Дисертації з теми "Échangeurs de chaleur – Simulation, Méthodes de"
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Averous, David. "Modélisation et simulation des échangeurs de chaleur multifluides à plaques brasées en configurations complexes." Toulouse, INPT, 2000. http://www.theses.fr/2000INPT004G.
Повний текст джерелаBarbouchi, Sami. "Pompe à chaleur haute température pour la réhabilitation des systèmes de chauffage dans le résidentiel." Paris, ENMP, 2007. http://www.theses.fr/2007ENMP1648.
Повний текст джерелаClimate change and the decrease in energy resources lead to seek for new solutions in order to improve energy efficiency and reduce emissions of greenhouse gases. In France, heating of buildings constitutes 22% of final energy consumption and 7% of CO2 emissions. The renewal of the installed base of buildings is slow (in the range of 1% per year). Thus the fast decrease (in the range of fifteen years) in CO2 emissions depends on the number of technical solutions adapted to the refurbishing market. Within this context, a high-energy efficiency heat pump has been developed. However, to take up the challenge, such a heat pump has to comply with various refurbishing constraints, especially in terms of temperature distribution. Its technical performances have to be high, for low outdoor air temperature (large temperature difference between the cold source and the hot sink) as well as moderate outdoor air temperature (lower temperature difference between the cold source and the hot sink). To comply with those technical requirements, a two-stage system allowing an easy switch to single stage configuration has been selected. Then the various components of the system have been designed with a specific attention to the sensitivity of the different design parameters on the global energy efficiency of the heat pump. The modelling of the components has allowed simulating the operation of the heat pump and to compare the results to tests results obtained on a prototype. Based on these test results, a computational tool has been developed for the simulation of single houses and their heating system, leading to the calculation of the HSPF (heating seasonal performance factor), and the study of the system behaviour. In order to improve seasonal performances, the gain of variable capacity through speed variation has been evaluated using a prototype and calculations of HSPF, showing its interest
Fan, Yilin. "Distribution des fluides et intensification des transferts thermiques dans un échangeur thermique par l'intégration des distributeurs constructals." Chambéry, 2008. http://www.theses.fr/2008CHAMS040.
Повний текст джерелаThis thesis contributes to the advances in the conception, fabrication, modeling, experiment, and optimization of multi-scale fluid distributors. The function of such fluid distributors is to deliver a controlled amount or rate of fluid to an array of distributing ports, in order for example to feed uniformly the channels of a multi-channel heat exchanger and consequently intensify the heat transfer with the least increase of pressure drop. Their multi-scale internal channel structures are optimized by minimizing the viscous dissipation and the residence time simultaneously according to the "constructal theory". Polymer and metallic prototypes of the constructal components were fabricated using Stereolithography. Constructal distributor prototypes were assembled with a mini crossflow heat- exchanger to evaluate the effects of flow distribution on its thermal and hydraulic performances by experiments and by Computational Fluid Dynamics (CFD) simulations. The enhancement of heat transfer realized by flow uniform distribution and the thermal- hydraulic balance are discussed. The results indicate that the integration of one constructal collector at the outlet of the heat exchanger can approach the uniform flow distribution and consequently better intensify the heat transfer. It is also the most advantageous configuration based on a balanced consideration of heat transfer intensification and pump power consumption under the investigation conditions. The results may provide some original information and thoughts to the design and optimization of heat exchangers and flow distribution/collection systems
Tang, Fu-Jiao. "Investigation numérique sur l'échangeur de chaleur installé dans des sols peu profonds." Thesis, Strasbourg, 2019. https://publication-theses.unistra.fr/public/theses_doctorat/2019/TANG_Fujiao_2019_ED269.pdf.
Повний текст джерелаShallow geothermal energy is an energy that can help humanity to reach the goal of sustainable development. Ground-Coupled Heat Pump system is traditionally used to benefit this energy. As a main element of the system, ground heat exchanger performance directly influences its energy efficiency. The shallow ground heat exchangers are normally installed in soils, which show high heterogeneity of hydrothermal properties along the soil profiles. The main objective of this project is identifying how ground heat exchanger behaves in the soil. In summary, the following investigations were conducted: the first is introducing hydrothermal transfer in the numerical modeling of Borehole Heat Exchanger installed at a site in Alsace region (France); the second is identifying the factors influencing the performance of a shallow Borehole Heat Exchanger installed in soils; the third is conducting sensitive analysis of Thermal Response Tests for Borehole Heat Exchanger installed in soils; the fourth is identifying the performance difference of a numerical simulation model with Neumann and Dirichlet boundaries on the ground surface for a Horizontal Ground Heat Exchanger
Sarraf, Kifah. "Echangeurs à plaques corruguées en mode monophasique et en condensation : études expérimentale, numérique et analytique, et analyse des écoulements et des transferts thermiques." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4760/document.
Повний текст джерелаThis research work examines at the global and local scales the thermo-hydraulic characteristics of plate heat exchangers with corrugated chevron plates, for single-phase and condensation flows. The study is divided into two parts:The first part concerns the analysis of flow structures of single-phase flows using numerical simulations, which are validated using the results of the experimental campaign. The analysis of the simulations results, from a flow characteristic observable that has been carefully chosen, has allowed quantifying the main flow categories as a function of the heat exchanger geometric parameters and the flow characteristics. This new information on the flow structures has led to the proposal of an original generalized model of the friction law inside this type of heat exchanger with complex geometry.The second part concerns the study of condensation with and without vapor superheating at the inlet of the heat exchanger. Thus, a specific experimental setup allowing precise control of the boundary conditions has been developed. Otherwise a specific metrology, based on infrared thermography, has been set to the point in order to determine the variation of certain local quantities along the condenser (vapor mass fraction, heat transfer coefficient...). Thus, we observe a high and wide variability of the heat transfer coefficients and the heat flux density along the condenser, and the superheating of the vapor tends to increase the heat transfers. These additional measures question certain assumptions of the literature regarding the development of heat transfer correlations in plate heat condensers
Aoun, Bernard. "Micro-cogénération pour les bâtiments résidentiels fonctionnant avec des énergies renouvelables." Phd thesis, École Nationale Supérieure des Mines de Paris, 2008. http://pastel.archives-ouvertes.fr/pastel-00005092.
