Дисертації з теми "Hydrodynamics- Liquid flow"
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Abadie, Thomas. "Hydrodynamics of gas-liquid Taylor flow in microchannels." Phd thesis, Toulouse, INPT, 2013. http://oatao.univ-toulouse.fr/11986/1/abadie.pdf.
Повний текст джерелаWelsh, Susan A. "Hydrodynamic characteristics of countercurrent gas-pseudoplastic liquid two-phase channel flow." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/16923.
Повний текст джерелаVan, der Merwe Werner. "The Morphology of Trickle Flow Liquid Holdup." Diss., University of Pretoria, 2005. http://hdl.handle.net/2263/31385.
Повний текст джерелаDissertation (MEng)--University of Pretoria, 2004.
Chemical Engineering
Unrestricted
Stoodley, Paul. "The influence of liquid flow and nutrients on biofilm structure and behaviour." Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286538.
Повний текст джерелаCui, Zhe. "Hydrodynamics in a bubble column at elevated pressures and turbulence energy distribution in bubbling gas-liquid and gas-liquid-solid flow systems." Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1109956144.
Повний текст джерелаTitle from first page of PDF file. Document formatted into pages; contains xxiii, 187 p.; also includes graphics Includes bibliographical references (p. 179-187). Available online via OhioLINK's ETD Center
Xie, Tao. "Hydrodynamic characteristics of gas/liquid/fiber three-phase flows based on objective and minimally-intrusive pressure fluctuation measurements." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-09192004-033703/unrestricted/xie%5Ftao%5F200412%5Fphd.pdf.
Повний текст джерелаD. William Tedder, Committee Member ; Minami Yoda, Committee Member ; Tom McDonough, Committee Member ; Andrei G. Fedorov, Committee Member ; S. Mostafa Ghiaasiaan, Committee Chair ; Seppo Karrila, Committee Member. Includes bibliographical references.
Van, Houwelingen ArJan. "Liquid-solid contacting in trickle-bed reactors." Thesis, University of Pretoria, 2009. http://hdl.handle.net/2263/30008.
Повний текст джерелаThesis (PhD)--University of Pretoria, 2009.
Chemical Engineering
unrestricted
Yang, Li. "CFD MODELING OF MULTIPHASE COUNTER-CURRENT FLOW IN PACKED BED REACTOR FOR CARBON CAPTURE." UKnowledge, 2015. http://uknowledge.uky.edu/me_etds/59.
Повний текст джерелаSerres, Marion. "Étude hydrodynamique d'un écoulement gaz-liquide dans un milieu poreux confiné." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEN018/document.
Повний текст джерелаThis thesis focuses on gas-liquid flow in porous media, a common problem encountered in various domains from fundamental physics to applied chemical engineering. We have characterized the hydrodynamic regimes based on two different experimental devices geometry: a millichannel (1D flow) and a Hele-Shaw cell (2D flow). The originality of this work is to analyze the influence of the porous medium (monodisperse micro-packed beds or open cell solid foams), confinement (1D/2D) and gravity by coupling global and local analysis from either chemical engineering or fundamental physics community. On the one hand, a global analysis made it possible to quantify pressure drops, residence time distributions (RTD) based on fluorescent dye transport and gas-liquid mass transfer on the 1D device. On the other hand, a local analysis of the liquid fraction and the spatio-temporal evolution of its frequency pointed out the existence of two hydrodynamic regimes: a Taylor-like regime in which the characteristics of the periodic flow upstream are conserved in the porous medium and a modulated regime characterized by the flow disorganization at the porous medium entrance. A phenomenological model is developed based on bubbles propagation inside the medium and reproduces well both regimes. These two analyses are finally coupled to study multiphase flows inside the Hele-Shaw cell. The effects of gravity and confinement are discussed
Barrios, Evelyn. "Hydrodynamique des reacteurs a lit fixe avec ecoulement en co-courant ascendant de gaz et de liquide." Paris 6, 1987. http://www.theses.fr/1987PA066066.
Повний текст джерелаBraga, Maria. "Étude des phénomènes de transfert et de l'hydrodynamique dans des réacteurs agités à panier catalytique." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10011/document.
