Dissertations / Theses on the topic 'Flux de chaleur au divertor'
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Gallo, Alberto. "Impact of the plasma geometry on the divertor power exhaust in a magnetic fusion reactor." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0001/document.
Full textA deep understanding of plasma transport at the edge of a magnetically confined fusion device is mandatory for a sustainable and controlled handling of the power exhaust. In the next-generation fusion device ITER, technological limits constrain the peak heat flux on the divertor. For a given exhaust power the peak heat flux is determined by the extent of the plasma footprint on the wall. Heat flux profiles at the divertor targets of X-point configurations can be parametrized by using two length scales for the transport of heat in SOL. In this work, we challenge the current interpretation of these two length scales by studying the impact of divertor geometry modifications on the heat exhaust. In particular, a significant broadening of the heat flux profiles at the outer divertor target is diagnosed while increasing the length of the outer divertor leg. Modelling efforts showed that diffusive simulations well reproduce the experimental heat flux profiles for short-legged plasmas. Conversely, the broadening of the heat flux for a long divertor leg is reproduced by a turbulent model, highlighting the importance of turbulent transport not only in the main SOL but also in the divertor. These results question the current interpretation of the heat flux width as a purely main SOL transport length scale. In fact, long divertor leg magnetic configurations highlighted the importance of asymmetric divertor transport. We therefore conclude that main SOL and divertor SOL transport cannot be arbitrarily disentangled and we underline the importance of the divertor magnetic geometry in enhancing asymmetric turbulent transport with the potential benefit of an unexpected power spreading
Gallo, Alberto. "Impact of the plasma geometry on the divertor power exhaust in a magnetic fusion reactor." Electronic Thesis or Diss., Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0001.
Full textA deep understanding of plasma transport at the edge of a magnetically confined fusion device is mandatory for a sustainable and controlled handling of the power exhaust. In the next-generation fusion device ITER, technological limits constrain the peak heat flux on the divertor. For a given exhaust power the peak heat flux is determined by the extent of the plasma footprint on the wall. Heat flux profiles at the divertor targets of X-point configurations can be parametrized by using two length scales for the transport of heat in SOL. In this work, we challenge the current interpretation of these two length scales by studying the impact of divertor geometry modifications on the heat exhaust. In particular, a significant broadening of the heat flux profiles at the outer divertor target is diagnosed while increasing the length of the outer divertor leg. Modelling efforts showed that diffusive simulations well reproduce the experimental heat flux profiles for short-legged plasmas. Conversely, the broadening of the heat flux for a long divertor leg is reproduced by a turbulent model, highlighting the importance of turbulent transport not only in the main SOL but also in the divertor. These results question the current interpretation of the heat flux width as a purely main SOL transport length scale. In fact, long divertor leg magnetic configurations highlighted the importance of asymmetric divertor transport. We therefore conclude that main SOL and divertor SOL transport cannot be arbitrarily disentangled and we underline the importance of the divertor magnetic geometry in enhancing asymmetric turbulent transport with the potential benefit of an unexpected power spreading
Grosjean, Alex. "Impact of geometry and shaping of the plasma facing components on hot spot generation in tokamak devices." Electronic Thesis or Diss., Aix-Marseille, 2020. http://www.theses.fr/2020AIXM0556.
Full textThis PhD falls within ITER project support, aiming to study the thermal behavior of ITER-like PFC prototypes in two superconducting tokamaks: EAST (Hefei) and WEST (Cadarache). These prototypes correspond to castellated tungsten monoblocks placed along a cooling tube with small gaps (0.5 mm) between them, called plasma-facing units, to extract the heat from the components. The introduction of gaps between monoblocks (toroidal) and plasma-facing units (poloidal), to relieve the thermomechanical stresses in the divertor, implies that poloidal leading edges may be exposed to near-normal incidence angle. A local overheating is expected in a thin lateral band at the top of each monoblocks, which can be enhanced when the neighboring components are misaligned. In this work, we propose to study the impact of two geometries (sharp and chamfered LEs) of these components, as well as their misalignments on local hot spot generation, by means of embedded diagnostics (TC/FBG), and a submillimeter infrared system (~0.1 mm/pixel), whose emissivity varies with wavelength, and the temperature, but above all, the surface state of the component, which evolves under plasma exposure, during the experimental campaigns. The divertor Langmuir probes measure the plasma temperature, and thus estimate the ion Larmor radius that may play a role in the local heat flux distribution around poloidal and toroidal edges. The results presented in this thesis, confirming the modelling predictions by experimental measurements, support the final decision by ITER to include 0.5 mm toroidal beveling of monoblocks on the vertical divertor targets to protect poloidal leading edges from excessive heat flux
Moshman, Nathan David. "Implantation, flux and recoil distributions for plasma species impinging on tokamak divertor materials." Diss., [La Jolla] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p1464056.
Full textTitle from first page of PDF file (viewed June 16, 2009). Available via ProQuest Digital Dissertations. Includes bibliographical references (p. 88).
Costanzo, Laurent. "Etude expérimentale des aspects topologiques du divertor ergodique de Tore Supra." Aix-Marseille 1, 2001. http://www.theses.fr/2001AIX11033.
Full textGable, Robert. "Température, gradient et flux de chaleur terrestre : mesures, interprétation /." Orléans : Éd. du Bureau de recherches géologiques et minières, 1986. http://catalogue.bnf.fr/ark:/12148/cb377010343.
Full textCrosatti, Lorenzo. "Experimental and numerical investigation of the thermal performance of gas-cooled divertor modules." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24717.
Full textCommittee Co-Chair: Minami Yoda, Co-Advisor; Committee Co-Chair: Said I. Abdel-Khalik; Committee Member: Donald R. Webster; Committee Member: Narayanan M. Komerath; Committee Member: S. Mostafa Ghiaasiaan; Committee Member: Yogendra Joshi
Gwon, Hyoseong. "Study on the Transport of High Heat Flux and the Thermal Mechanical Response of Fusion Reactor Divertor." Kyoto University, 2014. http://hdl.handle.net/2433/192208.
Full textAthier, Gilles. "Optimisation des flux thermiques au sein de réseaux d'échangeurs de chaleur." Toulouse, INPT, 1997. http://www.theses.fr/1997INPT005G.
Full textJakubowski, Marcin. "Magnetic field topology and heat flux patterns under the influence of the dynamic ergodic divertor of the TEXTOR tokamak." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972555390.
Full textToudji, Sid-Ali Amine. "Pervaporation de composés purs : approche expérimentale du couplage entre transfert de matière et transfert de chaleur." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0100.
Full textThe aim of this work is to study the pervaporation process and specifically to understand the mass and heat transport mechanisms in a dense polymeric membrane. A better understanding of these mechanisms would make it possible to improve the limiting parameters for the development of this process, such as the low mass fluxes as well as the origin and the quantity of heat required for transport through the membrane. In order to answer these questions, we have developed an experimental setup that allows simultaneous measurement of mass flux and heat flux density. The dead-end permeation of the setup developed gives access to the temperature profile of the liquid feed. These temperature data make possible the estimation of the heat flux densities engaged during the pervaporation experiments by means of an inverse computation coupled with a STAR CCM + simulation. The mass flux is measured by a new method in addition to the gravimetric method used as a reference. The new method uses a pressure sensor located in the feed tank to continuously measure the mass flux with 1Hz raw acquisition frequency synchronized with the temperature measurement. In order to simplify the experimental constraints, we applied only permeation of pure liquids. The correlation of the two fluxes (mass and heat density) measured led us to observe that the amount of heat taken to the feed side to pervaporate a unit mass of pure liquid is less than the amount of heat required to vaporize the same liquid. It represents 50% of it in the case of water and only 25% in the case of the ethanol
Delarochelambert, Thierry. "Etude expérimentale et théorique des transferts thermiques couples en convection naturelle à travers une double paroi verticale à haute densité de flux de chaleur." Mulhouse, 1997. http://www.theses.fr/1997MULH0506.
Full textPatej, Stéphanie. "Structure d'écoulement au sein d'une nappe liquide soumise à un flux de chaleur." Poitiers, 2000. http://www.theses.fr/2000POIT2291.