Повний текст джерелаPingaud, Hervé. "Simulation statique et simulation dynamique des échangeurs à plaques brasées." Toulouse, INPT, 1988. http://www.theses.fr/1988INPT028G.
Повний текст джерелаWeber, Christophe. "Développement de méthodes d'analyse avancées de données expérimentales sur les phénomènes d'encrassement d'échangeurs thermiques en conditions réelles de fonctionnement." Thesis, Nantes, 2018. http://www.theses.fr/2018NANT4045.
Повний текст джерелаThe lack of dedicated tools, enabling at industrials to act effectively on the fouling phenomena in heat exchanger is the origin of this study. The purpose of the thesis is to develop a methodology in order to assess - in situ -at the characteristic parameters of the fouling effects, implement and then validate the data analysis methods to extract a fouling effects prediction tools from the knowledge of a limited number of operating data. This approach realized for different identified and instrumented thermohydraulic systems favors the fouling process in heat exchangers on charged water. We will focus on the phenomena of fouling of heat exchangers in a real environment, with emphasis on the development of methodologies to identify the fouling kinetic's and on the approach for validation of practical and concrete cases. Finally, application of a maintenance program by different cleaning strategies limiting the degradation of the efficiency of the facilities studied will be conducted: it will identify the most appropriate strategies. The purpose of the initiative, intended to run for any installation, is to develop an expert tool from reduced amount of information. This tool assesses to evaluate the kinetics of fouling of the thermal equipment for a future period and develop a maintenance practice from the perspective of reducing energy costs and costs of intervention
Thiers, Stéphane. "Bilans énergétiques et environnementaux de bâtiments à énergie positive." Phd thesis, École Nationale Supérieure des Mines de Paris, 2008. http://pastel.archives-ouvertes.fr/pastel-00004692.
Повний текст джерелаCazenave, Florian. "Modélisation et simulation de l’encrassement des échangeurs de chaleur pour eaux géothermales." Thesis, Pau, 2019. http://www.theses.fr/2019PAUU3013/document.
Повний текст джерелаIn the framework of the theme devoted to the energy transition, the “Laboratoire de Thermique Energétique et Procédés” (LaTEP) is working on deep geothermal energy. This thesis focuses on the study of the fouling phenomenon of surface heat exchangers and more specifically on the modelling and the simulation of the evolution of a deposit. Fouling leads to loss of efficiency and requires means of prevention and cleaning, leading to huge over-costs. The proposed general model describes heterogeneous reactions between two multi-component phases, one liquid and the other solid. The liquid phase is a solution containing ions diluted in a solvent, while the solid is composed of immobile constituents. Transport by electro-migration is taken into account in the description. At the interface between the two phases, multiple heterogeneous reactions occur. The boundary conditions involves the interface’s velocity and allow a complete coupling between the two domains. This general model is then applied to the particular case of fouling of a pipe by salt formation and is solved using Comsol Multiphysics. Simulation of a simplified case of fouling from barium sulfate allowed an analysis of the phenomenology of the deposit growth. It highlights the effects of changes in solubility and kinetics caused by the temperature drop in the tube, as well as the effect of radial mobility of the species by diffusion, limiting the growth. Electro-migration contributes significantly to transport but does not influence the thickness of the deposit. The hypothesis of an instantly balanced barite crystallization reaction leads to an overestimation of the fouling. In a second time, more species are added to the water’s composition in order to study the influence of the presence of sodium chloride at 1 mol.L-1. Finally, the addition of strontium ions leads to co-precipitation of barite and celestine
El, Abbadi Abdelilah. "Développement de méthodes de mesure des transferts convectifs par thermographie infrarouge : application aux ailettes d'échangeurs à hautes performances." Valenciennes, 2006. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/1e108508-defe-4dbb-bc55-cf5ec4fdea4f.
Повний текст джерелаThe study presented in this memory concern the measurement and the improvement of the convective heat transfer in finned tubes heat exchangers. For the measurement of convective heat transfer coefficient, two techniques are developed: A transient method that calculate local heat transfer coefficient on the surface of slightly heat conducting fins at constant temperature. And an inverse method with a second-order regularization to calculate this coefficient on fins by taking account of side conduction in these last one. The two methods require the use of temperature fields that we measure using an infrared thermography system. These techniques were then applied to the characterization of the fins of heat exchanger. They also allowed the study of high efficiency thermal fins. The increase of heat transfer on the surface of the latter ones is obtained by the addition of vortex generators
Laurent, Mathieu. "Modélisation thermomécanique et analyse de la durabilité d'échangeurs thermiques à plaques soudées." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00961182.
Повний текст джерелаJacquot, Cédric. "Transfert instationnaire de chaleur en échangeur récupérateur de moteur de fusée : simulation expérimentale en échangeur bitube." Nancy 1, 2007. http://docnum.univ-lorraine.fr/public/SCD_T_2007_0010_JACQUOT.pdf.