Повний текст джерелаStationary catalytic basket stirred reactors are often used among the various three-phase laboratory reactors for primary screening of commercial shaped catalysts. Until today, hydrodynamics and mass transfer studies concerning the impact of the presence of the basket in the flow are scarce which can be an obstacle to catalyst screening mainly in the case of fast reactions. The aim of this study is to know the range of applicability of these devices and optimize them if necessary. A characterization methodology that couples hydrodynamics and mass transfer was developed. The hydrodynamic studies allowed establishing a flow regime map of the gas/liquid flow for different reactor designs and operational conditions. This study has allowed as well understanding the influence of the basket and gas bubbles on gas/liquid and solid/liquid mass transfer. For the studied reactor, the liquid/solid mass transfer is the limiting phenomena. This system can however be used for catalyst screening for reaction rate constants smaller than 0.02 s-1. For faster reactions, these devices must be improved by changing the design of basket and impeller and the tank diameter. The optimized configuration should improve de radial flow through the porous medium and avoid the flow bypassing around the basket
Viré, Axelle. "Study of the dynamics of conductive fluids in the presence of localised magnetic fields: application to the Lorentz force flowmeter." Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210062.
Повний текст джерелаThis interaction is the object of magnetohydrodynamics, a discipline which covers a wide range of applications, from electromagnetic processing to plasma- and astro-physics.
In this dissertation, the attention is restricted to turbulent liquid metal flows, typically encountered in steel and aluminium industries. Velocity measurements in such flows are extremely challenging because liquid metals are opaque, hot and often corrosive. Therefore, non-intrusive measurement devices are essential. One of them is the Lorentz force flowmeter. Its working principle is based on the generation of a force acting on a charge, which moves in a magnetic field. Recent studies have demonstrated that this technique can measure efficiently the mean velocity of a liquid metal. In the existing devices, however, the measurement depends on the electrical conductivity of the fluid.
In this work, a novel version of this technique is developed in order to obtain measurements that are independent of the electrical conductivity. This is particularly appealing for metallurgical applications, where the conductivity often fluctuates in time and space. The study is entirely numerical and uses a flexible computational method, suitable for industrial flows. In this framework, the cost of numerical simulations increases drastically with the level of turbulence and the geometry complexity. Therefore, the simulations are commonly unresolved. Large eddy simulations are then very promising, since they introduce a subgrid model to mimic the dynamics of the unresolved turbulent eddies.
The first part of this dissertation focuses on the quality and reliability of unresolved numerical simulations. The attention is drawn on the ambiguity that may arise when interpretating the results. Owing to coarse resolutions, numerical errors affect the performances of the discrete model, which in turn looses its physical meaning. In this work, a novel implementation of the turbulent strain rate appearing in the models is proposed. As opposed to its usual discretisation, the present strain rate is in accordance with the discrete equations of motion. Two types of flow are considered: decaying turbulence located far from boundaries, and turbulent flows between two parallel and infinite walls. Particular attention is given to the balance of resolved kinetic energy, in order to assess the role of the model.
The second part of this dissertation deals with a novel version of Lorentz force flowmeters, consisting in one or two coils placed around a circular pipe. The forces acting on each coil are recorded in time as the liquid metal flows through the pipe. It is highlighted that the auto- or cross-correlation of these forces can be used to determine the flowrate. The reliability of the flowmeter is first investigated with a synthetic velocity profile associated to a single vortex ring, which is convected at a constant speed. This configuration is similar to the movement of a solid rod and enables a simple analysis of the flowmeter. Then, the flowmeter is applied to a realistic three-dimensional turbulent flow. In both cases, the influence of the geometrical parameters of the coils is systematically assessed.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Zhang, Tong. "Hydrodynamique et étude des transferts de matière gaz-liquide avec réaction dans des microcanaux circulaires." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00804363.
Повний текст джерелаPani, Fatos. "Hydrodynamique et transferts de matiere en reacteurs agites gaz-liquide et gaz-liquide-liquide : application oxydante du cuivre par lix 65n-hs." Paris, ENMP, 1987. http://www.theses.fr/1987ENMP0034.
Повний текст джерелаRoy, Ajoy Krishna. "Application of smooth particle hydrodynamics to solid-liquid flows." Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/2108/.
Повний текст джерелаGreco, Edwin F. "Thermal and hydrodynamic interactions between a liquid droplet and a fluid interface." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22548.
