Download or read book CONVECTION NATURELLE MHD DANS UNE CAVITE HORIZONTALE ELANCEE written by Laurent Davoust and published by . This book was released on 1996 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: LORS DE LA CROISSANCE DES MONOCRISTAUX SEMI-CONDUCTEURS A PARTIR D'UN BAIN FONDU, LA CONVECTION NATURELLE GOUVERNE DE MANIERE DETERMINANTE LES TRANSFERTS DE MASSE ET DE CHALEUR. COMME LA MICRO-GRAVITE, L'IMPOSITION D'UN CHAMP MAGNETIQUE PERMANENT SUR LE BAIN - ELECTRO-CONDUCTEUR - EST UN MOYEN DE STABILISER, DE REORGANISER L'ECOULEMENT DE CONVECTION NATURELLE ET, FINALEMENT, DE LE FREINER AFIN DE S'APPROCHER AU MIEUX DES CONDITIONS IDEALES D'UN TRANSPORT DIFFUSIF DES ESPECES CHIMIQUES. DANS UN PREMIER TEMPS, UNE SYNTHESE DES CONNAISSANCES ACQUISES SUR LES ECOULEMENTS THERMOGRAVITAIRES, MAGNETOHYDRODYNAMIQUES (MHD) OU NON, EST PRESENTEE. PUIS, SUR LA BASE DU DISPOSITIF EXPERIMENTAL MASCOT (MAGNETIC STABILISATION OF CONVECTION AND TURBULENCE), LES PHENOMENES QUI GOUVERNENT L'ECOULEMENT THERMOGRAVITAIRE MHD DU MERCURE DANS UNE CAVITE CYLINDRIQUE HORIZONTALE ELANCEE, SOUMISE A LA FOIS A UN CHAMP MAGNETIQUE UNIFORME ET A UN GRADIENT DE TEMPERATURE HORIZONTAL, SONT MIS EN EVIDENCE PUIS INTERPRETES A L'AIDE DE LA MHD. DANS CETTE CONFIGURATION PARTICULIERE, LES COUCHES DE HARTMANN DEMEURENT ELECTRIQUEMENT INACTIVES. L'INERTIE N'INFLUENCE L'ECOULEMENT QUE LOCALEMENT (AUX EXTREMITES DE LA CAVITE), ET SURTOUT DANS LE CAS OU LA CONVECTION EST INTENSE (A GRAND NOMBRE DE GRASHOFF). AILLEURS, LE COUPLAGE ENTRE COURANTS ELECTRIQUES INDUITS ET DISTRIBUTION DE TEMPERATURE EST ILLUSTRE PAR L'EQUILIBRE ENTRE LE ROTATIONNEL DE LA FORCE DE LAPLACE ET LE ROTATIONNEL DE LA FORCE DE FLOTTABILITE. CET EQUILIBRE PILOTE L'ECOULEMENT POUR UN NOMBRE DE RAYLEIGH MODIFIE, DIT EFFECTIF, SUFFISAMMENT FAIBLE. UNE SIMULATION NUMERIQUE 3-D AUX ELEMENTS FINIS DE CET ECOULEMENT (LAMINAIRE) APPORTE UNE CONFIRMATION SATISFAISANTE DE CES RESULTATS EXPERIMENTAUX. CE MEMOIRE EST L'ETUDE DE LA TRANSITION DE CET ECOULEMENT VERS LA TURBULENCE, A L'AIDE DE L'EXPERIENCE MASCOT. TROIS ONDES OSCILLANTES PROGRESSIVES OU STATIONNAIRES SONT CLAIREMENT IDENTIFIEES PENDANT LA TRANSITION. SI LA CONVENTION EST INTENSE, CES ONDES INTERAGISSENT AVEC DES INSTABILITES STATIONNAIRES EVOLUANT FAIBLEMENT DANS LE TEMPS. LE COUPLAGE NON-LINEAIRE ASSOCIE AU TERME DE CONVECTION DANS L'EQUATION DE L'ENERGIE ENGENDRE UNE BIFURCATION SOUS-CRITIQUE. PUIS, SI LE REGIME D'ECOULEMENT EST FAIBLEMENT CONVECTIF, LE CHAOS SURVIENT A LA SUITE D'UNE BIFURCATION SUPERCRITIQUE DE HOPF. CES RESULTATS OUVRENT DES PERSPECTIVES DE DEVELOPPEMENT TECHNOLOGIQUE POUR LE PROCEDE BRIDGMAN DE CROISSANCE CRISTALLINE. ET PLUS GENERALEMENT, CE PROGRES DANS LA COMPREHENSION DE LA CONVECTION NATURELLE MHD POURRAIT S'APPLIQUER DANS D'AUTRES SITUATIONS: EN GENIE METALLURGIQUE OU DANS LES COUVERTURES TRITIGENES DU FUTUR REACTEUR DE FUSION THERMONUCLEAIRE

