CFD Simulation of Two-phase Flows in a Vertical Duct

CFD Simulation of Two-phase Flows in a Vertical Duct PDF Author: Iffat Tasneem Shaik Mohammad
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 184

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CFD Simulation of Two-phase Flows in a Vertical Duct

CFD Simulation of Two-phase Flows in a Vertical Duct PDF Author: Iffat Tasneem Shaik Mohammad
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 184

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CFD Simulation of Two-phase Gas/non-newtonian Fluid Flows in Pipes

CFD Simulation of Two-phase Gas/non-newtonian Fluid Flows in Pipes PDF Author: Miguel Andrés Mauricio Daza Gómez
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The multiphase flow has always been a major concern since it is encountered in many industrial processes that are crucial. Gas/non-Newtonian two-phase flow is found in the upstream of the petroleum industry, where slug flow is the most common flow pattern. This flow pattern has complex hydrodynamics which are crucial to study and evaluate. This study assessed the two-phase gas/non-Newtonian fluid flow in different configurations of pipes. The model was developed using Computational Fluid Dynamics (CFD) with an orthogonal mesh to evaluate the behavior of the slug dynamics in the different configurations. The model Volume of Fluid (VOF) was used to estimate and predict the most important parameters: pressure drop, slug frequency and length. First the model was validated with experimental data found in literature in a horizontal 9 m long glass pipe, with an inner diameter of 22.8 mm. The validation was made with CarboxyMethyl Cellulose CMC-water solutions as test fluids...

Computational Methods in Multiphase Flow V

Computational Methods in Multiphase Flow V PDF Author: Andrea Alberto Mammoli
Publisher: WIT Press
ISBN: 1845641884
Category : Science
Languages : en
Pages : 545

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Book Description
Together with turbulence, multiphase flow remains one of the most challenging areas of computational mechanics and experimental methods and numerous problems remain unsolved to date. Multiphase flows are found in all areas of technology, at all length scales and flow regimes. The fluids involved can be compressible or incompressible, linear or nonlinear. Because of the complexity of the problems, it is often essential to utilize advanced computational and experimental methods to solve the complex equations that describe them. Challenges in these simulations include modelling and tracking interfaces, dealing with multiple length scales, modelling nonlinear fluids, treating drop breakup and coalescence, characterizing phase structures, and many others. Experimental techniques, although expensive and difficult to perform, are essential to validate models. This book contains papers presented at the Fifth International Conference on Computational Methods in Multiphase Flow, which are grouped into the following topics: Multiphase Flow Simulation; Interaction of Gas, Liquids and Solids; Turbulent Flow; Environmental Multiphase Flow; Bubble and Drop Dynamics; Flow in Porous Media; Heat Transfer; Image Processing; Interfacial Behaviour.

Multiphase Flow Dynamics 4

Multiphase Flow Dynamics 4 PDF Author: Nikolay Ivanov Kolev
Publisher: Springer Science & Business Media
ISBN: 3642207499
Category : Technology & Engineering
Languages : en
Pages : 337

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Book Description
The present Volume 4 of the successful monograh package “Multiphase Flow Dynamics”is devoted to selected Chapters of the multiphase fluid dynamics that are important for practical applications but did not find place in the previous volumes. The state of the art of the turbulence modeling in multiphase flows is presented. As introduction, some basics of the single phase boundary layer theory including some important scales and flow oscillation characteristics in pipes and rod bundles are presented. Then the scales characterizing the dispersed flow systems are presented. The description of the turbulence is provided at different level of complexity: simple algebraic models for eddy viscosity, simple algebraic models based on the Boussinesq hypothesis, modification of the boundary layer share due to modification of the bulk turbulence, modification of the boundary layer share due to nucleate boiling. The role of the following forces on the mathematical description of turbulent flows is discussed: the lift force, the lubrication force in the wall boundary layer, and the dispersion force. A pragmatic generalization of the k-eps models for continuous velocity field is proposed containing flows in large volumes and flows in porous structures. A Methods of how to derive source and sinks terms for multiphase k-eps models is presented. A set of 13 single- and two phase benchmarks for verification of k-eps models in system computer codes are provided and reproduced with the IVA computer code as an example of the application of the theory. This methodology is intended to help other engineers and scientists to introduce this technology step-by-step in their own engineering practice. In many practical application gases are solved in liquids under given conditions, released under other conditions and therefore affecting technical processes for good of for bad. Useful information on the solubility of oxygen, nitrogen, hydrogen and carbon dioxide in water under large interval of pressures and temperatures is collected, and appropriate mathematical approximation functions are provided. In addition methods for the computation of the diffusion coefficients are described. With this information solution and dissolution dynamics in multiphase fluid flows can be analyzed. For this purpose the non-equilibrium absorption and release on bubble, droplet and film surfaces under different conditions is mathematically described. A systematic set of internally consistent state equations for diesel fuel gas and liquid valid in broad range of changing pressure and temperature is provided. This new second edition includes various updates, extensions, improvements and corrections. In many practical application gases are solved in liquids under given conditions, released under other conditions and therefore affecting technical processes for good of for bad. Useful information on the solubility of oxygen, nitrogen, hydrogen and carbon dioxide in water under large interval of pressures and temperatures is collected, and appropriate mathematical approximation functions are provided. In addition methods for the computation of the diffusion coefficients are described. With this information solution and dissolution dynamics in multiphase fluid flows can be analyzed. For this purpose the non-equilibrium absorption and release on bubble, droplet and film surfaces under different conditions is mathematically described. A systematic set of internally consistent state equations for diesel fuel gas and liquid valid in broad range of changing pressure and temperature is provided. This new second edition includes various updates, extensions, improvements and corrections.

