Some aspects of annular two-phase flow in a horizontal tube PDF Download

Author: Prabir Chakrabarti
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Geoffrey Hewitt
Publisher: Elsevier
ISBN: 1483285235
Category : Technology & Engineering
Languages : en
Pages : 327

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Book Description
Annular Two-Phase Flow presents the wide range of industrial applications of annular two-phase flow regimes. This book discusses the fluid dynamics and heat transfer aspects of the flow pattern. Organized into 12 chapters, this book begins with an overview of the classification of the various types of interface distribution observed in practice. This text then examines the various regimes of two-phase flow with emphasis on the regions of occurrence of the annular flow regime. Other chapters consider the single momentum and energy balances, which illustrate the differences and analogies between single- and two-phase flows. This book discusses as well the simple modes for annular flow with consideration to the calculation of the profile of shear stress in the liquid film. The final chapter deals with the techniques that are developed for the measurement of flow pattern, entrainment, and film thickness. This book is a valuable resource for chemical engineers.

Author: Volfango Bertola
Publisher: Springer
ISBN: 3709125383
Category : Technology & Engineering
Languages : en
Pages : 433

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Book Description
This is an up-to-date review of recent advances in the study of two-phase flows, with focus on gas-liquid flows, liquid-liquid flows, and particle transport in turbulent flows. The book is divided into several chapters, which after introducing basic concepts lead the reader through a more complex treatment of the subjects. The reader will find an extensive review of both the older and the more recent literature, with abundance of formulas, correlations, graphs and tables. A comprehensive (though non exhaustive) list of bibliographic references is provided at the end of each chapter. The volume is especially indicated for researchers who would like to carry out experimental, theoretical or computational work on two-phase flows, as well as for professionals who wish to learn more about this topic.

Author: Lawrence Robert Williams
Publisher:
ISBN:
Category :
Languages : en
Pages : 322

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The effect of pipe diameter on horizontal annular flow is examined. Measurements of the local film height, the local droplet flux, the local velocity, and the entrained fraction for annular flow in a 9.53 cm horizontal pipe have been obtained. The measurements are compared with the results from previous investigators for horizontal annular flow in pipes with diameters of 2.54 cm and 5.08 cm. A new large scale two-phase flow facility has been designed and constructed. The facility has the ability to incline a 26.5 m pipe at angles between positive and minus 2.5 degrees from the horizontal. Local film height measurements show that the film distribution becomes increasingly asymmetric with increasing pipe diameter. The effect of pipe diameter on the asymmetries of the liquid film distribution is predicted approximately by a Froude number. At Froude numbers below 50, the liquid is stratified as a pool at the pipe bottom. A turbulent diffusion model developed by a co-researcher for the droplet concentration distribution is in good agreement with measurements at low gas velocities and low droplet concentrations. At higher droplet concentrations, velocity measurements suggest the existence of a secondary flow in the gas which inhibits droplet settling. Entrainment correlations developed from experiments in small diameter pipes, over predict the entrained fraction in large diameter pipes. A generalized entrainment correlation based on an equilibrium rate balance between the rate of atomization of droplets from the liquid film and the rate of deposition of droplets back to the liquid film is developed. The correlation is easily interpreted for two extremes of the liquid film distribution. When the film is distributed uniformly around the pipe wall, the entrainment relation reduces to a form developed by previous researchers. For conditions where the liquid film is stratified as a pool at the pipe bottom, a new entrainment relation is developed which is in good agreement with the results.

Author: William Bryan Durant
Publisher:
ISBN:
Category :
Languages : en
Pages : 446

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Author: Afshin J. Ghajar
Publisher: Springer Nature
ISBN: 3030416267
Category : Science
Languages : en
Pages : 136

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This book provides design engineers using gas-liquid two-phase flow in different industrial applications the necessary fundamental understanding of the two-phase flow variables. Two-phase flow literature reports a plethora of correlations for determination of flow patterns, void fraction, two- phase pressure drop and non-boiling heat transfer correlations. However, the validity of a majority of these correlations is restricted over a narrow range of two -phase flow conditions. Consequently, it is quite a challenging task for the end user to select an appropriate correlation/model for the type of two-phase flow under consideration. Selection of a correct correlation also requires some fundamental understanding of the two-phase flow physics and the underlying principles/assumptions/limitations associated with these correlations. Thus, it is of significant interest for a design engineer to have knowledge of the flow patterns and their transitions and their influence on two-phase flow variables. To address some of these issues and facilitate selection of appropriate two-phase flow models, this volume presents a succinct review of the flow patterns, void fraction, pressure drop and non-boiling heat transfer phenomenon and recommend some of the well scrutinized modeling techniques.

Author: B. J. Azzopardi
Publisher:
ISBN:
Category : Fluid mechanics
Languages : en
Pages :

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Author: John H. Vohr
Publisher:
ISBN:
Category : Two-phase flow
Languages : en
Pages : 64

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Author: John R Thome
Publisher: World Scientific
ISBN: 9814623229
Category : Technology & Engineering
Languages : en
Pages : 1109

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Book Description
The aim of the two-set series is to present a very detailed and up-to-date reference for researchers and practicing engineers in the fields of mechanical, refrigeration, chemical, nuclear and electronics engineering on the important topic of two-phase heat transfer and two-phase flow. The scope of the first set of 4 volumes presents the fundamentals of the two-phase flows and heat transfer mechanisms, and describes in detail the most important prediction methods, while the scope of the second set of 4 volumes presents numerous special topics and numerous applications, also including numerical simulation methods.Practicing engineers will find extensive coverage to applications involving: multi-microchannel evaporator cold plates for electronics cooling, boiling on enhanced tubes and tube bundles, flow pattern based methods for predicting boiling and condensation inside horizontal tubes, pressure drop methods for singularies (U-bends and contractions), boiling in multiport tubes, and boiling and condensation in plate heat exchangers. All of these chapters include the latest methods for predicting not only local heat transfer coefficients but also pressure drops.Professors and students will find this 'Encyclopediaa of Two-Phase Heat Transfer and Flow' particularly exciting, as it contains authored books and thorough state-of-the-art reviews on many basic and special topics, such as numerical modeling of two-phase heat tranfser and adiabatic bubbly and slug flows, the unified annular flow boiling model, flow pattern maps, condensation and boiling theories, new emerging topics, etc.

Author: National Aeronautics and Space Adm Nasa
Publisher:
ISBN: 9781728958446
Category :
Languages : en
Pages : 38

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Two new versions of the k-omega two-equation turbulence model will be presented. The new Baseline (BSL) model is designed to give results similar to those of the original k-omega model of Wilcox, but without its strong dependency on arbitrary freestream values. The BSL model is identical to the Wilcox model in the inner 50 percent of the boundary-layer but changes gradually to the high Reynolds number Jones-Launder k-epsilon model (in a k-omega formulation) towards the boundary-layer edge. The new model is also virtually identical to the Jones-Lauder model for free shear layers. The second version of the model is called Shear-Stress Transport (SST) model. It is based on the BSL model, but has the additional ability to account for the transport of the principal shear stress in adverse pressure gradient boundary-layers. The model is based on Bradshaw's assumption that the principal shear stress is proportional to the turbulent kinetic energy, which is introduced into the definition of the eddy-viscosity. Both models are tested for a large number of different flowfields. The results of the BSL model are similar to those of the original k-omega model, but without the undesirable freestream dependency. The predictions of the SST model are also independent of the freestream values and show excellent agreement with experimental data for adverse pressure gradient boundary-layer flows. Menter, Florian R. Ames Research Center RTOP 505-59-40...