Повний текст джерелаCommittee Chair: Roman O. Grigoriev; Committee Member: Daniel Goldman; Committee Member: Michael Schatz; Committee Member: Minami Yoda; Committee Member: Predrag Cvitanovic.
Rapisarda, Andrea. "Hydrodynamic characterization of two/three phase flow regimes in stirred tank." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Знайти повний текст джерелаNaderifar, Abbas. "Étude expérimentale locale et globale du transfert de matière liquide/solide à la paroi d'un réacteur à lit fixe." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL149N.
Повний текст джерелаHineman, Jay Lawrence. "THE HYDRODYNAMIC FLOW OF NEMATIC LIQUID CRYSTALS IN R3." UKnowledge, 2012. http://uknowledge.uky.edu/math_etds/7.
Повний текст джерелаWu, Xuemei. "Hydrodynamic characteristics of countercurrent two-phase flows involving highly viscous liquids." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/17293.
Повний текст джерелаScarratt, Liam Ronald John. "Wetting and Liquid Flow on Lubricant Infused Nano- and Micro-Structured Surfaces." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/20048.
Повний текст джерелаBudakli, Mete [Verfasser], Peter [Akademischer Betreuer] Stephan, Tatiana [Akademischer Betreuer] Gambaryan-Roisman, and Cameron [Akademischer Betreuer] Tropea. "Hydrodynamics and Heat Transfer in Gas-Driven Liquid Film Flows / Mete Budakli. Betreuer: Peter Stephan ; Tatiana Gambaryan-Roisman ; Cameron Tropea." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2015. http://d-nb.info/111098068X/34.
Повний текст джерелаFernandes, Hipolito Ana Isabel. "Étude des phénomènes de transport dans un réacteur catalytique pilote de type filaire." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10285/document.
Повний текст джерелаSmall size fixed-bed reactors are a common choice for testing industrial supported catalyst under industrial operating conditions. The most common criterion for reactor’s scale-down is based on the conservation of the liquid hourly space velocity which leads to a very low fluid flow velocity at the laboratory scale. Under these conditions, the external mass transfer flux can become the limiting step of the process. In this context, a new reactor geometry was proposed to intensify mass and heat transfers and to increase fluid flow velocities: the single pellet string reactor. This reactor is composed of a tube with an internal diameter close to that of the catalyst particles and with a high length over diameter ratio. The main goal of this thesis is to characterise the hydrodynamic and external mass transfer performances of this new reactor in order to define its application domain. In two-phase gas-liquid flow, the reactor flow is plug flow and the liquid hold-up values are high, which insures a complete wetting of the catalyst particles. The mass transfer coefficients were quantified and the measured rates are much higher than those observed in conventional pilot fixed-bed reactors, which can be explained by the increased local liquid velocities and by the modified Taylor flow regime. Catalytic tests with a very fast model reaction revealed that the external mass transfer performances of the single pellet string reactor are close to those measured in a stirred tank reactor equipped with a catalytic basket. In conclusion, the single pellet string reactor represents a new and efficient alternative to fixed-bed pilot reactors to study shaped catalysts
Fourtakas, Georgios. "Modelling multi-phase flows in nuclear decommissioning using SPH." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/modelling-multiphase-flows-in-nuclear-decommissioning-using-sph(f5ed0b5b-ea62-431a-bb6e-a18635d396bc).html.
Повний текст джерелаLiedtke, Anne-Kathrin. "Study of a new gas-liquid-solid three phase contact mode at millimetric scale : catalytic reactors using “slurry Taylor” flow." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10137/document.
Повний текст джерелаSlurry reactors, widely encountered in chemical industry (laboratory scale up to manufactaring), offer good mass and heat transfer capacities and their high flexibility ensures the simple changeover of solid phases enables a continuous online fresh catalyst feed for fast deactivating catalysts. However slurry reactors promote a high degree of backmixing which can be a drawback for reactions with selectivity issues or when very high conversions are required. In microreaction technology, Taylor flow is often employed providing excellent heat and mass transfer and almost ideal plug flow behavior. Solid handing in these small structures is often resolved by immobilizing the solid catalyst which impinges on the flexibility. One possible solution to combine beneficial properties of Taylor flow with the operational flexibility of conventional slurry reactors is a “slurry Taylor” flow (STF) where catalyst particles are suspended and kept in motion by the internal circulations present in the liquid slugs. The focus of this work is the design and characterization of this innovative gas-liquid-solid contactor. Particles were transported in millimetric horizontal and vertical tubing without the risk of clogging. Hydrodynamic studies revealed different flow patterns depending mainly on velocity and flow orientation. Ion exchange resin particles were used to study the liquid-solid mass transfer and first correlation for the Sherwood number in STF is proposed
Fanzar, Abdelaziz. "Développement d’un code numérique pour la simulation et l’étude de l’hydrodynamique et de la physico-chimie de milieux diphasiques incompressibles. Cas d’une goutte d’eau dans l’huile de paraffine." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4339.
