<p>Supercritical Water-cooled Reactor (SCWR) is a Generation-IV nuclear reactor design that operates on a direct energy conversion cycle above the thermodynamic critical point of water (374⁰C and 22.1 MPa), and offers higher thermal efficiency and considerable design simplification. As an essential step in the design of SCWR safety systems, the accident behaviour of the reactor is evaluated to ensure that the safety systems can achieve safe shutdown for all the design basis accidents. Unfortunately, the computational tools and computer codes that are currently employed for safety analysis have little application in the supercritical region, and faces significant challenges in simulating the transitions from subcritical to supercritical conditions.</p> <p>This thesis examines the predictive capabilities of Computational Fluid Dynamics (CFD) code STAR-CCM+ by evaluating critical flow (or choked flow) due to accidental release of coolant from supercritical fluid systems. The biggest challenge of this research is that the current version of STAR-CCM+ does not support supercritical simulations because the steam tables included in the package are only limited to the subcritical subset of the thermodynamic fluid properties.</p> <p>The research was carried out in two stages. In the first stage, the CFD code STAR-CCM+ was customized to simulate supercritical conditions by, (i) Generating updated steam tables to include subcritical and supercritical fluid properties and using more pressure and temperature points in the pseudo critical region (22 – 25 MPa, 645 -660 K) to handle the rapid changes in the fluid properties, and (ii) Implementing a multi-dimensional steam table interpolation scheme to access the fluid property data at any thermodynamic state during the simulation. In the second stage, the customized CFD code was extensively evaluated by simulating several accidental release scenarios from supercritical conditions using rounded-edge and sharp-edge nozzles and the model results were validated with experimental data. To overcome the solution stability (or convergence) issues encountered during the supercritical simulations, a fine tuning procedure was proposed that guaranteed convergence for all the case studies considered in this thesis.</p> <p>The simulation results revealed that the CFD model produced results that were in good agreement with experimental data and only about 10% prediction error was noticed for most cases considered in the thesis. Considering the sensitivity of the CFD model for upstream temperatures and pressures, these results appear to be quite reasonable. From the computational experience gained in this research , we believe that the CFD code STAR-CCM+ is a very useful tool to perform thermal hydraulic simulations for supercritical systems. However, an appropriate customization and extensive validation of the code is required before it can be exclusively used for safety analysis.</p> / Master of Applied Science (MASc)

Les phénomènes d'adsorption interviennent dans les processus géochimiques gouvernant ainsi le transport des contaminants. Par ailleurs, les variations de température sont susceptibles d'influencer significativement leur comportement vis-à-vis de la surface des minéraux. Aussi, l'influence de la température sur la sorption doit être étudiée afin de mieux appréhender le devenir des éléments dans l'environnement. Dans cette optique, l'interaction entre un ion modèle, l'uranyle et deux minéraux a été étudiée. Dans un premier temps, un composé méthodologique, la monazite, a été choisi afin de déterminer la démarche à suivre pour étudier l'influence de la température sur la sorption de l'uranyle dans trois milieux plus ou moins complexants. Puis, des tests préliminaires ont été réalisés pour étudier la sorption de l'uranyle sur un composé d'intérêt industriel, la magnétite, en appliquant la démarche mise en place. Le solide a d'abord été caractérisé d'un point de vue massif puis les caractéristiques acido-basiques de sa mise en suspension dans les trois électrolytes (NaClO4, NaNO3 et Na2SO4) ont été étudiées en fonction de la température. Les constantes d'équilibre associées aux réactions de déprotonation des sites de surface ont été déterminées entre 25°C et 95°C par modélisation de courbes de titrages potentiométriques. Les simulations ont été effectuées en limitant au maximum le nombre de degrés de liberté du système. Le modèle 1-pK a donc été préféré au modèle 2-pK en raison du nombre de paramètres ajustables plus limité dans ce modèle. Des contraintes expérimentales telles que le pH de point de charge nulle ou les enthalpies déterminées par mesure directe des chaleurs associées par microcalorimétrie de mélange ont été imposées pour déterminer les constantes d'équilibre acido-basiques. La sorption de l'uranyle en fonction du pH sur le même intervalle de température a été étudiée en alliant l'acquisition de données macroscopiques telles que les sauts de sorption et la spéciation en solution à une étude structurale menée par analyse par spectrofluorimétrie laser permettant l'identification des espèces sorbées. La simulation des sauts de sorption permettant d'accéder aux constantes associées aux réactions de sorption a été réalisée en imposant les caractéristiques acido-basiques préalablement déterminées. Des mesures directes, par microcalorimétrie de mélange, des chaleurs mises en jeu lors de la sorption de l'uranyle ont permis de tester la validité de la loi de Van't Hoff sur ce phénomène. La même démarche a été suivie pour étudier l'influence de la température sur la sorption de l'uranyle sur la magnétite en milieu NaClO4 et NaNO3. Cependant, l'étude structurale par spectrofluorimétrie laser n'a pu être réalisée en raison de la couloration noire de la magnétite.

