Дисертації з теми "Thermo-Rhéologie"
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Boudet, Chantal. "Systèmes mixtes gélatine/polymère thermo-sensible : contrôle de la gélification chimique et propriétés des films." Paris 6, 2005. http://www.theses.fr/2005PA066018.
Bailly, Laurence. "Etude du comportement de deux grades cyanates esters pour des applications structurales en matériaux composites en environnement tiède." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0064.
Composite materials made of cyanate ester resins and in particular phenolic triazine resins such as PT15 and PT30 are selected to replace structural metal parts in aircraft at operating temperatures between 200 and 300°C. The main advantages of these resins are their high glass transition temperature, above 300°C, and their low viscosity at 80°C make them suitable for Resin Transfert Molding (RTM) process. The main goals of this work are to understand the resins’ behavior during crosslinking and then to study their durability through thermo-oxidative aging at operating temperatures. Physico-chemical characterizations of PT15 and PT30 resins at their initial state showed a similar chemical composition and spatial configuration but a different molar mass distribution. Triazine rings have only been detected in PT30 only, indicating a “pre-cured” state. These differences have consequences on the crosslinking kinetics and promote an autocatalytic mechanism for PT30. After cure optimization, PT15 has a glass transition temperature 70°C lower than the one of PT30. Among different analysis techniques, the rheological study during crosslinking provided an understanding of the networks’ structuration dissimilarities between the two grades, highlighting the formation of an intermediate structure which relaxes at lower temperatures in PT15. This different networks’ organization is the key element to understand dissimilar thermal stabilities analyzed during thermo-oxidative aging
Heinrich, Alban. "Modélisation thermomécanique de la coulée continue d'acier en 2 dimensions." Paris, ENMP, 2003. https://pastel.archives-ouvertes.fr/pastel-00001342.
In this work, we introduce a thermo-mechanical model of the steel continuous casting process, in two dimensions. With our approach, it is possible to obtain thermo-mechanical steady-state solution of the process, for the whole product. The thermo-mechanical history of the product can thus be deduced, by viewing the stress and temperature fields, for instance. One of the expected results deals with the bulging between rolls, which is known to give birth to segregation phenomena. We base our study on the global non steady-state strategy using a Lagrangian approach. The flow of matter in the studied domain is simulated through one injection tool located in the upper face of the domain. The lower face is supposed to be driven down at the starting block velocity. Thus the matter is led throughout the CC machine. Concerning the model, non-steady thermo-mechanical conservation equations are solved. The thermal problem is for the enthalpy variable. The approach to the mechanical problem is of monophasic type (velocity and pressure are the unknows). In our approach, natural convection and macrosegregation are neglected. Solid, mushy and liquid states obey respectively to elasto-viscoplastic, viscoplastic and Newtonian behaviours. The rheology of the solid state is calculated thanks laws from the litterature. The liquid and mushy states are modelled with high consistencies so that natural convection may be neglected. These developments have been validated on industrial cases, showing a good qualitative and quantitative agreement
Derouineau, Thibault. "Synthèse et étude de polymères thermo-associatifs pour le domaine des lubrifiants." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLET018.
Controlling the viscosity of engine lubricants is a key issue to reduce the fuel consumption of engines. A new approach based on the use of thermo-associative polymers has been developed in order to compensate the natural loss of viscosity of lubricants when the temperature increases. To this aim, complementary low molecular weight polymers (for engine targeted application) that can reversibly associate with temperature through the diol-boronic ester exchange reaction have been designed and synthesized. The low molecular weights of the polymers and the dynamic behavior of the boronic ester bond decrease the high shear sensitivity of the system and so limits the shear-thinning behavior of the lubricant. The increase of polymeric function availability as the temperature rises induces polymer association. The reversibility of the thermo-associative association of polymers in non polar oil is seen over several cycles of warming-cooling with the increase of the relative viscosity of the solutions with increasing temperature. Part of the study was also dedicated to the improvement of polymers’ thermal stability in order to maintain the good lubricant properties of the thermo-associative formulations up to 150°C. Many polymers of different natures, sizes and topologies have been synthesized. The flow behavior of these polymers in both individual state in solution or in thermo-associative formulations was studied by rheology, thus enabling to determine the impact of these levers on the solutions properties as a function of temperature
Derouineau, Thibault. "Synthèse et étude de polymères thermo-associatifs pour le domaine des lubrifiants." Electronic Thesis or Diss., Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLET018.