Повний текст джерелаFor several decades, an important scientific activity has focused on the numerical, theoretical and experimental hydrodynamics of drops. This work presents numerical results of a single droplet in the gravity field and in non-isothermal conditions. The simulation such a multiphase system is important in both academic and industrial world. This is particularly the case in the field of emulsions, wetting problems and evaporation. To achieve this goal, there are still important algorithmic problems due to the free moving interfaces and the description of capillary effects. Here, a Volume of Fluid technique has been implemented with high order temporal and spatial schemes to preserve the sharpness of the drop interface. The system under consideration is a simplified model consisting in a single water droplet in a continuous paraffin oil phase. These liquids are immiscible and non-compressible and the overall evolution is unsteady. Capillary contributions such as temperature and surfactant dependent surface tension are fully accounted for. This presentation is aimed to show the capabilities of VOF techniques for the simulations of unsteady multiphase systems in non-isothermal configurations. The role of the droplet initial position and temperature field is described with good numerical stability. There are still important problems remaining in the simulation of free interface systems with such a technique. Spurious currents induced by the description of capillarity can in particular come into play. But these latter can be controlled once the droplet average velocity due to drainage becomes large enough
Toupoint, Clément. "Path and wake of cylinders falling in a liquid at rest or in a bubble swarm towards the hydrodynamical modeling of ebullated bed reactors." Thesis, Toulouse, INPT, 2018. http://oatao.univ-toulouse.fr/24120/1/Clement_Toupoint.pdf.
Повний текст джерелаTijani, Niass. "Instabilités d'interfaces dans un écoulement gaz-liquide à contre courant." Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL111N.
Повний текст джерелаMarth, Wieland. "Hydrodynamic Diffuse Interface Models for Cell Morphology and Motility." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-204651.
Повний текст джерелаDiese Dissertation beschäftigt sich mit mathematischen Modellen zur Beschreibung von Gleichgewichts- und dynamischen Zuständen von verallgemeinerten biologischen Zellen. Die Zellen werden dabei als thermodynamisches System aufgefasst, bei dem Strömungseffekte innerhalb und außerhalb der Zelle zusammen mit einem Helfrich-Modell für Zellmembranen kombiniert werden. Schließlich werden durch einen Energie-Variations-Ansatz die Evolutionsgleichungen für die Zelle hergeleitet. Es ergeben sie dabei Mehrphasen-Systeme, die Strömungseffekte mit einem freien Randwertproblem, das zusätzlich physikalischen Einflüssen wie Biegung und Oberflächenspannung unterliegt, vereinen. Um solche Probleme effizient zu lösen, wird in dieser Arbeit die Diffuse-Interface-Methode verwendet. Ein Vorteil dieser Methode ist, dass es sehr einfach möglich ist, Modelle, die verschiedenste Prozesse beschreiben, miteinander zu vereinen. Dies erlaubt es, komplexe biologische Phänomene, wie zum Beispiel Zellmotilität oder auch die kollektive Bewegung von Zellen, zu beschreiben. In den Modellen für Zellmotilität wird ein biologisches Netzwerk-Modell für GTPasen oder auch ein Active-Polar-Gel-Modell, das die Aktinfilamente im Inneren der Zellen als Flüssigkristall auffasst, mit dem Multi-Phasen-Modell kombiniert. Beide Modelle erlauben es, komplexe Vorgänge bei der selbst hervorgerufenen Bewegung von Zellen, wie das Vorantreiben der Zellmembran durch Aktinpolymerisierung oder auch die Kontraktionsbewegung des Zellkörpers durch kontraktile Spannungen innerhalb des Zytoskelets der Zelle, zu verstehen. Weiterhin ist die kollektive Bewegung von vielen Zellen von großem Interesse, da sich hier viele nichtlineare Phänomene zeigen. Um das Diffuse-Interface-Modell für eine Zelle auf die Beschreibung mehrerer Zellen zu übertragen, werden mehrere Phasenfelder eingeführt, die