Повний текст джерелаThe present thesis is concerned by experimental study of gas-gas bitubular heat exchangers, submitted to transient conditions, for counter current and cocurrent configurations. The transient imposes conditions are respective to entrance temperature or mass flux from one of the system fluids. After a synthesis of the state of the art, a study of a bitubular heat exchanger is developed, with two different modelling approachs. The first one considers the heat exchanger system as a whole (lumped system analysis) : only entrance and exit state are concerned. In the second approach, the heat exchanger is modelled on a local point of view : the various local 1D sections are taken into account ; the transient heat exchanger response to the solicitation is reported relative to temperatures evolution, and also heat fluxes exchanged. The various exposed models allow to consider fluid temperatures, but also internal and external walls temperatures. It is shown that the temperature response of the system is obtained with a first order exponential model for the walls and the non perturbed fluid ; a two exponent model is necessary for the temperature of the perturbed fluid. So we observe that a specific time constant exist for each subsystem inside the HEX ; the biexponential model allows us to take account of the non ideality of the perturbation, and implies to introduce a transition parameter in place of time lag. This last notion currently used for liquid-liquid HEX has not been caracterized until now. The time lag does not appear in the models concerning perturbed fluid, and internal wall ; however this time lag is necessary to describe adequately the internal wall
Hoyon, Guy. "Etude thermodynamique de l'encrassement des échangeurs de chaleur : application à la géométrie plane : simulation expérimentale par dépôt de glace." Nancy 1, 1997. http://docnum.univ-lorraine.fr/public/SCD_T_1997_0292_HOYON.pdf.
Повний текст джерелаThis report is a study of plate heat exchangers fouling. This problem is dealt with a new point of view, the entropic criterion, which allows to take into account both the mechanical and therrmal energy losses. Different models are developped: mono-dimensionnal model for the half-exchanger and the whole exchanger. A global model for the whole exchanger (exchanger taken as a "black box") is also applied. These models are used with different kinds of parameters (temperatures, regimes and kinds. Of flow) and adimensionnements (compared with the initial power or compared with non fouling initial state) for the basic geometry of a plate exchanger. Moreover the study of industrial cases for corrugated plates heat exchangers is done for the global model. The experimental aspect of this work is an ice deposit simulation. The different devices used for this part are detailed. The analysis of the first results allowed to understand the influence of parameters like temperatures and flows, in the ice formation growth. These results agreed with the models described above, for the range of the experiments done
Russeil, Serge. "Expérimentation et modélisation des transferts de chaleur et de masse dans un canal bidimensionnel : Application aux géométries complexes des échangeurs de chaleur." Valenciennes, 1997. https://ged.uphf.fr/nuxeo/site/esupversions/045d17fe-3635-42b9-82b0-d1f122d8226d.
Повний текст джерелаDubot, Claire. "Modélisation CFD thermohydraulique des générateurs de vapeur et application de techniques de réduction de modèle." Electronic Thesis or Diss., La Rochelle, 2022. http://www.theses.fr/2022LAROS029.
Повний текст джерелаNAVAL GROUP has been carrying out a R&D approach for the modeling and simulation of heat exchangers. This led to the thermal-hydraulic calculation code SIMEC-CFD based on the analogy between the tube bundle and a porous medium. In this work, the steam generator is studied. It is proposed here to use the mixture model where the drift velocity is reformulated as a function of slip in order to implement a model from the literature suitable to flows in tube bundles. SIMEC-CFD is defined mainly by correlations or empirical models. To compensate for the lack of data in the literature, this thesis evaluates the use of model reduction techniques based on POD (Proper Orthogonal Decomposition) in order to supply more precise elements to SIMEC-CFD. These are thus used to calculate the flow and for the inside-tube heat exchange coefficient by a intrusive reduced order model obtained by Galerkin projection on the POD basis and to define the outside-tube two-phase friction pressure loss by the interpolation of reduced solutions Bi-CITSGM. Finally, in the near future, the aim is to expand the system simulation of the secondary loop using SIMEC-CFD. However, these CFD simulations being costly in computation time and in resources, the non-intrusive model reduction by interpolation of the parametric coefficients of the whole heat exchanger is implemented
Quenum, Alphonse Codjo. "Étude de l'encrassement des échangeurs de chaleur en géométrie plane modélisation et simulation expérimentale par dépôt de glace." Vandoeuvre-les-Nancy, INPL, 1998. http://www.theses.fr/1998INPL139N.
Повний текст джерелаMathieu, Myriam. "Caractérisation expérimentale et analyse de fonctionnement d'un échangeur cyclone original." Nancy 1, 1994. http://www.theses.fr/1994NAN10430.
Повний текст джерелаSmaili, Farida. "Contribution de la simulation dynamique à la conception optimale des réseaux d'échangeurs de chaleur : application à un procédé industriel." Châtenay-Malabry, Ecole centrale de Paris, 1997. http://www.theses.fr/1997ECAP0657.
Повний текст джерелаEcrabey, Kraidy Jacques. "Contribution à la simulation électrothermique des circuits intégrés analogiques." Ecully, Ecole centrale de Lyon, 1996. http://www.theses.fr/1996ECDL0037.
Повний текст джерелаTabloul, Samir. "Accroissement du transfert convectif dans une couche limite turbulente perturbée par un obstacle décollé de la paroi." Valenciennes, 2006. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/1ede393d-918c-4d45-b28f-8d5f5e156ad0.