Download or read book Convection naturelle MHD dans une cavit horizontale lanc e written by Laurent Davoust and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lors de la croissance des monocristaux semi-conducteurs a partir d'un bain fondu, la convection naturelle gouverne de maniere determinante les transferts de masse et de chaleur. Comme la micro-gravite, l'imposition d'un champ magnetique permanent sur le bain - electro-conducteur - est un moyen de stabiliser, de reorganiser l'ecoulement de convection naturelle et, finalement, de le freiner afin de s'approcher au mieux des conditions ideales d'un transport diffusif des especes chimiques. Dans un premier temps, une synthese des connaissances acquises sur les ecoulements thermogravitaires, magnetohydrodynamiques (mhd) ou non, est presentee. Puis, sur la base du dispositif experimental mascot (magnetic stabilisation of convection and turbulence), les phenomenes qui gouvernent l'ecoulement thermogravitaire mhd du mercure dans une cavite cylindrique horizontale elancee, soumise a la fois a un champ magnetique uniforme et a un gradient de temperature horizontal, sont mis en evidence puis interpretes a l'aide de la mhd. Dans cette configuration particuliere, les couches de hartmann demeurent electriquement inactives. L'inertie n'influence l'ecoulement que localement (aux extremites de la cavite), et surtout dans le cas ou la convection est intense (a grand nombre de grashoff). Ailleurs, le couplage entre courants electriques induits et distribution de temperature est illustre par l'equilibre entre le rotationnel de la force de laplace et le rotationnel de la force de flottabilite. Cet equilibre pilote l'ecoulement pour un nombre de rayleigh modifie, dit effectif, suffisamment faible. Une simulation numerique 3-d aux elements finis de cet ecoulement (laminaire) apporte une confirmation satisfaisante de ces resultats experimentaux. Ce memoire est l'etude de la transition de cet ecoulement vers la turbulence, a l'aide de l'experience mascot. Trois ondes oscillantes progressives ou stationnaires sont clairement identifiees pendant la transition. Si la convention est intense, ces ondes interagissent avec des instabilites stationnaires evoluant faiblement dans le temps. Le couplage non-lineaire associe au terme de convection dans l'equation de l'energie engendre une bifurcation sous-critique. Puis, si le regime d'ecoulement est faiblement convectif, le chaos survient a la suite d'une bifurcation supercritique de hopf. Ces resultats ouvrent des perspectives de developpement technologique pour le procede bridgman de croissance cristalline. Et plus generalement, ce progres dans la comprehension de la convection naturelle mhd pourrait s'appliquer dans d'autres situations: en genie metallurgique ou dans les couvertures tritigenes du futur reacteur de fusion thermonucleaire.

Download or read book Electronics Cooling written by S. M. Sohel Murshed and published by BoD – Books on Demand. This book was released on 2016-06-15 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Featuring contributions from the renowned researchers and academicians in the field, this book covers key conventional and emerging cooling techniques and coolants for electronics cooling. It includes following thematic topics: - Cooling approaches and coolants - Boiling and phase change-based technologies - Heat pipes-based cooling - Microchannels cooling systems - Heat loop cooling technology - Nanofluids as coolants - Theoretical development for the junction temperature of package chips. This book is intended to be a reference source and guide to researchers, engineers, postgraduate students, and academicians in the fields of thermal management and cooling technologies as well as for people in the electronics and semiconductors industries.

Download or read book Gas Transport in Porous Media written by Clifford K. Ho and published by Springer Science & Business Media. This book was released on 2006-10-07 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: CLIFFORD K. HOAND STEPHEN W. WEBB Sandia National Laboratories, P. O. Box 5800, Albuquerque, NM 87185, USA Gas and vapor transport in porous media occur in a number of important applications includingdryingofindustrialandfoodproducts,oilandgasexploration,environm- tal remediation of contaminated sites, and carbon sequestration. Understanding the fundamental mechanisms and processes of gas and vapor transport in porous media allows models to be used to evaluate and optimize the performance and design of these systems. In this book, gas and vapor are distinguished by their available states at stan- ? dard temperature and pressure (20 C, 101 kPa). If the gas-phase constituent can also exist as a liquid phase at standard temperature and pressure (e. g. , water, ethanol, toluene, trichlorothylene), it is considered a vapor. If the gas-phase constituent is non-condensable at standard temperature and pressure (e. g. , oxygen, carbon di- ide, helium, hydrogen, propane), it is considered a gas. The distinction is important because different processes affect the transport and behavior of gases and vapors in porous media. For example, mechanisms specific to vapors include vapor-pressure lowering and enhanced vapor diffusion, which are caused by the presence of a g- phase constituent interacting with its liquid phase in an unsaturated porous media. In addition, the “heat-pipe” exploits isothermal latent heat exchange during evaporation and condensation to effectively transfer heat in designed and natural systems.

