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1

Nobili, Camilla. "Rayleigh-Bénard convection: bounds on the Nusselt number." Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-202241.

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We examine the Rayleigh–Bénard convection as modelled by the Boussinesq equation. Our aim is at deriving bounds for the heat enhancement factor in the vertical direction, the Nusselt number, which reproduce physical scalings. In the first part of the dissertation, we examine the the simpler model when the acceleration of the fluid is neglected (Pr=∞) and prove the non-optimality of the temperature background field method by showing a lower bound for the Nusselt number associated to it. In the second part we consider the full model (Pr<∞) and we prove a new upper bound which improve the existi
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2

Schallert, Anthony R. "A study of Nusselt number distributions in a curved channel." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/24054.

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3

Taroni, Giorgia. "Valutazione numerica del numero di Nusselt per una regione di ingresso termico." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2016.

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L’idea di questa tesi è nata dalla volontà di verificare il lavoro svolto come oggetto di studio di illustri scienziati che si prefissero come traguardo la risoluzione di questo problema, che aveva come obiettivo la comprensione, la previsione e l’ottimizzazione dei fenomeni legati allo scambio termico convettivo attraverso le svariate geometrie di superficie. Gli steps per il raggiungimento dello scopo oggetto di questa tesi, pertanto, possono essere così riassunti: 1. definizione di una corretta metodologia di calcolo dei campi fluidodinamico e termico, per un condotto piano infinitament
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4

Manning, Spencer Haynes. "The prediction of fully-developed friction factors and Nusselt Numbers for randomly rough surfaces." Master's thesis, Mississippi State : Mississippi State University, 2005. http://library.msstate.edu/content/templates/?a=72.

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5

Venter, Daniel Petrus Rocco. "Friction factors and nusselt numbers for laminar flow in ducts / Daniel Petrus Rocco Venter." Thesis, North-West University, 2009. http://hdl.handle.net/10394/3995.

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By using the finite element method to solve the appropriate momentum and energy equations the friction factors and Nusselt numbers for fully developed laminar flow were determined for one- and two-dimensional flow systems. The Nusselt numbers were determined for domain boundaries subjected to a constant heat flux (H1) or a constant surface temperature (T) around the computational boundaries and in the axial directions. C++ programs, that were rewritten and extended from previous programs, were used to solve the laminar flow and to determine the values. The required wall shear stresses and heat
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6

Zareifard, Mohammad Reza. "Evaluation of fluid-to-particle heat transfer coefficient under tube-flow conditions involving particle motion with relevance to aseptic processing." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ55397.pdf.

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7

Day, Jerod. "Laminar Natural Convection From Isothermal Vertical Cylinders." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc177190/.

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Laminar natural convection heat transfer from the vertical surface of a cylinder is a classical subject, which has been studied extensively. Furthermore, this subject has generated some recent interest in the literature. In the present investigation, numerical experiments were performed to determine average Nusselt numbers for isothermal vertical cylinders (103 < RaL < 109, 0.5 < L/D <10, and Pr = 0.7) with and without an adiabatic top in a quiescent ambient environment which will allow for plume growth. Results were compared with commonly used correlations and new average Nusselt number corre
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8

Venter, Philip van Zyl. "A supercritical R-744 heat transfer simulation implementing various Nusselt number correlations / Philip van Zyl Venter." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4234.

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During the past decade research has shown that global warming may have disastrous effects on our planet. In order to limit the damage that the human race seems to be causing, it was acknowledged that substances with a high global warming potential (GWP) should be phased out. In due time, R-134a with a GWP = 1300, may probably be phased out to make way for nature friendly refrigerants with a lower GWP. One of these contenders is carbon dioxide, R-744, with a GWP = 1. Literature revealed that various Nusselt number (Nu) correlations have been developed to predict the convection heat transfer coe
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9

Nobili, Camilla [Verfasser], Felix [Akademischer Betreuer] Otto, and Charles [Gutachter] Doering. "Rayleigh-Bénard convection: bounds on the Nusselt number / Camilla Nobili ; Gutachter: Charles Doering ; Betreuer: Felix Otto." Leipzig : Universitätsbibliothek Leipzig, 2016. http://d-nb.info/1240481306/34.

