京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18272号 / 工博第3864号 / 新制||工||1593(附属図書館) / 31130 / 京都大学大学院工学研究科原子核工学専攻 / (主査)教授 功刀 資彰, 教授 中部 主敬, 准教授 横峯 健彦 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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Ce travail de thèse concerne l'étude d'extracteurs d'air hybrides éoliens. Il se décompose en des investigations amont et appliquées. Dans la partie amont, des simulations fines ont été effectuées en conduite carrée avec et sans rotation, pour des nombres de Reynolds turbulents de l'ordre de 600, afin d'analyser l'impact de la rotation sur la turbulence. Elles ont montré que la rotation rompt la symétrie de l'écoulement. La partie appliquée est dédiée à la conception d'une nouvelle géométrie d'extracteur d'air. Cette géométrie a été proposée à partir de l'analyse de simulations RANS. Ses performances ont été confirmées par des mesures expérimentales sur banc d'essais. Les tests en soufflerie d'un système de captage d'énergie éolienne, conçu pour l'extracteur, ont mis en évidence son adéquation au régime de fonctionnement de l'extracteur. Les essais expérimentaux de l'extracteur complet, montrent que le système de captage apporte une part significative de l'énergie. Des essais en soufflerie ont permis d'observer le comportement global de l'extracteur. / This PhD work concerns the study of hybrid air extractors. It is composed of upstream and applied investigations. In the upstream part, fine simulations are realized in square duct flow with and without rotation to analyse the impact of rotation on turbulence. It is found that rotation removes symmetry property of the flow with turbulent Reynolds number of 600. The applied part is dedicated to the conception of a new air extractor geometry. This geometry is proposed from the analyse of RANS simulations. Its performances are confirmed by experimental measurements on test rig. Wind tunnel tests of a wind power capturing system, designed for the extractor, show a good adequation to the operating regime of the extractor. Experimental investigations on the complete air extractor, show the wind power capturing system brings a significant part of the energy. Wind tunnel tests allow to observe the complete air extractor behaviour.

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.