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This thesis presents a detailed investigation of the capability of a modern three-dimensional Navier-Stokes solver to predict the secondary flows and losses in a linear cascade of high turning turbine rotor blades. Three codes were initially tested, to permit selection of the best of the available numerical solvers for this case. This program was then tested in more detail. Results showed that although very accurate prediction of the effects of inviscid fluid mechanics is now possible, the Reynolds stress modelling can have profound effects upon the quality of the solutions obtained. Solutions using two different calculation meshes, have shown that the results are not significantly grid dependent. The flowfield of the cascade was traversed with hot-wires to obtain measurements of the turbulent Reynolds stresses. A turbulence generating grid was placed upstream of the cascade, to produce a more realistic inlet turbulence intensity. Results showed that regions of high turbulent kinetic energy are associated with regions of high total pressure loss. Calculation of eddy viscosities from the Reynolds stresses showed that downstream of the -cascade the eddy viscosity is fairly isotropic. Evaluation of terms in the kinetic energy equation, also indicated that both the normal and shear Reynolds stresses are important as loss producing mechanisms in the downstream flow. The experimental Reynolds stresses have been compared with those calculated from the eddy viscosity and velocity fields of Navier-Stokes predictions using a mixing length turbulence model, a one equation model, and K - ϵ model. It was found that in the separated, shear flows, agreement was poor, although the K - ϵ model performed best. Further experimental work is suggested to obtain data with which to determine the accuracy of the models within the blade and endwall boundary layers.

This thesis provides a numerical and theoretical investigation of transitional and turbulent enclosed rotating flows, with a focus on the formation of macroscopic coherent flow structures. The underlying processes are strongly threedimensional due to the presence of boundary layers on the discs and on the walls of the outer (resp. inner) cylindrical shroud (resp. shaft). The complexity of these flows poses a great challenge in fundamental research however the present work is also of importance for industrial rotating machinery, from hard-drives to space engines turbopumps - the design issues of the latter being behind the motivation for this thesis. The present work consists of two major investigations. First, industrial cavities are modeled by smooth rotor/stator cavities and therein the dominant flow dynamics is investigated. For the experimental campaigns on industrial machinery revealed dangerous unsteady phenomena within the cavities, the emphasis is put on the reproduction and monitoring of unsteady pressure fluctuations within the smooth cavities. Then, the LES of three configurations of real industrial turbines are conducted to study in situ the pressure fluctuations and apply the diagnostics already vetted on academic problems.

Ce manuscrit présente une étude couplée, numérique et théorique, portant sur les écoulements tournants transitionnels et turbulents. L'accent y est mis sur la formation de structures macroscopiques cohérentes au sein de l'écoulement, générées par des procédés rendus fortement tri-dimensionnels par la présence des couches limites sur les disques et le long des parois cylindriques extérieure (carter) et/ou intérieure (moyeu). La complexité de ces écoulements pose de véritables difficultés en recherche fondamentale mais les résultats de ces travaux ont aussi une importance non négligeable pour les machines industrielles tournantes, depuis les disque-durs jusqu'aux turbopompes spatiales, la conception de ces dernières étant la motivation première pour ces travaux de thèse. Ce travail peut être divisé en deux sous-parties. Dans un premier temps, les cavités industrielles sont modélisées par de simples cavités rotor/stator lisses pour y étudier la dynamique de l'écoulement. Comme les campagnes expérimentales sur les machines industrielles ont révélé de dangereux phénomènes instationnaires en leur sein, l'accent est mis sur l'obtention et l'étude des fluctuations de pression dans les écoulements modèles. Ensuite, les SGE de trois configurations de turbine industrielle réelle sont réalisées pour étudier les fluctuations de pression in situ et appliquer les diagnostiques éprouvés sur les géométries modèles. / This thesis provides a numerical and theoretical investigation of transitional and turbulent enclosed rotating flows, with a focus on the formation of macroscopic coherent flow structures. The underlying processes are strongly threedimensional due to the presence of boundary layers on the discs and on the walls of the outer (resp. inner) cylindrical shroud (resp. shaft). The complexity of these flows poses a great challenge in fundamental research however the present work is also of importance for industrial rotating machinery, from hard-drives to space engines turbopumps - the design issues of the latter being behind the motivation for this thesis. The present work consists of two major investigations. First, industrial cavities are modeled by smooth rotor/stator cavities and therein the dominant flow dynamics is investigated. For the experimental campaigns on industrial machinery revealed dangerous unsteady phenomena within the cavities, the emphasis is put on the reproduction and monitoring of unsteady pressure fluctuations within the smooth cavities. Then, the LES of three configurations of real industrial turbines are conducted to study in situ the pressure fluctuations and apply the diagnostics already vetted on academic problems.

