Download or read book Mean Pressure Gradient Effects on Flame flow Dynamics in a Cavity Combustor written by David Michael Smerina and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pressure gradient confinement effects are experimentally investigated within a cavity combustor to analyze the flame interactions of premixed, cavity stabilized, flames in a high-speed combustor. Pressure gradient confinement effects are generated in a dual mode ramjet-scramjet (DMSR) by varying the wall geometry to form converging, diverging, and nominal configurations. The velocity field and flame position are captured temporally using simultaneous high-speed particle image velocimetry (PIV) and CH chemiluminescence. The evolution of the flow field and flame structure are analyzed, and the high temporal resolution of these measurements allows for the characterization of turbulence-flame interactions. Consideration of the combustion mode and inlet conditions, such as the inflow velocity and turbulence, are vital in studying flame-vortex interaction dynamics and its effect on the flame stabilization process and is essential in ensuring efficient, complete combustion. The results from the experiment will provide a greater understanding of how flame-vorticity interactions and pressure gradient confinement effects play a key role in the flame-stabilization and combustion process.
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 Flame vortex Dynamics in a Model Ramjet Combustor written by Chandler W. Crimmins and published by . This book was released on 2020 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: Previous research into the flame-vortex dynamics of bluff-body stabilized flames has helped to verify the characteristic flame-flow field and identify the effects of turbulence and pressure gradient tailoring. Such work has indicated that increases in a favorable pressure gradient will both increase the material acceleration of the flow and increase the total magnitude of vorticity seen in domain. This result is specifically tied to the increased baroclinicity of the flow. In addition, it has been shown that as the turbulence level of an incoming flow is increased, the vortex stretching transport term will come to dominate the flow dynamics. This results in the flow beginning to resemble the characteristics of a nonreacting case. In more specific terms, Bénard von Kármán vortex shedding, which is usually suppressed due to combustive heat release, will begin to reappear in the domain. To further cement and verify these conclusions, six experimental test cases were carried out to study the flame-vortex dynamics of a stoichiometric propane-air flame stabilized on a ballistic-type bluff body. Particle imaging velocimetry data was recorded using an optically accessible combustion facility. Velocity vector fields were derived using PIVLab software and further analyzed using both Eulerian and Lagrangian analysis methods. The results and analysis have been plotted and included within the following document.
Download or read book Pylon Effects on a Scramjet Cavity Flameholder Flowfield written by Andrew B. Freeborn and published by . This book was released on 2008 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Computational Fluid Dynamics Analysis of a Cavity Based Flameholder for Scramjet Combustor Applications written by Stephen Alexander Schumaker and published by . This book was released on 2004 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics of Gaseous Combustion written by A. L. Kuhl and published by AIAA. This book was released on 1993 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scramjet Propulsion written by E. T. Curran and published by AIAA. This book was released on 2001 with total page 1354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Applied Mechanics Reviews written by and published by . This book was released on 1973 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Combustion Noise written by Anna Schwarz and published by Springer Science & Business Media. This book was released on 2009-06-17 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: November, 2008 Anna Schwarz, Johannes Janicka In the last thirty years noise emission has developed into a topic of increasing importance to society and economy. In ?elds such as air, road and rail traf?c, the control of noise emissions and development of associated noise-reduction techno- gies is a central requirement for social acceptance and economical competitiveness. The noise emission of combustion systems is a major part of the task of noise - duction. The following aspects motivate research: • Modern combustion chambers in technical combustion systems with low pol- tion exhausts are 5 - 8 dB louder compared to their predecessors. In the ope- tional state the noise pressure levels achieved can even be 10-15 dB louder. • High capacity torches in the chemical industry are usually placed at ground level because of the reasons of noise emissions instead of being placed at a height suitable for safety and security. • For airplanes the combustion emissions become a more and more important topic. The combustion instability and noise issues are one major obstacle for the introduction of green technologies as lean fuel combustion and premixed burners in aero-engines. The direct and indirect contribution of combustion noise to the overall core noise is still under discussion. However, it is clear that the core noise besides the fan tone will become an important noise source in future aero-engine designs. To further reduce the jet noise, geared ultra high bypass ratio fans are driven by only a few highly loaded turbine stages.
