This thesis explores the topic of flow of two immiscible liquids in horizontal pipeline. For this purpose, the experimental apparatus has been set up, that allows to observe the flow of mixture through the transparent pipe. Moderately viscous oil and water (viscosity ratio: 52,81, density ratio: 0.86, interfacial tension: 41,64 mN/m) have been chosen for the experiment. Both fluids were introduced into the pipe through a T-junction. At the end of the apparatus, a mixture of liquids flowed into the separation tank, where both phases were separated. The separated oil was then reused for further measurements. The oil and water flow rates could be individually changed by use control valves, that led to identification of different flow regimes. These varied from stratified flows to fully dispersed ones as the mixture speed increased. All observed flow regimes were plotted in the flow map, that is a function of the inlet velocities of both fluids. For further analysis, a second type of flow map has been created that displays rates as a function of mixture velocity and phase volume fraction. Selected regime was also simulated using software ANSYS FLUENT. The VOF method was used to simulate multiphase flow. This thesis critically evaluates the results of the study and shows the direction for further research in the field of immiscible liquids flow.

This master's thesis analyses fluid flow in an open cylindrical tank with vortex using numerical simulation. The theoretical part introduces a set of equations governing fluid flow and relations used to describe vortex motion. A general overview of terms used in computational fluid dynamics is presented. The experimental section consists of three parts. The vortex modelling is performed using ANSYS Fluent software. Data are consequently analysed within ANSYS CFD-Post software tool. Special focus is put on the vortex shape that is fitted with a curve corresponding to a probability density function of the Cauchy distribution. Results are then plotted in MATLAB software.

Aufgrund fluiddynamischer Effekte bei der Schnellerwärmung für die Warmumformung wird die Applikation der Technologie erschwert. Die vorliegende Arbeit thematisiert diesen Effekt und evaluiert die Triebkräfte sowohl numerisch als auch im Experiment. Aufbauend darauf werden Vermeidungsstrategien aufgezeigt und experimentell validiert um eine Verschiebung der Beschichtung zu verhindern. Es können insbesondere die temperatursensitive Marangonikraft als auch die magnethydrodynamische Wirkung der Lorentzkraft bei einer induktiven Erwärmung als Haupttriebkräfte identifiziert werden, die sich aufgrund identischer Kraftvektorrichtungen überlagern und verstärken. Es hat sich gezeigt, dass für den vorliegenden Fall einer 20-30 μm dünnen AlSi-Beschichtung die Marangonikraft gegenüber der Lorentzkraft um einen Faktor von mindestens 68 überwiegt. Ein vergleichbarer Effekt ist auch bei konduktiver Erwärmung zu beobachten. Hinsichtlich möglicher Vermeidungsstrategien einer globalen Beschichtungsverschiebung bietet die Applikation von lokalen Flussbarrieren mittels Laser, Induktion oder Walztexturierung, sowie das Vermeiden einer freien Flüssigkeitsoberfläche durch Aufbringen einer Zusatzbeschichtung, das größte Potential. / The application of fast heating technologies for hot forming is hindered by fluiddynamic effects and a resulting coating shift. Present thesis investigates this effect to evaluate the driving forces numerically as well as experimentally. Based on this evaluation, strategies are developed and investigated to avoid a global displacement of the AlSi-coating. In case of inductive fast heating the main driving force is represented by a superposition of Lorentzian forces as well as surface tension related Marangoni forces with a force vector pointing from hot to cold regions on the blank. The numerical evaluation shows that in case of 20-30 μm thin layers of AlSi the Marangoni force is at least 68 times higher than the Lorentz force and therefore represents the main driving force. A comparable effect is observable in case of conduction heating. Local flow barriers realized by Laser, inductive heating or texturing as well as the avoidance of a free liquid-surface due to application of additional coating layers show huge potential to prevent a global coating flow.

