Cette thèse est une contribution à la simulation numérique des transferts de quantité de mouvement et de chaleur dans les écoulements turbulents de fluides non-Newtoniens dans une conduite cylindrique fixe. La viscosité du fluide utilisé est décrite par la loi d'Ostwald de Waele. Deux modèles sous-mailles dans l'approche des simulations des grandes échelles ont été considérés : le modèle dynamique de Germano et al. (1991) et le modèle de Smagorinsky non-Newtonien. Ils sont utilisés pour décrire les mécanismes physiques mis en jeu dans les écoulements isothermes de ces fluides à rhéologie complexe. Les transferts thermiques sont simulés avec le modèle de Smagorinsky non-Newtonien. Ces derniers sont traités en deux parties. La première concerne les échanges de chaleur sans influence sur la distribution des vitesses. Il s'agit des écoulements non-thermo dépendants ou écoulements isothermes. La deuxième partie concerne la résolution des écoulements thermo dépendants qui mettent l'accent sur les modifications induites par le couplage vitesse-température. Les champs turbulents sont analysés statistiquement en moyennant dans le temps et dans l'espace (suivant les directions périodiques) les champs instantanés de vitesse et de température pour établir les profils moyens de vitesse et de température, les rms, la tension de Reynolds, les flux de chaleur, les moments d'ordre plus élevé (coefficients de dissymétrie et d'aplatissement), les pdf (fonction de densité de probabilté), les jpdf (fonction de densité de probabilité jointe), le coefficient de frottement, le nombre de Nusselt... Ces différentes grandeurs sont analysées en fonction des divers paramètres qui gouvernent le problème: les nombres de Reynolds et de Prandtl, l’indice d'écoulement et le nombre de Pearson / 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

The existence of hydrodynamically developed, laminar Viscoelastic Secondary Flows (VSFs) of non-Newtonian fluids in straight ducts of non-circular cross-section was proposed in the 1950's. VSFs have since been observed sporadically, and only once with a velocimetric technique. Using axial and transverse full flow-field velocity-position raster maps made with Rheological Nuclear Magnetic Resonance (Rheo-NMR), Newtonian and non-Newtonian fluid flows were quantified in Hagen-Poiseuille and Power Law contexts, over more than two orders of magnitude of flow rate, in ducts of circle, square, triangle, and pentagon cross-section. VSF was reliably and repeatedly observed to occur at between one part in 130 and one part in 600 of the primary axial flow velocity. Velocity measurements ranged from <10 µm/s to approximately 30 cm/s, suggesting a velocity dynamic range >3E4 without optimization. To obtain VSF flow direction information, a novel flow directional phantom was developed and characterized. Aqueous solutions of Polyethylene Oxide (PEO), Viscarin GP-109NF, Viscarin GP-209NF (V209), Hyaluronan (HA) in a Phosphate-Buffered Saline-like solvent, and an aqueous Polyethylene Glycol/PEO-based Boger fluid were investigated. Axial data was corroborated with related data gathered by an independent method. Basic simulations corroborated the VSF observations. Duct hydraulic diameters (>= 1.6 mm) approached the micro-channel regime. VSF detections in HA --- synovial fluid's principal component --- and V209 were novel, as were observations of some artifacts which were subsequently characterized and corrected. The detection of VSF in HA represents the first experimental evidence suggesting that its second normal stress (N_2) is comparable to that of better-characterized fluids. In the first application of a new VSF-based method, a particular Boger fluid's constant viscosity and, in the square duct, its lack of VSF were used with established criteria to suggest that the fluid's N_2 approached zero. The development of a rudimentary, but versatile and inexpensive home-built velocimetric spectrometer is detailed, as are several new components. An exhaustive VSF literature review is included. The remarkable transverse velocimetric ability of Rheo-NMR in both optically opaque and transparent system is highlighted, suggesting that perhaps the technique might represent, in both micro-channels and conventional ducts, the gold-standard in flow velocimetry.