Seafloor hydrothermal systems play a key role in Earth fs energy and geochemical budgets. They also support the existence and development of complex chemosynthetic biological ecosystems that use the mineral-laden fluids as a source of energy and nutrients. This dissertation focuses on two inter-related topics: (1) heat output and geochemical fluxes at mid-ocean ridges, and (2) structural deformation of oceanic lithosphere related to subsurface serpentinization in submarine settings. The determination of heat output is important for several reasons. It provides important constraints on the physics of seafloor hydrothermal processes, on the nature of the heat sources at mid-ocean ridges, and on nutrient transport to biological ecosystems. Despite its importance, measurements of hydrothermal heat outputs are still scarce and cover less than 5% of active hydrothermal vent sites. In this work, we report development of two new devices designed to measure fluid flow velocities from the submersible at temperatures of up to 450 C and depths 5,000 m. By using these instruments on 24 Alvin dives, new measurements of hydrothermal heat output have been conducted at the Juan de Fuca Ridge, including first measurements from the High Rise and Mothra hydrothermal fields. The collected data suggest that the high-temperature heat output at the Main Endeavour Field (MEF) may be declining since the 1999 eruption. The flow measurement results, coupled with in-situ geochemical measurements, yielded the first estimates of geochemical fluxes of volatile compounds at MEF and Mothra. Our findings indicate that geochemical flux from diffuse flows may constitute approximately half of the net geochemical flux from Juan de Fuca Ridge. It has recently been recognized that serpentinization of mantle peridotites, due to its exothermic nature, may be a mechanism contributing to the heat output at mid-ocean ridges. The tectonic response of the crust to serpentinization of extensively distributed peridotites at mid-ocean ridges and subduction zones could provide a means of characterizing serpentinized regions in the oceanic lithosphere. These regions are often associated with surface topographic anomalies that may result from the volume expansion caused by the serpentinization reactions. Although there is a clear correlation between tectonics and serpentinization, the link is complex and still not understood. In this dissertation, we calculated the transformation strain and surface uplift associated with subsurface serpentinization of variously shaped ultramafic inclusions. Application of the results to explain the anomalous topographic salient at the TAG hydrothermal field (Mid-Atlantic Ridge) suggests that this feature may result from a serpentinized body beneath the footwall of a detachment fault. Because the depth of the potential serpentinized region appears to be more than 1.5 times the size of the inclusion, the uplift profile is relatively insensitive to the exact location or shape of the serpentinized domain. The rate of exothermic heat release needed to produce the serpentinized volume may contribute to the ongoing diffuse flow. Application of the results to an uplift feature associated with the Kyushu ]Palau subduction zone in the western Pacific, shows that approximately 3% transformational strain in an inclined serpentinized region of the mantle wedge near the subducted Kyushu ]Palau Ridge may result in the observed uplift on the Miyazaki Plain. Using the uplift data may help to constrain the level of the subsurface serpentinization.

Subject of this master's thesis is to design 70 MW single-casing steam turbine for the incernetion plant without reheating steam. The turbine has uncontrolled extraction points for another technology and axial flow outlet.

<p>In the development of turbo machinery components it's desirable to not spend more time than necessary when setting up aero-thermal calculations to investigate uncertainties in the design. This report aims to describe general thoughts used in the development of an ICEM-mesh script and the possible configurations in the script file which enables the user to build mesh-grids with/without clearance gap at the hub and/or shroud for different blade geometries. It also aims to illustrate the performance analysis made on the Vinci LH2 turbine, a next generation upper stage engine to the Ariane 5 rocket, in which the effect of the tip gap size on the efficiency has been studied.</p><p>The calculations made have shown good agreement with experimental data. The efficiency loss due to the mixing of fluid where leakage flow passes the tip gap, which results in growth of a strong vortex, and the fluid passing the blade tip, with almost no work extracted from it, has shown a quite linear efficiency dependence depending on the tip gap size.</p>

In the development of turbo machinery components it's desirable to not spend more time than necessary when setting up aero-thermal calculations to investigate uncertainties in the design. This report aims to describe general thoughts used in the development of an ICEM-mesh script and the possible configurations in the script file which enables the user to build mesh-grids with/without clearance gap at the hub and/or shroud for different blade geometries. It also aims to illustrate the performance analysis made on the Vinci LH2 turbine, a next generation upper stage engine to the Ariane 5 rocket, in which the effect of the tip gap size on the efficiency has been studied. The calculations made have shown good agreement with experimental data. The efficiency loss due to the mixing of fluid where leakage flow passes the tip gap, which results in growth of a strong vortex, and the fluid passing the blade tip, with almost no work extracted from it, has shown a quite linear efficiency dependence depending on the tip gap size.

Master’s thesis deals with design and calculation of one body condensing steam turbine of 25 MW with samples for paper-making industry. The thesis is focused on calculation of the turbine’s heat balance with two technological samples and regeneration which consists of two low pressure heaters and a deaerator with a power reservoir. The steam turbine is designed with a water cooling condenser with down output. The flow part is calculated with lengths of blades. There are basic strength and proportion calculations. In the end of the thesis the turbine’s heat balance is recalculated to 80% and 105% scheme according to an assignment. Another part of this thesis is a drawing of a longitudinal cut of the turbine including a connector with a gearbox.