Controlling the viscosity of engine lubricants is a key issue to reduce the fuel consumption of engines. A new approach based on the use of thermo-associative polymers has been developed in order to compensate the natural loss of viscosity of lubricants when the temperature increases. To this aim, complementary low molecular weight polymers (for engine targeted application) that can reversibly associate with temperature through the diol-boronic ester exchange reaction have been designed and synthesized. The low molecular weights of the polymers and the dynamic behavior of the boronic ester bond decrease the high shear sensitivity of the system and so limits the shear-thinning behavior of the lubricant. The increase of polymeric function availability as the temperature rises induces polymer association. The reversibility of the thermo-associative association of polymers in non polar oil is seen over several cycles of warming-cooling with the increase of the relative viscosity of the solutions with increasing temperature. Part of the study was also dedicated to the improvement of polymers’ thermal stability in order to maintain the good lubricant properties of the thermo-associative formulations up to 150°C. Many polymers of different natures, sizes and topologies have been synthesized. The flow behavior of these polymers in both individual state in solution or in thermo-associative formulations was studied by rheology, thus enabling to determine the impact of these levers on the solutions properties as a function of temperature
Mezri, Leila. "Rôle des fluides pendant l'exhumation continentale : modélisation hydro-thermo-mécanique." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066175.
Strain localization is essential to the existence of plate tectonic on Earth. Yet, it is the result of non-linear interaction across several temporal and spatial scales and to date no unique rheological model exists that captures the effect of all these interactions at crustal scale. The work presented here is an attempt to fill part of the gap between out- crop scale and crustal scale models, between petrological scale and crustal scale. The central question is how to measure the effects of fluids and fluid-rock interactions on the dynamics and the kinematics of continental metamorphic core complexes by the mean of crustal scale numerical models. To answer this question, we have tried to esta- blish an empirical model of fluid flow and fluid-rock interaction, which could be valid at the scale of the crust. At that specific scale, it is important to capture the effects of free fluids both on the density of rocks, because it determines the body forces that are driving the exhumation of the crust, and on the strength of rocks and particularly on shear zones which constitute the ’hand-break’, the surface tractions, which resist this exhumation. This empirical model is based on a first order observation related to the behaviour of metamorphic rocks along the retrograde P − T path of their exhumation. High-grade metamorphic rocks (amphibolite/granulite) are indeed exhumed to the sur- face with very little retromorphose except those located within the shear bands where deformation localises. This works first consisted in parameterising this observation in a manner that could be implemented into a 2D thermo-mechanical code as an hydro- thermo-mechanical coupling which could account for free-water/rock-water exchange. In second part, a simplified scheme is introduced to account for hydrothermal cooling of the crust in the late stage of exhumation. The results show that this parameterization al- lows to better account for field observation in a range of parameters that are compatible with laboratory experiments. Limiting the retromorphose of rocks by the availability of free water is shown to produce significantly different metamorphic domes kinematics as compared to prior studies. We indeed demonstrate that it is not necessary to introduce heterogeneity in crustal composition to form asymmetric structures but that the effect of water is modulated by the chemistry of the protolith rocks which influences strain localization
Charles, Antoine Henri Etienne. "Étude thermo-rhéologique de boues digérées : application à l’écoulement en conduite dans les procédés de méthanisation." Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Lille Douai, 2023. http://www.theses.fr/2023MTLD0008.
The society’s wastewater treatment needs are met by waste water treatment plants that produce sludges. In order to anticipate the increase in this requirement in the future, the sludge treatment processes must achieve a certain level of efficiency in terms of sludge treatment and recovery. The anaerobic digestion process significantly reduces the volume of sludge generated and can the be used for agricultural and energy purposes, in the form of digestate, biogas, electricity or heat. It is nevertheless limited by ineffective control of the transport of digested sludge within it, due to a lack of knowledge of thermo-rheology, in terms of understanding and characterisation methods, and of the hydrodynamics involved in handling these very diverse sludges. This manifests itself operationally, downstream of the sizing and design phase, in inefficient pumping, matrix heterogeneity or component clogging.It is in this context of providing scientific elements, on the one hand of the therm-rheological characerisation of digested sludge and on the other hand of the demonstration of the hydrodynamics of these fluids in operation, that the research work carried out within the framework of this thesis falls within the scope of.Firstly, protocols dedicated to the specific characterisation of each non-Newtonian behaviour have been established. The application of these protocols, at the ITM Nord Europe – Energy Environment research centre and on the industrial partner’s Characterisation plateform, shows that the thermo-rheological characteristics of digested sludge are accurately modelled by a non-modified Herschel-Bulkley model. Yield stress and shear-thinning are significantly more important than the other thermo-rheological characteristics of thixotropy, viscoelasticity and thermo-dependence. The unanticipated physical phenomon of wall slip is observed in these digested sludges, leading to heterogeneous flow hydrodynamics under conditions of low inertia and loaw wall roughness.Secondly, an experimental set-up dedicated to studying the flow of such fluids in pipe is being set up, with a visualisation to determining their hydrodynamic behaviour. Using working fluids (Carbopol solutions), it was demonstrated that these fluids undergo a rheo-inertial transition (RIT) towards turbulence. This transition is characterised by the existence of a pre-transition regime, non-existent for a Newtonian fluid, within which the flow exibits an asymmetry, which is observed by direct visualisation. These visualisations, coupled with the measurement of pressure drops, also make it possible to quantify the intermittency of the RIT on the basis of the turbulent structures visualised. This makes it possible to control the movement of such fluids through knowledge of the stabilisation of their flows and the increase in the residence time of turbulent structures, due to the non-Newtonian characteristics without viscoelasticity.Thus, this thesis manuscipt summarises the scientific elements developed within the framework of this thesis to respond to the problems of the operational obstacles encountered. As these problems stem from a lack of fundamental knowledge of the thermo-rheology and hydrodynamics of the sludge that flows through it, the study focuses its research on these two areas in order to provide the fundamentals that will make it possible to improve the control of sludge transport within the anaerobic digestion process in wastewater treatment plants
Hertgen, Solenn. "Comportement mécanique des roches et dynamique des lithosphères dans les zones de convergence." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1B070/document.
