Instability of Premixed Lean Hydrogen Laminar Tubular Flames

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ISBN 13 :
Total Pages : 91 pages
Book Rating : 4.:/5 (944 download)

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Book Synopsis Instability of Premixed Lean Hydrogen Laminar Tubular Flames by : Carl Alan Hall

Download or read book Instability of Premixed Lean Hydrogen Laminar Tubular Flames written by Carl Alan Hall and published by . This book was released on 2016 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Stability and Structure of Lean Hydrogen-air Flames

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ISBN 13 :
Total Pages : 15 pages
Book Rating : 4.:/5 (482 download)

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Book Synopsis The Stability and Structure of Lean Hydrogen-air Flames by : G. Patnaik

Download or read book The Stability and Structure of Lean Hydrogen-air Flames written by G. Patnaik and published by . This book was released on 1990 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed, time-dependent, two-dimensional numerical simulations with full hydrogen-oxygen chemistry are used to investigate the effects of gravity on the stability and structure of laminar flames in lean, premixed hydrogen - air mixtures. The calculations show that the effects of gravity becomes more important as the lean flammability limit is approached. In a 12% hydrogen - air mixture, gravity plays only a secondary role in determining the multidimensional structure of the flame with the stability and structure of the flame controlled primarily by the thermo-diffusive instability mechanism. However, in leaner hydrogen-air mixtures gravity becomes more important. Upward-propagating flames are highly curved and evolve into a bubble rising upwards in the tube. Downward-propagating flames are flat or even oscillate between structures with concave and convex curvatures. The zero-gravity flame shows only cellular structures. Cellular structures which are present in zero gravity can be suppressed by the effect of buoyancy for mixtures leaner than 11% hydrogen. These observations are explained on the basis of an interaction between the processes leading to buoyancy-induced Reyleigh-Taylor instability and the thermo-diffusive stability.

The Stability and Structure of Lean Hydrogen-air Flames

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (482 download)

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Book Synopsis The Stability and Structure of Lean Hydrogen-air Flames by : G. Patnaik

Download or read book The Stability and Structure of Lean Hydrogen-air Flames written by G. Patnaik and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed, time-dependent, two-dimensional numerical simulations with full hydrogen-oxygen chemistry are used to investigate the effects of gravity on the stability and structure of laminar flames in lean, premixed hydrogen - air mixtures. The calculations show that the effects of gravity becomes more important as the lean flammability limit is approached. In a 12% hydrogen - air mixture, gravity plays only a secondary role in determining the multidimensional structure of the flame with the stability and structure of the flame controlled primarily by the thermo-diffusive instability mechanism. However, in leaner hydrogen-air mixtures gravity becomes more important. Upward-propagating flames are highly curved and evolve into a bubble rising upwards in the tube. Downward-propagating flames are flat or even oscillate between structures with concave and convex curvatures. The zero-gravity flame shows only cellular structures. Cellular structures which are present in zero gravity can be suppressed by the effect of buoyancy for mixtures leaner than 11% hydrogen. These observations are explained on the basis of an interaction between the processes leading to buoyancy-induced Reyleigh-Taylor instability and the thermo-diffusive stability.

Turbulent Premixed Flames

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Publisher : Cambridge University Press
ISBN 13 : 1139498584
Total Pages : 447 pages
Book Rating : 4.1/5 (394 download)

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Book Synopsis Turbulent Premixed Flames by : Nedunchezhian Swaminathan

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.

Flashback Mechanisms in Lean Premixed Gas Turbine Combustion

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Publisher : Academic Press
ISBN 13 : 0128008261
Total Pages : 134 pages
Book Rating : 4.1/5 (28 download)

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Book Synopsis Flashback Mechanisms in Lean Premixed Gas Turbine Combustion by : Ali Cemal Benim

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

A New Type of Steady and Stable, Laminar, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (893 download)

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Book Synopsis A New Type of Steady and Stable, Laminar, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion by :

Download or read book A New Type of Steady and Stable, Laminar, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra-lean, hydrogen-air mixtures are found to support another kind of laminar flame that is steady and stable beside flat flames and flame balls. Direct numerical simulations are performed of flames that develop into steadily and stably propagating cells. These cells were the original meaning of the word"flamelet'' when they were observed in lean flammability studies conducted early in the development of combustion science. Several aspects of these two-dimensional flame cells are identified and are contrasted with the properties of one-dimensional flame balls and flat flames. Although lean hydrogen-air flames are subject to thermo-diffusive effects, in this case the result is to stabilize the flame rather than to render it unstable. The flame cells may be useful as basic components of engineering models for premixed combustion when the other types of idealized flames are inapplicable.