Full textBourras, Denis. "Estimation par satellite du flux de chaleur latente a la surface des oceans." Paris 6, 1999. http://www.theses.fr/1999PA066073.
Full textBen, Moussa Hocine. "Etude des transferts de chaleur et de masse dans un silo à grains soumis à un flux de chaleur pariétal instationnaire." Poitiers, 1989. http://www.theses.fr/1989POIT2313.
Full textSuleiman, Ahed. "Evaluation par méthode inverse de la distribution de flux de chaleur pariétaux d'une plaque plane verticale en présence d'une perturbation radiative." Toulouse, INSA, 2002. http://www.theses.fr/2002ISAT0017.
Full textThe aim of this research is to identify, with the help of an inverse method, the value of convective heat exchanges generated by a uniformly heated vertical plane plate on which a radiative local perturbation is imposed. Experimental and numerical approaches were necessary to develop this work. The experimental system was composed of an enclosure with reduced dimensions, of the plane plate and of the radiative source of which the power was first determined by calibration. The use of the inverse method leads to the knowledge of the global flux leaving the plate and of the surface temperatures. Flux radiative calculations lead, by application of a thermal balance, to the determination of the convective heat exchanges. Finally, we can determine the values of the convective heat exchange coefficients. Two types of results are proposed. Those, corresponding to the steady state lead to the correct validation of the inverse method by comparison with a relation provided by the literature. The other ones lead in unsteady state give the evaluation of the heat exchange coefficients depending from the time. Uncertainty calculations confirm the viability of the inverse method. Finally, the main results given by this work correspond to the algorithm's robustness, which can lead to the use of the method for other applications
Moraes, Jorge Marcos de. "Etude de la convection naturelle laminaire permanente entre deux plans paralleles avec des conditions pariétales imposées sur la densité du flux de chaleur." Perpignan, 1992. http://www.theses.fr/1992PERP0118.
Full textCrespy, Charles. "Contribution à la mesure de champs de température bi et tri-dimensionnels par photographie de Speckle : application à l'estimation des flux de chaleur pariétaux." Lyon, INSA, 2009. http://theses.insa-lyon.fr/publication/2009ISAL0031/these.pdf.
Full textThis study deals with the implementation of a Speckle Photography experimental device in order to measure temperature fields in bidimensional and tridimensional air flows, specially it focuses on near wall heat transfers estimation. First of all, an experimental device is designed and optimized for thermal phase object studies. Then, an original metrology to measure convective parietal heat flux is developed. It allows to increase spatial resolution and measurement accuracy, and to correct measurements from diffraction phenomenon which introduces a bias in parietal measurement. This technique is successfully validated with a measurement campaign on an air jet impingement flow simultaneously perform with the Speckle Photography technique and with a balance method. Finally, a tridimensionnal field estimation algorithm which needs a narrow viewing angle is developed. This technique has the advantage to be used in the parietal problems. It's implemented to estimate the thickness and the position of a free convective boundary layer
Seghouani, Lotfi. "Étude expérimentale de la convection mixte avec flux uniforme sur la paroi pour un conduit circulaire incliné." Sherbrooke : Université de Sherbrooke, 2003.
Find full textCheng, Li Zhen. "Interprétation des données de flux de chaleur et de gravité dans le bouclier canadien." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0020/NQ49058.pdf.
Full textPhordoy, Jacques. "Influence d'une transpiration sur un écoulement turbulent en canal, mesure des flux de chaleur." Toulouse, INPT, 1992. http://www.theses.fr/1992INPT108H.
Full textMarraffa, Lionel. "Contribution du calcul numérique à l'évaluation de flux de chaleur pour des écoulements hypersoniques." Châtenay-Malabry, Ecole centrale de Paris, 1992. http://www.theses.fr/1992ECAP0270.
Full textCheng, Li Zhen. "Interprétation des données de flux de chaleur et de gravité dans le Bouclier Canadien /." Thèse, Montréal : Chicoutimi : Université du Québec à Montréal ;. Université du Québec à Chicoutimi, 1999. http://theses.uqac.ca.
Full textLopez, Lopez Ma Guadalupe. "Mesure de coefficients de transfert thermique Gaz Solide. Application au réacteur à l'inversion de flux." Aix-Marseille 3, 2002. http://www.theses.fr/2002AIX30086.
Full textCompact heat exchangers allow heat recovery. With an intermediate heat storage in compact surfaces, they provide at the same time a low pressure drop and a high heat transfer efficiency. Stacks of woven screen offer particularly interesting performances, at relatively low costs. We have measured the heat transfer coefficients and the friction factors for woven screens. The transient technique was used, which basis is the analysis of responses to a step change in inlet temperature. The pressure drop has been directly measured in an U tube manometer. Woven screens differ in materials nature, porosity and wire diameter. The stack length and compactness as well as gas flow have been modified in a wide range. Correlations relating woven screens performances and their associated geometric properties, have been established. They govern the efficiency pattern of a compact heat exchanger, enhancing their design
Hassaine, Ahmed. "Etude des transferts d'impulsion et de chaleur par convection forcée dans un canal à parois sinusoïdales soumises à un flux de chaleur de densité constante." Lyon 1, 1993. http://www.theses.fr/1993LYO10046.
Full textKalla, Lamine. "Convection naturelle au sein d'une couche horizontale poreuse soumise à des flux de chaleur uniformes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0027/MQ49796.pdf.
Full textDupland, Laure. "Modélisation de la turbulence thermique : modèles algébriques pour la prévision des flux de chaleur turbulents." Toulouse, ENSAE, 2005. http://www.theses.fr/2005ESAE0023.
Full textRingenbach, Nicolas. "Bilan radiatif et flux de chaleur en climatologie urbaine : Mesures,modélisation et validation sur Strasbourg." Université Louis Pasteur (Strasbourg) (1971-2008), 2004. https://publication-theses.unistra.fr/public/theses_doctorat/2004/RINGENBACH_Nicolas_2004.pdf.
Full textBelattar, Sougrati. "Le traitement par corrélation des mesures simultanées de flux thermique et de température de surface appliqué à l'analyse des échanges énergétiques sur la surface d'une paroi en régime variable." Lille 1, 1985. http://www.theses.fr/1985LIL10048.
Full textGeitner, Mickaël. "Température effective d'un système hors équilibre : fluctuations thermiques d'un microlevier soumis à un flux de chaleur." Thesis, Lyon, École normale supérieure, 2015. http://www.theses.fr/2015ENSL1026/document.
Full textThanks to a home made quadrature phase differential interferometer, we measure the thermal fluctuations ofa cantilever. It is then possible to infer various mechanical properties such as eigenfrequencies, stiffness,quality factor, etc. In such system, the maximal precision on the measure is limited by the shotnoise of thephotodiodes. To increase the signal-noise ratio we raise the light intensity of the laser, lowering thebackground noise. Doing so, the cantilever eigen frequencies shifts to lower values. A fisrt part of this thesiswork has for objective the understanding of this phenomenon. Thus, we associate this frequency shift with aheating of the cantilever by the laser. We develop a model linking this effect to the temperature at the freeend of the cantilever assuming a linear temperature profile.A second part of this thesis leads us to estimate the effective temperature of a cantilever using thefluctuation-dissipation theorem. We show that the fluctuations of our out of equilibrium system are lower thanthe fluctuations expected at equilibrium.In the last part, we estimate the temperature profiles on cantilevers by varying their geometry, absorptioncoefficient and laser position
Biotteau, Emilie. "Caractérisation d'un milieu poreux réactif soumis à de forts flux de chaleur : application au bois Redwood." Poitiers, 2004. http://www.theses.fr/2004POIT2327.
