Download or read book Mixing and Combustion in Vortex Dominated Combustors with Distributed Air and Fuel Injection written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of temperature, velocity and emissions were performed in two trapped vortex combustor configurations, and several strategies for improving key performance metrics (e.g., circumferential uniformity in temperature and NOx emissions) were examined. The measurements show that introducing swirl with the primary cavity air reduces NOx emissions, extends the Lean Blow Out (LBO) limit and decreases circumferential non- uniformity in the temperature. With the inner-cavity configuration, LBO values as low as 0. 1 and single-digit NOx were achieved. With the outer-cavity configuration, LBO occurred at 0.3. Computations performed indicate that the cavity vortex has a toroidal donut shape, and has large scale dynamics. Distributed micro-scale fuel injectors were fabricated as part of this effort, and have the potential for generating an uniform dispersion of small droplets desirable for improved combustion characteristic & Temperature-actuated bi-morph valves were also develop%d for control of dilution air and local stoichiometry.
Download or read book Scramjets written by Mostafa Barzegar Gerdroodbary and published by Butterworth-Heinemann. This book was released on 2020-07-21 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scramjet engines are a type of jet engine and rely on the combustion of fuel and an oxidizer to produce thrust. While scramjets are conceptually simple, actual implementation is limited by extreme technical challenges. Hypersonic flight within the atmosphere generates immense drag, and temperatures found on the aircraft and within the engine can be much greater than that of the surrounding air. Maintaining combustion in the supersonic flow presents additional challenges, as the fuel must be injected, mixed, ignited, and burned within milliseconds. Fuel mixing, along with the configuration and positioning of the injectors and the boundary conditions, play a key role in combustion efficiency. Scramjets: Fuel Mixing and Injection Systems discusses how fuel mixing efficiency and the advantage of injection systems can enhance the performance of the scramjets. The book begins with the introduction of the supersonic combustion chamber and explains the main parameters on the mixing rate. The configuration of scramjets is then introduced with special emphasis on the main effective parameters on the mixing of fuel inside the scramjets. In addition, basic concepts and principles on the mixing rate and fuel distribution within scramjets are presented. Main effective parameters such as range of fuel concentration for the efficient combustion, pressure of fuel jet and various arrangement of jet injections are also explained. This book is for aeronautical and mechanical engineers as well as those working in supersonic combustion who need to know the effects of compressibility on combustion, of shocks on mixing and on chemical reactions, and vorticity on the flame anchoring. - Explains the main applicable approaches for enhancement of supersonic combustion engines and the new techniques of fuel injection - Shows how the interaction of main air stream with fuel injections can develop the mixing inside the scramjets - Presents results of numerical simulations and how they can be used for the development of the combustion engines
Download or read book Simulation of Fuel air Mixing and Combustion in a Trapped vortex Combustor written by Christopher Stone and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Innovative Techniques to Improve Mixing and Penetration in Scramjet Combustors written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Scramjet combustors are characterized by an extremely short residence time for the completion of fuel atomization, mixing and combustion. It is therefore desired to develop fuel injection schemes that will accelerate the mixing process by improving penetration, achieving small-dispersed fuel droplets, and enhancing mixing. To date, scramjet-fueling schemes require multiple fuel-injection locations in conjunction with flame-holding cavities. This thesis involves the design, development and testing of two innovative fuel injection strategies that could be used to precisely enhance mixing and control the fuel distribution in a scramjet combustor. The first approach employs a high frequency-forcing injector where the amplitude and frequency of excitation was chosen to affect both jet spread and penetration depth, independently, by excitation at different jet instability modes. Another novel fuel injection technique is to employ a vortex-breakdown-controlled injector, which includes a swirling annular jet combined with a control non-swirling jet. The vortex is stabilized by injection of a continuous jet near the core of the vortex. When the control jet introduces additional momentum along the vortex mean flow, the breakdown is delayed. This has been used to control both the intensity of vortex breakdown and penetration of the jet, which could be effectively applied to enhance mixing and penetration.
Download or read book Coarse Grained Simulation and Turbulent Mixing written by Fenando F. Grinstein and published by Cambridge University Press. This book was released on 2016-06-30 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews our current understanding of the subject. For graduate students and researchers in computational fluid dynamics and turbulence.