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10

Popescu, Elena-Roxana. "Numerical simulation of the interaction between an external flow, laminar or turbulent, and liquid/vapor phase change." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0058.

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Dans le réservoir d’un satellite, le carburant cryogénique peut se transformer en vapeur à cause de la présence d’un gradient de température à la paroi, induit par le rayonnement solaire ou la diffusion thermique résiduelle des moteurs du lanceur. La quantité de vapeur transformée peut fortement augmenter la pression à l’intérieur du réservoir. En raison d’une connaissance incomplète des ces phénomènes, aujourd’hui, les opérations faites pour régulariser la pression interne entraînent une perte de carburant. Il est donc très important d’étudier le changement de phase liquide/vapeur et les proc
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11

Duan, Yuping Khodadadi J. M. "Effect of a baffle on pseudosteady-state natural convection inside sperical containers." Auburn, Ala., 2007. http://hdl.handle.net/10415/1399.

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12

CALIANNO, LUCA. "SENSITIVITY STUDIES ON THE THERMAL MODEL OF A SOLAR STEAM TURBINE." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-192810.

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Förr i tiden, ångturbiner har främst använts för baskraft operation. Numera med den ökade utvecklingen av varierande förnyelsbara är samma ångturbiner motstå högre cykliska operativa system med mer frekvent uppstarter och snabbt föränderliga laster. Som sådan, förbättra den operativa flexibiliteten hos installerade och framtida utformad ångturbiner är en viktig aspekt för att övervägas av utrustning. Ångturbin uppstart är en intressant fas eftersom anses vara den mest intrikata av transienter. Under denna fas kan maskinen potentiellt utsättas för omåttlig termiska spänningar och axiella gnugga
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13

Thiam, Elhadji Ibrahima. "Modélisation et simulation numérique directe des transferts de chaleur dans les écoulements fortement chargés en particules." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30086.

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Les travaux de simulation menés au cours de cette thèse ont eu pour but de caractériser et de comprendre les phénomènes liés au transfert de chaleur dans des configurations de réseau aléatoire de particules ou de lit fluidisé. Sur la base de simulations numériques résolues à l'échelle des particules, ces configurations d'écoulements diphasiques anisothermes permettent d'extraire des grandeurs physiques locales liées à la microstructure de la suspension ou des informations globales tel que le coefficient de transfert moyen du lit. La première étape des travaux a consisté en la vali- dation de l
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14

Davies, Jason W. "Analysis of Viscous Drag Reduction and Thermal Transport Effects for Microengineered Ultrahydrophobic Surfaces." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1205.pdf.

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15

Lehnen, Matheus Vicenzo. "Caracterização fluidodinâmica e térmica de jatos sintéticos." Universidade do Vale do Rio dos Sinos, 2012. http://www.repositorio.jesuita.org.br/handle/UNISINOS/4318.

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Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-07-08T14:34:31Z No. of bitstreams: 1 Matheus Vicenzo Lehnen.pdf: 7507080 bytes, checksum: 1036a30adcb3840ea0e5fcb545f29987 (MD5)<br>Made available in DSpace on 2015-07-08T14:34:31Z (GMT). No. of bitstreams: 1 Matheus Vicenzo Lehnen.pdf: 7507080 bytes, checksum: 1036a30adcb3840ea0e5fcb545f29987 (MD5) Previous issue date: 2012-05<br>Milton Valente<br>Nos dias atuais, os componentes eletrônicos estão cada vez mais potentes e com mais dispositivos integrados e há a necessidade de uma dissipação térmica mais eficiente.
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16

Trisch, Marino. "Resfriamento de componentes eletrônicos por jatos sintéticos tangenciais." Universidade do Vale do Rio dos Sinos, 2015. http://www.repositorio.jesuita.org.br/handle/UNISINOS/4984.

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Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-02-04T15:21:28Z No. of bitstreams: 1 Marino Trisch_.pdf: 3535397 bytes, checksum: 4cc7a6dc219d9c91a6de57725e4515d1 (MD5)<br>Made available in DSpace on 2016-02-04T15:21:28Z (GMT). No. of bitstreams: 1 Marino Trisch_.pdf: 3535397 bytes, checksum: 4cc7a6dc219d9c91a6de57725e4515d1 (MD5) Previous issue date: 2015-06-22<br>CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Este trabalho apresenta um estudo experimental relacionado ao resfriamento de dispositivos eletrônicos utilizando jatos sintético
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17

BENUCCI, MAURIZIO. "Experimental and numerical analysis of natural convection in a square cavity with a vertical baffle." Doctoral thesis, Università Politecnica delle Marche, 2018. http://hdl.handle.net/11566/252980.

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Il presente documento descrive il lavoro di ricerca effettuato relativamente alla convezione naturale in una cavità quadrata in presenza di un ostacolo verticale posizionato internamente. Il fluido analizzato è aria in condizioni di flusso laminare e stazionario; le pareti laterali della cavità sono raffreddate e riscaldate attraverso degli scambiatori a piastre. Gli effetti della posizione e dell’altezza dell’ostacolo, valutate a diversi angoli di inclinazione della cavità sono stati studiati attraverso prove sperimentali (PIV) e indagine numerica (CFD) e valutati per mezzo di mappe scalari d
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18

Bernardini, Luca. "Studio non lineare della convezione naturale in uno strato poroso orizzontale." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/17256/.

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In questo elaborato si costituisce un modello numerico del problema di Darcy-Bénard con l’obiettivo di definire la sua risoluzione mediante il pacchetto software Mathematica 11.1 (© Wolfram, inc.). La struttura della tesi comprenderà, nel capitolo 2, una descrizione delle equazioni fondamentali che governano il moto di un fluido condotta avvalendosi dell’approssimazione di Oberbeck-Boussinesq, inoltre si descriveranno le condizioni al contorno e le condizioni iniziali applicabili ad un generico sistema di equazioni differenziali. Nel capitolo 3 verrà descritto il problema di Darcy-Bénard rif
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19

Seis, Christian. "Scaling laws in two models for thermodynamically driven fluid flows." Doctoral thesis, Universitätsbibliothek Leipzig, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-81228.

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In this thesis, we consider two models from physics, which are characterized by the interplay of thermodynamical and fluid mechanical phenomena: demixing (spinodal decomposition) and Rayleigh--Bénard convection. In both models, we investigate the dependencies of certain intrinsic quantities on the system parameters. The first model describes a thermodynamically driven demixing process of a binary viscous fluid. During the evolution, the two components of the mixture separate into two domains of the different equilibrium volume fractions. One observes a clear tendency: Larger domains grow at t
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20

Guy, Ashley Ray. "Effect of Blowing Ratio on the Nusselt Number and Film Cooling Effectiveness Distributions of a Showerhead Film Cooled Blade in a Transonic Cascade." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/43764.

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This paper investigates the effect of blowing ratio on the film cooling performance of a showerhead film cooled first stage turbine blade. The blade was instrumented with double-sided thin film heat flux gages to experimentally characterize the Nusselt number and film cooling effectiveness distributions over the surface of the blade. The blade was arranged in a two-dimensional, linear cascade within a transonic, blowdown type wind tunnel. The wind tunnel freestream conditions were varied over two exit Mach numbers, Me=0.78 and Me=1.01, with an inlet freestream turbulence intensity of 12% ,
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21

Calianno, Luca. "SENSITIVITY STUDIES ON THE THERMAL MODEL OF A SOLAR STEAM TURBINE." Thesis, KTH, Kraft- och värmeteknologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-193017.

