generation industries. Under the leadership of Charles E. Baukal, Jr., top engineers and technologists from John Zink Hamworthy Combustion examine industry applications such as process burners, boiler burners, process flares, thermal oxidizers, and vapor control. This volume builds on the concepts covered in the first two volumes and shows how they are used in combustion applications. The book also features a wealth of color illustrations, photographs, and tables throughout. What’s New in This Edition Expanded to three volumes, with Volume 3 focusing on important industry applications Extensive updates and revisions throughout, reflecting new standards, energy sources, processes, and conservation concerns Expanded coverage of flares and new coverage of biogas flares and flare gas recovery Information on vapor combustors Discussion of pollution control equipment Expanded coverage of commercial and utility boiler burners Chapters on process and air heaters More material on thermal oxidizers A new chapter on marine and offshore applications The third of three volumes in the new, expanded edition of the bestselling handbook, this volume helps you broaden your knowledge of industrial combustion applications to better meet the challenges of this field. For the other volumes in the set, see The John Zink Hamworthy Combustion Handbook, Second Edition: Three-Volume Set.

Book Approaches for Clean Combustion in Gas Turbines

Download or read book Approaches for Clean Combustion in Gas Turbines written by Medhat A. Nemitallah and published by Springer Nature. This book was released on 2020-03-24 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the development of novel combustion approaches and burner designs for clean power generation in gas turbines. It shows the reader how to control the release of pollutants to the environment in an effort to reduce global warming. After an introduction to global warming issues and clean power production for gas turbine applications, subsequent chapters address premixed combustion, burner designs for clean power generation, gas turbine performance, and insights on gas turbine operability. Given its scope, the book can be used as a textbook for graduate-level courses on clean combustion, or as a reference book to accompany compact courses for mechanical engineers and young researchers around the world.

Book The Slipcover for The John Zink Hamworthy Combustion Handbook

Download or read book The Slipcover for The John Zink Hamworthy Combustion Handbook written by Charles E. Baukal Jr. and published by CRC Press. This book was released on 2018-10-03 with total page 1184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the length of time it has been around, its importance, and vast amounts of research, combustion is still far from being completely understood. Issues regarding the environment, cost, and fuel consumption add further complexity, particularly in the process and power generation industries. Dedicated to advancing the art and science of industr

Book Effect of Noise on a Model Thermoacoustic System at its Stability Boundary

Download or read book Effect of Noise on a Model Thermoacoustic System at its Stability Boundary written by Richard Steinert and published by Springer. This book was released on 2016-04-20 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: In experiments on a prototypical combustor, Richard Steinert identifies new insights on the impact of noise on the phenomenon known as thermoacoustic instability. The phenomenon is a concerning issue which creates a technical limit on the efficiency and environmental impact of fossil fuels combustion in industrial combustors. It poses a threat to the structural integrity of practical systems such as gas turbine combustors and rocket engines. The experiments demonstrate that thermoacoustic systems feature an interesting noise-induced behaviour known as coherence resonance – a coherent response of dynamical systems close to their stability boundary that is induced by stochastic excitation. The work contained in this publication is an example illustrating the importance of fundamental considerations in solving perplexing engineering issues.

Book Thermoacoustic Combustion Instability Control

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

Book Emissions Combustion Dynamics and Control of a Multiple Swirl Combustor

Download or read book Emissions Combustion Dynamics and Control of a Multiple Swirl Combustor written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To achieve single digit NOx emission from gas turbine combustors and prevent the combustion dynamics encountered in Lean Premixed Combustion, it is essential to understand the correlations among emission characteristics, combustion dynamics, and dynamics and characteristics of swirling flow field. The focus of this dissertation is to investigate the emission characteristics and combustion dynamics of multiple swirl dump combustors either in premixing or non-premixed combustion (e.g. Lean Direct Injection), and correlate these combustion characteristics (emissions, combustion instability and lean flammability) to the fluids dynamics (flow structures and its evolution). This study covers measurement of velocity flow field, temperature field, and combustion under effects of various parameters, including inlet flow Reynolds number, inlet air temperature, swirl configurations, downstream exhaust nozzle contraction ratios, length of mixing tube. These parameters are tested in both liquid and gaseous fuel combustions. Knowledge obtained through this comprehensive study is applied to passive and active controls for improving gas turbine combustion performance in the aid of novel sensor and actuator technologies. Emissions and combustion characteristics are shown closely related to the shape and size of central recirculation zone (CRZ), the mean and turbulence velocity and strain rate, and dynamics of large vortical structures. The passive controls, mostly geometry factors, affect the combustion characteristics and emissions through their influences on flow fields, and consequently temperature and radical fields. Air assist, which is used to adjust the momentum of fuel spray, is effective in reducing NOx and depress combustion oscillation without hurting LBO. Fuel distribution/split is also one important factor for achieving low NOx emission and control of combustion dynamics. The dynamics of combustion, including flame oscillations close to LBO and acoustic combustion instability, can be characterized by OH*/CH* radical oscillations and phase-locked chemiluminescence imaging. The periodic fluctuation of jet velocity and formation of large vortical structures within CRZ are responsible for combustion instability in multiple swirl combustors.

Book Effects of Turbulence on Nox Emissions from Lean Perfectly premixed Combustion

Download or read book Effects of Turbulence on Nox Emissions from Lean Perfectly premixed Combustion written by Ahmed S. AlAdawy and published by . This book was released on 2014 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Effect of turbulence on NOx emissions is studied for a perfectly-premixed combustor running on methane/air at the mixture inlet temperature of 495 K and the combustor pressure of 5 atm over a range of equivalence ratios (0.54 - 0.85). Turbulence level is varied by a factor of 2-3 by changing the length of a portion of channels in a perforated plate on which the flame is stabilized. Simultaneous PIV and OH-PLIF measurements are used to calculate the relevant turbulence parameters such as turbulence intensity and turbulence mixing time scales, and define the flame structure such as average flame height and hence flame zone residence time scales, respectively. Effect of turbulence level is found to have negligible effect on NOx emissions level. NOx emissions are predicted by using a partially-stirred reactor (PaSR) model in CHEMKIN-PRO package with the measured turbulence parameters as the input. The modeling results agree very well with the measured NOx emission level but show that it slightly increases with the increase of turbulence level.

Book The Coen Hamworthy Combustion Handbook

Download or read book The Coen Hamworthy Combustion Handbook written by Stephen Londerville and published by CRC Press. This book was released on 2013-03-25 with total page 555 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rigorous treatment of combustion can be so complex that the kinetic variables, fluid turbulence factors, luminosity, and other factors cannot be defined well enough to find realistic solutions. Simplifying the processes, The Coen & Hamworthy Combustion Handbook provides practical guidance to help you make informed choices about fuels, burne

Book Combustion Instabilities in Gas Turbine Engines

Download or read book Combustion Instabilities in Gas Turbine Engines written by Timothy C. Lieuwen and published by AIAA (American Institute of Aeronautics & Astronautics). This book was released on 2005 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers gas turbine users and manufacturers a valuable resource to help them sort through issues associated with combustion instabilities. In the last ten years, substantial efforts have been made in the industrial, governmental, and academic communities to understand the unique issues associated with combustion instabilities in low-emission gas turbines. The objective of this book is to compile these results into a series of chapters that address the various facets of the problem. The Case Studies section speaks to specific manufacturer and user experiences with combustion instabilities in the development stage and in fielded turbine engines. The book then goes on to examine The Fundamental Mechanisms, The Combustor Modeling, and Control Approaches.

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: