Drift-flux Analysis of Two-phase Flow in Microgravity PDF Download

Author: Jonathan David Braisted
Publisher:
ISBN:
Category :
Languages : en
Pages : 116

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Author: Benjamin Andrew Larsen
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The current knowledge of flow parameters for terrestrial two-phase flow was developed through experiments that collected hundreds to thousands of data points. However, the cost associated with microgravity testing make collecting such amounts of microgravity two-phase flow data difficult. Multiple researchers have postulated the microgravity drift flux model parameters to predict void fraction, however, these methods were initially developed with no consideration given to a microgravity environment. The purpose of this thesis was to develop a process by which results from multiple microgravity experiments can be compared on a similar medium and used to develop a larger viable data set than what was previously available and to reliably calculate a value for the void fraction from the available data. Development of multiphase systems for microgravity requires accurate prediction methods. Utilizing data from multiple microgravity two-phase flow experiments, a statistically consistent slug flow database has been created. The data from 13 different microgravity two-phase flow experiments was vetted using a combination of parametric and non-parametric statistical tests to develop a valid model for the drift flux parameters that meet the axioms of a linear model. The result was a statistically consistent microgravity slug flow data base consisting of 220 data points from 8 different experiments and the associated values for the concentration parameter, Co, and drift velocity, u[subscript]gj. A key component for this model was redefining the assumptions in the drift flux model to accurately represent microgravity conditions in calculating the drift flux parameters. The resultant drift flux parameters are a distribution parameter, Co = 1.336 ± 0.013 and a drift velocity, u[subscript]gj = -0.126 ± 0.020. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/152740

Author: Luca Valota
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Knowledge of the two-phase flow state is fundamental for two-phase flow system design and operation. In traditional two-phase flow studies, the flow regime refers to the physical location of the gas and liquid in a conduit. Flow configuration is important for engineering correlations of heat and mass transfer, pressure drop, and wall shear. However, it is somewhat subjective since it is mostly defined by experimental observation, resulting in an approximate and equivocal definition. Thus, there is need for a better, objective flow regime identification. The void fraction is a key parameter in monitoring the operating state of a two-phase system and several tools have been developed in order to measure it. The purpose of this study is to use the void fraction and other parameters of the system to achieve a model for flow pattern identification. Recently, an experimental program using the Foster-Miller two-phase flow test bed and Creare Inc. capacitance void fraction sensors was conducted in the microgravity environment of the NASA KC-135 aircraft. Several data types were taken for each phase, such as flow rate, superficial velocity, density and transient void fraction at 100Hz. Several analytical approaches were pursued, including a statistical approach of the fluctuation of the void fraction, Martinelli analysis, and Drift Flux analysis, in order to reach a model for flow pattern identification in microgravity conditions. Several parameters were found to be good flow pattern identifiers such as the statistical moments variance and skewness, Signal -to- noise ratio (SNR), Half Height Value (HHV) and Linear Area Difference (LAD). Moreover, relevant conclusions were achieved using the Martinelli parameter and the Drift Flux model in microgravity conditions. These results were compared with the basic literature.

Author: Mamoru Ishii
Publisher: Springer Science & Business Media
ISBN: 1441979859
Category : Technology & Engineering
Languages : en
Pages : 518

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Book Description
Thermo-fluid Dynamics of Two-Phase Flow, Second Edition is focused on the fundamental physics of two-phase flow. The authors present the detailed theoretical foundation of multi-phase flow thermo-fluid dynamics as they apply to: Nuclear reactor transient and accident analysis; Energy systems; Power generation systems; Chemical reactors and process systems; Space propulsion; Transport processes. This edition features updates on two-phase flow formulation and constitutive equations and CFD simulation codes such as FLUENT and CFX, new coverage of the lift force model, which is of particular significance for those working in the field of computational fluid dynamics, new equations and coverage of 1 dimensional drift flux models and a new chapter on porous media formulation.

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: Mamoru Ishii
Publisher: Springer
ISBN: 9781441979841
Category : Technology & Engineering
Languages : en
Pages : 518

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Book Description
Thermo-fluid Dynamics of Two-Phase Flow, Second Edition is focused on the fundamental physics of two-phase flow. The authors present the detailed theoretical foundation of multi-phase flow thermo-fluid dynamics as they apply to: Nuclear reactor transient and accident analysis; Energy systems; Power generation systems; Chemical reactors and process systems; Space propulsion; Transport processes. This edition features updates on two-phase flow formulation and constitutive equations and CFD simulation codes such as FLUENT and CFX, new coverage of the lift force model, which is of particular significance for those working in the field of computational fluid dynamics, new equations and coverage of 1 dimensional drift flux models and a new chapter on porous media formulation.

Author: Carlos Moreno Tavira
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Two-phase flows have gained importance over the last years due to their multiple and useful applications in space systems. For example, two-phase flows are used in fuel cells micro-channel networks, in the fluid management of Environmental Control and Life Support Systems (ECLSS) or in thermal management systems. However, many problems regarding two-phase flows in microgravity conditions are still open, so further research is needed. In this study, numerical simulations of gas-liquid two-phase flow are performed in a T-junction capillary. Bubbles are formed as a consequence of the interaction between air and water. The geometry used is the same as in [1, 2, 3] in order to make reliable comparisons with the results extracted from the laboratory experiments performed in the mentioned literature. OpenFOAM is used as the main software for the simulations, and ParaView and MATLAB are used to post-process the data. InterFoam is selected as the solver since it uses an incompressible, immiscible and isothermal Volume of Fluid (VOF) method. Some validations were made before setting up the definitive cases of the simulations. These validations were related to the adequate capillary length in order to obtain fully-developed flows, to the appropriate mesh quality to get good results and maintain an acceptable computational complexity, to the optimal contact angle value to get close to reality bubble behavior in terms of adherence to the walls, and to the right location of the sampling surfaces responsible for extracting the data. An analysis of the fluid velocity profiles along both of the capillaries of the T-junction was also made. Bubbles are analyzed in terms of their generating frequency, volume, length and velocity. Bubble volume dispersion is quantified using the polydispersity index. A pressure probe is used to measure the gauge pressure at the very center of the T-junction. Visual comparisons are made between simulation bubbles and experimental bubbles. In the end, the results of the simulations qualitatively fitted the experimental data, validating Computational Fluid Dynamics (CFD) as an alternative and correct tool to perform two-phase flow studies under microgravity conditions.

Author: Cl Kleinstreuer
Publisher: Routledge
ISBN: 1351406485
Category : Science
Languages : en
Pages : 472

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Book Description
This graduate text provides a unified treatment of the fundamental principles of two-phase flow and shows how to apply the principles to a variety of homogeneous mixture as well as separated liquid-liquid, gas-solid, liquid-solid, and gas-liquid flow problems, which may be steady or transient, laminar or turbulent.Each chapter contains several sample problems, which illustrate the outlined theory and provide approaches to find simplified analytic descriptions of complex two-phase flow phenomena.This well-balanced introductory text will be suitable for advanced seniors and graduate students in mechanical, chemical, biomedical, nuclear, environmental and aerospace engineering, as well as in applied mathematics and the physical sciences. It will be a valuable reference for practicing engineers and scientists. A solutions manual is available to qualified instructors.

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

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The executive summary includes the following topics of discussion: the state of affairs; the fundamental governing equations; the one-dimensional mixture model; the drift-flux model; the Denver Research Institute two-phase geothermal flow program; two-phase flow pattern transition criteria; a two-fluid model under development; the mixture model as applied to geothermal well flow; DRI downwell instrumentation; two-phase flow instrumentation; the Sperry Research Corporation downhole pump and gravity-head heat exchanger systems; and the Brown University two-phase flow experimental program. (MHR).

Author: Robert Iskanderovich Nigmatulin
Publisher: CRC Press
ISBN: 9780891163282
Category : Fluid dynamics
Languages : en
Pages : 402

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Book Description
Volume 2 of a monograph on current knowledge of phenomena and the theory and analysis of multiphase systems, offering a systematic treatment of energy, mass and momentum exchange in multiphase systems along with other applications which include shock hardening of metals and boiling heat transfer.