The subject of this study is the determination of the resistance of an inland vessel engaged in cargo transport in the lower course of the Magdalena River, considering that the hydrodynamic effects in shallow water navigation are very different compared to the effects in deep water navigation. The hydrodynamic analysis is realized numerically using Computational Fluid Dynamics (CFD). The Reynolds-Averaging Navier-Stokes equation (RANS) solver is applied to simulate viscous and pressure effects around a tank and a hull in confined tank considering the wall bottom and side effects in shallow water navigation. For turbulence effects, realizable k-? model is used. The motion of the vessel causes elevations of the free surface, in which, is captured using the Volume of Fluid method (VOF). For discretization of flow domain, the Finite Volume Method (FVM) is applied. The motion of the fluids is updated for each time step that allows the calculation of the resistance acting on the hull. The numerical simulation results are compared with experimental data obtained by the Technological Research Institute of the State of São Paulo (IPT, acronym in Portuguese) together with the existing empirical methods for this type of cases. / É apresentado um estudo para determinar a resistência de uma barcaça empregada no transporte de carga que poderia operar no setor baixo do rio Magdalena. Os efeitos hidrodinâmicos de um navio em águas rasas são muito diferentes, comparados a esses efeitos em águas com profundidade infinita. A análise hidrodinâmica é realizada numericamente usando a Dinâmica dos Fluidos Computacional (CFD, acrônimo em inglês). A solução das equações de Navier-Stokes (NS) junto com a decomposição do Reynolds (RANS, acrônimo em inglês) é aplicada para simular os efeitos viscosos e de pressão em torno de um tanque e de uma embarcação em um tanque confinado que é caracterizado pelos efeitos do fundo e das paredes. Para efeitos de turbulência, o modelo realizado k-? é usado. O movimento da embarcação do rio provoca elevações da superfície livre que são capturadas usando o método do Volume de Fluido (VOF, acrônimo em inglês). Para a discretização do domínio de fluxo, o Método dos Volumes Finitos (FVM, acrônimo em inglês) é utilizado. O movimento dos fluidos é atualizado para cada intervalo de tempo o que permite o cálculo da resistência atuando no casco. Os resultados da simulação numérica são comparados com dados experimentais obtidos pelo Instituto de Pesquisas Tecnológicas do Estado de São Paulo (IPT), juntamente com os métodos empíricos existentes para esse tipo de casos.

Les processus dynamiques présents en zone de swash ont un impact significatif sur l'évolution des zones côtières. Une part importante du transport sédimentaire cross-shore se produit dans cette zone, plus particulièrement dans cette zone où se produisent le run-up et le run-down. La zone située au-delà de la ligne de rivage au repos est le plus souvent décrite par des modèles intégrés sur la verticale. La décroissance des vagues est bien reproduite, cependant l'étude du transport sédimentaire impose une paramétrisation du frottement sur le fond. Nous présentons les résultats de simulations RANS de la propagation d'un mascaret (obtenu par un "lâcher de barrage") sur une plage en pente et le run-up et le run-down ainsi générés. Les résultats numériques sont comparés aux résultats expérimentaux de Yeh et al. (1989). Les simulations ont été réalisées avec le code Navier-Stokes diphasique AQUILON. Deux méthodes de suivi d'interface VOF (VOF TVD ET VOF PLIC) sont implémentées. La viscosité turbulente est calculée par un modèle V2-F (Durbin, 1991). Une estimation des grandeurs turbulentes k et epsilon basée sur la théorie des ondes longues pour la propagation d'un ressaut hydraulique est présentée. Une modélisation VOF-PLIC & V2-F est appliquée pour reproduire les caractéristiques macroscopiques du lâcher de barrage, qui comme on pouvait s'y attendre dépendent peu de la turbulence. Nous étudions aussi l'impact des conditions initiales sur k et epsilon sur l'établissement de l'écoulement turbulent. Après ces validations vis-à-vis de la turbulence, des simulations du cas décrit par Yeh et al. (1989) sont menées pour optimiser le choix des paramètres de calcul. La théorie de Whitham (1958), prédit un effondrement du mascaret au niveau de la ligne de rivage au repos. La théorie de Shen and Meyer (1963) est toujours à l'heure actuelle le modèle de référence. Les résultats expérimentaux de Yeh et al. (1989) montrent clairement un phénomène différent. L'utilisation conjointe de la technique VOF-TVD et du modèle de turbulence V2-F semble apporter les meilleurs résultats par rapport aux expériences de Yeh et al. (1989). Une étude de la transition mascaret/lame de swash est proposée. Nos résultats montrent que la théorie de Whitham décrit de façon assez précise le mécanisme de d'effondrement du mascaret. Les résultats de nos simulations sont utilisés pour décrire la transition entre l'effondrement du mascaret et l'écoulement du run-up. L'analyse des processus de frottement dans le jet de rive met en évidence une forte dissymétrie entre le run-up et le run-down avec cisaillement plus faible lors du run-down

Worldwide demand for energy is increasing rapidly, partly driven by dramatic economic growth in developing countries. This growth has sparked concerns over the finite availability of fossil fuels and the impact of their combustion on climate change. Consequently, many recent research efforts have been devoted to the development of renewable fuels and sustainable energy systems. Interest in liquid biofuels, such as ethanol, has been particularly high because these fuels fit into the conventional infrastructure for the transportation sector. Ethanol is a renewable fuel produced through the anaerobic fermentation of sugars obtained from biomass. However, the relatively high energy demand of its production process is a major factor limiting the usefulness of ethanol as a fuel. Due to the dilute nature of the fermentation product stream and the presence of the ethanol-water azeotrope, the separation processes currently used to recover anhydrous ethanol are particularly inefficient. In fact, the ethanol separation processes account for a large fraction of the total process energy demand. In the conventional ethanol separation process, ethanol is recovered using several distillation steps combined with a dehydration process. In this dissertation, a new hybrid pervaporation-distillation system, named Membrane Dephlegmation, was proposed and investigated for use in ethanol recovery. In this process, countercurrent vapour-liquid contacting is carried out on the surface of a pervaporation membrane, leading to a combination of distillation and pervaporation effects. It was intended that this new process would lead to improved economics and energy efficiency for the entire ethanol production process. The Membrane Dephlegmation process was investigated using both numerical and experimental techniques. Multiphase Computational Fluid Dynamics (CFD) was used to study vapour-liquid contacting behaviour in narrow channels and to estimate heat and mass transfer rates. Results from the CFD studies were incorporated into a simplified design model and the Membrane Dephlegmation process was studied numerically. The results indicated that the Membrane Dephlegmation process was more efficient than simple distillation and that the ethanol-water azeotrope could be broken. Subsequently, a pilot-scale experimental system was constructed using commercially available, hydrophilic NaA zeolite membranes. Results obtained from the experimental system confirmed the accuracy of the simulations.

Worldwide demand for energy is increasing rapidly, partly driven by dramatic economic growth in developing countries. This growth has sparked concerns over the finite availability of fossil fuels and the impact of their combustion on climate change. Consequently, many recent research efforts have been devoted to the development of renewable fuels and sustainable energy systems. Interest in liquid biofuels, such as ethanol, has been particularly high because these fuels fit into the conventional infrastructure for the transportation sector. Ethanol is a renewable fuel produced through the anaerobic fermentation of sugars obtained from biomass. However, the relatively high energy demand of its production process is a major factor limiting the usefulness of ethanol as a fuel. Due to the dilute nature of the fermentation product stream and the presence of the ethanol-water azeotrope, the separation processes currently used to recover anhydrous ethanol are particularly inefficient. In fact, the ethanol separation processes account for a large fraction of the total process energy demand. In the conventional ethanol separation process, ethanol is recovered using several distillation steps combined with a dehydration process. In this dissertation, a new hybrid pervaporation-distillation system, named Membrane Dephlegmation, was proposed and investigated for use in ethanol recovery. In this process, countercurrent vapour-liquid contacting is carried out on the surface of a pervaporation membrane, leading to a combination of distillation and pervaporation effects. It was intended that this new process would lead to improved economics and energy efficiency for the entire ethanol production process. The Membrane Dephlegmation process was investigated using both numerical and experimental techniques. Multiphase Computational Fluid Dynamics (CFD) was used to study vapour-liquid contacting behaviour in narrow channels and to estimate heat and mass transfer rates. Results from the CFD studies were incorporated into a simplified design model and the Membrane Dephlegmation process was studied numerically. The results indicated that the Membrane Dephlegmation process was more efficient than simple distillation and that the ethanol-water azeotrope could be broken. Subsequently, a pilot-scale experimental system was constructed using commercially available, hydrophilic NaA zeolite membranes. Results obtained from the experimental system confirmed the accuracy of the simulations.

Cette thèse vise à améliorer le fonctionnement de la boîte à eau d'un véhicule automobile, organe destiné à évacuer l'eau de pluie et à alimenter l'habitacle en air propre et sec. Elle se concentre plus particulièrement sur le phénomène de tourbillon de vidange qui a pour effet de limiter le débit d'évacuation et d'augmenter le niveau d'eau dans la boîte. Cette hausse de niveau peut être source de problèmes allant de l'inconfort pour les occupants du véhicule jusqu'à une panne du boîtier de ventilation, chauffage et climatisation. Une étude expérimentale de l'écoulement est d'abord réalisée sur une géométrie simplifiée. La vélocimétrie par images de particules (PIV) et des mesures de niveau par sonde capacitive sont mises en oeuvre. A partir d'images obtenues par caméra rapide, un algorithme d'analyse d'images est développé pour mesurer le diamètre du noyau d'air au coeur du tourbillon. Ces techniques de mesure permettent d'étudier la structure du tourbillon et montrent qu'il existe une interaction entre le tourbillon et l'écoulement d'air destiné à la ventilation de l'habitacle. Cette interaction est liée à la dépression générée par l'écoulement d'air : elle modifie temporairement la structure du tourbillon et conduit à un nouvel état d'équilibre à un niveau inférieur au niveau initial. Un dispositif permettant de réduire efficacement le niveau d'eau en modifiant l'écoulement en amont du tourbillon est aussi étudié et a fait l'objet d'un dépôt de brevet. Des simulations numériques sont ensuite réalisées à l'aide du code de calcul OpenFOAM et reproduisent qualitativement l'écoulement observé expérimentalement. Bien que des différences existent sur la valeur du niveau d'eau, les dimensions et la position du noyau d'air sont correctement simulées. Enfin, les résultats expérimentaux et numériques sont comparés aux modèles de tourbillon de la littérature.

Worldwide demand for energy is increasing rapidly, partly driven by dramatic economic growth in developing countries. This growth has sparked concerns over the finite availability of fossil fuels and the impact of their combustion on climate change. Consequently, many recent research efforts have been devoted to the development of renewable fuels and sustainable energy systems. Interest in liquid biofuels, such as ethanol, has been particularly high because these fuels fit into the conventional infrastructure for the transportation sector. Ethanol is a renewable fuel produced through the anaerobic fermentation of sugars obtained from biomass. However, the relatively high energy demand of its production process is a major factor limiting the usefulness of ethanol as a fuel. Due to the dilute nature of the fermentation product stream and the presence of the ethanol-water azeotrope, the separation processes currently used to recover anhydrous ethanol are particularly inefficient. In fact, the ethanol separation processes account for a large fraction of the total process energy demand. In the conventional ethanol separation process, ethanol is recovered using several distillation steps combined with a dehydration process. In this dissertation, a new hybrid pervaporation-distillation system, named Membrane Dephlegmation, was proposed and investigated for use in ethanol recovery. In this process, countercurrent vapour-liquid contacting is carried out on the surface of a pervaporation membrane, leading to a combination of distillation and pervaporation effects. It was intended that this new process would lead to improved economics and energy efficiency for the entire ethanol production process. The Membrane Dephlegmation process was investigated using both numerical and experimental techniques. Multiphase Computational Fluid Dynamics (CFD) was used to study vapour-liquid contacting behaviour in narrow channels and to estimate heat and mass transfer rates. Results from the CFD studies were incorporated into a simplified design model and the Membrane Dephlegmation process was studied numerically. The results indicated that the Membrane Dephlegmation process was more efficient than simple distillation and that the ethanol-water azeotrope could be broken. Subsequently, a pilot-scale experimental system was constructed using commercially available, hydrophilic NaA zeolite membranes. Results obtained from the experimental system confirmed the accuracy of the simulations.

At the Torpshammar dam two rectangular beams are situated upstream of the spillway gates to stabilize the sidewalls holding the embankment of the dam. A computational fluid dynamics (CFD) simulation of the dam with the bottom outlets open was made to investigate how the flow and discharge capacity is affected by the beams. The results can be used to avoid unexpected consequences due to turbulence caused by the beams, make the beams strong enough to hold the pressure from the flow and get an estimation of the discharge capacity with the beams. Turbulence is one of the hardest things to simulate so the results were compared with previous simulation work made without the beams and physical model tests to validate the results. Also, a sensitivity analysis was made to investigate the method used. The beams lowered the velocity (to 17 m/s) and the discharge capacity (to 255 m3/s) compared to the previous work. The force on the beams was directed upward and downstream. The beams increased the turbulence and the vortex shedding frequency was higher for the beam closest to the outlet. The velocity and discharge capacity differed with 6 % compared to model test results. The results can therefore only be used as an estimation, a more detailed computational model and more computational cells are needed to get a better result. The sensitivity analysis showed that the velocity and turbulence depend on the method and further studies need to be made to decide which method gives the closest similarity with reality.