Convergence zones are key objects to the understanding of the lithosphere dynamics. They are the location correspond to places of intense deformation as evidenced by the concentration and magnitude of recorded earthquakes. On a larger scale of time and space, these deformations generally result in nappes stacking whose study offers access to the different structural levels involved in the mountain belt structuration. Precisely characterizing the structuring dynamics of these units as well as the parameters controlling this dynamic is a crucial step that would allow in particular a better quantification of lithospheric dynamics. The aim of this thesis is twofold: (1) clarifying the rheological behavior of rocks in the Pressure-Temperature (P-T) conditions of the eclogitic facies at the subduction interface and (2) characterizing and quantifying the influence of the overriding plate rheology, and more specifically, the role of its crustal part, on the spatio-temporal evolution of convergence zones. For this, I used a multi-disciplinary approach. First, I present a multi-scale analysis combining fieldwork and metamorphic petrology, which allowed me to study the deformation within High Pressure-Low Temperature (HP-LT) rocks at the subduction interface in the Mont-Emilius klippe (Western Alps, Italy). Then, I show the results of a quantitative study combining 3D and 2D thermo-mechanical modeling of convergence zones. The entire set of models allowed me to analyze different parameters influencing the rheological structure of the overriding plate, such as the initial geotherm, the thicknesses of the lithosphere and the crust, and the nature of the involved materials. All the performed models are constrained/compared by/with data from natural examples. The results of the study on deformed rocks within the subduction interface highlight the possible brittle behavior of rocks at pressure and temperature conditions on the order of 2.15-2.40 GPa and 500-550 °C, i.e., in the eclogitic facies. The recording of such a deformation mode is of paramount importance because it challenges the paradigm of subduction interface caracterized by ductile behavior without resistance. The results obtained with the numerical models show that the rheology of the overriding plate, as well as that of only its crustal part, has a first-order influence on the overall dynamics of the convergence zones by modifying the mode of subduction, trench kinematics, the mode of exhumation during collision, the timing for slab break-off and back-arc basin formation, the location and intensity of deformation within the overriding plate. The combination of petrology and numerical modeling methods allowed me to obtain a quantified analysis of the influence of the rheology of the lithospheres involved in convergence zones on the dynamics of these zones. This thesis presents new constraints for our understanding of the mechanical response of the lithosphere at different spatial scales as a function of its rheological structure. The new data presented here reveal the major impact of the lithosphere rheology in convergence zones. This parameter leads us to reconsider our current view of the convergence zones
Mezri, Leila. "Rôle des fluides pendant l'exhumation continentale : modélisation hydro-thermo-mécanique." Electronic Thesis or Diss., Paris 6, 2016. http://www.theses.fr/2016PA066175.
