Flashback Mechanisms in Lean Premixed Gas Turbine Combustion


Book Description

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




Establishing Flashback and Blowout Limits in a Commercial Lean Premixed Combustor Operating on Synthesis Gas


Book Description

Flashback and lean blowout are operability issues that must be addressed for successful operation of stationary gas turbines. The present work focuses on flashback and lean blowout of premixed jet flames in a combustor from a commercially available gas turbine operating on synthesis gas of various compositions. The issues of flashback and lean blowout are exacerbated when operating on fuels with high hydrogen content due to the increased reactivity of hydrogen, thus increasing the propensity for flashback. Operating margins for mixtures of natural gas (NG) and carbon monoxide (CO) in hydrogen (H2) are reported. The results demonstrate less stability near lean blowout for mixtures of H2/NG than for H2/CO. Increasing H2 concentration extends the lean operating limit from [phi] = 0.63 to [phi] = 0.29 for H2/NG and [phi] = 0.42 to [phi] = 0.29 for H2/CO. Modeling of the experimental data using a perfectly stirred reactor indicates that the Damköhler number well characterizes the effects of the addition of H2 to NG on the lean blowout limits. In addition, key factors dominating flashback behavior are identified and included in a predictive methodology. A response surface, developed from a turbulent flame speed database, is used to create a flashback propensity index as a design tool for quantifying flashback based upon experimental data from the combustor. Furthermore, the Damköhler number is explored as an index for predicting flashback and was determined to be effective at capturing the effect of pressure, making it able to link data taken at atmospheric conditions to expected engine results.




Unsteady Combustor Physics


Book Description

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.







Lean Combustion


Book Description

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




Stabilization and Dynamic of Premixed Swirling Flames


Book Description

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




Swirl Flows


Book Description




Combustion Instabilities in Gas Turbine Engines


Book Description

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.




Gas Turbine Combustion


Book Description

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




Approaches for Clean Combustion in Gas Turbines


Book Description

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.