One Component Two Phase Flow in Horizontal and Vertical Ducts

One Component Two Phase Flow in Horizontal and Vertical Ducts PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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For a description and analysis of the flow they consider the conservation equations of the two phases separately, but in thermal and mechanical equilibrium, coupled by the itnerface shear forces (two fluid model, drift flux model). Coupling may be weak or strong, depending on Froude and Mach numbers of the flow. The fluid is highly compressible, not because the individual phases move at such speeds that their individual density changes are significant but because evapiration (phase change) results in large density changes of the system at moderate pressure or temperature changes once flashing occurs. The slip between the phases is caused by unequal wall shear stress, acceleration of the fluid or gravitational forces and is hindered by the interface interaction. if they denote by? the ratio of the liquid density to the vapor density and by? the ratio of the vapor speed to the liquid speed they find that in horizontal flows? =?12 yields the maximum slip (neglecting acceleration effects) that can be reached with no interface force acting (assuming equal friction coefficients for both phases at the wall). If one investigates the conditions of thermodynamic flow similarity between different substances in two phase flow, one finds that the latent heat of vaporization is the principal controlling parameter. Thus, a 5 cm diameter test section in two phase R-114, at room temperature, corresponds to a 30 cm diameter duct in water-steam at boiling conditions at high temperatures such as encountered in geothermal and other power production systems.

Computational Techniques for Multiphase Flows

Computational Techniques for Multiphase Flows PDF Author: Guan Heng Yeoh
Publisher: Butterworth-Heinemann
ISBN: 0081024541
Category : Technology & Engineering
Languages : en
Pages : 640

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Book Description
Computational Techniques for Multiphase Flows, Second Edition, provides the latest research and theories covering the most popular multiphase flows The book begins with an overview of the state-of-the-art techniques for multiple numerical methods in handling multiphase flow, compares them, and finally highlights their strengths and weaknesses. In addition, it covers more straightforward, conventional theories and governing equations in early chapters, moving on to the more modern and complex computational models and tools later in the book. It is therefore accessible to those who may be new to the subject while also featuring topics of interest to the more experienced researcher. Mixed or multiphase flows of solid/liquid or solid/gas are commonly found in many industrial fields, and their behavior is complex and difficult to predict in many cases. The use of computational fluid dynamics (CFD) has emerged as a powerful tool for understanding fluid mechanics in multiphase reactors, which are widely used in the chemical, petroleum, mining, food, automotive, energy, aerospace and pharmaceutical industries. This revised edition is an ideal reference for scientists, MSc students and chemical and mechanical engineers in these areas. Includes updated chapters in addition to a brand-new section on granular flows. Features novel solution methods for multiphase flow, along with recent case studies. Explains how and when to use the featured technique and how to interpret the results and apply them to improving applications.

CFD Applications in Nuclear Engineering

CFD Applications in Nuclear Engineering PDF Author: Wenxi Tian
Publisher: Frontiers Media SA
ISBN: 2832533264
Category : Technology & Engineering
Languages : en
Pages : 219

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Book Description
High fidelity nuclear reactor thermal hydraulic simulations are a hot research topic in the development of nuclear engineering technology. The three-dimensional Computational Fluid Dynamics (CFD) and Computational Multi-phase Fluid Dynamics (CMFD) methods have attracted significant attention in predicting single-phase and multi-phase flows under steady-state or transient scenarios in the field of nuclear reactor engineering. Compared with three-dimensional thermal hydraulic methods, the traditional one-dimensional system analysis method contains inherent defects in the required accuracy and spatial resolution for a number of important nuclear reactor thermal-hydraulic phenomena. At present the CFD method has been widely adopted in the nuclear industry, across both light water reactors and liquid metal cooled fast reactors, providing an effective solution for complex issues of thermal hydraulic analysis. However, the CFD method employs empirical models for turbulence simulation, heat transfer, multi-phase interaction and chemical reactions. Such models must be validated before they can be used with confidence in nuclear reactor applications. In addition, user practice guidelines play a critical role in achieving reliable results from CFD simulations.

Numerical Simulation of Two-phase Flows Through Complex Duct Geometries

Numerical Simulation of Two-phase Flows Through Complex Duct Geometries PDF Author: Vivek Sharma
Publisher:
ISBN:
Category :
Languages : en
Pages : 236

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Industrial Two-phase Flow CFD

Industrial Two-phase Flow CFD PDF Author: J-M. Buchlin
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 418

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Computational Flow Modeling for Chemical Reactor Engineering

Computational Flow Modeling for Chemical Reactor Engineering PDF Author: Vivek V. Ranade
Publisher: Academic Press
ISBN: 0125769601
Category : Science
Languages : en
Pages : 476

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Book Description
The book relates the individual aspects of chemical reactor engineering and computational flow modeling in a coherent way to explain the potential of computational flow modeling for reactor engineering research and practice.