Strain localization is essential to the existence of plate tectonic on Earth. Yet, it is the result of non-linear interaction across several temporal and spatial scales and to date no unique rheological model exists that captures the effect of all these interactions at crustal scale. The work presented here is an attempt to fill part of the gap between out- crop scale and crustal scale models, between petrological scale and crustal scale. The central question is how to measure the effects of fluids and fluid-rock interactions on the dynamics and the kinematics of continental metamorphic core complexes by the mean of crustal scale numerical models. To answer this question, we have tried to esta- blish an empirical model of fluid flow and fluid-rock interaction, which could be valid at the scale of the crust. At that specific scale, it is important to capture the effects of free fluids both on the density of rocks, because it determines the body forces that are driving the exhumation of the crust, and on the strength of rocks and particularly on shear zones which constitute the ’hand-break’, the surface tractions, which resist this exhumation. This empirical model is based on a first order observation related to the behaviour of metamorphic rocks along the retrograde P − T path of their exhumation. High-grade metamorphic rocks (amphibolite/granulite) are indeed exhumed to the sur- face with very little retromorphose except those located within the shear bands where deformation localises. This works first consisted in parameterising this observation in a manner that could be implemented into a 2D thermo-mechanical code as an hydro- thermo-mechanical coupling which could account for free-water/rock-water exchange. In second part, a simplified scheme is introduced to account for hydrothermal cooling of the crust in the late stage of exhumation. The results show that this parameterization al- lows to better account for field observation in a range of parameters that are compatible with laboratory experiments. Limiting the retromorphose of rocks by the availability of free water is shown to produce significantly different metamorphic domes kinematics as compared to prior studies. We indeed demonstrate that it is not necessary to introduce heterogeneity in crustal composition to form asymmetric structures but that the effect of water is modulated by the chemistry of the protolith rocks which influences strain localization
Costes, Frédéric. "Modélisation thermomécanique tridimensionnelle par éléments finis de la coulée continue d'aciers." Phd thesis, École Nationale Supérieure des Mines de Paris, 2004. http://pastel.archives-ouvertes.fr/pastel-00001334.
Heinrich, Alban. "Modélisation thermomécanique de la coulée continue d'acier en deux dimensions." Phd thesis, École Nationale Supérieure des Mines de Paris, 2003. http://pastel.archives-ouvertes.fr/pastel-00001342.
Vasile, Virginia. "Experimental study of the thermal and rheological behaviour of paraffin-in-water emulsions used as a secondary refrigerants." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI056/document.
A phase change material emulsion (PCME) is a fluid consisting of an emulsion of a phase change material (PCM), such as paraffin, dispersed in a carrier fluid (contiunuous phase), often water of an aqueous solution of surfactant. PCMEs can be considered as potential high performance thermal fluids (used as secondary refrigerants or as heat transport fluids) owing to their latent heat involved in the fusion of cristalisation of the PCM. This thesis reports experimental results concerning the thermo-rheological behavior of different versions of a PCME (30%wt. paraffin concentration in various acqueous solutions of surfactant) over the temperature range [0 – 20 °C]. The thermophysical properties of the PCMEs were determined. Then, an experimental study of forced convection heat transfer during laminar flow was carried out. The convective heat transfer coefficient of the PCMEs during cooling was determined in an experimental configuration mocking up applications in plate heat exchangers. The configuration mainly consists of two 1 m long rectangular channels (80 x 6 mm2). Correlations were developped for the prediction of the (local and overall) heat transfers coefficients, based on the Nussel, Reynolds and Prandtl numbers. A specific test bench was also used to analyse the rheological behaviour of the PCMEs. Tests were carried out using a viscometer at different temperatures. The stability of the emulsion was examined under various thermo-mechanical loads. Experiments revealed a pseudoplastic behavior for all tested versions of the PCME. All these results show that PCMEs are an attractive candidate for their applications in the field of air conditioning
Diouf-Lewis, Audrey. "Elaboration et évaluation d'additifs verts pour polymères et composites respectueux de l'environnement." Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC028/document.
This thesis work falls within the identified context of the need to develop new polymers that are more environmentally friendly. We are convinced that the development of these "green" materials requires the use of "green" additives during formulation. To develop environmentally friendly additives capable of stabilizing the polymer, with respect to the life cycle, and paying special attention to biomass valorization, three approaches have been studied. The first is an innovative way of using a mixture of polyphenols from winery by-products and tea industry. The second way is the valorisation of a molecule from the major by-product of the wheat industry. The third is a recent route of innovation, which proposes the use of layered double hydroxides nanocomposites (LDH) functionalized with bio based stabilizers. The evaluation of their stabilizing properties is carried out in polyolefins, against thermo- and photo-oxidation processes. The very promising results of the project highlight the strong potential of bio based molecules and composites to maintain polymers properties under conditions of use
Jaber, Ahmad. "Interfacial Viscoelastic moduli of bare, surfactant-laden and nanoparticle-laden interfaces oscillating in a weak gel." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0104.