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In the past, steam turbines were mostly used for base load operation. Nowadays, with the increased development of variable renewable technologies, these same steam turbines are withstanding higher cyclic operational regimes with more frequent start-ups and fast changing loads. As such, improving the operational flexibility of installed and future designed steam turbines is a key aspect to be considered by equipment manufacturers. Steam turbine start-up is a phase of particular interest since is considered to be the most intricate of transient operations. During this phase, the machine can pote
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22

Reid, W. J. "Experimental investigation of circumferentially non-uniform heat flux on the heat transfer coefficient in a smooth horizontal tube with buoyancy driven secondary flow." Diss., University of Pretoria, 2005. http://hdl.handle.net/2263/66236.

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Most heat transfer tubes are designed for either fully uniform wall temperature or fully uniform wall heat flux boundary conditions under forced convection. Several applications, including but not limited to the solar collectors of renewable energy systems, do however operate with non-uniform boundary conditions. Limited research has been conducted on non-uniform wall heat flux heat transfer coefficients in circular tubes, especially for mixed convection conditions. Such works are normally numerical in nature and little experimental work is available. In this experimental investigation th
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23

Voicu, Ionut Marian. "Convection mixte dans une conduite isotherme et dans un échangeur de chaleur à tubes coaxiaux : Approches numérique et expérimentale." Rennes, INSA, 2007. http://www.theses.fr/2007ISAR0019.

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Ce travail de recherche s’inscrit dans le contexte de l’approche des connaissances fondamentales de la convection mixte laminaire à l’intérieur des conduites. Pour cela, un travail tant numérique (code de calcul Fluent) que expérimental (technique PIV) a été entrepris. Dans une première partie, cette investigation s’articule autour de l’écoulement en convection mixte dans un tube incliné isotherme. Les résultats montrent l’influence de l’inclinaison du tube sur l’apparition, l’ampleur et la position des zones de renversement. La deuxième partie concerne le transfert thermique en convection mix
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24

Dongaonkar, Amruta J. "Numerical Modeling and Analysis of Fluid Flow and Heat Transfer in Circular Tubes Fitted with Different Helical Twisted Core-Fins." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1377866455.

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25

Esteves, Fernanda Munhoz. "Análise das características de operação e desempenho de micro jatos sintéticos." Universidade do Vale do Rio dos Sinos, 2012. http://www.repositorio.jesuita.org.br/handle/UNISINOS/3074.

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Submitted by Maicon Juliano Schmidt (maicons) on 2015-03-20T19:50:03Z No. of bitstreams: 1 000002F2.pdf: 1101205 bytes, checksum: 35ea0ac880e5841836ff1b5e64d2f9ff (MD5)<br>Made available in DSpace on 2015-03-20T19:50:04Z (GMT). No. of bitstreams: 1 000002F2.pdf: 1101205 bytes, checksum: 35ea0ac880e5841836ff1b5e64d2f9ff (MD5) Previous issue date: 2012-11-27<br>CNPQ – Conselho Nacional de Desenvolvimento Científico e Tecnológico<br>Componentes eletrônicos estão cada vez mais potentes, necessitando de dissipações térmicas maiores. Os ventiladores atuais, conhecidos comercialmente como "cool
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26

Sbaragli, Camilla. "Campi di moto e termici in microcanali soggetti a flussi elettro-osmotici." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21328/.

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Partendo dallo studio del fenomeno fisico dell'elettroosmosi e utilizzando poi un modello matematico appropriato si va a studiare il comportamento di un fluido mosso attraverso un campo elettrico all'interno di un microcanale. Nello specifico si analizza lo scambio termico per convezione in un microcondotto a sezione rettangolare con quattro lati scaldati a temperatura uniforme su tutto il condotto. Importante è lo studio del numero di Nusselt che dà informazioni sull'efficienza dello scambio termico. L'analisi di Nu viene eseguita al variare di due parametri quali il fattore di farma e il
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27

Pachev, Benjamin Alexander. "Bounds on Heat Transfer in the Presence of Ekman Pumping." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8424.

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Rigorous bounds on heat transfer in rapidly rotating convection have existed for several years in the case of free-slip or stress-free boundary conditions. No-slip boundary conditions result in a phenomenon known as Ekman pumping, which significantly impacts the heat transport. A recent collaborative effort in which the author was involved significantly sharpened the bound on heat transfer in the presence of Ekman pumping. The resulting publication was targeted for an audience consisting primarily of physicists and other non-mathematicians. This work stems from the same effort, but is intended
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28

Souza, Edilson Guimarães de [UNESP]. "Análise experimental e numérica de convecção forçada em arranjo de obstáculos dentro de canal." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/88857.