Повний текст джерелаThis dissertation deals with convective heat transfer in a turbulent boundary layer disturbed by a detached obstacle. A previous study devoted to the experimental measurement (velocity field and wall heat transfer) highlighted the periodic characteristic of this flow dynamics. While, two-dimensional simulations carried on, by RANS/URANS models, resulted in an unsatisfactory thermal field. In this context, the objective of the present study consisted in a complementary experimental investigation and a better modeling of the physical phenomena. First of all, a revised examination of the bibliographical work showed a close similarity between the phenomena encountered in our configuration (inclined rectangular rod) and other geometries (cylindrical or rectangular obstacle). Furthermore, temperature measurement, by a thermocouple, has confirmed the hypotheses of the first study. Secondly, two equation turbulence models was applied on a refined grid. In the case of the SST k-w model, encouraging results of heat transfer are obtained, without, however, improving the flow field. Moreover, a large eddy simulation (LES) has been conducted in this configuration. The main difficulty, in our case (high Reynolds number), is on the compromise between computational cells number and the capture of the unsteady phenomena. At this point, a multiblock strategy has made it possible to obtain a better flow field and to identify the heat transfer mechanism involved in this flow dynamics
Trinh, Quoc Van. "Contribution à la simulation numérique de transferts de masse et de chaleur : Application aux ouvrages de stockage des déchets radioactifs." Rennes, INSA, 2006. http://www.theses.fr/2006ISAR0007.
Повний текст джерелаThe work of thesis presented in this memory relates to the numerical simulation of the transfers of water heat and mass in bentonite compact and unsaturated. It falls under the general context of the feasibility study of storage of radioactive waste of high activity and with long life in profound geological formation. The analysis of the test of the ECA made up of partially saturated a bentonite column subjected to a heat gradient (THM 1G), shows that there is a transfer of water of the hot part towards the cold part for temperatures quite lower than 100°C. In addition, the numerical simulations of such a test with the dominant mechanisms (Darcy, Fick and Fourier) cannot to represent this mass transfer under the effect of the only heat gradient. A new mechanism of thermo-osmotic transfer object of this thesis is proposed and quantified in this work. The quantification of the transfer of thermo-osmosis, was carried out starting from test THM1G by back analysis. In fact it is necessary of déconvoluer the hydrous profiles resulting from different times of application of the heat gradient since they result from two antagonistic coupled mechanisms: one relating to the transfer under the heat gradient and the other under the effect of the hydraulic gradient. The first stage of the validation was carried out by the confrontation of the numerical simulations with the experimental results of the test on column THM2G submitted to two opposed gradients, one thermal and other hydraulic. Finally, the confrontation of the models of transfer of mass and heat with the experimental results of an in situ work test TBT (Temperature Buffer Test) installed in the underground laboratory to Aspö in Sweden, is present in this work. The comparison of the whole of these modelling compared to the experimental results shows that only the model using the transfer of thermo-osmosis gives satisfactory results
Introïni, Clément. "Interaction entre un fluide à haute température et un béton : contribution à la modélisation des échanges de masse et de chaleur." Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0074/document.
Повний текст джерелаIn the late phases of some scenario of hypothetical severe accident in Pressurized Water Reactors, a molten mixture of core and vessel structures, called corium, comes to interact with the concrete basemat. The safety numerical tools are lumped parameter codes. They are based on a large averaged description of heat and mass transfers which raises some uncertainties about the multi-scale description of the exchanges but also about the adopted boundary layer structure in the vicinity of the ablation front. In this context, the aim of this work is to tackle the problem of the boundary layer structure by means of direct numerical simulation. This work joins within the more general framework of a multi-scale description and a multi-scale modeling, namely from the local scale associated with the vicinity of the ablation front to the scale associated with the lumped parameter codes. Such a multi-scale description raises not only the problem of the local description of the multiphase multicomponent flow but also the problem of the upscaling between the local- and the macro-scale which is associated with the convective structures within the pool of corium. Here, we are particularly interested in the building of effective boundary conditions or wall laws for macro-scale models. The difficulty of the multiphase multicomponent problem at the local scale leads us to consider a relatively simplified problem. Effective boundary conditions are built in the frame of a domain decomposition method and numerical experiments are performed for a natural convection problem in a stamp shaped cavity to assess the validity of the proposed wall laws. Even if the treated problem is still far from the target applications, this contribution can be viewed as a first step of a multi-scale modeling of the exchanges for the molten core concrete issue. In the more complicated case of multiphase multicomponent flows, it is necessary to have a direct numerical simulation tool of the flow at the local scale to build wall laws for macro-scale models. Here, the developed tool corresponds to a Cahn-Hilliard/Navier-Stokes model for a two-phase compositional system. It relies on a description of the system by three volume fractions and on a free energy composed by a two-phase part and a compositional part. The governing equations are derived in the frame of the thermodynamic of irreversible processes. They are solved on the basis of a finite element application of the object-oriented software component library PELICANS. Several numerical experiments illustrate the validity and the potentialities of application of this tool on two-phase compositional problems. Finally, using the developed tool, we tackle by means of direct numerical simulation the problem boundary layer structure in the vicinity of the ablation front for limestone-sand and siliceous concretes
Bigoin, Gaëtan. "Etude expérimentale et numérique de l'encrassement particulaire des échangeurs de chaleur à plaques en phase liquide : influence de la vitesse d'écoulement." Grenoble INPG, 2000. http://www.theses.fr/2000INPG0115.
Повний текст джерелаMichallon, Emmanuelle. "Étude du comportement de l'écoulement dans des canaux de section rectangulaire constitués de plaques et d'ailettes brasées." Nancy 1, 1993. http://www.theses.fr/1993NAN10351.