Download or read book Hydrogen Energy written by Dragica Minic and published by BoD – Books on Demand. This book was released on 2012-10-17 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogen economy represents the future of human civilization. Limited resources of our planet are compelling us to turn to renewable clean energy resources and hydrogen figures prominently as the energy carrier of a future sustainable energy system. There are significant challenges to be overcome in order to make hydrogen viable, in production, storage and power generation, while safety of operation is an ever-present factor that determines success or failure of a proposed solution. Recent developments in all of these aspects are reviewed in this book, along with some latest research in the field of hydrogen energy and use.
Download or read book Papers Presented at the AIAA ASME SAE ASEE 25th Joint Propulsion Conference written by and published by . This book was released on 1989 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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
Download or read book Combustion Measurements written by Norman Chigier and published by CRC Press. This book was released on 1991-04-01 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book begins with an introduction to the general problems of making measurements in high temperature and a presentation of chemically reacting flow systems. It describes each instrument with the various diagnostic techniques and discusses measurements that have been made in furnaces, flames, and rocket engines. The detailed measurement techniques described in this book cover a wide spectrum of applications in combustion systems, including gas turbine, rocket measurement techniques that were developed in laboratories. Information obtained on detailed temperature, velocity, particle size, and gas concentration distribution is leading to improve understanding of the chemical combustion process and to design imporvements in combustors.
Download or read book Combustion Dynamics and Fluid Mechanics in Acoustically Perturbed Non premixed Swirl stabilized Flames written by Uyi O. Idahosa and published by . This book was released on 2010 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: The prevalence of gas turbines operating in primarily lean premixed modes is predicated on the need for lower emissions and increased efficiency. An enhancement in the mixing process through the introduction of swirl in the combustion reactants is also necessary for flame stabilization. The resulting lean swirling flames are often characterized by a susceptibility to feedback between velocity, pressure and heat release perturbations with a potential for unstable self-amplifying dynamics. The existing literature on combustion dynamics is predominantly dedicated to premixed flame configurations motivated by power generation and propulsive gas turbine applications. In the present research effort, an investigation into the response of atmospheric, non-premixed swirling flames to acoustic perturbations at various frequencies (f[subscript p] = 0-315Hz) and swirl intensities (S=0.09 and S=0.34) is carried out. The primary objective of the research effort is to broaden the scope of fundamental understanding in flame dynamics in the literature to include non-premixed swirling flames. Applications of the research effort include control strategies to mitigate the occurrence of combustion instabilities in future power generation gas turbines. Flame heat release is quantitatively measured using a photomultiplier with a 430nm bandpass filter for observing CH* chemiluminescence which is simultaneously imaged with a phase-locked CCD camera. Acoustic perturbations are generated with a loudspeaker at the base of an atmospheric co-flow burner with resulting velocity oscillation amplitudes, [vertical line]u'/U[subscript avg][vertical line] in the 0.03-0.30 range. The dependence of flame dynamics on the relative richness of the flame is investigated by studying various constant fuel flow rate flame configurations. The effect of varying fuel flow rates on the flame response is also examined using with dynamic time-dependent fuel supply rates over the data acquisition period. The Particle Image Velocimetry (PIV) method is used to study the isothermal flow field associated with acoustic pulsing. The acoustic impedance, wavelet analysis, Rayleigh criteria and phase conditioning methods are used to identify fundamental mechanisms common to highly responsive flame configurations.
Download or read book Vortex Driven Flame Dynamics and Combustion Instability written by Hurrem Murat Altay and published by . This book was released on 2005 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) On the other hand, in long cavities, the vortex breakup is initiated as the wake vortex impinges on the upper cavity wall in single expansion dump combustor, or the vortex forming in the other half of the combustor in double expansion dump combustor. Furthermore, the effect of the air injection in the cross stream direction close to the dump plane on equivalence ratio is investigated. It is shown experimentally that high amplitude pressure oscillation in the combustor during unstable operation causes fluctuation in the injected jet velocity. The oscillatory jet velocity affects the incoming equivalence ratio depending on the momentum ratio of the jet to the primary stream. A critical momentum ratio is defined at which the amplitude of the equivalence ratio oscillations reaches a maximum.