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Made available in DSpace on 2014-06-11T19:23:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-12-20Bitstream added on 2014-06-13T19:47:44Z : No. of bitstreams: 1 souza_eg_me_ilha.pdf: 959550 bytes, checksum: b4784dbcc883b1be2d0c6b7cce83f54b (MD5)<br>Fundação de Ensino Pesquisa e Extensão de Ilha Solteira (FEPISA)<br>O objetivo deste trabalho é a análise numérica e experimental de escoamento viscoso, incompressível, permanente, com transferência de calor, em um canal estreito contendo um arranjo de obstáculos retangulares. A análise experimental envolveu determinação de coeficiente d
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29

Vitali, Raffaella. "Natural convection in a square cavity with discrete heat sources: an experimental and numerical analysis." Doctoral thesis, Università Politecnica delle Marche, 2016. http://hdl.handle.net/11566/242977.

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Lo studio della convezione naturale in cavità quadrata con sorgenti discrete è svolto sia sperimentalmente che numericamente. Sperimentalmente attraverso l'interferometria olografica e il Particle Image Velocimetry mentre numericamente attraverso l'utilizzo del software CFD ANSYS Fluent. Sono presentati 7 diversi studi di configurazioni della cavità dove vengono esaminati gli effetti sulla trasmissione di calore della dimensione delle sorgenti, dell'aspect ratio, della presenza di uno o due ostacoli orizzontali o verticali di diversa lunghezza e della presenza di una quinta sorgente al centro
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30

Hollweg, Fabiano Da Rosa. "Análise numérica sobre a influência de variações da seção transversal de microcanais no escoamento laminar." Universidade do Vale do Rio dos Sinos, 2012. http://www.repositorio.jesuita.org.br/handle/UNISINOS/4361.

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Submitted by William Justo Figueiro (williamjf) on 2015-07-08T23:40:19Z No. of bitstreams: 1 19b.pdf: 2923099 bytes, checksum: f04244aa991c1a65ebc9273c29c4aa38 (MD5)<br>Made available in DSpace on 2015-07-08T23:40:19Z (GMT). No. of bitstreams: 1 19b.pdf: 2923099 bytes, checksum: f04244aa991c1a65ebc9273c29c4aa38 (MD5) Previous issue date: 2012-11<br>Nenhuma<br>Nas últimas décadas, a miniaturização de dispositivos de natureza eletroeletrônica em diversas áreas de aplicação, como biomédica, química e de tecnologia de computadores, tem proporcionado alta eficiência de espaço em equipamentos.
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31

Mechergui, Olfa. "Etude numérique des transferts de masse et de chaleur en convection naturelle dans un canal : influence de la forme de la paroi." Thesis, Perpignan, 2017. http://www.theses.fr/2017PERP0020/document.

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Le présent travail apporte une contribution à la compréhension des mécanismes des transferts combinés de chaleur et de masse en convection naturelle lors de l’évaporation d’un film liquide d’eau d’épaisseur négligeable dans un canal vertical ondulé. L’écoulement est laminaire et bidimensionnel. Les équations régissant le phénomène sont résolues à l’aide d’une méthode aux volumes finis et le traitement du couplage vitesse-pression est réalisé par la méthode de projection. Les influences de la densité de flux de chaleur, de la température ainsi que l’humidité de l’air à l’entrée et la forme de l
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32

Abdelali, Ahmed. "Etude expérimentale des instabilités thermoconvectives de Rayleigh-Bénard dans les fluides viscoplastiques." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00845453.