die Zellen jeweils kennzeichnen. Schließlich werden die Zellen durch ein lokales Abstoßungspotential gekoppelt. Das Modell wird angewendet, um White blood cell margination, das die Annäherung von Leukozyten an die Blutgefäßwand bezeichnet, zu verstehen. Dieser Prozess wird dabei bestimmt durch den komplexen Zusammenhang zwischen Kollisionen, den jeweiligen mechanischen Eigenschaften der Zellen, sowie deren Auftriebskraft innerhalb der Adern. Die Simulationen zeigen, dass diese Annäherung sich in bestimmten Gebieten des kardiovaskulären Systems stark vermindert, in denen die Blutströmung das Stokes-Regime verlässt. Schließlich wird das Active-Polar-Gel-Modell mit dem Modell für die kollektive Bewegung vom Zellen kombiniert. Dies macht es möglich, die kollektive Bewegung der Zellen und den Einfluss von Hydrodynamik auf diese Bewegung zu untersuchen. Es zeigt sich dabei, dass der Zustand der kollektiven gerichteten Bewegung sich spontan aus der Neuausrichtung der jeweiligen Zellen durch inelastische Kollisionen ergibt. Obwohl die Hydrodynamik einen großen Einfluss auf solche Systeme hat, deuten die Simulationen nicht daraufhin, dass Hydrodynamik die kollektive Bewegung vollständig unterdrückt. Weiterhin wird in dieser Arbeit gezeigt, wie die stark gekoppelten Systeme numerisch gelöst werden können mit Hilfe der Finiten-Elemente-Methode und wie die Effizienz der Methode gesteigert werden kann durch die Anwendung von Operator-Splitting-Techniken und Problemparallelisierung mittels OPENMP
Antariksawan, Anhar Riza. "Interaction thermique acier inoxydable fondu-eau sur l'installation SEIZIES : analyse et interprétation." Grenoble INPG, 1993. http://www.theses.fr/1993INPG0038.
Повний текст джерелаHassen, Barkai Allatchi. "Caractérisation d’un écoulement diphasique dans un airlift sous dépression. Application pour l’extraction des matières solides en suspension." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI038.
Повний текст джерелаBubble columns are gas-liquid contactors widely used in industry, especially in chemical, biological and mineralogical process applications. In the range of bubble columns available, the vacuum airlift is a French innovation with very interesting characteristics for hydraulic pumping, mass transfer and suspended matter separation. This thesis work is part of the development of this improved airlift, which is widely used in the industrial environment. The objective of the thesis is the hydrodynamic characterization of the airlift column under vacuum and analysis of its capacities to ensure the solid-liquid separation function. This work is exclusively experimental and the experimental setup is a vertical bubble column in plexiglass under vacuum and connected to a recirculation basin. The hydrodynamic analysis was carried out using a differential pressure sensor for the global study and using a double optical probe for local characterization. Results obtained made it possible to study flow regime. The main parameters obtained are the void fraction, superficial velocity and bubbles diameter. Particle Image Velocimetry is applied to visualize and analyze the flow structures in the recirculation basin. The extracting capacities of the column were studied in tap water with the addition of surfactants. Soluble casein and Methyl Iso Butyl Carbinol (MIBC) are the two surfactants that have given the best results in terms of solid-liquid separation of suspended matter. This work contributed to the understanding hydrodynamics for vacuum airlift column and helped to highlight the potential of this column in the solid-liquid separation process. This work also opens the way to numerical modelling of airlift column hydrodynamics from experimental results
Maquet, Jean. "Contribution à l'étude des mécanismes de surstabilité d'une surface libre chauffée par un laser ou un fil chaud." Rouen, 1987. http://www.theses.fr/1987ROUES047.
Повний текст джерелаCorot, Théo. "Simulation numérique d'ondes de choc dans un milieu bifluide : application à l'explosion vapeur." Thesis, Paris, CNAM, 2017. http://www.theses.fr/2017CNAM1125/document.
Повний текст джерелаThis thesis studies numerical simulation of steam explosion. This phenomenon correspond to a fast vaporization of a liquid leading to a pressure shock. It is of interest in the nuclear safety field. During a core-meltdown crisis, molten fuel rods interacting with water could lead to steam explosion. Consequently we want to evaluate the risks created by this phenomenon.In order to do it, we use Euler equations written in a Lagrangian form. This description has the advantage of following the fluid motion and consequently preserves interfaces between the liquid and its vapor. To solve these equations, we develop a new Godunov type scheme using nodal fluxes. The nodal solver developed here only depends on the angular repartition of the physical variables around the node.Moreover, we study liquid-vapor phase changes. We describe a method to take it into account and highlight the advantages of using this method into a Lagrangian framework
Thiébaud, Marine. "Quelques aspects de la physique des interfaces cisaillées : Hydrodynamique et Fluctuations." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2011. http://tel.archives-ouvertes.fr/tel-00769006.
Повний текст джерелаSantos, Tiago Sotto Mayor Moura. "Hydrodynamics of gas-liquid flows in slug flow regime." Doctoral thesis, 2007. http://hdl.handle.net/10216/11060.
Повний текст джерелаSantos, Tiago Sotto Mayor Moura. "Hydrodynamics of gas-liquid flows in slug flow regime." Tese, 2007. http://hdl.handle.net/10216/11060.
Повний текст джерелаElekaei, Behjati Hamideh. "Study of immiscible liquid-liquid microfluidic flow using SPH-based explicit numerical simulation." Thesis, 2016. http://hdl.handle.net/2440/102887.
Повний текст джерелаThesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Chemical Engineering, 2016.
Van, der Merwe Werner. "The Morphology of trickle flow liquid holdup." 2004. http://upetd.up.ac.za/thesis/available/etd-02162005-085324/.
Повний текст джерелаEvans, Geoffrey Michael. "A Study of a Plunging Jet Bubble Column." Thesis, 1990. http://hdl.handle.net/1959.13/24721.
Повний текст джерелаPhD Doctorate
Evans, Geoffrey Michael. "A Study of a Plunging Jet Bubble Column." Diss., 1990. http://hdl.handle.net/1959.13/24721.
Повний текст джерелаPhD Doctorate
Budakli, Mete. "Hydrodynamics and Heat Transfer in Gas-Driven Liquid Film Flows." Phd thesis, 2015. https://tuprints.ulb.tu-darmstadt.de/4347/1/Dissertation_BU.pdf.
Повний текст джерелаSung, Hung-Ming, and 宋鴻明. "Nonlinear Hydrodynamic Stability Analysis of Non-Newtonian Liquid Film Flows." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/37739393960858511161.
Повний текст джерела國立成功大學
機械工程學系碩博士班
92
This paper presents a stability analysis of thin viscoelastic and micropolar liquid films flowing down a plate or cylinder moving in a vertical direction. The nonlinear rupture problem of thin micropolar liquid films on a cylinder is also investigated. The long-wave perturbation method is employed to derive the generalized nonlinear kinematic equations for a free film interface. The current thin liquid film stability analysis provides a valuable input to investigations into the influence of the style of motion of the vertical plate or cylinder on the stability behavior of the thin film flow. The normal mode method is employed to solve the linear solutions of the film flow, and the threshold conditions and linear growth rate of the amplitudes are obtained to analyze the linear stability behavior. This study utilizes the multiple scales method and derives the corresponding Ginzburg-Landau equation to characterize the nonlinear behavior of the flow. The subcritical stability, subcritical instability, supercritical stability, and supercritical instability states are obtained from the nonlinear stability analysis. The present rupture analysis of a thin liquid film on a cylinder supports investigations into the onset of film rupture and permits an understanding of the relative influences of factors such as micropolar parameter, cylinder radius, van der Waals potential, and surface tension on the rupture process. The following conclusions can be drawn from the current numerical modeling results: (1)Influence of style of motion of vertical plate or cylinder on stability behavior of thin film flow: A downward direction motion of the vertical plate or cylinder tends to enhance the stability of the downward-traveling film flow on the plate or cylinder. The film flow system becomes more stable as the downward direction velocity of the plate or cylinder increases. The effects of the viscoelastic parameter, , and the micropolar parameter, , on the stability of the thin film flow are diminished as the downward direction velocity of the plate or cylinder increases. Conversely, an upward direction motion of the plate or cylinder tends to reduce the stability of the down-traveling film flow. The film flow system becomes more unstable as the upward direction velocity of the plate or cylinder increases. The effects of the viscoelastic parameter, , and the micropolar parameter, , on the stability of the thin film flow become more pronounced as the upward direction velocity of the plate or cylinder increases. (2)Influence of cylinder radius on stability behavior of thin film flow: The film flow becomes more stable by increasing the radius of the cylinder as the cylinder moves either upward or downward. The effect of the cylinder radius on the stability of the thin film flow becomes less significant as the downward direction velocity of the cylinder increases. Conversely, the radius effect becomes more pronounced as the upward direction velocity of the cylinder increases. (3)Rupture analysis of thin liquid film on cylinder: The occurrence of film rupture is delayed as the value of the micropolar parameter, , is increased. Furthermore, the rupture time of the film flow decreases as the van der Waals potential effect increases. Conversely, increasing the surface tension or the cylinder radius delays the onset of the rupture process.
