Download or read book Crossed Plane Imaging of Premixed Turbulent Combustion Processes written by and published by . This book was released on 2003 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the last several years we have developed and applied advanced imaging methods - crossed-plane laser tomography and crossed-plane laser Rayleigh imaging -- for high-resolution studies of scalar fields in premixed combustion. Laser tomography with micron sized, silicone oil droplets marks 650 K isothermal surfaces, and we have used crossed-plane tomography to measure for the first time in three dimensions the instantaneous orientation of these surfaces and to determine the probability density function of the surface normal vector, a statistical measure of surface wrinkling. Rayleigh scattering from premixed flames can be used for temperature imaging, and we have developed crossed-plane Rayleigh imaging in order to measure with high-resolution instantaneous temperature fields, temperature gradient vectors and isothermal surface densities in premixed reacting flows. Most recently we have combined crossed-plane tomography with stereo particle image velocimetry to measure for the first time reactant flow velocities and the components of this velocity both perpendicular and tangent to the reaction sheet. In this report progress from the inception of Grant number DAAD 19-99-1-0324 is summarized, and relevant information regarding publications and participants in the research is presented.
Download or read book Crossed Plane Laser Imaging of Premixed Turbulent Combustion Processes written by F. C. Gouldin and published by . This book was released on 2001 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of our research is to measure, using crossed-plane imaging, normal vectors and the instantaneous thermal structure of flamelets in premixed turbulent flames. Data for surface normal vectors can be used to calculate important quantities such as Sigma, the flamelet surface density. Sigma is a measure of the wrinkling of the flamelet surface and is proportional to the rate of product formation per unit volume in the flame, w, which appears as an unclosed term in premixed flame models and is related to the burning intensity. Flamelet thermal structure data can be used to estimate the constant of proportionality between w and Sigma. Instantaneous flamelet normals have been measured in three dimensions using crossed-plane imaging via either laser tomography or planar laser induced acetone fluorescence. We are now exploiting crossed-plane imaging for flamelet normal measurements in different burners and over a range of conditions. In additional we are developing crossed-plane Rayleigh imaging in order to measure temperature gradients within flamelets and thereby to determine their thermal structure. Through measurements of flamelet normal and thermal structure we can estimate w.
Download or read book Support for Advanced Imaging of Premixed Turbulent Combustion Processes written by and published by . This book was released on 2004 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: The laser imaging diagnostics of crossed-plane laser tomography (CPLT) and stereo particle image velocimetry (SPIV) have been combined for a systematic study of premixed turbulent combustion in CH4-air, V-burner and swirl-burner flames. Data sets comprised of between 1500 and 2000 realizations have been obtained for 11 different V-flame conditions and 5 different swirl-burner flame conditions. These raw data sets are being analyzed to build a unique database that quantifies mean flame properties (e.g., mean progress variable fields), chemical reaction sheet wrinkling by turbulence (e. g., reaction sheet orientation statistics, curvatures and surface density data) and important velocities (e. g., velocity field of reactants, reaction sheet displacement speeds and gas velocity correlations at the reaction sheet surface). The most significant finding to date is that of negative displacement speeds and a correlation between displacement speed and reaction sheet curvature. These developments are outlined in this report.
Download or read book Application of Crossed plane Imaging for Three dimensional Analysis of Premixed Turbulent Flames written by Darin Alan Knaus and published by . This book was released on 2003 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Army Research Office and Air Force Office of Scientific Research 2002 Contractors Meeting in Chemical Propulsion written by David M. Mann and published by . This book was released on 2002 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstracts are given for 6.1 basic research in chemical propulsion sponsored by the Army Research Office and the Air Force Office of Scientific Research.
Download or read book Fundamentals of Premixed Turbulent Combustion written by Andrei Lipatnikov and published by CRC Press. This book was released on 2012-10-24 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lean burning of premixed gases is considered to be a promising combustion technology for future clean and highly efficient gas turbine combustors. Yet researchers face several challenges in dealing with premixed turbulent combustion, from its nonlinear multiscale nature and the impact of local phenomena to the multitude of competing models. Filling
Download or read book 41st AIAA Aerospace Sciences Meeting Exhibit written by and published by . This book was released on 2003 with total page 594 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of Crossed Plane Tomography and Stereo Particle Image Velocimetry for Three dimensional Analysis of Premixed Turbulent Flames written by Sandra Sheila Sattler and published by . This book was released on 2008 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combined CPLT and SPIV are applied to measure three-dimensional flamelet orientation, reactant velocity, and flamelet displacement data in premixed turbulent flames. Three-dimensional flamelet orientation information is calculated from two simultaneous, orthogonal imaging measurements. Using SPIV, three-dimensional seed particle velocity measurements are obtained using two cameras. Each camera records an image pair separated by a short time interval and views the same region of the flame from a different perspective. Based on these different views of particle displacements corrected for thermophoretic effects, all three components of reactant velocity are found. The combined CPLT and SPIV technique measured instantaneous, three-dimensional flamelet orientation, flamelet surface curvature and the flamelet displacement speed, defined as the component of the relative velocity between the reactants and the flame surface that is normal to the surface. Displacement speed data showed both a broad distribution of values and a significant probability of negative values. The breadth of the distribution and the presence of negative displacement speeds are attributed to high values of curvature and extensive tangential strain.
Download or read book Turbulent Combustion Modeling written by Tarek Echekki and published by Springer Science & Business Media. This book was released on 2010-12-25 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent combustion sits at the interface of two important nonlinear, multiscale phenomena: chemistry and turbulence. Its study is extremely timely in view of the need to develop new combustion technologies in order to address challenges associated with climate change, energy source uncertainty, and air pollution. Despite the fact that modeling of turbulent combustion is a subject that has been researched for a number of years, its complexity implies that key issues are still eluding, and a theoretical description that is accurate enough to make turbulent combustion models rigorous and quantitative for industrial use is still lacking. In this book, prominent experts review most of the available approaches in modeling turbulent combustion, with particular focus on the exploding increase in computational resources that has allowed the simulation of increasingly detailed phenomena. The relevant algorithms are presented, the theoretical methods are explained, and various application examples are given. The book is intended for a relatively broad audience, including seasoned researchers and graduate students in engineering, applied mathematics and computational science, engine designers and computational fluid dynamics (CFD) practitioners, scientists at funding agencies, and anyone wishing to understand the state-of-the-art and the future directions of this scientifically challenging and practically important field.
Download or read book Turbulence and Molecular Processes in Combustion written by T. Takeno and published by Elsevier. This book was released on 2012-12-02 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: An understanding of the intricacies in the turbulent combustion process may be a key to solving many of the current energy and environmental problems. The essential nature of turbulent combustion can be derived from the interaction between stochastic flow fluctuations and deterministic molecular processes, such as chemical reaction and transport processes. Undoubtedly, this is one of the most challenging fields of engineering science today, requiring as it does the interaction of scientists and engineers in the respective fields of chemical kinetics and fluid mechanics. The 28 papers in this volume review recent advances in these two disciplines providing new insights into the fundamental processes, addressing a great deal of recent progress. This progress ranges from descriptions of elementary chemical kinetics, to working those descriptions into combustion calculations with large numbers of elementary steps, to improved understanding of turbulent reacting flows and advances in simulations of turbulent combustion. The contributions will inspire further research on many fronts, advancing the understanding of combustion processes, as well as fostering a growing interdisciplinary cooperation.
Download or read book Theories of Turbulent Combustion in High Speed Flows written by Paul A. Libby and published by . This book was released on 1995 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies in Premixed Turbulent Combustion written by Jie Lin and published by . This book was released on 1991 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Premixed Hydrogen Air Flames written by and published by . This book was released on 1991 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: The properties of turbulent premixed flames were investigated both theoretically and experimentally. Attention was limited to hydrogen/air mixtures burning as either turbulent jet flames or a freely propagating flames in isotropic turbulence. The research has application to a variety to premixed turbulent combustion processes: underwater metal cutting at great depth, primary combustors for high-speed airbreathing propulsion systems, afterburners, fuel/ air explosions, and spark-ignition internal combustion engines. Major findings of this phase of the investigation are as follows: (1) effects of preferential diffusion are relevent for flames at high Reynolds number, retarding and enhancing the distortion of the flame surface by turbulence for stable and unstable conditions, respectively; (2) local turbulent burning velocity, flame brush thickness and the fractal dimension of the flame surface all increase with distance from the flameholder, with larger rates of increases at larger turbulence intensities; (3) estimates of flame properties using contemporary turbulence models were only fair because these methods cannot account for effects of preferential diffusion, distance from the flameholder and finite laminar flame speeds; and (4) the stochastic simulation duplicated measured trends of flame surface properties for neutral preferential diffusion conditions (the only case considered) but underestimated effects of turbulence (particularly near the flame tip) due to the limitations of a two-dimensional simulation.
Download or read book Joint Meeting of the U S Sections of the Combustion Institute Western States Central States Eastern States written by and published by . This book was released on 1999 with total page 954 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Crossed plane Laser Tomography written by Donald Cameron Bingham and published by . This book was released on 1998 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Premixed Turbulent Combustion in Counterflowing Streams written by Larry William Kostiuk and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