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Le phénomène de Rayleigh-Bénard correspond à l'état instable dans lequel se trouve une couche horizontale d'un fluide dilatable, soumise à un gradient de température DT. Si ce dernier dépasse une valeur critique DTc, des mouvements convectifs naissent à l'intérieur du fluide. Concernant les fluides à seuil, le phénomène devient plus complexe. Le seuil s'ajoute aux forces stabilisatrices au sein du fluide et modifie de manière fondamentale le transfert de matière et le transfert thermique. Au départ, le fluide est au repos ; le gradient de vitesse est alors nul et la viscosité efficace infinie
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33

Nguyen, Minh Nhat. "Etudes expérimentales des échanges convectifs dûs aux développements d'un film d'air froid." Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2012. https://theses.hal.science/docs/00/68/45/60/PDF/MA_moire_de_ThA_se_NGUYEN_MINH_NHAT.pdf.

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Nos travaux portent sur la technique de refroidissement par multiperforation (film cooling) utilisée, par exemple, pour le refroidissement d'une paroi de chambre de combustion. Cette étude se décompose en deux parties : La première partie consiste en une étude expérimentale du film cooling dans les conditions de basses températures: 40°C pour l'écoulement principal et 20°C pour l'écoulement secondaire. Le taux de soufflage M est variable de 1 à 4. Le banc d'essais est composé d'une plaque comportant 81 orifices d'injection inclinés de 30° par rapport à la surface de la plaque. Dans un premier
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34

Akbari, Mahmood. "Numerical and analytical study of nanofluids thermal and hydrodynamic characteristics." Thèse, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/6113.

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Résumé: Les mécanismes de perfectionnement du transfert thermique des nanofluids sont encore peu clairs. Les études précédentes au sujet des nanofluids ont essayé de résoudre certains des nombreux défis au sujet de la performance thermique et hydrodynamique des nanofluides et de leurs propriétés ; toutefois il reste beaucoup de problèmes non résolus et questions sans réponse certaine. Par conséquent, plus d'études sont nécessaires, qui peuvent être expérimentales, numériques ou théoriques. Dans la présente étude, des nanofluides sont étudiés intensivement en utilisant des approches numériques
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35

He, Long. "Study of Fluid Forces and Heat Transfer on Non-spherical Particles in Assembly Using Particle Resolved Simulation." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/91400.

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Gas-solid flow is fundamental to many industrial processes. Extensive experimental and numerical studies have been devoted to understand the interphase momentum and heat transfer in these systems. Most of the studies have focused on spherical particle shapes, however, in most natural and industrial processes, the particle shape is seldom spherical. In fact, particle shape is one of the important parameters that can have a significant impact on momentum, heat and mass transfer, which are fundamental to all processes. In this study particle-resolved simulations are performed to study momentum an
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36

Kumar, Vivek Mohan. "3D Numerical Simulation to Determine Liner Wall Heat Transfer and Flow through a Radial Swirler of an Annular Turbine Combustor." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/51949.

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RANS models in CFD are used to predict the liner wall heat transfer characteristics of a gas turbine annular combustor with radial swirlers, over a Reynolds number range from 50,000 to 840,000. A three dimensional hybrid mesh of around twenty five million cells is created for a periodic section of an annular combustor with a single radial swirler. Different turbulence models are tested and it is found that the RNG k-e model with swirl correction gives the best comparisons with experiments. The Swirl number is shown to be an important factor in the behavior of the resulting flow field. The swir
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37

Racine, Evan Michael. "Experimental Study - High Altitude Forced Convective Cooling of Electromechanical Actuation Systems." University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1450286609.

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38

FOURCHER, BERNARD. "Couplage conduction convection en regime periodique etabli application au stockage de la chaleur." Nantes, 1987. http://www.theses.fr/1987NANT2067.

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Cette etude comporte deux parties. Dans la premiere, on traite du couplage en regime periodique etabli entre un fluide caloporteur en ecoulement permanent et les parois d'un canal plan. Il s'agit de determiner la fonction de transfert complexe du systeme. Le probleme est d'abord examine a partir de l'utilisation classique d'un coefficient d'echange. Cette demarche est bien admise en ecoulement turbulent. Pour un regime laminaire on considere les conditions exactes a la frontiere, on se trouve ainsi en presence d'une extension du probleme de graetz. La solution proposee repose sur une formulati
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39

Ayat, Souad. "Etude de la stabilite des mouvements de convection naturelle dans une cavite a grand nombre de rayleigh par interferometrie holographique : application a l'habitat." Toulouse 3, 1988. http://www.theses.fr/1988TOU30026.