Cheng, Po-Jen, and 鄭博仁. "Nonlinear Hydrodynamic Stability Analysis of Gravity-Driven Non-Newtonian Liquid Film Flows." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/21488992840751674269.
Повний текст джерела國立成功大學
機械工程學系
89
The paper investigates the stability of thin non-Newtonian liquid film flowing down on a vertical wall or cylinder using a long-wave perturbation method to solve for generalized nonlinear kinematic equations with free film interface. To begin with a normal mode approach is employed to obtain the linear stability solution for the film flow. The threshold conditions, the linear growth rate of the amplitudes and the linear wave speeds are obtained subsequently as the by-products of linear solutions. To further investigate practical flow stability conditions, the weak nonlinear dynamics of a film flow is presented by using the method of multiple scales. It is shown that the necessary condition for the existence of such a solution is governed by the Ginzburg-Landau equation. The subcritical stability, subcritical instability, supercritical stability and supercritical explosive state will be obtained from the nonlinear film flow system. Some practical examples will be shown in the present thesis in order to illustrate the effectiveness on stability of the viscoelastic coefficient, the flow index of pseudoplastic liquid, the yield stress of Bingham liquid, the micropolar parameter and the cylinder size on the conclusive results. (1)Stability analysis of a thin viscoelastic film flow When a viscoelastic liquid film flow is modeled as a non-Newtonian flow, it possesses the characteristics of the so-called cross-viscosity and elastic properties. As the gravity-driven fluid is in motion, the flow energy is partially consumed by internal viscous forces and dissipated as heat to the environment, and partially stored as strain energy and the elastic stresses cannot be relaxed at a certain frequency. The degree of stability of the viscoelastic film flow decreases as the value of k increases. (2)Stability analysis of a thin pseudoplastic film flow When a pseudoplastic liquid film flow is modeled as a non-Newtonian flow, it possesses the characteristic of shear thinning effect. Physically, the gravity-driven pseudoplastic fluid of thin film flow will decrease the effective viscosity, it can, therefore, increase the convective motion of flow. The decreasing flow index indeed plays a significant role in destabilizing the flow and is thus of great practical importance. (3)Stability analysis of a thin Bingham plastic film flow For the film flow in stable states, the larger yield stress of the Bingham fluid decreases the convective motion of flow and tends to stabilize the flow. However, the yield stress of the Bingham fluid increases the disturbance energy in unstable states. Therefore, the flow will become relatively unstable as the value of yield stress is increased. (4)Stability analysis of a thin micropolar film flow The effect of the microrotation and couple stress will be taken into account in the Non-Newtonian fluid with the suspension micro-particle. Because the vortex viscosity parameter of the microstructure in micropolar fluid will increase the effective viscosity, it can, therefore, reduce the convective motion of flow. The flow field becomes relatively stable for a larger . (5) Stability analysis of a thin film flowing down on a vertical cylinder When the film flows down the outer surface has a destabilizing effect as the cylinder with a smaller radius . This destabilizing effect occurs because the surface tension will produce large capillary pressure at a smaller radius of curvature. This will induce the capillary pressure and force the fluid trough to move upward to the crest. Thus, the amplitude of the wave is increased.