We present a study implementing the oscillating drop method to probe the oil/water interface, modifiable by surfactants or nanoparticles, while surrounded by a continuous phase of controllable rheology. The key question posed in this work concerns the effect of the rheological properties of the continuous phase on the measurements of interfacial viscoelastic moduli extracted from the compression/expansion of an oscillating drop. With this in mind, the continuous phase consists of a thermo-reversible hydrogel K-carrageenan, selected for its interfacial inactivity but also for its hysteresis after the sol/gel transition which allows to have a gel or liquid at the same temperature according to the thermal history.In the case of a pure oil/water interface and under conditions where the KC solution is liquid, the elastic modulus of the interface remains weak. When the KC solution becomes a gel, even if it is weak to the point that the solution flows under its own weight, we witness the appearance of an elastic signature in interfacial viscoelastic measures attesting to the contribution of the rheology of the continuous phase being not negligible.The presence of a surfactant at the oil/water interface, generating an interfacial elastic modulus that increases with the concentration of surfactant in the case of a liquid surrounding medium. In the presence of a weak gel, the interfacial modulus decreases by despite that the modulus of the KC gel increases, this is attributed to a pseudo-localization of deformation at the interface. This phenomenon disappears in the case of an interface laden with solid nanoparticles (Pickering effect).All of this work reveals the importance of deconvoluting interfacial and volume contributions in an interfacial viscoelasticity test of the pendant drop
Costes, Frédéric. "Modélisation thermomécanique tridimensionnelle par éléments finis de la coulée continue d'aciers." Phd thesis, Paris, ENMP, 2004. http://www.theses.fr/2004ENMP1267.
Mussault, Cécile. "Temperature-induced phase transition of grafted hydrogels : from primary structure to mechanical properties." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS216.
To specifically study the impact of phase-separation processes on hydrogels mechanical reinforcement, we worked under isochoric conditions developing architectures not only thermo-responsive but also able to keep a high level of hydration on both sides of the phase-separation temperature. For this purpose, grafted hydrogels have been formulated from a chemically cross-linked hydrophilic polymer network grafted with thermo-sensitive side-chains of LCST type (PNIPAm). From this primary structure and keeping constant the weight ratio between the hydrophilic and thermo-responsive parts, we demonstrate that the thermodynamic characteristics of the phase transition (enthalpy and temperature transitions) are only very weakly dependent on the molar mass of PNIPAm grafts as well as their self-assembly process which leads to cylindrical domains concentrated in PNIPAm grafts. Like the nanocomposite materials, the formation of these dense polymer domains stabilized by physical interactions highly enhances both the gels stiffness and fracture resistance at high temperature by dissipating energy. We show that this temperature-controlled reinforcement increases with the molar mass of the PNIPAm grafts. Varying the hydrophilic/thermo-responsive parts weight ratio while keeping constant the molar mass of the grafts, opposite behaviours at low and high temperatures were established. When the hydrophilic cross-linked network weight is high compared to the one of thermo-responsive grafts, the hydrogels exhibit good properties at low temperature (entropic elasticity) whereas at high temperature, their mechanical behaviour is controlled by the phase-separated domains concentrated in PNIPAm grafts (energetic elasticity). The phase-separation phenomenon of PNIPAm grafts being thermo-reversible by nature and the interactions between these chains being weakly dynamic at high temperature, we demonstrate that these grafted hydrogels exhibit both adhesive and shape-memory properties. Finally, expanding the phase-separation concept, we show that replacing the hydrophilic network by a UCST type thermo-responsive one allows getting a dual thermo-response with phase-separation occurring at both low and high temperatures. While these transition temperatures are perfectly correlated to the thermodynamic characteristics of each polymer, the mechanical reinforcement is more dependent on the energy due to the nature of interactions developing inside the UCST network (H-bonds) or between the LCST grafts (H-bonds and hydrophobic interactions) during the phase-separation process
Diouf-Lewis, Audrey. "Elaboration et évaluation d'additifs verts pour polymères et composites respectueux de l'environnement." Electronic Thesis or Diss., Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC028.
This thesis work falls within the identified context of the need to develop new polymers that are more environmentally friendly. We are convinced that the development of these "green" materials requires the use of "green" additives during formulation. To develop environmentally friendly additives capable of stabilizing the polymer, with respect to the life cycle, and paying special attention to biomass valorization, three approaches have been studied. The first is an innovative way of using a mixture of polyphenols from winery by-products and tea industry. The second way is the valorisation of a molecule from the major by-product of the wheat industry. The third is a recent route of innovation, which proposes the use of layered double hydroxides nanocomposites (LDH) functionalized with bio based stabilizers. The evaluation of their stabilizing properties is carried out in polyolefins, against thermo- and photo-oxidation processes. The very promising results of the project highlight the strong potential of bio based molecules and composites to maintain polymers properties under conditions of use
Shiferaw, Benjamin. "Modélisation de la fissuration en milieu viscoélastique par approche Thick Level Set pour application au cas des enrobés bitumineux." Thesis, Ecole centrale de Nantes, 2019. http://www.theses.fr/2019ECDN0049.