Full textThe major purpose of this study is a better understanding of mechanisms involved in thermal degradation of porous medium (wood for instance). Numerical and experimental investigations have been carried out. A non linear coupled differential set of equations had to be solved to describe heat and mass transfer, pyrolysis reaction and the induced solid matrix transformation. Inclusion of anisotropy has been performed using 2D-simulation. Two experimental set up have been used to investigate pyrolysis under inert and ambient atmosphere. The reactive zone has been found to be very thin compared to slab length and to propagate into the sample as time proceeds. A pyrolysis front velocity has been defined experimentally and numerically. A detailed analysis of heat and mass transfer in the sample provided an improved understanding of the front propagation mechanism. Heat conduction has been found to play a major role in the heat balance whereas chemical reactions contribution has been shown to be negligible. Under oxidative atmosphere, smoldering combustion occurs at the irradiated surface and has been shown to supply three times more heat than incident heat flux so that pyrolysis starts at lower incident heat fluxes. Inclusion of structure anisotropy leads to a paradox: pyrolysis front propagates more rapidly across than along the fibres (although heat conductivity is lower across than along fibres)
Nicholas, Jack Robert. "Heat transfer for fusion power plant divertors." Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:efedf39b-401b-418f-b510-386a512314a8.
Full textVillemure, Charles. "Optimisation à l'aide d'algorithmes génétiques d'un stratifié poreux soumis à un flux thermique en convection naturelle." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24394/24394.pdf.
Full textLouleh, Ziad. "Modélisation et conduite des réacteurs discontinus par analyse des flux thermiques." Toulouse, INPT, 1996. http://www.theses.fr/1996INPT037G.
Full textOuzzane, Mohamed. "Développement simultané en convection mixte laminaire dans une conduite avec un flux de chaleur non uniforme sur sa surface externe : cas avec et sans ailettes." Sherbrooke : Université de Sherbrooke, 2000.
Find full textChambon, Gérard. "Contribution à l'étude des flux thermiques en projection plasma. Refroidissement cryogénique." Limoges, 1996. http://www.theses.fr/1996LIMO0052.
Full textYala, Malika. "Étude et réalisation de microcapteurs de flux thermique en technologie silicium." Lille 1, 2007. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2007/50376-2007-Yala.pdf.
Full textDoukouré, Moussa. "Variabilité des flux turbulents de surface au sein du bassin versant d'Ara au Bénin." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENU014/document.
Full textWest Africa atmosphere circulation is characterized by south-westerly wind (monsoon regime) during the wet season and north-easterly wind (harmattan regime) during the dry season. This alternation of wind regime is due to surface pressure variability linked to surface heterogeneities. Surface heterogeneities generate surface flux variability, secondary circulation and make complex analysis when trying to document surface-atmosphere feedbacks. LES modelling usually used for boundary-layer studies due to its potential to take into account 3D turbulence over complex topography, is used here to overcome these difficulties. Our site of interest is located in north of Benin characterized by Soudanian climate and heterogeneous surface properties. Climate analysis are first performed with radiosoundings, UHF radar, and EC station data in order to extract composite profile representing dry and wet season.. These composite profiles are then used to force atmosphere part of the Méso-NH LES model. To characterize turbulent fluxes length scales relative to dry and wet season, standard surface forcing data with Méso-NH like GTOPO30 orography (1km ) and ECOCLIMAP vegetation (1km) are respectively replaced by SRTM (90m) and SPOT/HRV vegetation data (20m) resampled to 90m. Along with statistical tools like 2D variography and Lagrangian, we notice that during dry season on heterogeneous vegetation, sensible heat flux H is more driven by wind and orography while we not able to discuss the latent heat flux E case. During wet season with the same surface forcing, it appears that H is driven by wind while E is more dependent to vegetation variability. Our study concludes in all case that H and E are not characterized by the same length scale
Didorally, Sheddia. "Prévision des flux de chaleur turbulents et pariétaux par des simulations instationnaires pour des écoulements turbulents chauffés." Thesis, Toulouse, ISAE, 2014. http://www.theses.fr/2014ESAE0015/document.