With the vast array of genetically altered (knockout) mice becoming available there is a need for quantitative, repeatable, and efficient methodologies to characterize the phenotypic consequences of knocking out specific genes. Since knockout animals often have the ability to compensate for a single missing gene, it is important to examine the structural, material and morphological properties to obtain a thorough understanding of the changes occurring. For this project, femurs of knockout mice were first scanned using microcomputed tomography (micro-CT) to obtain high-resolution images of the trabecular bone in the distal femur, as well as cortical bone in the mid-diaphysis. After scanning, the femurs were tested to destruction in four-point bending at the mid-diaphysis about the medial lateral axis of the femur. These methodologies allowed quantification of (1) morphologic properties such as bone volume fraction, trabecular properties and 2nd moment of the area (2) structural properties such as stiffness, maximum load at failure, and post yield deformation and (3) material properties such as bone mineral density, elastic modulus and yield strength. As part of two independent studies, two different knockout mice, cyclooxygenase-2 (COX-2 -/-) and Apolipoprotein E (APOE -/-), were examined for structure-function relationships using these methodologies. COX-2 knockout mice were found to have decreased mineral content in their femurs, and increased post yield deformation. APOE knockout mice at 10 weeks of age had decreased bone mass and structural properties. However, by 40 weeks of age APOE deficient mice caught up to and exceeded the structural properties and bone mass of their wild type counterparts.

Transmissions are an essential part of a vehicle powertrain. An optimally designed powertrain can result in energy savings, reduced environmental impact and increased comfort and reliability. Along with other components of the powertrain, efficiency is also a major concern in the design of transmissions. The churning power losses associated with the motion of gears through the oil represent a significant portion of the total power losses in a transmission and therefore need to be estimated. A lack of reliable empirical models for the prediction of these losses has led to the emergence of CFD (Computational Fluid Dynamics) as a means to (i) predict these losses and (ii) promote a deeper understanding of the physical phenomena responsible for theselosses in order to improve existing models. The commercial CFD solver STAR-CCM+ is used to investigate the oil distribution and the churning power losses inside two gearbox configurations namely an FZG (Technical Institute for the Study of Gears and Drive Mechanisms) gearbox and a planetary gearbox. A comparison of two motion handling techniques in STARCCM+ namely MRF (Moving Reference Frame) and RBM (Rigid Body Motion) models is made in terms of the accuracy of results and the computational requirements using the FZG gearbox. A sensitivity analysis on how the size of gap between the meshing gear teeth affects the flow and the computational requirements is also done using the FZG gearbox. Different modelling alternatives are investigated for the planetary gearbox and the best choices have been determined. The numerical simulations are solved in an unsteady framework where the VOF (Volume Of Fluid) multiphase model is used to track the interface between the immiscible phases. The overset meshing technique has been used to reconfigure the mesh at each time step. The results from the CFD simulations are presented and discussed in terms of the modelling choices made and their effect on the accuracy of the results. The MRF method is a cheaper alternative compared to the RBM model however, the former model does not accurately simulate the transient start-up and instead provides just a regime solution of the unsteady problem. As expected, the accuracy of the results suffers from having a large gap between the meshing gear teeth. The use of compressible ideal gas model for the air phase with a pressure boundary condition gives the optimum performance for the planetary gearbox. The outcomes can be used toeffectively study transmission flows using CFD and thereby improve the design of future transmissions for improved efficiency.