Повний текст джерелаBenabdallah, Moulay. "Simulation lagrangienne du transfert de chaleur dans un écoulement gaz-solide en conduite." Nancy 1, 1995. http://www.theses.fr/1995NAN10329.
Повний текст джерелаAssaf, Khattar. "Intégration d'une pompe à chaleur dans un procédé agroalimentaire : simulation, expérimentation et intégration." Phd thesis, École Nationale Supérieure des Mines de Paris, 2010. http://pastel.archives-ouvertes.fr/pastel-00573010.
Повний текст джерелаHugo, Jean-michel. "Transferts dans les milieux cellulaires à forte porosité : applications à l'optimisation structurale des échangeurs à ailettes." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4767/document.
Повний текст джерелаThis work is composed of two parts: the first one deals with the design of fins-and-tubes and metal foam heat exchangers; the second one deals with the relationship between foams morphology and their effective thermophysical properties. The first part is dedicated to Mota heat exchanger performance enhancement. We develop a multi-scale method to optimize both local heat transfer surfaces and global architecture of classical and foam units. We develop, using this method, new heat exchanger and we characterize it numerically and experimentally. An increase of 50% of energetic efficiency is obtained and new geometries are nowadays produced and commercialized. The second part deals with the analysis of transport phenomena in metal foams and the determination of their effectives properties. We develop an approach based on pore scale numerical simulation of conjugate heat transfer – validated by experimental results obtained on set-up developed for this study. We have generated 900 virtual samples obtained by deformation a periodic unit cell (Kelvin cell). Full effective properties tensors are determined. The influence of cell shape and classical geometrical parameters on physical properties is then studied. To conclude, in the last chapter, we present natural perspectives involved by this work: Geometrical optimization of heat exchanger architecture and foams morphology depending on the application; The use of a multi-scale approach to design modern –foam- heat exchangers
Farsane, Khaddouj. "Etude du refroidissement par convection forcée externe d'un moteur électrique." Besançon, 1996. http://www.theses.fr/1996BESA2008.
Повний текст джерелаThis work concerns the study of the cooling by external forced convection of electric motors with closed configuration. This study is first carried out experimentaly by associatingthree complementary investigation methods : flow visualization by laser sheet, measurement of velocity distribution by Laser Doppler Velocimetry and determinationn of wall temperature fields by infrared thermography. The results obtained on an already commercialized motor display important over heating of several zones at the motor surface. These results have lead to the design of a new configuration of carter, materialized by th design of two prototype motors. The diagnosis of these two motors show a significant improvement of the carter irrigation, and consequently an appreciable decrease of surface temperatures. Furthermore, data obtained from these tests are used to determine heat transfer coefficients by convection at the carter surface. The sizing of the fins forming the external exchange surface is then possible. A sizing procedure is proposed for the determination of the optimum values of the height and the base thichness of the fin, defined by the minimum volume for a given heat flux. Optimum values lead to an appreciable gain on the total mass of the fins. Parallel to this experimental study, a numerical tool has been developped for furter modelling of the cooling by forced convection between the fins of the carter. This required the adaptation of a numerical code (Flux-Expert finite element code) to the convection heat transfer simulation. The study is carried out for steady state conditions, by coupling between the aerodynamic and thermal phenomena. The flow is assumed to be two dimensional and incompressible. The turbulence of the flow is considererd by a recent k-e model (Abe at al. 1994). The equations programmed in Flux-Expert are validated for several flow test configurations, in laminar and turbulent conditions
Saad, Selma Ben. "Étude expérimentale et numérique des écoulements diphasiques et du diagnostic des échangeurs industriels à plaques et ondes." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0406/document.
Повний текст джерелаThis work deals with experimental and numerical studies of single and two-phase flow distribution in a plate and fin heat exchanger. Flow rates and pressure measurements, as well as visualization using speed camera have been used to characterize the air/water flow at atmospheric pressure and at adiabatic conditions. CFD simulations have permitted to calculate pressure drop in single phase flow of offset strip fins and to simulate two phase flow patterns (bubbles, slug, toric bubbles,...) in the distributor. Tracer experiments using salt and conductimetry allowed to characterize single and two phase flow distribution and to perform a diagnosis of the heat exchanger: find the defaults, their amplitudes and their localizations. All these methods: experimental data, CFD simulations and tracer methodology allowed to point out the important parameters affecting the distribution like same or opposed inlet fluid alimentations, physical properties, distributor design and the flow patterns, to improve overall performances of heat transfer systems
Debenest, Gérald. "Simulation numérique tridimensionnelle, à la microéchelle, de la combustion en lit fixe de schistes bitumineux." Poitiers, 2003. http://www.theses.fr/2003POIT2308.
Повний текст джерелаThis study, theorical and numerical, deals with the reaction front propagation phenomena in real porous media containing a small amount of organic compound. In order to do this, we choose to use a microscopic point of view to take into account all mechanisms involved. So, a three-dimensional numerical code has been developed. Direct simulations were made to characterize the various regimes we can encounter, to give a whole set of local thermochemical conditions, and finally to manage parametric studies, where physical properties and composition of the media were changed. Finally, the last part of this study is devoted to the discussion of the results obtained and to the comparison of the two approaches, namely macro- and microscopic. This last part allows to discuss the validity of the homogenized description and to provide criterion for its application. We finish with an estimate of the coefficients involved in the upsacled description
Mansur, Sergio Said. "Amélioration des échangeurs thermiques tubulaires par l'utilisation d'inserts hélicoïdaux à l'extérieur des tubes." Grenoble 1, 1993. http://www.theses.fr/1993GRE10192.