Download or read book Physical and Computational Aspects of Convective Heat Transfer written by T. Cebeci and published by Springer Science & Business Media. This book was released on 2013-04-18 with total page 497 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is concerned with the transport of thermal energy in flows of practical significance. The temperature distributions which result from convective heat transfer, in contrast to those associated with radiation heat transfer and conduction in solids, are related to velocity characteristics and we have included sufficient information of momentum transfer to make the book self-contained. This is readily achieved because of the close relation ship between the equations which represent conservation of momentum and energy: it is very desirable since convective heat transfer involves flows with large temperature differences, where the equations are coupled through an equation of state, as well as flows with small temperature differences where the energy equation is dependent on the momentum equation but the momentum equation is assumed independent of the energy equation. The equations which represent the conservation of scalar properties, including thermal energy, species concentration and particle number density can be identical in form and solutions obtained in terms of one dependent variable can represent those of another. Thus, although the discussion and arguments of this book are expressed in terms of heat transfer, they are relevant to problems of mass and particle transport. Care is required, however, in making use of these analogies since, for example, identical boundary conditions are not usually achieved in practice and mass transfer can involve more than one dependent variable.

Download or read book Magnetic Convection written by Hiroyuki Ozoe and published by Imperial College Press. This book was released on 2005 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: The manufacture of silicon single crystals is one of the most important processes in the information technology industry. This book explains the details of liquid metal convection, providing a guide for the elegant operation and control of Czochralski crystal growth, including the effect of magnetic control. Also covered is the newly emerging research field of the application of strong magnetic field using a superconducting magnet. Model equations for the phenomena in the magnetic field are treated in detail, which will be of much use to researchers and engineers in the field. The coverage includes the effect of the Lorentz force in materials processing and the magnetic force of recently developed superconducting magnets. It examines heat, mass and momentum transfer in electro-conducting and non-conducting fluids under normal and very strong magnetic fields. The book also treats the Czochralski single crystal growth process and continuous steel casting process as the most important current applications of magnetic fields. Numerical approaches are compared with the corresponding experimental measurements.

Download or read book The Engineering Index Annual written by and published by . This book was released on 1992 with total page 2264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its creation in 1884, Engineering Index has covered virtually every major engineering innovation from around the world. It serves as the historical record of virtually every major engineering innovation of the 20th century. Recent content is a vital resource for current awareness, new production information, technological forecasting and competitive intelligence. The world?s most comprehensive interdisciplinary engineering database, Engineering Index contains over 10.7 million records. Each year, over 500,000 new abstracts are added from over 5,000 scholarly journals, trade magazines, and conference proceedings. Coverage spans over 175 engineering disciplines from over 80 countries. Updated weekly.

Download or read book Heat Transfer Enhancement with Nanofluids written by Vincenzo Bianco and published by CRC Press. This book was released on 2015-04-01 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanofluids are gaining the attention of scientists and researchers around the world. This new category of heat transfer medium improves the thermal conductivity of fluid by suspending small solid particles within it and offers the possibility of increased heat transfer in a variety of applications. Bringing together expert contributions from

Download or read book Magnetohydrodynamics written by Sergei S. Molokov and published by Springer Science & Business Media. This book was released on 2007-08-26 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book revises the evolution of ideas in various branches of magnetohydrodynamics (astrophysics, earth and solar dynamos, pinch, MHD turbulence and liquid metals) and reviews current trends and challenges. Uniquely, it contains the review articles on the development of the subject by pioneers in the field as well as leading experts, not just in one, but in various branches of magnetohydrodynamics, such as liquid metals, astrophysics, dynamo and pinch.