The vast and rich body of literature covering the numerical modelling of hydrodynamic floating body systems has demonstrated their great power and versatility when applied to offshore marine energy systems. It is possible to model almost any type of physical phenomenon which could be expected within such a system, however, limitations of computing power continue to restrict the usage of the most comprehensive models to very narrow and focused design applications. Despite the continued evolution of parallel computing, one major issue that users of computational tools invariably face is how to simplify their modelled systems in order to achieve practically the necessary computations, whilst capturing enough of the pertinent physics, with great enough ‘resolution’, to give robust results. The challenge is, in particular, to accurately deliver a complete spectrum of results, that account for all of the anticipated sea conditions and allow for the optimisation of different control scenarios. This thesis examines the uncertainty associated with the effects of viscosity and nonlinear behaviour on a small scale model of an oscillating system. There are a wide range of Computational Fluid Dynamics (CFD) methods which capture viscous effects. In general however, the oscillating, six degree-of-freedom floating body problem is best approached using a linear potential flow based Boundary Element Method (BEM), as the time taken to process an equivalent model will differ by several orders of magnitude. For modelling control scenarios and investigating the effects of different sea states, CFD is highly impractical. As potential flows are inviscid by definition, it is therefore important to know how much of an impact viscosity has on the solution, particularly when different scales are of interest during device development. The first aim was to develop verified and validated solutions for a generic type decaying system. The arrangement studied was adapted from an array tank test experiment which was undertaken in 2013 by an external consortium (Stratigaki et al., 2014). Solutions were delivered for various configurations and gave relatively close approximations of the experimental measurements, with the modelling uncertainties attributed to transient nonlinear effects and to dissipative effects. It was not possible however to discern the independent damping processes. A set of CFD models was then developed in order to investigate the above discrepancies, by numerically capturing the nonlinear effects, and the effects of viscosity. The uncontrolled mechanical effects of the experiment could then be deduced by elimination, using known response patterns from the measurements and derived results from the CFD simulations. The numerical uncertainty however posed a significant challenge, with the outcomes supported by verification evidence, and detailed discussions relating to the model configuration. Finally, the impact of viscous and nonlinear effects were examined for two different interacting systems – for two neighbouring devices, and an in-line array of five devices. The importance of interaction behaviour was tested by considering the transfer of radiation forces between the model wave energy converters, due to the widely accepted notion that array effects can impact on energy production yields. As there are only very limited examples of multi-body interaction analysis of wave energy devices using CFD, the results with this work provide important evidence to substantiate the use of CFD for power production evaluations of wave energy arrays. An effective methodology has been outlined in this thesis for delivering specific tests to examine the effects of viscosity and nonlinear processes on a particular shape of floating device. By evaluating both the inviscid and viscous solutions using a nonlinear model, the extraction of systematic mechanical effects from experimental measurements can be achieved. As these uncontrolled frictional effects can be related to the device motion in a relatively straightforward manner, they can be accommodated within efficient potential flow model, even if it transpires that they are nonlinear. The viscous effects are more complex; however, by decomposing into shear and pressure components, it may in some situations be possible to capture partially the dynamics as a further damping term in the efficient time-domain type solver. This is an area of further work.

Atmospheric icing presents serious challenges to the development of wind power of the wind energy industry in cold regions. The potential detrimental impact on the safe operation of wind turbines and the energy harvest hasn't been fully understood and requires further investigation. This thesis presents the research on icing profiles under different weather conditions and their impact on natural frequency, fatigue life, and lift and drag of the wind turbine blade. The research aims to develop a further understanding of the effect of atmospheric ice accretion on the structural integrity and aerodynamic performance of wind turbine blades through numerical and aerodynamic investigations to address the challenges facing the industry. A 5-MW NREL (National Renewable Energy Laboratory) wind turbine blade was selected for this study, due to availability of required geometric design parameters and experimental data for verification. The turbine rotor and its three blades were modelled and numerically simulated with commercial finite element software ANSYS. Three icing scenarios were chosen according to the ISO Standard and the corresponding icing profiles were developed to investigate their influence on vibrational behaviours of the wind turbine blade and rotor under different weather conditions. Icing loads were applied on the leading edge of the blade and natural frequency results were compared between clean and iced blades. It was found that harsh icing weather drove the natural frequency down to the near resonance limit, which could lead to significant issue on structural integrity of the wind turbine. The effect of atmospheric ice accretion with additional load due to varying wind speeds on the fatigue life of the wind turbine blade has been investigated. Significant reduction of fatigue life was found due to the increase of the von Mises stresses. Finally, computational fluid dynamics (CFD) analysis was carried out to investigate the effect of atmospheric ice accretion on the aerodynamic performance of typical 1-MW and 5-MW wind turbine blades. Results of the drag and lift coefficients and power production under different icing scenarios were obtained for five angles of attack. Compared with the results of the clean aerofoil profile, remarkable reduction in the power generation was observed due to the accreted ice at various aerofoil sections in the spanwise direction of the blade, demonstrating the detrimental impact of atmospheric icing on energy harvest for the wind energy industry.

This study verified if the behavior since formation to dissipation on a Mesoscale Convective Complex (MCC) is somehow related to the sea level rising caused by ocean tide. The objective of this study is to find a possible link between ocean height variation and the MCC event. The ocean tide data were obtained from the Banco Nacional de Dados Oceanográficos (BNDO) between January 2005 and December 2009. The MCC event data in this period were collected in previous researches in UFAL Sinoptics Laboratory which add up the total of 41 cases. When relating the ocean tide forecast data with the MCC, a significant relationship was observed. A significant variation in sea surface temperature related with MCC was detected. There was an evident relationship between seasonality with tide behavior and lunar phase and duration of MCC. The major occurrence of the MCC are in Autumn with 63% of the cases. There are no records of a Winter MCC. The MCC events reached its maximum growth in 63% of cases in the flood tide. The dissipation occurred in 56% of the tidal flow. A probable association between the sea temperature variation with depth of 60 meters with the occurrence of MCC event was verified. A more detailed study of the temperature variations is needed to confirm the relationship. / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Este estudo verificou se o comportamento desde formação à dissipação dos Complexos Convectivos de Mesoescala (CCM) está de alguma forma relacionado a elevação do nível do mar causada pela maré oceânica. O objetivo deste estudo é encontrar uma possível relação entre a variação da altura do oceano e o evento CCM. Foram utilizados os dados de previsão de maré oceânica, obtidos no Banco Nacional de Dados Oceanográficos (BNDO) entre Janeiro de 2005 e Dezembro de 2009. Os dados de eventos CCM no período de estudo, foram adquiridos em trabalhos anteriores do Laboratório de Sinótica da UFAL e somam o total de 41 casos. Ao cruzar os dados da previsão de maré oceânica com os de CCM, observou-se relações relevantes para o estudo. Foram observadas algumas situações de variação significativa na temperatura da superfície do mar com o evento CCM. Ficaram evidentes as relações de sazonalidade com comportamento da maré e fase lunar e duração do CCM. A maior ocorrência dos casos 63% é no Outono. Não existem ocorrências no Inverno. Os eventos de CCM atingiram seu máximo desenvolvimento em 63% dos casos na enchente da maré. A dissipação ocorreu em 56% na vazão da maré. Foi verificada uma possível relação entre a variação de temperatura do mar na profundidade de 60 metros com a ocorrência do evento CCM. Um estudo mais detalhado sobre as variações de temperatura se faz necessário para confirmar a relação.

This diploma thesis is considering with computational modeling of flow field with separation. In the first part it contains theoretical bases of flow field computational modeling with RANS models equations and wall treatment modeling approaches included. There is also flow separation in asymmetric plane diffuser modeling described in the thesis where the most suitable turbulent model and the proper mesh parameters for the successful flow separation modeling should be chosen. Next the chosen turbulent model and parameters verification via flow separation modeling on the asymmetric 3D diffuser mesh. That analysis should ensure if the chosen turbulent model is applicable also for engineering problems. At the end of the thesis there is evaluation if the setup chosen in the thesis is suitable to apply in any practical aeroacoustics problem modeling.

The master’s thesis is focused on flow analysis work filling in turbocharged CNG engine. The research method is reverse engineering. The intake canal is casted and than scanned by 3D Scanner ATOS. The CAD model is created in program Creo Parametric 2.0. In the created interactive model is simulated flow in the CFD program Star CCM +. The air intake system is modified for increasing the charging efficiency of the engine.

Abstract Granfrid, Signe, 2022: Relationen mellan Gud och människa: En genuskritisk analys av Hillsongs musik (The Relationship Between God and human: A Gender Critical analysis of Hillsongs music) Acta Universitatis Upsaliensis. Uppsala studies in Theology and Religious Studies, - Philosophical Specialisation In this essay the relationship between God and human is studied in music produced by Hillsong Church. The overall purpose is to analyse how the relationship is constructed concerning gender and the characteristics of a relationship. I also critically review the theology’s potential to invite people to relate to and live with God. The purpose is reached through an analysis of five of the most essential Hillsong songs; What a Beautiful Name, Who you say I am, Resurrender, Still and From the Inside Out. The method used is a descriptive and critical idea analysis with a hermeneutical approach. The study makes use of the Jewish philosopher Martin Buber’s theory of the makings of relationship, which emphasizes mutuality in the present as constitutive, and the Christian feminist theologian Sallie McFague’s thoughts on traditional portrayals of God. The analysis shows that the relationship between God and human lacks mutuality and is built on past experience of God rather than presence with God. God and human relate to one another through their fixated positions; human being broken and unable, and God the benignant rescuer, portrayed traditionally as Father and King. In the last chapter I reflect upon the theology expressed in the songs and present my own constructive contribution. I discuss in what way the human is affected by the theology presented and argue that the context in which interpretation takes place is of key importance. I also discuss different models of God and argue that complex and transcendent ones are needed. I propose a brave theology allowing elaborative thought of different ways to imagine God. Lastly, I discuss the human-divine relationship as such and propose a relational model on the basis of dialogue as a beneficent alternative to the hierarchy-based model found in Hillsong’s music.   Keywords: Hillsong, Models of God, Gender, Contemporary Christian Music (CCM), Pentecostal, Human-Divine-Relationship, Worship