Повний текст джерелаRishmany, Jihad. "Comportement statique et dynamique d'une structure périodique 3d d'un échangeur aéronautique : étude expérimentale, modélisation et simulations numériques." Toulouse 3, 2007. http://www.theses.fr/2007TOU30032.
Повний текст джерелаAeronautical heat exchangers are subjected to a complex environment combining pressure, temperature and vibrations. The objective of this thesis is the analysis of the static and dynamic behavior of the core of an exchanger. The core is a 3D-periodic complex structure composed of an alternate stacking of fins where passes the hot and cold air respectively. Various analytical and numerical approaches based on the study of a basic cell of the structure are employed to model the global static behavior of the core at 20 and 350°C. Static results are validated by experimental tests on various types of specimens. At the end of this part, two models are proposed to replace the real structure of the core : a «homogeneous» model and a «laminated» model. The dynamic study, experimental and numerical, shows that these two models are capable of predicting satisfactorily the dynamic behavior of the core
Dabboura, Eyad. "Contribution à la simulation numérique de problèmes de transferts de chaleur par une méthode de type Meshless : application à la convection thermomagnétique." Poitiers, 2009. http://www.theses.fr/2009POIT2322.
Повний текст джерелаThe numerical simulation of transfer problems defined in complex geometries is usually made by finite element methods or by Meshless methods which developed since the last ten years. This paper presents a contribution to the development of this method using the collocation of the approximation to weighted least squares. Two, three and four orders of the approximation are considered and the results obtained are compared with examples of diffusion and transport-diffusion. The flexibility of discretizations by points is also discussed. We show that the methe method may be suitable for treating problems in fractal geometry and boundary mobile. The method is then applied to solving the convection problems. We propose in three dimensional the formulation in velocity-vorticity. The method is valitaded by comparison with solutions of reference and the results of the natural convection in cavities of some complex shapes are presented and discussed. The second part of this thesis is the application of the method and developed it to study the thermomagnetic convection. The flows of convection in a paramagnetic fluid (like air) with using an external magnetic field are studied with and without gravity. The results of the influence of the magnetic field in case of non-conducting paramagnetic fluid are explained by the generating of Kelvin's forces, whose intensity varies with temperature because the dependence of the magnetic susceptibility to the temperature by law Curie-Weiss. With gravity, we show that a judicious arrangement of magnets or coils can accelerate or slow the flow of natural convection. Without gravity, it shows that the forces of Kelvin can generate magnetoconvection
Oter-Duthoit, Liliane. "Application des méthodes de la théorie des systèmes à la simulation de l'évolution des flux thermiques sur les faces d'entrée et de sortie d'une paroi multicouche." Lille 1, 1985. http://www.theses.fr/1985LIL10062.
Повний текст джерелаSoupart-Caron, Adèle. "Stockage de chaleur dans les matériaux à changement de phase." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI078/document.
Повний текст джерелаThis PhD thesis deals with the understanding of the heat transfer mechanisms and with the development of thermal energy storage system for the industrial waste heat recovery application. The use of Phase Change Materials (PCM) is attractive for its high storage density and its possibility to deliver heat at constant temperature. However, the PCM low thermal conductivity leads to develop heat transfer improvement methods, such as heat exchangers with increased heat transfer surface. The goal is to characterize the behavior of such heat exchangers An experimental study, where four several heat exchangers have been tested with different orientations (horizontal/vertical) and injection types (upward/downward), highlighted the impact of natural convection during the melting process and the volume contraction one during the solidification. These results have been validated through a 3D numerical model. A performance comparison method based on an energy calculation through an experimental mesh is proposed and enables to select a heat exchanger on criteria such as the storage density, the characteristic time and the cost. Three PCM, adapted to our application, have been tested at the intended temperature (100-200 °C) by integrating them into a storage system made of a stainless steel tube with aluminum circular fins. Their ability to resist to repeated cycles has been assessed and their behavior has been compared. The salts mixture, H105 (Tmelting = 122 °C), is not selected for the application because of it low storage density (≈ 56 kWh/m3) and its large melting area. The sebacic acid (Tmelting = 132 °C) has a repeatable behavior with cycles and a higher storage density (≈ 66 kWh/m3) and is appropriate as storage material. The sugar alcohol, erythritol (Tmelting = 118 °C), has good thermo-physical properties (128 kWh/m3) but the crystallization control is a key point to use it as a PCM
Hoang, Thanh Tung. "Récupération et valorisation d'énergie thermique sur gaz chauds- Approche expérimentale et numérique." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2018. http://www.theses.fr/2018ESMA0016/document.
Повний текст джерелаThe aim of the thesis is to analyze the heat recovery on hot gases at intermediate temperature range (250°C - 450°C). For this purpose, the thermosyphon heat exchanger recuperation technology has been chosen. The choice of a working fluid adapted to these temperature levels is one of the crucial points. A literature review identified naphthalene as a potentialfluid for this temperature range. However, because of the lack of information about naphthalene heat pipes, the development of a fundamental test-rig was necessary to fully characterize the thermal behavior and transport capacities of this fluid.A thermosyphon heat-pipe charged with naphthalene in the shape of a smooth stainless steel tube with a diameter of 23.9mm, a length of 1 m (evaporator zone: 20 cm, condenser zone: 20 cm) has been manufactured and tested. The experimental results obtained demonstrate the feasibility of such system in this temperature range and for the thermal powers required.They reveal an unusual behavior of the thermosyphon during the start-up process. In steady state, the analysis deals with the influence of the saturation temperatures, the transferred heat power and the thermosyphon inclination. In terms of performances, the thermal conductance (evaporator, condenser, system) increases with the vapor temperature and decreases with the heat power supplied to the evaporator. The heat flow rate can be applied from 0.2 to 1.5 kW, or 1 to 8W/cm² at the evaporator. During the tests, the system is found to be less sensitive to inclination (0° to 78°), but more important for 84°. In the horizontal position, the thermosyphon operates, but its heat transfer remains high even far away from the thermosyphon mode. A theoretical model has been developed in which the local heat transfer coefficients(evaporator and condenser) are evaluated by different correlations from literature. The comparison with the experimental results allowed to validate the models retained with good agreement, and to make it possible to predict the heat pipe operation for other solicitations.Thus, and finally, a first thermosyphon charged naphthalene recuperator prototype was designed, manufactured and coupled to the "hot gas" line designed and performed in the laboratory. The first results obtained from the complete system allowed us to develop a strategy for heat recovery system on the exhaust line of an automotive application
Carlier, Julien. "Schémas aux résidus distribués et méthodes à propagation des ondes pour la simulation d’écoulements compressibles diphasiques avec transfert de chaleur et de masse." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLY008/document.