Download or read book Porous and Complex Flow Structures in Modern Technologies written by Adrian Bejan and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Porous and Complex Flow Structures in Modern Technologies represents a new approach to the field, considering the fundamentals of porous media in terms of the key roles played by these materials in modern technology. Intended as a text for advanced undergraduates and as a reference for practicing engineers, the book uses the physics of flows in porous materials to tie together a wide variety of important issues from such fields as biomedical engineering, energy conversion, civil engineering, electronics, chemical engineering, and environmental engineering. Thus, for example, flows of water and oil through porous ground play a central role in energy exploration and recovery (oil wells, geothermal fluids), energy conversion (effluents from refineries and power plants), and environmental engineering (leachates from waste repositories). Similarly, the demands of miniaturization in electronics and in biomedical applications are driving research into the flow of heat and fluids through small-scale porous media (heat exchangers, filters, gas exchangers). Filters, catalytic converters, the drying of stored grains, and a myriad of other applications involve flows through porous media. By providing a unified theoretical framework that includes not only the traditional homogeneous and isotropic media but also models in which the assumptions of representative elemental volumes or global thermal equilibrium fail, the book provides practicing engineers the tools they need to analyze complex situations that arise in practice. This volume includes examples, solved problems and an extensive glossary of symbols.

Download or read book Numerical Simulation of Convective Radiative Heat Transfer written by Mikhail Sheremet and published by . This book was released on 2020 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents numerical, experimental, and analytical analysis of convective and radiative heat transfer in various engineering and natural systems, including transport phenomena in heat exchangers and furnaces, cooling of electronic heat-generating elements, and thin-film flows in various technical systems. It is well known that such heat transfer mechanisms are dominant in the systems under consideration. Therefore, in-depth study of these regimes is vital for both the growth of industry and the preservation of natural resources. The authors included in this book present insightful and provocative studies on convective and radiative heat transfer using modern analytical techniques. This book will be very useful for academics, engineers, and advanced students.

Download or read book Conjugate Problems in Convective Heat Transfer written by Abram S. Dorfman and published by CRC Press. This book was released on 2009-08-26 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Illustrates Calculations Using Machine and Technological Processes The conjugate heat transfer (CHT) problem addresses the thermal interaction between a body and fluid flowing over or through it. This is an essential consideration in nature and different areas of engineering, including mechanics, aerospace, nuclear engineering, biology, and meteorology. Advanced conjugate modeling of the heat transfer process is now used extensively in a wide range of applications. Conjugate Problems in Convective Heat Transfer addresses the latest theory, methods, and applications associated with both analytical and numerical methods of solution CHT problems and their exact and approximate solutions. It demonstrates how the true value of a CHT solution is derived by applying these solutions to contemporary engineering design analysis. Assembling cutting-edge information on modern modeling from more than 200 publications, this book presents more than 100 example applications in thermal treatment materials, machinery operation, and technological processes. Creating a practical review of current CHT development, the author includes methods associated with estimating heat transfer, particularly that from arbitrary non-isothermal surfaces in both laminar and turbulent flows. Harnesses the Modeling Power of CHT Unique in its consistent compilation and application of current knowledge, this book presents advanced CHT analysis as a powerful tool for modeling various device operations and technological processes, from relatively simple procedures to complex multistage, nonlinear processes.

Download or read book NBS Special Publication written by and published by . This book was released on 1968 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Publications written by United States. National Bureau of Standards and published by . This book was released on 1976 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Software Engineering Perspectives in Intelligent Systems written by Radek Silhavy and published by Springer Nature. This book was released on 2020-12-14 with total page 954 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the refereed proceedings of the 4th Computational Methods in Systems and Software 2020 (CoMeSySo 2020) proceedings. Software engineering, computer science and artificial intelligence are crucial topics for the research within an intelligent systems problem domain. The CoMeSySo 2020 conference is breaking the barriers, being held online. CoMeSySo 2020 intends to provide an international forum for the discussion of the latest high-quality research results.

Download or read book Publications of the National Institute of Standards and Technology Catalog written by National Institute of Standards and Technology (U.S.) and published by . This book was released on 1976 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applications of Fluid Dynamics written by M.K. Singh and published by Springer. This book was released on 2017-11-04 with total page 691 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents high-quality papers presented at 3rd International Conference on Applications of Fluid Dynamics (ICAFD 2016) organized by Department of Applied Mathematics, ISM Dhanbad, Jharkhand, India in association with Fluid Mechanics Group, University of Botswana, Botswana. The main theme of the Conference is "Sustainable Development in Africa and Asia in context of Fluid Dynamics and Modeling Approaches". The book is divided into seven sections covering all applications of fluid dynamics and their allied areas such as fluid dynamics, nanofluid, heat and mass transfer, numerical simulations and investigations of fluid dynamics, magnetohydrodynamics flow, solute transport modeling and water jet, and miscellaneous. The book is a good reference material for scientists and professionals working in the field of fluid dynamics.