Download or read book Combustion Behavior Associated with Alternative Fuels in Lean Premixed High swirl Stabilized Distributed Reactions written by Amin Akbari and published by . This book was released on 2013 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lean blowoff, flashback and pollutant emission associated with lean premixed combustion of alternative fuels stabilized by high swirl are evaluated in this work. Alternative fuel compositions include blends of natural gas and hydrogen. Lean blowoff refers to events where the fuel-to-air ratio is not sufficient to sustain the reaction. Blowoff is often a dynamic process consisting of several stages. Correlations based on constant Damköhler (Da) number are able to estimate the impact of fuel composition on lean blowoff for the conditions studied. The accuracy of estimating initiation of blowoff is superior compared to estimation of subsequent stages of blowoff. Flashback refers to propagation of the reaction upstream into the premixing zone. In high swirl combustion applications, the concept of a quench criterion has been proposed for predicting flashback. For the present work, this concept only holds for some measured cases, which indicates multiple flashback modes even in high swirl combustion applications. The other major combustion challenge is pollutant emission. In this study NOx, CO, and N2O levels are experimentally measured. In addition, a chemical reaction network (CRN) was developed to study the details of emission formation. To develop a CRN, details of the reacting flow were needed. Hence, computational fluid dynamics (CFD) simulations were conducted. To validate CFD simulations, particle image velocimetry (PIV) and OH* chemiluminescence flame front imaging were applied. OH* chemiluminescence was also employed to visualize the flame structure and shape for different fuel compositions. The CRN simulations indicate that the NNH NOx formation pathway dominates the other formation pathways. Thus, conditions that enhance NNH NOx, such as an increase of hydrogen in fuel composition, and decrease of residence time, will result in more total NOx. The CRN also illustrates how the relative contribution of each NOx formation pathway to total NOx changes with adiabatic flame temperature (AFT). The NNH NOx formation pathway is dominant for AFT below 1900K; the Zeldovich mechanism is dominant for AFT above 1900K. In terms of N2O emissions measured and simulated results suggest the levels are negligible even for very low combustion temperatures.

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

Download or read book A Study of Lean Premixed Swirl stabilized Combustion of Gaseous Alternative Fuels written by Donald McKinley Wicksall and published by . This book was released on 2004 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lean Combustion written by Derek Dunn-Rankin and published by Academic Press. This book was released on 2016-07-01 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lean Combustion: Technology and Control, Second Edition outlines and explains the latest advances in lean combustion technology and systems. Combustion under sufficiently fuel-lean conditions can have the desirable attributes of high efficiency and low emissions. The book offers readers both the fundamentals and latest developments in how lean burn (broadly defined) can increase fuel economy and decrease 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. 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). This book offers abundant references and examples of real-world applications. New to this edition are significantly revised chapters on IC engines and stability/oscillations, and new case studies and examples. Written by a team of experts, this contributed reference book aims to teach its reader to maximize efficiency and minimize both economic and environmental costs. - Presents a comprehensive collection of lean burn technology across potential applications, allowing readers to compare and contrast similarities and differences - Provides an extensive update on IC engines including compression ignition (diesel), spark ignition, and homogeneous charge compression ignition (HCCI) - Includes an extensive revision to the Stability/Oscillations chapter - Includes use of alternative fuels such as biogas and hydrogen for relevant technologies - Covers new developments in lean combustion using high levels of pre-heat and heat recirculating burners, as well as the active control of lean combustion instabilities