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 Numerical Simulation of the Air and Fuel Mixing Process in Fuel Injected Engines Using Discrete Vortex Dynamics written by Asuquo Bassey Ebiana and published by . This book was released on 1990 with total page 646 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Chemical Propulsion written by Gabriel D. Roy and published by CRC Press. This book was released on 2001-10-25 with total page 553 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by the scientists who performed the research, this book reports on the progress achieved by the outstanding team of researchers participating in the ONR Propulsion Program. It covers all aspects of the combustion process, from chemical synthesis, reaction pathways of the fuel, and combustor performance to the reduction of emissions, thrust vectoring, and control. The chapter authors discuss the relevant issues, describe their approach and results, and explain how the findings can be extended to practical applications. Richly illustrated and carefully edited for clarity, uniformity, and readability, this book offers a comprehensive survey of the field, from pre- to post-combustion.
Download or read book Influence of Injector Geometry on Fuel air Mixing and Combustion Performance of a Model Combustor written by Leonel Arellano-Ochoa and published by . This book was released on 2000 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Fuel Vaporization Fuel Air Mixing and Combustion in Integrated Mixer Flame Holders written by National Aeronaut Administration (Nasa) and published by . This book was released on 2020-08-05 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Requirements to limit pollutant emissions from the gas turbine engines for the future High-Speed Civil Transport (HSCT) have led to consideration of various low-emission combustor concepts. One such concept is the Integrated Mixer-Flame Holder (IMFH). This report describes a series of IMFH analyses performed with KIVA-II, a multi-dimensional CFD code for problems involving sprays, turbulence, and combustion. To meet the needs of this study, KIVA-II's boundary condition and chemistry treatments are modified. The study itself examines the relationships between fuel vaporization, fuel-air mixing, and combustion. Parameters being considered include: mixer tube diameter, mixer tube length, mixer tube geometry (converging-diverging versus straight walls), air inlet velocity, air inlet swirl angle, secondary air injection (dilution holes), fuel injection velocity, fuel injection angle, number of fuel injection ports, fuel spray cone angle, and fuel droplet size. Cases are run with and without combustion to examine the variations in fuel-air mixing and potential for flashback due to the above parameters. The degree of fuel-air mixing is judged by comparing average, minimum, and maximum fuel/air ratios at the exit of the mixer tube, while flame stability is monitored by following the location of the flame front as the solution progresses from ignition to steady state. Results indicate that fuel-air mixing can be enhanced by a variety of means, the best being a combination of air inlet swirl and a converging-diverging mixer tube geometry. With the IMFH configuration utilized in the present study, flashback becomes more common as the mixer tube diameter is increased and is instigated by disturbances associated with the dilution hole flow. Deur, J. M. and Cline, M. C. Glenn Research Center NASA/CR-2004-213116, E-14610 NAS3-27235; WBS 714-09-46 GAS TURBINE ENGINES; FLAME HOLDERS; VAPORIZING; COMBUSTION; COMPUTATIONAL FLUID DYNAMICS; MIXERS; FUEL INJECTION; CONVERGENT-DIVERGENT NOZZLES; COMBUSTION CHAMBERS; FLAME PROPAGATION; FUEL SPRAYS; SECONDARY INJECTION
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 Engineering Turbulence Modelling and Experiments 5 written by W. Rodi and published by Elsevier. This book was released on 2002-08-21 with total page 1029 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence is one of the key issues in tackling engineering flow problems. As powerful computers and accurate numerical methods are now available for solving the flow equations, and since engineering applications nearly always involve turbulence effects, the reliability of CFD analysis depends increasingly on the performance of the turbulence models. This series of symposia provides a forum for presenting and discussing new developments in the area of turbulence modelling and measurements, with particular emphasis on engineering-related problems. The papers in this set of proceedings were presented at the 5th International Symposium on Engineering Turbulence Modelling and Measurements in September 2002. They look at a variety of areas, including: Turbulence modelling; Direct and large-eddy simulations; Applications of turbulence models; Experimental studies; Transition; Turbulence control; Aerodynamic flow; Aero-acoustics; Turbomachinery flows; Heat transfer; Combustion systems; Two-phase flows. These papers are preceded by a section containing 6 invited papers covering various aspects of turbulence modelling and simulation as well as their practical application, combustion modelling and particle-image velocimetry.