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Etude de la convection naturelle dans l'habitat, avec determination des criteres de stabilite de l'ecoulement d'une part et des variations des densites des flux convectes d'autre partm par essais sur une maquette 1/4, remplie d'un gaz dense (r12b1). Determination des courbes de stabilite neutre et des zones de stabilite en fonction des conditions aux limites et du nombre de rayleigh. Mesures de densite, montrant l'insuffisance des correlations classiques donnant le nombre de nusselt en fonction de ceux de rayleigh et de prandtl: necessite de prendre en compte des conditions aux limites
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40

Kassem, Talal. "Contribution à l'étude de la convection naturelle entre deux cylindres excentrés horizontaux." Compiègne, 1989. http://www.theses.fr/1989COMPD219.

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L'auteur étudie la convection naturelle, thermique, laminaire et permanente, qui se développe dans un fluide newtonien confiné entre deux cylindres excentrés d'axes horizontaux lorsque la paroi du cylindre extérieur est isotherme et celle du cylindre intérieur traversée par un flux de chaleur de densité non-uniforme. Il introduit la fonction de courant, la vorticité, les coordonnées bi -cylindriques et intègre les équations de transfert à l'aide de la méthode aux différences-finies de Patankar. Les distributions des vitesses et des températures sont calculées ainsi que les valeurs locales et m
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41

Modekurti, Arvind. "Numerical Investigation of Fluid Flow and Heat Transfer for Non-Newtonian Fluids Flowing through Twisted Ducts with Elliptical Cross-sections." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1504782280273333.

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42

Oliva, Fabrizio. "Studio delle prestazioni termoidrauliche di microcanali a spigoli arrotondati nel caso di efflussi rarefatti." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7007/.

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Analisi di campi di moto e temperatura in micro condotti al variare delle condizioni operative e della geometria. Dopo una breve introduzione al settore della microfluidica, si presentano, dal punto di vista teorico, le condizioni operative che caratterizzano il moto in presenza di rarefazione, sottolineando come il modello matematico di base per la fluidodinamica debba essere modificato per tenerne conto. Segue una breve parentesi dedicata all’illustrazione delle tecnologie e dei procedimenti di fabbricazione dei moderni microcanali utilizzati in questa recente branca della termofluidodina
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43

Mitori, Tiffany Leilani. "Flight and Stability of a Laser Inertial Fusion Energy Target in the Drift Region between Injection and the Reaction Chamber with Computational Fluid Dynamics." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1154.

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A Laser Inertial Fusion Energy (LIFE) target’s flight through a low Reynolds number and high Mach number regime was analyzed with computational fluid dynamics software. This regime consisted of xenon gas at 1,050 K and approximately 6,670 Pa. Simulations with similar flow conditions were performed over a sphere and compared with experimental data and published correlations for validation purposes. Transient considerations of the developing flow around the target were explored. Simulations of the target at different velocities were used to determine correlations for the drag coefficient and Nus
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44

Ahmed, Zahir Uddin. "An experimental and numerical study of surface interactions in turbulent swirling jets." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2016. https://ro.ecu.edu.au/theses/1790.

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Convective heat transfer and drying processes are found in industrial applications from gas turbine blade cooling to drying of food products and paper. In many instances, these processes rely on either a single or an array of fluid jets which impinge onto a surface. Traditionally, non-swirling impinging jets have been used, but interest surrounds possible advantages from imposing swirl into these jets to further promote heat and mass transfer at the surface. The challenge of resolving this question is that including swirl further complicates fluid-surface interactions. Studies are faced with t
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45

Brouilliot, Denis. "Etude expérimentale de l'aérothermique et de la dynamique des jets impactants." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30300/document.