Повний текст джерелаThe topic of this thesis is the numerical simulation of two-phase flows in an industrial framework. Two-phase flows modelling is a challenging domain to explore, mainly because of the complex phenomena involved, such as cavitation and other transfer processes between phases. Furthermore, these flows occur generally in complex geometries, which makes difficult the development of efficient resolution methods. The models that we consider belong to the class of diffuse interface models, and they allow an easy modelling of transfers between phases. The considered class of models includes a hierarchy of sub-models, which take into account different levels of interactions between phases. To pursue our studies, first we have compared the so-called four-equation and six-equation two-phase flow models, including the effects of mass transfer processes. We have then chosen to focus on the four-equation model. One of the main objective of our work has been to extend residual distribution schemes to this model. In the context of numerical solution methods, it is common to use the conservative form of the balance law. In fact, the solution of the equations under a non-conservative form may lead to a wrong solution to the problem. Nonetheless, solving the equations in non-conservative form may be more interesting from an industrial point of view. To this aim, we employ a recent approach, which allows us to ensure conservation while solving a non-conservative system, at the condition of knowing its conservative form. We then validate our method and apply it to problems with complex geometry. Finally, the last part of our work is dedicated to the evaluation of the validity of the considered diffuse interface model for applications to real industrial problems. By using uncertainty quantification methods, the objective is to get parameters that make our simulations the most plausible, and to target the possible extensions that can make our simulations more realistic
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.
Повний текст джерелаThe 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
Louleh, Ziad. "Modélisation et conduite des réacteurs discontinus par analyse des flux thermiques." Toulouse, INPT, 1996. http://www.theses.fr/1996INPT037G.
Повний текст джерелаSadouk, Hamza Chérif. "Modélisation de l'encrassement en régime turbulent dans un échangeur de chaleur à plaques avec un revêtement fibreux sur les parois." Phd thesis, Université Paris-Est, 2009. http://tel.archives-ouvertes.fr/tel-00499251.
Повний текст джерелаVo, Minh Toàn. "Assessment of heat pump operating faults coupled with building energy simulation using Petri net model." Thesis, La Rochelle, 2021. https://tel.archives-ouvertes.fr/tel-03685404.
Повний текст джерелаHeat pumps give an efficient and sustainable solution for both heating and cooling. However, these systems sometimes operate with a lower efficiency, because of the faults. In this research, we focus on three operating faults : refrigerant leakage, condenser fouling, and evaporator fouling. They are the most frequent and most impacted operating faults. They evolve undetectably over time until they start to create the energy and comfort problems. We propose to develop a method to model these operating faults and to associate them with a building simulation model. In the first place, we developed physical models of an air-to-air residential heat pump in order to predict the coefficient of performance (COP/EER) of the heat pump, as a function of the use intensity, and operating fault. Then, a Petri net model was proposed to determine a priori structure of fault evolution. In the second step, we apply a notion of uncertainty of fault database to take into account different working cases and generalize the fault occurrence model. We associated it with the dynamic energy simulation tool COMETh, a building simulation model developed by CSTB, to simulate the annual energy consumption. This method helps us to analyze and determine the global uncertainty of fault impacts on the heat pump performance and on the whole energy consumption of the building. The method was applied to a case study of residential building in Paris over 15 years. With three heat pump operating faults, the building consumption remarkably increased from the third year. At the 15th year, the building consumption is double than the standard value. The results underline the possibility of the proposed methodology
Maunay, Matthieu. "Echangeur de chaleur obtenu par soudage-diffusion : simulation des déformées et prédiction de la tenue mécanique des interfaces." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI038.
Повний текст джерелаA new concept of compact plate heat exchanger is developed for the energy conversion system performances of the ASTRID reactor. Manufacturing the complex geometry is possible by a diffusion-welding process: engraved 316L stainless steel plates are stacked and bonded during a Hot Isostatic Pressing cycle (HIP). The problematic is to get strong interfaces without deforming the channels which is harmful for the exchanger efficiency. To reach a good compromise, this thesis work will help to optimize the HIP parameters (pressure/temperature/ time).The first line of work is about the simulation of the heat exchanger deformation along manufacturing process. The influence of numerical parameters (elements size, convergence criterion) was studied to optimize the accuracy and the calculation time. Simulations have shown the importance of structure stack faults (sliding and plate ripples) in the increase of exchanger deformation. Then, a mechanical characterisation of plates was carried out to identify the constitutive equation between 20°C and 1040°C.The second line is about the interface modelling along welding and the prediction of their mechanical strength, as a whole can lead to the definition of an interface acceptability criterion. A microstructural and mechanical study has enabled to correlate the mechanical strength of a diffusion-bonded junction and its bonded area. Indeed, residual porosity disappearance is the main criterion to get good interfaces mechanical strength. However, the grain boundary migration is required to reach the rolled material properties. A void closure analytical model (Hill and Wallach) was used to estimate the bonded area of an interface according to HIP cycle parameters by modelling the contribution of (visco)plastic and diffusion (surface and boundary) mechanisms. Associated with the correlation between mechanical strength and the fraction of bonded area, it enables to propose a predictive tool for the mechanical strength of diffusion-bonded interfaces
Abushammala, Omran. "Optimal Helical Tube Design for Intensified Heat / Mass Exchangers." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0091.