Full textThe improvement of aerothermal predictions is a major concern for aeronautic manufacturers. In line with this issue, SAS approaches are assessed on the prediction of wall and turbulent heat fluxes for heated-turbulent flows. This study also aims at evaluating these advanced URANS methods in regard to DRSM models and hybrid RANS/LES approaches as ZDES. Firstly, we proposed to combine the SAS approach and a DRSM model in order to better reproduce both resolved and modelled Reynolds stresses. This new model, called SAS-DRSM, was implemented in ONERA Navier-Strokes code elsA. Unsteady simulations of two heated turbulent flows encountered in an aircraft engine compartment were then performed to evaluate all the SAS models available in the code. These numerical studies demonstrated that SAS approaches improve prediction of the flows compared to classical URANS models. They lead to full 3D flows with many turbulent structures. These structures favour turbulent mixing and thus induce a better prediction of the wall heat fluxes. Moreover, the numerical simulations showed that SAS methods are more accurate than classical URANS models without increasing significantly calculation costs. SAS approaches are not able to resolve the smallest turbulent structures in relation to ZDES which provides better predictions. Finally, the investigation of the turbulent heat flux suggested that the constant turbulent Prendtl number assumption, that is characteristic of classical URANS models, may not be valid in some regions of the flow
Piraccini, Giacomo. "Modeling of heat and particle transport in nuclear fusion plasmas in a tokamak: study of density regimes and ionization front control." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textDoukoure, Moussa. "Variabilité des flux turbulents de surface au sein du bassin versant d'Ara au Bénin." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00693477.
Full textSamodi, Mohamed. "La théorie des systèmes appliquée à l'analyse du partage des flux thermiques à l'interface de deux milieux en régime variable." Lille 1, 1985. http://www.theses.fr/1985LIL10047.
Full textSalomé, Adrien. "Développement d'un outil de contrôle de la répartition du flux solaire concentré sur un récepteur de centrale à tour : application à la centrale de Thémis." Perpignan, 2012. http://www.theses.fr/2012PERP1123.
Full textLife time of components is one of the technological bottle-neck in the development of solar tower power plant technology. The receiver, which is submitted to high and variable concentrated solar flux density is particularly affected: High, variable and non-homogeneous solar flux on the solar receiver walls results in strong stresses because of high temperatures, thermal shocks and temperature gradient that contribute to the reduction of the life time of this key component. This work aims at presenting an open loop approach to control the flux density distribution delivered on a flat plate receiver for a solar power tower. Various distributions of aiming points on the aperture of the receiver are considered. The flux density distribution on the aperture is simulated by a computer code. The TABU optimization algorithm is modified according to the size of the image of each individual heliostat. This modified algorithm is implemented to select the best aiming point for each heliostat. This approach has been validated using the example of THEMIS Solar Power Tower in Targasonne, France
Seghir-Ouali, Souhil. "Echanges convectifs à l'intérieur d'un cylindre tournant soumis à un flux d'air axial : application à l'étude thermique d'un moteur à aimants permanents de puissance élevée." Valenciennes, 2006. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/7beb69f5-85d1-475d-a9f4-6b64f8b75bf3.
Full textThis thesis deals with the thermal behavior of an electric machine with permanent magnets and used for naval propulsion. A permanent three-dimensional model based on a nodal approach was developed to predict the thermal behavior of the machine in steady state. Due to the wide interest that the air region of the interior of the hollow rotor offers to cool down the machine, particular attention is carried out to the experimental identification of the heat exchange coefficient of the inner rotor surface. For this purpose, we designed a specific experimental setup and developed a procedure to identify this exchange coefficient. The results show the existence of domains where the axial flow and the rotation of the cylinder are influent. At the end of the study, dimensionless correlations connecting the heat transfer rate to the aerodynamic parameters are proposed. A parametric study using this model is carried out aiming at two objectives. The first one consists in an evaluation of the influence of several physical quantities on the temperature field. The second one aims at obtaining the inception of the thermal optimization and evaluating the most efficient cooling techniques or solutions
Mauran, Sylvain. "Flux de gaz en milieu poreux réactif déformable : relation entre texture, propriétés mécaniques et transferts : incidence sur la mise en oeuvre des réactifs et les performances de pompes à chaleur chimiques solide-gaz." Perpignan, 1990. http://www.theses.fr/1990PERP0097.
Full textUnnikrishnakurup, Sreedhar. "Etude expérimentale et numérique d'un essai de soudage TIG statique et estimation des paramètres du flux de chaleur." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20013/document.