Synthesis Gas Combustion

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Publisher : CRC Press
ISBN 13 : 1420085352
Total Pages : 388 pages
Book Rating : 4.4/5 (2 download)

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Book Synopsis Synthesis Gas Combustion by : Tim Lieuwen

Download or read book Synthesis Gas Combustion written by Tim Lieuwen and published by CRC Press. This book was released on 2009-09-16 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coal, still used to generate more than half of the electric power in the U.S., will likely be part of any future global energy plan. But this finite resource is also responsible for 80 percent of the CO2 emissions from power production, and its continued use will require improved processing techniques that are less damaging to the environment and l

Unsteady Combustor Physics

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Publisher : Cambridge University Press
ISBN 13 : 1139576836
Total Pages : 427 pages
Book Rating : 4.1/5 (395 download)

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Book Synopsis Unsteady Combustor Physics by : Tim C. Lieuwen

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.

Turbulent Combustion

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Publisher : Cambridge University Press
ISBN 13 : 1139428063
Total Pages : 322 pages
Book Rating : 4.1/5 (394 download)

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Book Synopsis Turbulent Combustion by : Norbert Peters

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.

Numerical investigation of the dynamics of unstable lean premixed hydrogen/air flames

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (745 download)

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Book Synopsis Numerical investigation of the dynamics of unstable lean premixed hydrogen/air flames by : Christos Altantzis

Download or read book Numerical investigation of the dynamics of unstable lean premixed hydrogen/air flames written by Christos Altantzis and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Experimental Studies of the Effect of Gravity on the Stability of Premixed Laminar Flames

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ISBN 13 :
Total Pages : 642 pages
Book Rating : 4.:/5 (33 download)

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Book Synopsis Experimental Studies of the Effect of Gravity on the Stability of Premixed Laminar Flames by : Corey Martin Dunsky

Download or read book Experimental Studies of the Effect of Gravity on the Stability of Premixed Laminar Flames written by Corey Martin Dunsky and published by . This book was released on 1991 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Theoretical and Numerical Combustion

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Publisher : R.T. Edwards, Inc.
ISBN 13 : 9781930217102
Total Pages : 544 pages
Book Rating : 4.2/5 (171 download)

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Book Synopsis Theoretical and Numerical Combustion by : Thierry Poinsot

Download or read book Theoretical and Numerical Combustion written by Thierry Poinsot and published by R.T. Edwards, Inc.. This book was released on 2005 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introducing numerical techniques for combustion, this textbook describes both laminar and turbulent flames, addresses the problem of flame-wall interaction, and presents a series of theoretical tools used to study the coupling phenomena between combustion and acoustics. The second edition incorporates recent advances in unsteady simulation methods,

Models to Include Laminar Flame Instability Effects for Premixed Turbulent Combustion

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (894 download)

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Book Synopsis Models to Include Laminar Flame Instability Effects for Premixed Turbulent Combustion by : Rabindra Nath Paul

Download or read book Models to Include Laminar Flame Instability Effects for Premixed Turbulent Combustion written by Rabindra Nath Paul and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Transition to Renewable Energy Systems

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Publisher : John Wiley & Sons
ISBN 13 : 352767389X
Total Pages : 882 pages
Book Rating : 4.5/5 (276 download)

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Book Synopsis Transition to Renewable Energy Systems by : Detlef Stolten

Download or read book Transition to Renewable Energy Systems written by Detlef Stolten and published by John Wiley & Sons. This book was released on 2013-05-13 with total page 882 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this ready reference, top academic researchers, industry players and government officers join forces to develop commercial concepts for the transition from current nuclear or fossil fuel-based energy to renewable energy systems within a limited time span. They take into account the latest science and technology, including an analysis of the feasibility and impact on the environment, economy and society. In so doing, they discuss such complex topics as electrical and gas grids, fossil power plants and energy storage technologies. The contributions also include robust, conceivable and breakthrough technologies that will be viable and implementable by 2020.

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

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Publisher :
ISBN 13 :
Total Pages : 271 pages
Book Rating : 4.:/5 (986 download)

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Book Synopsis 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 by : Omid Askari

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.

Effects of Diluents on Laminar Premixed Hydrogen Flames in Microgravity

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ISBN 13 :
Total Pages : 320 pages
Book Rating : 4.3/5 (91 download)

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Book Synopsis Effects of Diluents on Laminar Premixed Hydrogen Flames in Microgravity by : Li Qiao

Download or read book Effects of Diluents on Laminar Premixed Hydrogen Flames in Microgravity written by Li Qiao and published by . This book was released on 2007 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Direct Numerical Simulation of Lean Premixed Turbulent Flames at High Karlovitz Numbers Under Elevated Pressures

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (11 download)

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Book Synopsis Direct Numerical Simulation of Lean Premixed Turbulent Flames at High Karlovitz Numbers Under Elevated Pressures by : Xujiang Wang

Download or read book Direct Numerical Simulation of Lean Premixed Turbulent Flames at High Karlovitz Numbers Under Elevated Pressures written by Xujiang Wang and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: