Download or read book Etude de la combustion turbulente faible richesse haute temp rature et haute pression written by Benoît Taupin and published by . This book was released on 2003 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: La combustion de pré-mélange pauvre est un procédé très prometteur pour réduire les émissions polluantes d'oxyde d'azote. Malheureusement, dans ce mode de combustion, des extinctions locales, sources d'imbrûlés, des intabilités de combustion ou le retour de flamme dans l'injecteur peuvent être occasionnés. Cette étude expérimentale traite des résultats obtenus sur un brûleur transparent pressurisé avec air de combustion préchauffé. Ce brûleur muni d'un injecteur à "swirl" avec "Bluff-Body" génère des conditions représentatives de turbine à gaz. L'objectif de cette étude est de comprendre les mécanismes qui entraînent la déstabilisation de la flamme et d'une manière générale d'étudier la structure de flamme turbulente de pré-mélange pauvre sous l'influence de la pression et de la température de l'air de combustion dans une configuration proche de la réalité. Une étude de la stabilité et de la structure de la flamme caractérisée par son émission spontanée CH* en fonction des paramètres pression, température de l'air de combustion et richesse met en évidence une influence relativement faible de la pression tandis que la température de l'air joue un rôle prépondérant. L'étude du mélange par Fluorescence induite par plan laser sur de l'acétone montre la présence d'inhomogénéité du mélange à la sortie de l'injecteur. La comparaison avec une flamme obtenue dans le cadre d'un pré-mélange parfait montre que ces inhomogénéités participent à la stabilisation de la flamme. Cette stabilisation s'effectue par le biais d'une zone nommée pied de flamme où la flamme se propage d'un mélange riche vers un mélange pauvre permettant la combustion de mélange globalement plus pauvre. Nous terminons par l'étude en combustion de deux cas instables.

Download or read book Etude de la stabilit et des missions polluantes des flammes turbulentes de pr m lange pauvre haute pression appliqu es aux turbines gaz written by David Vauchelles and published by . This book was released on 2004 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: La combustion en mode pauvre prémélangé permet de réduire les émissions polluantes, mais elle est limitée par l'apparition de fortes instabilités. Afin d'étudier ces instabilités, nous avons conçu une chambre de combustion proche d'une configuration industrielle fonctionnant au gaz naturel. La chambre, pressurisée à 5 bar, est munie de deux dispositifs d'injection d'air : air secondaire et air de dilution. Le prémélange est créé par un injecteur constitué d'un swirl axial et d'un bluff body. L'étude de l'instabilité a été effectuée en fonction de plusieurs paramètres : température d'entrée d'air, débit, richesse de combustion, angle du swirl, présence d'une flamme pilote, position des orifices d'injection d'air et géométrie du fond de la chambre. Pour chaque configuration nous avons mesuré le champ de vitesse, les émissions polluantes, l'émission spontanée du radical CH* et l'évolution temporelle de la pression dans la chambre de combustion. Le résultat principalmontre que les injections d'air secondaire jouen un rôle important et complexe dans les chambres de combustion, notamment sur la structure et la dynamique de la flamme. Les spectres temporels de pression et de CH* ont montré plusieurs fluctuations temporelles de la combustion que nous avons classées en trois catégories : - Les fluctuation basses fréquences dues aux instabilités de combustion, - les fluctuations convectives dont les fréquences ne dépendent que de la vitesse de l'écoulement, - les fluctuations acoustiques dont les fréquences ne dépendent que de la température de l'écoulement. L'étude locale des émissions de CH* montre que les positions des maximums de fluctuations se situent à des emplacements différents dans la zone de réaction suivant le régime de combustion. Nous avons adapté localement le modèle du temps de retard (time lag) qui permet de connaître les conditions favorables d'amplification d'une perturbation convective. Les résultats montrent que nous pouvons prédire la position et l'intensité des fluctuations convectives dans la zone réactive en fonction de la température d'entrée ou de la puissance de l'installation. Toutefois, ce modèle trouve ses limites lorsque l'interaction de l'air de dilution secondaire devient trop importante avec la zone de réaction.