Full textGas Tungsten Arc Welding (GTAW) process is generally used for assemblies that requires high quality weld joint. The microstructure and the weld joint relies mainly on the thermal cycle due to the welding operation, the chemical composition of the metallic material and the complex flow of molten metal in the weld pool. Moreover the fluid flow in the weld pool play a major role in the temperature distribution and the final weld pool shape. Better understanding of the physical phenomena involved in the welding operation, more exactly in the weld pool, are the fundamental step for improving the GTAW operation, for example increase the productivity or avoid defects. In the present research work, a two dimensional axi-symmetric multiphysics model was established in order to predict the weld pool shape evolution in the frame of a stationary Gas Tungsten Arc Welding using a finite element numerical approach. The weld pool model included various driving forces such as self-induced electromagnetic (Lorentz force), surface tension (Marangoni force), buoyancy and the arc plasma drag force. The stated GTAW model is used for predicting the velocity and temperature distribution in the fusion zone and the final weld pool shape. In order to validate the GTAW model, an experimental set up was defined for synchronizing the acquisition of time dependent data such as temperature, weld pool radius and welding process parameters (current and voltage). Image processing algorithms were developed for the time dependent weld pool size identification from the high speed camera images. Comparison between experimental and calculated data exhibited important discrepancies on the temperature field and weld pool radius. These discrepancies are due to the incoming heat flux from the arc plasma into the work piece. The heat flux was modeled with a Gaussian function itself described with few parameters;two of these required to be estimated: GTAW efficiency and Gaussian distribution.An inverse approach is used for estimating these parameters from the available experimental data: temperature, weld pool radius and macrographs. The Levenberg-Marquardt method is used to solve the inverse heat transfer problem coupled to an iterative process regularization. Afterward the inverse heat transfer problem was investigated through few numerical cases in order to verify its robustness to three sorts of error in the input data (measurement noise, sensor location error and inaccuracies associated with the thermophysical properties). The inverse approach was robust to errors introduced on measurement data. However, errors on the position of sensors or on the knowledge of material thermo-physical properties are problematic on the GTAW efficiency estimation. Finally the inverse problem was solved with experimental measurement. The estimated parameters are in good agreement with the literature. The evaluated error on the estimated parameters is less than 10%
Es-Sakhy, Moulay Rachid. "Convection de Rayleigh-Bénard-Marangoni en récipient cylindrique à fond conducteur soumis à un flux de chaleur localisé." Thesis, Pau, 2012. http://www.theses.fr/2012PAUU3029/document.
Full textThe present research work concerns the study of Rayleigh-Bénard-Marangoni convection in a cylindrical container with a solid substrate base. This solid substrate is heated by a localized heat flux on its underside. The study is divided into two parts : The first part of the work consists of a physical modelling of the problem associated with numerical simulations. The Navier-Stokes and energy equations are solved by using a 3D finite volume method. A conjugate solid-liquid heat transfer is considered. Original morphology of cells (type and number) are observed, they are linked to the geometrical conditions, the dimensionless numbers which govern the physical problem (Prandtl, Rayleigh and Marangoni numbers and the ratio of solid substrate to liquid thermal conductivities). The heat transfers are also evaluated in each case. In the second part of the work, we present an experimental study of Rayleigh-Bénard-Marangoni convection in the same configuration as that studied numerically. Convective structures and their evolutions are studied from images recorded by infrared thermography. Different modes of organization of convective cells have been highlighted for this type of heating with imposed non-uniform heat flux
Saidi, Azouaou. "Etude du comportement thermique d'une paroi verticale dans l'air, soumise à une répartition non uniforme de flux de chaleur : couplage convection-conduction-rayonnement." Evry-Val d'Essonne, 1993. http://www.theses.fr/1993EVRY0003.
Full textEl, Ammouri Fouad. "Etude théorique des transferts couplés conductif, convectif et radiatif dans des écoulements gazeux hétérogènes et turbulents : mesure du flux conductif par déviation de faisceau laser." Châtenay-Malabry, Ecole centrale de Paris, 1993. http://www.theses.fr/1993ECAP0310.
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