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L'étude des jets impactants a fait l'objet d'une multitude de travaux depuis plusieurs dizaines d'années en raison de la variété des domaines d'applications. Il existe une grande diversité de jets tels que les jets axisymétriques et les jets bidimensionnels pour les plus classiques ou tels que les jets à géométrie lobée, c'est à dire des jets axisymétriques sur lesquels il a été appliqué un contrôle passif, pour les plus complexes. Dans nos travaux, nous avons réalisé une étude fondamentale des jets plans confinés pour une gamme de faibles nombres de Reynolds. Nous avons étudié la stabilité de
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46

Souza, Edilson Guimarães de. "Análise experimental e numérica de convecção forçada em arranjo de obstáculos dentro de canal /." Ilha Solteira : [s.n.], 2010. http://hdl.handle.net/11449/88857.

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Resumo: O objetivo deste trabalho é a análise numérica e experimental de escoamento viscoso, incompressível, permanente, com transferência de calor, em um canal estreito contendo um arranjo de obstáculos retangulares. A análise experimental envolveu determinação de coeficiente de transferência de calor médio bem como o número de Nusselt médio e medidas de temperatura em esteira térmica para comparação com os resultados obtidos por simulação numérica. Para a análise numérica usamos o programa comercial de mecânica dos fluidos e transferência de calor computacional ICEPAK®. Verificamos que quant
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47

Manfroni, Michele. "Controllo del flusso termico in convezione mista tramite fluidi visco-elastici." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/6107/.

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L'obiettivo del lavoro è stato quello di valutare l'influenza di fluidi viscoelastici sullo scambio termico in flussi in convezione mista, tramite l'analisi di simulazioni numeriche dirette del campo. Si è osservato che il numero di Nusselt aumenta se il numero di Deborah della soluzione cresce, ma l'incremento della componente di convezione forzata inibisce tale effetto positivo.
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48

Venter, Johann Christiaan. "The optimal hydraulic diameter of semicircular and triangular shaped channels for compact heat exchangers / J.C. Venter." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4629.

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All heat pump cycles have one common feature that connects them to one another; this feature is the presence of a heat exchanger. There are even some heat–driven cycles that are completely composed of heat exchangers, every heat exchanger fulfilling a different, though critical role. The need therefore exists to optimize heat exchangers, more specifically Compact Heat Exchangers (CHE). This study deals with the optimization of such a CHE by determining an optimal hydraulic diameter of the micro–channels in a CHE, for minimal hydraulic losses. Two Computational Fluid Dynamics (CFD) models were
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49

Machicoane, Nathanaël. "Particules matérielles en écoulement turbulent. Transport, dynamique aux temps longs et transfert thermique." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2014. http://tel.archives-ouvertes.fr/tel-01070651.

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Nous nous intéressons au transport turbulent de particules de taille grande devant l'échelle de Kolmogorov. Cette situation se retrouve à la fois dans les écoulements naturels (comme le transport de sédiments) et dans les écoulements industriels (solutés solides dans un mélangeur par exemple). Pour aborder ce problème, nous étudions la dynamique de particules de taille proche de l'échelle intégrale, de densité égale ou légèrement différente de celle du fluide, dans un écoulement turbulent de von Kármán contra-rotatif, à l'aide d'un montage de suivi lagrangien rapide. L'étude de la dynamique rapi
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50

Sochinskii, Arkadii. "Premier pas vers la miniaturisation des cryoréfrigérateurs spatiaux." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAY065/document.

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Ce travail a été effectué dans le cadre d’études de la miniaturisation d’un cryo-réfrigérateur de type tube à gaz pulsé (TGP) et particulièrement pour mieux comprendre l’écoulement et le transfert de chaleur dans un régénérateur, l’élément clé du TGP.Nous présentons les études numérique et expérimentale du facteur de frottement et du nombre de Nusselt pour les écoulements stationnaires et continus à nombre de Reynolds modéré O(1 − 100) au sein d’un régénérateur micro-fabriqué. L’influence de la porosité et de la géométrie est étudiée. La micro-structure précisément contrôlée représente des can
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