Download or read book Handbook of Fluid Dynamics written by Richard W. Johnson and published by CRC Press. This book was released on 2016-04-06 with total page 1544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Fluid Dynamics offers balanced coverage of the three traditional areas of fluid dynamics—theoretical, computational, and experimental—complete with valuable appendices presenting the mathematics of fluid dynamics, tables of dimensionless numbers, and tables of the properties of gases and vapors. Each chapter introduces a different fluid dynamics topic, discusses the pertinent issues, outlines proven techniques for addressing those issues, and supplies useful references for further research. Covering all major aspects of classical and modern fluid dynamics, this fully updated Second Edition: Reflects the latest fluid dynamics research and engineering applications Includes new sections on emerging fields, most notably micro- and nanofluidics Surveys the range of numerical and computational methods used in fluid dynamics analysis and design Expands the scope of a number of contemporary topics by incorporating new experimental methods, more numerical approaches, and additional areas for the application of fluid dynamics Handbook of Fluid Dynamics, Second Edition provides an indispensable resource for professionals entering the field of fluid dynamics. The book also enables experts specialized in areas outside fluid dynamics to become familiar with the field.
Download or read book Combustion Processes in Propulsion written by Gabriel Roy and published by Butterworth-Heinemann. This book was released on 2006 with total page 505 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical propulsion comprises the science and technology of using chemical reactions of any kind to create thrust and thereby propel a vehicle or object to a desired acceleration and speed. Cumbustion Processes in Propulsion focuses on recent advances in the design of very highly efficient, low-pollution-emitting propulsion systems, as well as advances in testing, diagnostics and analysis. It offers unique coverage of Pulse Detonation Engines, which add tremendous power to jet thrust by combining high pressure with ignition of the air/fuel mixture. Readers will learn about the advances in the reduction of jet noise and toxic fuel emissions-something that is being heavily regulated by relevant government agencies. Lead editor is one of the world's foremost combustion researchers, with contributions from some of the world's leading researchers in combustion engineering Covers all major areas of chemical propulsion-from combustion measurement, analysis and simulation, to advanced control of combustion processes, to noise and emission control Includes important information on advanced technologies for reducing jet engine noise and hazardous fuel combustion emissions
Download or read book Flow and Combustion in Reciprocating Engines written by C. Arcoumanis and published by Springer Science & Business Media. This book was released on 2009-06-29 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optimization of combustion processes in automotive engines is a key factor in reducing fuel consumption. This book, written by eminent university and industry researchers, investigates and describes flow and combustion processes in diesel and gasoline engines.
Download or read book Droplets and Sprays written by Saptarshi Basu and published by Springer. This book was released on 2017-12-11 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on droplets and sprays relevant to combustion and propulsion applications. The book includes fundamental studies on the heating, evaporation and combustion of individual droplets and basic mechanisms of spray formation. The contents also extend to the latest analytical, numerical and experimental techniques for investigating the behavior of sprays in devices like combustion engines and gas turbines. In addition, the book explores several emerging areas like interactions between sprays and flames and the dynamic characteristics of spray combustion systems on the fundamental side, as well as the development of novel fuel injectors for specific devices on the application side. Given its breadth of coverage, the book will benefit researchers and professionals alike.
Download or read book Vortex Controlled Multifuel Combustion written by D. A. Willis and published by . This book was released on 1963 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation was undertaken to determine the effect vortex-type flow has on the multifuel operation of a 3.5in. bore x 4.5in. stroke, two-stroke cycle, loop scavenged, air cooled high-speed compression-ignition engine. The open-type, Lanz-type and Ricardo-type chambers were investigated but the most effective results were obtained with a vortex combustion chamber concentric to the cylinder axis and separated from the cylinder by a plate having swirl producing passages around its periphery and a protruding central throat which the piston engaged near TDC. This chamber operated smoothly, effeciently and at high specific output on a number of fuels at a compression ratio of 25:1 without the necessity of intake air throttling at light load. High-speed photographs were taken of the combustion process within this chamber after it had been modified and fitted with a quartz window. The combustion photographs along with the engine test results provided a means by which the flow pattern and combustion process could be analyzed. (Author).