Fracture of asphalt concrete (AC) layers is a major mode of deterioration in pavements, whose understanding of the various mechanisms requires the development of theoretical models and numerical tools. In this context, the research focuses on damage and fracture in thermo-viscoelastic materials. Hence, a local damage model is developed based on the principle of effective stresses and the Poynting-Thomson rheological law. The damage criterion considered relies on the elastic energy release rate. This model is then regularized according to the Thick Level Set (TLS) approach. The semi-analytical study of the 1D rod subjected to monotonous direct tension is performed to investigate the ability of the model to mimic the main experimental observations made for AC materials. An algorithm dedicated to the finite element solution of 2D problems is proposed and implemented subsequently in the eXlibris numerical code developed at ECN. The potential of this model to simulate damage and crack growth from initiation to collapse is demonstrated through the example of a viscoelastic beam under three-point bending test loading conditions. The simulations reflect the more or less brittle/ductile nature of the test results observed on AC materials depending on temperature and the loading rate. This work offers a theoretical and numerical basis for future applications in pavement mechanics
Toussaint, Gisèle. "Modélisations numériques thermo-mécaniques de subduction continentale." Paris 6, 2003. http://www.theses.fr/2003PA066323.
Gnambode, Sourou. "Simulation des grandes échelles des transferts thermo-convectifs dans les écoulements turbulents d'un fluide non-Newtonien en conduite cylindrique." Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1143/document.
This thesis is a numerical contribution of momentum and heat transfer of turbulent pipe flows of non-Newtonian fluids. The apparent viscosity of the fluid is modelled by a power-law (Ostwald de Waele model). Two models subgrid of LES were considered: the dynamic model of Germano et al. (1991) and model Smagorinsky non-Newtonian. They are used to describe the physical mechanisms involved in the isothermal flow of these complex rheology fluids. Heat transfer are simulated with the model of non-Newtonian Smagorinsky. These are processed in two parts. The first concerns the heat exchange without affecting the velocity distribution. This is non-thermo dependent flow or isothermal flow. The second part concerns the resolution of thermo dependent flows that focus on changes induced by the temperature-velocity coupling. The turbulent fields are analyzed statistically by averaging over time and space (according to the periodic directions) the instantaneous field of velocity and temperature to establish the average profiles of velocity and temperature, the root mean square of turbulent fluctuations (rms), Reynolds stress, the heat flow, the moments of higher order (skewness and flatness), the pdf (probability density function), the jpdf (attached probability density function), the coefficient of friction, the number of Nusselt ... These differents variables are analyzed for various parameters governing the problem: the Reynolds and Prandtl flow index and the number of Pearson
Claudel, Dimitri. "Modélisation et identification de lois rhéologiques de polymères chargés : Application au procédé de moulage par injection de poudres de superalliages." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2069.
The works presented in this paper were realized in collaboration between the mechanical department of FEMTO-ST Institute and the company SAFRAN/SNECMA. A part of the works of this thesis focused the thermo-physical characterizations of loaded polymers that is mixtures based of thermoplastic binders and metallic powders suitable be shaped by powder injection molding process.For this work, three different loaded mixtures composed of superalloy powder were investigated.Two were supplied by SAFRAN/SNECMA used to repair (Rene80®/AmdryD15® and RBD61) and another is composed of Inconel 718 powder. Characterizations were to carry out to optimize the development of loaded polymers and to obtain homogenous materials with high solid fraction. Then, the data were used to identified parameters of usual rheological laws. The development of specific rheological models were realized by including different parameters related to the specific surface area, binder viscosities used in the formulation. The development of these models increasingly exhaustive allows the improvement of behavior laws and to better describe the rheological behavior of superalloy-loaded polymers. Finally, a simulation of the injection molding stage of a aeronautical component was realized in the Moldflow© software for the Rene80®/AmdryD15® loaded polymer
Supper, Stéphanie. "Development and characterization of parenteral in situ gelling chitosan/glucose-1-phosphate depot systems for controlled drug release." Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAF048.
The aim of this work was to develop a new parenteral in situ forming depot (ISFD) system for the controlled delivery of drugs. Chitosan (CS)-based systems that undergo sol / gel transition upon heating at physiological temperature were selected among the different categories of ISFDs due to their well-known biocompatibility and biodegradability. After an overall review of the recent progresses on standard CS-based ISFD systems, the synergistic mechanisms underlying the temperature-induced gelation of the CS / gelling agent systems were investigated through comprehensive rheological studies completed by 31P-NMR measurements. These investigations emphasized the key role of the polyol part of the gelling agent. The next step consisted in developing a new system combining CS and glucose-1-phosphate (G1-P). The physico-chemical characteristics and storage stability of this system were investigated. The results highlighted a sol / gel transition under physiological conditions and improved storage stability compared to the standard CS / glycerophosphate system. Local tolerability studies of the hydrogels in rats showed that the system was reasonably well tolerated. Finally, the last chapter, dedicated to the study of the in vitro release behavior of several model compounds, emphasized the ability of the polymeric CS / G1-P network to sustain the release of the incorporated substances
Benzarti, Ep Miladi Meriem. "Caractéristique et modélisation de l’endommagement du cheveu suite à une sollicitation thermo mécanique." Saint-Etienne, EMSE, 2012. http://www.theses.fr/2012ENIS0013.
