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Showing result 1 - 5 of 19 swedish dissertations matching the above criteria.

2. 1. A numerical study of two-fluid models for dispersed two-phase flow

   Author : Reynir Levi Gudmundsson; Björn Sjögreen; Anders Petersson; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Numerical analysis; two-phase flow; two-fluid mode; well-posedness; numerical experiments; Numerisk analys; Numerical analysis; Numerisk analys;

   Abstract : In this thesis the two-fluid (Eulerian/Eulerian) formulation for dispersed two-phase flow is considered. Closure laws are needed for this type of models. We investigate both empirically based relations, which we refer to as a nongranular model, and relations obtained from kinetic theory of dense gases, which we refer to as a granular model. READ MORE

4. 2. Input Calibration, Code Validation and Surrogate Model Development for Analysis of Two-phase Circulation Instability and Core Relocation Phenomena

   Author : Viet-Anh Phung; Pavel Kudinov; Cristophe Demaziere; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Reactor system code; input calibration; code validation; surrogate model; two-phase circulation flow instability; in-vessel core relocation; genetic algorithm; artificial neural network; Reaktorsystemkod; indata kalibrering; kodvalidering; surrogatmodell; två-fas cirkulationsflöde; instabilitet; härdrelokering i reaktortanken; genetisk algoritm; artificiella neurala nätverk; Fysik; Physics;

   Abstract : Code validation and uncertainty quantification are important tasks in nuclear reactor safety analysis. Code users have to deal with large number of uncertain parameters, complex multi-physics, multi-dimensional and multi-scale phenomena. READ MORE

5. 3. On stability of solutions to the two-fuid models for dispersed two-phase flow

   Author : Reymir Levi Gudmundsson; KTH; []
   Keywords : ;

   Abstract : In this thesis the two-fluid (Eulerian/Eulerian) formulationfor dispersed two-phase flow is considered. The inviscidformulation in one space dimension is known to be conditionallywell-posed. On the other hand the viscous formulation islocally in time well-posed for smooth initial data, but with amedium to high wave number instability. READ MORE

6. 4. Flow structures in solid-liquid suspensions in mixing and confined jets

   Author : Matthias Eng; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Lomb algorithm; macro-instabilities; stirred tank; integral length scale; solid-liquid; confined jet; LDV; parcticle flow; jet instability;

   Abstract : This thesis investigates the influence of solid particles on different liquid flow systems.Large-scale periodic fluctuations such as macro instability (MI) phenomena in a mixingvessel and jet flows in a confined jet were experimentally analyzed by means of LDV. Theinfluences of different sized (0.5mm-2mm) glass particles (0%vol - 6. READ MORE

7. 5. Fluid Dynamics in Stirred Vessels - Experiments and simulations of single-phase and liquid-liquid systems

   Author : Fredrik Svensson; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Particle Image Velocimetry PIV ; single-phase; Laser Doppler Anemometry LDA ; mixing; liquid-Liquid; immiscible; stirred tank; Rushton turbine; Computational Fluid Dynamics CFD ; macro-instability; frequency analysis; refraction index matched;

   Abstract : This thesis applies experimental measurement techniques and computational fluid dynamics to evaluate turbulent mixing of liquid-liquid systems in stirred vessels. Also studies of macro-instabilities in a single-phase system and how they affect flow and thus mixing are conducted. READ MORE