Janke, Thomas. "Hydrodynamical investigations of liquid ventilation by means of advanced optical measurement techniques." 2020. https://tubaf.qucosa.de/id/qucosa%3A75406.
Повний текст джерелаTrotz intensiver Forschung in den letzten sechs Jahrzehnten, befindet sich die Flüssigkeitsbeatmung immernoch weit entfernt vom klinischen Alltag. Mit dieser Arbeit soll ein Beitrag geleistet werden, um das Wissen um die strömungsmechanischen Effekte während der Flüssigkeitsbeatmung zu vertiefen. Dazu werden verschiedene Modellexperimente durchgeführt, bei welchen moderne laseroptische Strömungsmessmethoden zum Einsatz kommen. Untersucht werden dabei unterschiedlich komplexe Geometrien der leitenden menschlichen Atemwege mit dem Ziel wesentliche Strömungsstrukturen, globale Geschwindigkeitsfelder und wichtige Transportwege des gelösten Sauerstoffs zu identifiziern. Die Geschwindigkeitsmessungen zeigen ein stark durch sekundäre Strömungseffekte dominiertes Geschwindigkeitsfeld, welches wesentlich von der lokalen Geometrie abhängig ist. Durch die qualitative und quantitative Erfassung der gelösten Sauerstoffkonzentrationsfelder können wichtige Transportwege aufgedeckt werden. Diese unterscheiden sich deutlich zwischen inspiratorischer und expiratorischer Strömungsrichtung. Die initialen Konzentrationsfelder stimmen mit den unterliegenden Geschwindigkeitsfeldern überein, unterscheiden sich ab der verzögernden Strömungsphase jedoch. Höhere Volumenströme/Tidalvolumen tragen dabei zu einer gleichmäßigeren Konzentrationsverteilung bei.:List of Figures ....................................................................................... VII List of Tables ........................................................................................XIII Nomenclature ........................................................................................ XV 1 Introduction......................................................................................... 1 1.1 Motivation ........................................................................................1 1.2 Research objectives........................................................................... 3 1.3 Outline............................................................................................ 4 2 State of the art .................................................................................... 5 2.1 Liquid Ventilation............................................................................. 5 2.2 In vitro modeling.............................................................................. 8 2.3 Flow measurements ......................................................................... 11 2.4 Gas transport..................................................................................13 3 Flow field measurements ................................................................... 16 3.1 Hydrodynamic Model.......................................................................16 3.1.1 Lung replica ..........................................................................16 3.1.2 Flow parameter .....................................................................18 3.1.3 Limitations ...........................................................................22 3.2 Particle Tracking Velocimetry (PTV) ................................................24 3.2.1 Measurement principle ...........................................................24 3.2.2 Double-frame 2D-PTV ...........................................................25 3.2.3 Time-resolved 3D-PTV ..........................................................28 3.2.4 Phase-locked ensemble PTV ................................................... 31 3.3 Experimental set-up and measurement procedure ...............................33 3.3.1 Lung flow facility...................................................................33 3.3.2 2D-PTV configuration............................................................36 3.3.3 3D-PTV configuration............................................................36 3.4 Results & Discussion........................................................................38 3.4.1 Artificial lung........................................................................38 3.4.2 Realistic lung ........................................................................52 3.5 Conclusion ......................................................................................59 4 Oxygen transport ...............................................................................61 4.1 Hydrodynamic Model....................................................................... 61 4.1.1 Lung replica .......................................................................... 61 4.1.2 Flow parameter .....................................................................62 4.1.3 Limitations ...........................................................................65 4.2 Oxygen Sensitive Dye ......................................................................66 4.3 Experimental set-up......................................................................... 71 4.4 Results & Discussion........................................................................75 4.4.1 Constant flow rate .................................................................75 4.4.2 Oscillatory flow .....................................................................83 4.5 Conclusion ......................................................................................90 5 Summary............................................................................................ 92 6 Outlook .............................................................................................. 95 Bibliography ............................................................................................ 97
Wales, Nadine Jenifer. "The effect of prewetting on the residence time distribution and hydrodynamic parameters in trickle bed reactors." Diss., 2008. http://hdl.handle.net/2263/27723.
Повний текст джерела- Non-wetted
- Levec-wetted
- Super-wetted
Dissertation (MEng)--University of Pretoria, 2008.
Chemical Engineering
unrestricted