The thermo mechanical solicitation caused by using a hair crimper can induce various changes in hair form and structure. And, in some cases, can destroy the hair. The aims of this thesis is to identify hair damage caused by this type of solicitation and determine the hair crimper characteristics and limitations. This study is based on a simulation that straightens the hair using a capillary tribometer. This latter reproduces the major functions of the crimper. A characterisation of the hair surface and the crimper plates in addition to mechanical tests are done in order to acquire mechanical and surface properties of the hair after each solicitation. These tests permit to control their evolution according to the different stresses and temperature applied. A numerical modelling is then performed in order to determine the hair law behaviour resulting from mechanical solicitations. Tribological behaviour is characterised by experimental work considering the effects of the temperature and forces applied during the straightening operation on the friction. Therefore, this work allows us to characterise the influence of a hair crimper on the mechanical and tribological properties of the hair. Finally, sensory perception is attained using sensory metrology tools allowing us to access physical effects on the brightness and shape of the hair tress
Yadav, Pankaj. "Time and thermo-mechanical coupling effects in polymers." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS061.
The study of the mechanical and thermal behaviour of polymers is of prime importance for engineering applications. Therefore, the ability of predicting these properties for several decades of loading frequencies and/or several tens of degree Celsius, is a strong motivation. Based on experimental combination of mechanical and thermal rheological-analysis (DMTA), phenomenological models are thus developed to predict the linear viscoelastic behaviour of polymers with the traditional use of the so-called “time-temperature superposition principle (TTSP)”. While implementing these models, the consideration of (i) effects linked to the real temperature of the sample or of (ii) the time effects induced by thermo-mechanical couplings are not taken into account. However, polymer materials are very sensitive to temperature variations and even slight temperature variations can be due to thermo-mechanical coupling or dissipation sources. The TTSP applicability in such a context is thus not straightforward. Therefore, an accurate knowledge of the mechanical and thermal behaviour of this class of materials, under the Thermodynamics of Irreversible processes, taking into account the dissipative effect and thermo-mechanical coupling, can become of prime importance.To achieve these objectives, the present study was performed starting from a literature review on the thermo-mechanical behaviour of vitreous and amorphous polymers and the TTSP. This was followed by understanding the theoretical framework of thermodynamics of irreversible processes and its implementation in the Generalized Standard Material (GSM) formalism. The theoretical framework of GSM allowed us to consider the temperature as an internal state variable and to derive the constitutive behavioural equations from a thermodynamic and a dissipation potential. This formalism also induced the possibilities to define and then compute the different heat sources involved in the heat diffusion equation.Second, measurements were performed to characterize the linear viscoelastic properties below the glass transition temperature of selected amorphous and rheologically simple polymers (PS, PMMA and PA-6.6). This was followed by the application of a classical TTSP using an Arrhenius law to predict the linear viscoelastic behaviour on a very large temperature/frequency range, which cannot be experimentally reachable. A first set of measurements was performed on PS in several laboratories to check for its monochromatic response to a monochromatic loading and build a reference database for the calibration and validation of different correction procedures (machine stiffness and electronic phase shift) of our DMTA. Later, synchronized thermography measurements were performed to measure the temperature variations of the sample during DMTA measurements. This allows for the estimation of the average mechanical energy dissipated during one cycle together with the heat losses and thermoelastic coupling.Finally, these experimental results were used to identify the optimum branches of a generalized Maxwell model (GMM) using non negative least squares method for the 3 different polymers. In each branch of this model, the viscoelastic time constant and the associated elastic modulus depend on the temperature (through an Arrhenius law and an activation energy determined previously experimentally). Using the GSM formalism, the different heat sources (thermomechanical couplings, dissipation) were also computed. The energy rate balance showed the predominance of the thermomechanical couplings sources. To conclude this study, we stressed that a GMM assuming the rheological simple material hypothesis is TTSP compatible
Davy, Philippe. "Modélisation thermo-mécanique de la collision continentale." Phd thesis, Université Rennes 1, 1986. http://tel.archives-ouvertes.fr/tel-00626782.