Download or read book Development and Evaluation of Gas Fuel Interchangeability Criteria and Methodologies written by Vincent G. McDonell and published by . This book was released on 2014 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structure Stability and Emissions of Lean Direct Injection Combustion Including a Novel Multi point Ldi System for Nox Reduction written by Rodrigo Villalva Gómez and published by . This book was released on 2013 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental research on lean direct injection (LDI) combustors for gas turbine applications is presented. LDI combustion is an alternative to lean premixed combustion which has the potential of equivalent reduction of oxides of nitrogen (NOx) emissions and of peak combustor exit temperatures, but without some drawbacks of premixed combustors, such as flashback and autoignition. Simultaneous observations of the velocity field and reaction zone of an LDI swirl-stabilized combustor with a mixing tube at atmospheric conditions, with the goal of studying the flame stabilization mechanism, are shown. The flame was consistently anchored at the shear layer formed by the high-speed reactants exiting the mixing tube and the low speed recirculation region. Individual image analysis of the location of the tip of the recirculation zone and tip of the reaction region confirmed previously observed trends, but showed that calculation of the distance between these two points for corresponding image pairs yields results no different than when calculated from random image pairs. This most likely indicates a lag in the anchoring of the flame to changes in the recirculation zone, coupled with significant stochastic variation. An alternate LDI approach, multi-point LDI (MLDI), is also tested experimentally. A single large fuel nozzle is replaced by multiple small fuel nozzles to improve atomization and reduce the total volume of the high-temperature, low velocity recirculation zones, reducing NOx formation. The combustor researched employs a novel staged approach to allow good performance across a wide range of conditions by using a combination of nozzle types optimized to various power settings. The combustor has three independent fuel circuits referenced as pilot, intermediate, and outer. Emissions measurements, OH* chemiluminescence imaging, and thermoacoustic instability studies were run in a pressurized combustion facility at pressures from 2.0 to 5.3 bar.Combustor performance was analyzed for three fuel staging configurations, using local equivalence ratio of the individual circuits as a predictive parameter. Pilot-only mode enabled combustor operation at very low overall equivalence ratios while limiting NOx formation in idle power settings due to its configuration approximating a rich-quench-lean combustor. Pilot and intermediate staging tests demonstrated the range of equivalence ratios that are effective in reducing NOx formation while keeping other pollutants in check; very low equivalence ratio results in high unburned hydrocarbon and carbon monoxide, while very high equivalence ratios result in a detrimental effect as more fuel is routed through the intermediate fuel circuit. Using all three fuel circuits simultaneously in high power operation resulted in very low NOx levels (emissions index at or below 0.5 g/kg), particularly when fuel distribution was such that local equivalence ratio was equal among all circuits. The observed NOx levels compared favorably with other MLDI designs which do not have the operational flexibility of the combustor tested. Thermoacoustic instabilities occurred in the MLDI combustor for some test conditions. The local equivalence ratio of the intermediate fuel circuit was found to be one of the major predictor of the onset of instabilities. Detailed analysis of a two-circuit instability (pilot and intermediate) is presented.

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 Controlling Nitrogen Oxides written by Alice Hastings and published by . This book was released on 1980 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Combustion written by J. Warnatz and published by Springer Science & Business Media. This book was released on 2006-09-23 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a rigorous treatment of the coupling of chemical reactions and fluid flow. Combustion-specific topics of chemistry and fluid mechanics are considered and tools described for the simulation of combustion processes. This edition is completely restructured. Mathematical Formulae and derivations as well as the space-consuming reaction mechanisms have been replaced from the text to appendix. A new chapter discusses the impact of combustion processes on the atmosphere, the chapter on auto-ignition is extended to combustion in Otto- and Diesel-engines, and the chapters on heterogeneous combustion and on soot formation are heavily revised.

Download or read book Experimental Investigation of Physical Combustion Characteristics for Alternative Liquid Fuels written by Justin Legg and published by . This book was released on 2012 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of alternative liquid fuels has shifted from fuels such as ethanol and biodiesel, which are often created from food sources, to more advanced feedstocks, such as Algae, and synthetic fuels, such as Fischer-Tropsch diesel and other "renewable" fuels. This study was designed to characterize the physical combustion performance of ethanol, biodiesel, and an algae-derived "Hydrotreated Renewable Diesel." The physical properties of the fuels were characterized in order to describe the atomization behavior. In addition, Gas Chromatography/Mass Spectrometry provided insight into the chemical composition of each fuel. A swirl-stabilized research combustor was used to conduct experiments to simulate gas turbine combustion, and emissions and lean stability limits were measured. At cold-flow conditions, ensemble laser diffraction provided measurements of atomization characteristics, and high-speed cinematography provided additional insight. Most of the fuels had similar atomization characteristics, despite having a wide range of physical properties, which is attributed to the atomization strategy used in this work. However, biodiesel did exhibit larger droplets (5 microns larger on average), indicating that viscosity does have some effect on prompt atomization. Due to the nature of its production, the Hydrotreated Renewable Diesel performed similar to the conventional petroleum fuels, suggesting a high degree of interchangeability with conventional fuels. Ethanol, with the highest oxygen content, and the lowest heating value produced the lowest NOx emissions. Among the fuels examined, differences in emissions were attributed to differences in the evaporation and chemical behavior; with alternative fuels showing benefit over the conventional fuel.

Download or read book Gas Turbine Combustion written by Arthur H. Lefebvre and published by CRC Press. This book was released on 2010-04-26 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflecting the developments in gas turbine combustion technology that have occurred in the last decade, Gas Turbine Combustion: Alternative Fuels and Emissions, Third Edition provides an up-to-date design manual and research reference on the design, manufacture, and operation of gas turbine combustors in applications ranging from aeronautical to po