Повний текст джерелаThe search for technological solutions aimed at minimizing the size of a device, known as intensification, is a classic objective of process engineering. In this thesis, the intensification possibilities offered by helical tubes are studied, both for heat and mass exchangers. The use of helical tubes instead of straight tubes is indeed of interest both in terms of increasing the exchange surface per unit volume between the two fluids circulating in the exchanger and by the possibility of increasing the transfers by generating Dean vortices in the tubes. A set of CFD (Computational Fluid Dynamics) type simulations was carried out and compared with experimental results. In the end, on the basis of a systematic approach using correlations, a volume reduction of a factor of 8 was obtained, both for heat exchangers and for membrane contactors
Jarrier, Laurent. "Comportement thermique transitoire après un démarrage à froid des moteurs à combustion interne : étude expérimentale et simulation." Versailles-St Quentin en Yvelines, 1999. http://www.theses.fr/1999VERS0025.
Повний текст джерелаZhu, Feng. "Experimental and numerical study of metal foam composites in innovative application of thermal energy storage." Thesis, Troyes, 2017. http://www.theses.fr/2017TROY0009/document.
Повний текст джерелаThe objective of this Ph.D. thesis is to study the thermal behavior of the aluminum foam and phase change material (PCM) composite by both experimental and numerical methods in order to know the phenomena of storage of thermal energy in these materials. The manufacturing process of open-cell aluminum foam is firstly analyzed numerically to reduce the manufacturing defects in the samples. The heat transfer characteristics of PCM embedded in aluminum foams with different porosities are then investigated by analyzing the melting processes and the temperature variations in the composites. Two numerical models for low and high porosity aluminum foam are established to evaluate the energy storage performance of the composites. The results show that the aluminum foam can greatly improve the heat transfer performance in PCM due to its high thermal conductivity. The energy storage performance depends strongly on the porosity of the aluminum foam/PCM composite. An optimized porosity highlights this performance and improves the thermal behavior. The last part of this thesis proposes an improved structure of aluminum foam with respect to the uniform structure: Association of the metal fin and the foam with graded porosity. This new structure possesses a better energy storage performance especially in the case of the isothermal heat source
Azos, Diaz Karina. "Étude multi-échelle des transferts de chaleur et de masse appliquée à un bâtiment parisien rénové, en condition météorologique normale et en période de vague de chaleur." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066108/document.
Повний текст джерелаIn Paris 44% of the dwellings were built before 1914 with uninsulated thick walls made of porous materials, characterized by high thermal inertia and hygroscopic properties. The hygrothermal properties of existing buildings materials have effects that: (i) give (to these buildings) good thermal qualities in summer and (ii) help to regulate indoor temperature and relative humidity. In France the energy saving policies and thermal regulation have resulted in the implementation of thermal regulation to reduce energy consumption during winter. Though the installation of thermal insulation in existing buildings poses a number of difficulties. Moreover, it is expected that extreme heat conditions become more frequent in future climate scenarios. Thus, the possible evolutions of future climate must be integrated into the evaluation of renovation strategies in old buildings. This thesis focuses on the assessment of the hygrothermal behavior of old renovated Parisian buildings, in current and heat wave weather. At the building scale (housing), a model was built in dynamic thermal simulation tool. The model was calibrated and validated through recorded data from a measurement campaign launched in 2014 on the studied housings. At the wall scale, a macroscopic model in 2D is proposed to study the heat and mass transfer through a multilayered porous wall, renovated with internal thermal insulation and external thermal insulation
Nabhani, Messaoud. "Application d'un modèle de transfert de masse et de chaleur au séchage à haute température : détermination expérimentale des paramètres du modèle et sa validation." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24701/24701.pdf.
Повний текст джерелаSarthou, Arthur Jean. "Méthodes de domaines fictifs d'ordre élevé pour les équations elliptiques et de Navier-Stokes : application au couplage fluide-structure." Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13867/document.
Повний текст джерелаAbstract
Nugue, Frédéric. "Recherche d'une méthode rapide de détermination du coefficient de diffusion en milieu cimentaire saturé." Toulouse, INSA, 2002. http://www.theses.fr/2002ISAT0019.
Повний текст джерелаThe aim of our study consist in developing quick methods of diffusion coefficient determination in saturated cement based materials. Analytical and experimental studies of the HTO molecular diffusion have been conducted. Three ways were studied : the unsteady state in upstream or downstream compartment, the simultaneous exploitation of upstream and downstream compartments and preliminary doping of samples. Experimental and numerical studies by Ms-Diff code of chloride ionic diffusion allowed us to re-examine the influence of electrical interactions during the unsteady state regime. A new method of physico-chemical interactions determination on massive sample and a substantial reduction of time consuming have been found. Chloride migration tests allowed us to study the influence of experimental conditions. The experimental results were in good agreement with modelling by Ms-Diff. The multi-species approach has been validated