Le, Solleuz Antoine. "Modélisation thermo-mécanique et stratigraphique de la genèse et de l'évolution d'un bassin sédimentaire intraplaque : exemple du Bassin de Paris." Paris 6, 2003. http://www.theses.fr/2003PA066190.
Brocato, Maurizio. "Un modèle thermo-mécanique de polycristal pour l'étude des bandes de cisaillement." Phd thesis, Ecole Nationale des Ponts et Chaussées, 1994. http://tel.archives-ouvertes.fr/tel-00523014.
JAMIN, Frédéric. "Contribution à l'étude du transport de matière et de la rhéologie dans les sols non saturés à différentes températures." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2003. http://tel.archives-ouvertes.fr/tel-00006051.
Le volet théorique (partie I) présente une modélisation générale du comportement thermo-hydro-mécanique de sols non saturés. Le modèle prend en compte la déformation du squelette, la filtration des phases liquide et gazeuse, la diffusion de vapeur, la conduction de chaleur et le changement de phase liquide-vapeur. Cette modélisation est utilisée pour décrire le transport d'eau dans un sol non saturé en favorisant les phénomènes de filtration de liquide, de diffusion de vapeur d'eau et de changement de phase d'eau liquide-vapeur.
Le volet instrumental (partie II) porte sur la réalisation d'un banc de sorption et d'un dispositif de type plaque de pression en température. Ces matériels permettent de réaliser des essais de désaturation et de déterminer la courbe caractéristique sol-eau. Un autre aspect concerne la rénovation d'un appareil triaxial thermique en le dotant d'une instrumentation plus adaptée à l'étude du comportement thermo-hydro-mécanique de sols non saturés.
Le volet expérimental est double. Le premier aspect (partie III), relatif à l'étude de la désaturation et à la détermination de la courbe caractéristique d'une argile plastique et d'un sable limoneux argileux à 20°C et 60°C, porte sur la détermination d'un coefficient de transport en phase liquide. Le second aspect (partie IV) s'intéresse à la représentation de surfaces de charge dans le cas du sable limoneux argileux non saturé à différentes températures. Cette surface de charge présente un caractère thermo-extensif dont on propose une modélisation et une interprétation physique.
Brocato, Maurizio. "Un modèle thermo-mécanique de polycristal pour l'étude des bandes de cisaillement." Phd thesis, Marne-la-vallée, ENPC, 1994. http://www.theses.fr/1994ENPC9405.
Halelfadl, Salma. "Caractérisation des propriétés thermo-physiques et d’échanges de chaleur des nanofluides à base de nanotubes de carbone." Thesis, Rennes, INSA, 2014. http://www.theses.fr/2014ISAR0008/document.
Heat transfer is one of the most important industrial processes in our daily lives. Nowadays, the intensification of the heat transfer and the improving of the energy efficiency have become a major problem in industry, regulatory agencies, and also the society that becomes conscious of the progressive exhaustion of the world’s energy resources and cares about the future of energy. Due to these energy and environmental issues, the technological challenge is to develop new processes for better energy management. This work fits in that context and applies particularly the problems associated to the improvements of heat exchanger’s energy efficiency. The conventional methods for increasing the heat transfer in heat exchangers have already been extensively explored and have reached their objective limits. There is therefore an urgent need for new strategies with improved performances. The novel concept of improving the thermal properties of the working fluids used in thermal system, especially in heat exchangers, has been proposed as a means of meeting these challenges. The innovative concept of nanofluids heat transfer fluids consisting of suspended of nanoparticles with very high thermal conductivities has been proposed for these challenges. The aim of this work is therefore to characterize profoundly the thermal and the rheological behavior of nanofluids containing carbon nanotubes CNTs used throughout of this work. This is in order to quantify the main parameters influencing their thermophysical properties and physical phenomena governing the intensification of heat transfer induced by these nanofluids. An analysis of previous researches has been conducted for the purpose of establishing various parameters that may influence the thermal and rheological behavior of nanofluids, which including the parameters related to the composition of nanofluids (volume fraction of CNTs, type of surfactant, aspect ratio of CNTs), the temperature, the base fluid... Following this study, experiments have been carried out on the thermal physical properties of tested nanofluids (thermal conductivity, dynamic viscosity, density) and thermal performances in a heat exchanger. Analyses of the results have been presented in order to study the influence of the abovementioned parameters. The results obtained are compared and discussed vis-à-vis the existing conventional models, suggesting improvements and interpretations according to the trends obtained. The promising results of this study are very encouraging and show that the use of nanofluids containing carbon nanotubes clearly improved the thermal performances compared to the conventional base fluids. The CNT-based nanofluids can thus be a promising candidate for heat transfer and presents good perspective and development