Download or read book On the Experimental and Theoretical Investigations of Lean Partially Premixed Combustion Burning Speed Flame Instability and Plasma Formation of Alternative Fuels at High Temperatures and Pressures written by Omid Askari and published by . This book was released on 2016 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation investigates the combustion and injection fundamental characteristics of different alternative fuels both experimentally and theoretically. The subjects such as lean partially premixed combustion of methane/hydrogen/air/diluent, methane high pressure direct-injection, thermal plasma formation, thermodynamic properties of hydrocarbon/air mixtures at high temperatures, laminar flames and flame morphology of synthetic gas (syngas) and Gas-to-Liquid (GTL) fuels were extensively studied in this work. These subjects will be summarized in three following paragraphs. The fundamentals of spray and partially premixed combustion characteristics of directly injected methane in a constant volume combustion chamber have been experimentally studied. The injected fuel jet generates turbulence in the vessel and forms a turbulent heterogeneous fuel-air mixture in the vessel, similar to that in a Compressed Natural Gas (CNG) Direct-Injection (DI) engines. The effect of different characteristics parameters such as spark delay time, stratification ratio, turbulence intensity, fuel injection pressure, chamber pressure, chamber temperature, Exhaust Gas recirculation (EGR) addition, hydrogen addition and equivalence ratio on flame propagation and emission concentrations were analyzed. As a part of this work and for the purpose of control and calibration of high pressure injector, spray development and characteristics including spray tip penetration, spray cone angle and overall equivalence ratio were evaluated under a wide range of fuel injection pressures of 30 to 90 atm and different chamber pressures of 1 to 5 atm. Thermodynamic properties of hydrocarbon/air plasma mixtures at ultra-high temperatures must be precisely calculated due to important influence on the flame kernel formation and propagation in combusting flows and spark discharge applications. A new algorithm based on the statistical thermodynamics was developed to calculate the ultra-high temperature plasma composition and thermodynamic properties. The method was applied to compute the thermodynamic properties of hydrogen/air and methane/air plasma mixtures for a wide range of temperatures (1,000-100,000 K), pressures (10−6-100 atm) and different equivalence ratios within flammability limit. In calculating the individual thermodynamic properties of the atomic species, the Debye-Huckel cutoff criterion has been used for terminating the series expression of the electronic partition function. A new differential-based multi-shell model was developed in conjunction with Schlieren photography to measure laminar burning speed and to study the flame instabilities for different alternative fuels such as syngas and GTL. Flame instabilities such as cracking and wrinkling were observed during flame propagation and discussed in terms of the hydrodynamic and thermo-diffusive effects. Laminar burning speeds were measured using pressure rise data during flame propagation and power law correlations were developed over a wide range of temperatures, pressures and equivalence ratios. As a part of this work, the effect of EGR addition and substitution of nitrogen with helium in air on flame morphology and laminar burning speed were extensively investigated. The effect of cell formation on flame surface area of syngas fuel in terms of a newly defined parameter called cellularity factor was also evaluated. In addition to that the experimental onset of auto-ignition and theoretical ignition delay times of premixed GTL/air mixture were determined at high pressures and low temperatures over a wide range of equivalence ratios.

Download or read book Effect of Variable Fuel Composition on Emissions and Lean Blowoff Stability Performance written by Andrés Colorado and published by . This book was released on 2017 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Swirl stabilized Lean premixed Flame Combustion Dynamics An Experimental Investigation of Flame Stabilization Flame Dynamics and Combustion Instability Control Strategies written by Rajavasanth Rajasegar 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 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 Modeling of Real Fuels and Knock Occurrence for an Effective 3D CFD Virtual Engine Development written by Francesco Cupo and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: To drastically reduce the emission of greenhouse gases, the development of future internal combustion engines will be strictly linked to the development of CO2 neutral fuels (e.g. biofuels and e-fuels). This evolution implies an increase in development complexity, which needs the support of engine 3D-CFD simulations. Francesco Cupo presents approaches to accurately describe fuel characteristics and knock occurrence in SI engines, thus improving the current simulation capability in investigating alternative fuels and innovative combustion processes. The developed models are successfully used to investigate the influence of ethanol-based fuels and water injection strategies on knock occurrence and to conduct a virtual fuel design for and engine operating with the innovative SACI combustion strategy. Contents Detailed description of real fuels Locally-distributed auto-ignition model and knock detection Influence of ethanol-based fuels and water injection on combustion and knock Virtual fuel design for SACI combustion strategy Target Groups Researchers and students in the field of automotive engineering Automotive engineers The Author Francesco Cupo obtained a PhD at the research Institute of Automotive Engineering (IFS) in Stuttgart, Germany. His activity is currently focusing on the design of advanced internal combustion engines and alternative fuels.

Download or read book Fundamentals of Combustion Processes written by Sara McAllister and published by Springer Science & Business Media. This book was released on 2011-05-10 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Combustion Processes is designed as a textbook for an upper-division undergraduate and graduate level combustion course in mechanical engineering. The authors focus on the fundamental theory of combustion and provide a simplified discussion of basic combustion parameters and processes such as thermodynamics, chemical kinetics, ignition, diffusion and pre-mixed flames. The text includes exploration of applications, example exercises, suggested homework problems and videos of laboratory demonstrations