Download or read book Etude des effets de la haute pression sur la structure et la dynamique des flammes turbulentes de pr m lange pauvre de m thane air written by Thierry Lachaux and published by . This book was released on 2004 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'étude expérimentale porte sur l'influence de la haute-pression jusqu'à 0.9 MPa pour la combustion d'une flamme de prémélange méthane-air, pauvre, turbulente stabilisée sur un brûleur de type Bunsen. La vitesse débitante et la richesse sont fixées à 2.1 m/s et 0.6. Le champ de vitesses et les échelles de la turbulence sont déterminés à l'aide de l'anémométrie Laser Doppler. Les mesures de diffusion Rayleigh renseignent sur la fluctuation du scalaire. De l'imagerie de Mie deux dimensions sont obtenus la courbure, l'angle d'orientation, les longueurs de plissement et enfin, la densité de surface de flamme et l'intensité de combustion qui sont comparées avec les valeurs données par le modèle BML. Lorsque la pression augmente les échelles de Taylor et de Kolmogorov diminuent avec la viscosité cinématique, l'échelle intégrale et la vitesse fluctuante restent constantes, les structures du front de flamme deviennent plus petites et plus pointues, augmentant la densité de surface de flamme.

Download or read book Genie Civil written by and published by . This book was released on 1929 with total page 754 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Mediterranean region under climate change written by Collectif and published by IRD Éditions. This book was released on 2018-11-19 with total page 736 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book has been published by Allenvi (French National Alliance for Environmental Research) to coincide with the 22nd Conference of Parties to the United Nations Framework Convention on Climate Change (COP22) in Marrakesh. It is the outcome of work by academic researchers on both sides of the Mediterranean and provides a remarkable scientific review of the mechanisms of climate change and its impacts on the environment, the economy, health and Mediterranean societies. It will also be valuable in developing responses that draw on “scientific evidence” to address the issues of adaptation, resource conservation, solutions and risk prevention. Reflecting the full complexity of the Mediterranean environment, the book is a major scientific contribution to the climate issue, where various scientific considerations converge to break down the boundaries between disciplines.

Download or read book Genmix written by D Brian Spalding and published by Elsevier. This book was released on 2014-05-18 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: Genmix: A General Computer Program for Two-dimensional Parabolic Phenomena explains a computer program called GENMIX. The main intention of the program is to be used as a tool of instructions. The name of the program is a mixture of two considerations: its generality and its concern for mixing processes. The book aims to help the potential user to understand the physical and mathematical basis of the topic computer program. It is also the aim of the book to make the program applicable to practical problems. The book is arranged in such a way as to parallel a course of lectures and associated computer-workshop sessions wherein the student is allowed to do some elementary computations as soon as he has gained some knowledge of the method. The book contains the mathematical, physical, and computer-coding aspects of the program. Concepts such as the boundary layer, two-dimensional, and steady- flow are defined and discussed in depth. The text will be a useful tool for computer instructors and students.

Download or read book ICREEC 2019 written by Ahmed Belasri and published by Springer Nature. This book was released on 2020-06-10 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.

Download or read book Faecal Sludge Management written by Linda Strande and published by IWA Publishing. This book was released on 2014-08-15 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is estimated that literally billions of residents in urban and peri-urban areas of Africa, Asia, and Latin America are served by onsite sanitation systems (e.g. various types of latrines and septic tanks). Until recently, the management of faecal sludge from these onsite systems has been grossly neglected, partially as a result of them being considered temporary solutions until sewer-based systems could be implemented. However, the perception of onsite or decentralized sanitation technologies for urban areas is gradually changing, and is increasingly being considered as long-term, sustainable options in urban areas, especially in low- and middle-income countries that lack sewer infrastructures. This is the first book dedicated to faecal sludge management. It compiles the current state of knowledge of the rapidly evolving field of faecal sludge management, and presents an integrated approach that includes technology, management, and planning based on Sandecs 20 years of experience in the field. Faecal Sludge Management: Systems Approach for Implementation and Operation addresses the organization of the entire faecal sludge management service chain, from the collection and transport of sludge, and the current state of knowledge of treatment options, to the final end use or disposal of treated sludge. The book also presents important factors to consider when evaluating and upscaling new treatment technology options. The book is designed for undergraduate and graduate students, and engineers and practitioners in the field who have some basic knowledge of environmental and/or wastewater engineering.

Download or read book In Vessel Melt Retention and Ex Vessel Corium Cooling IAEA Tecdoc No 1906 written by International Atomic Energy Agency and published by International Atomic Energy Agency. This book was released on 2020-08-06 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication results from a technical meeting on phenomenology and technologies relevant to in-vessel melt retention (IVMR) and ex-vessel corium cooling (EVCC). The purpose of the publication is to capture the state of knowledge, at the time of that meeting, related to phenomenology and technologies as well as the challenges and pending issues relevant to IVMR and EVCC for water cooled reactors by summarizing the information provided by the meeting participants in a form useful to practitioners in Member States.

Download or read book Heat and Mass Transfer in Boundary Layers written by Suhas V. Patankar and published by . This book was released on 1970 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book El Ni o written by Bruno Voituriez and published by UNESCO. This book was released on 2000 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: El Nino, caprice of the heavens, scapegoat for every calamity? The general public cannot really understand what is behind the El Nino phenomenon. The book offers a tour of the Earth's climate to understand one of its normal but extreme components.

Download or read book The GEO Handbook on Biodiversity Observation Networks written by Michele Walters and published by Springer. This book was released on 2016-11-25 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biodiversity observation systems are almost everywhere inadequate to meet local, national and international (treaty) obligations. As a result of alarmingly rapid declines in biodiversity in the modern era, there is a strong, worldwide desire to upgrade our monitoring systems, but little clarity on what is actually needed and how it can be assembled from the elements which are already present. This book intends to provide practical guidance to broadly-defined biodiversity observation networks at all scales, but predominantly the national scale and higher. This is a practical how-to book with substantial policy relevance. It will mostly be used by technical specialists with a responsibility for biodiversity monitoring to establish and refine their systems. It is written at a technical level, but one that is not discipline-bound: it should be intelligible to anyone in the broad field with a tertiary education.

Download or read book Theory and Design for Mechanical Measurements written by Richard S. Figliola and published by John Wiley & Sons. This book was released on 2020-06-23 with total page 599 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theory and Design for Mechanical Measurements merges time-tested pedagogy with current technology to deliver an immersive, accessible resource for both students and practicing engineers. Emphasizing statistics and uncertainty analysis with topical integration throughout, this book establishes a strong foundation in measurement theory while leveraging the e-book format to increase student engagement with interactive problems, electronic data sets, and more. This new Seventh edition has been updated with new practice problems, electronically accessible solutions, and dedicated Instructor Problems that ease course planning and assessment. Extensive coverage of device selection, test procedures, measurement system performance, and result reporting and analysis sets the field for generalized understanding, while practical discussion of data acquisition hardware, infrared imaging, and other current technologies demonstrate real-world methods and techniques. Designed to align with a variety of undergraduate course structures, this unique text offers a highly flexible pedagogical framework while remaining rigorous enough for use in graduate studies, independent study, or professional reference.

Download or read book Peaceful Uses of Atomic Energy written by United States. Department of State and published by . This book was released on 1955 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Uranium Ore Processing and Recovery from Non conventional Resources written by International Atomic Energy Agency and published by Agency. This book was released on 1985 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Conservation de la For t Dense en Afrique Centrale Et de L Ouest written by Kevin M. Cleaver and published by World Bank Publications. This book was released on 1992 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume brings together selected papers presented and discussed at the Conference on Conservation of West and Central African Rainforests, held in Abidjan, November 5-9, 1990.

Download or read book Environmental Implications of Combustion Processes written by Ishwar K. Puri and published by CRC Press. This book was released on 1993-09-22 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although there is a large body of research literature pertaining to the environmental implications of combustion processes, this book is the first to present a concise treatment of fundamental issues that can be quickly and easily used by entry-level researchers. The book is arranged so that it logically flows from fundamentals to pollutants, through theory, and on to modeling. Chapters cover combustion fundamentals, gaseous pollution, and heterogeneous combustion. Combustion theory in the form of Activation Energy Asymptotics is included for the lay reader, followed by a presentation of reduced mechanisms in the context of burning, a topic of environmental significance. Turbulent combustion modeling is also discussed.