Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Methodology Development Of A Gas Liquid Dynamic Flow Regime Transition Model
Download Methodology Development Of A Gas Liquid Dynamic Flow Regime Transition Model full books in PDF, epub, and Kindle. Read online Methodology Development Of A Gas Liquid Dynamic Flow Regime Transition Model ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Methodology Development of a Gas-liquid Dynamic Flow Regime Transition Model by : Benjamin Casey Doup
Download or read book Methodology Development of a Gas-liquid Dynamic Flow Regime Transition Model written by Benjamin Casey Doup and published by . This book was released on 2014 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Safety codes often employ the one-dimensional two-fluid model to model two-phase flows. The area-averaged relative velocity correlation necessary to close this model is derived from the drift flux model. The effects of the necessary assumptions used to derive this correlation are investigated using local measurements and these effects are found to have a limited impact on the prediction of the area-averaged relative velocity.
Book Synopsis Dynamic Modeling Strategy for Flow Regime Transition in Gas-Liquid Two-Phase Flows by :
Download or read book Dynamic Modeling Strategy for Flow Regime Transition in Gas-Liquid Two-Phase Flows written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In modeling gas-liquid two-phase flows, the concept of flow regime has been used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are often flow regime dependent. Currently, the determination of the flow regimes is primarily based on flow regime maps or transition criteria, which are developed for steady-state, fully-developed flows and widely applied in nuclear reactor system safety analysis codes, such as RELAP5. As two-phase flows are observed to be dynamic in nature (fully-developed two-phase flows generally do not exist in real applications), it is of importance to model the flow regime transition dynamically for more accurate predictions of two-phase flows. The present work aims to develop a dynamic modeling strategy for determining flow regimes in gas-liquid two-phase flows through the introduction of interfacial area transport equations (IATEs) within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation and destruction of the interfacial area, such as the fluid particle (bubble or liquid droplet) disintegration, boiling and evaporation; and fluid particle coalescence and condensation, respectively. For the flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shape (which are correlated), namely small bubbles and large bubbles. A preliminary approach to dynamically identifying the flow regimes is provided, in which discriminators are based on the predicted information, such as the void fraction and interfacial area concentration of small bubble and large bubble groups. This method is expected to be applied to computer codes to improve their predictive capabilities of gas-liquid two-phase flows, in particular for the applications in which flow regime transition occurs.
Book Synopsis Direct Modeling For Computational Fluid Dynamics: Construction And Application Of Unified Gas-kinetic Schemes by : Kun Xu
Download or read book Direct Modeling For Computational Fluid Dynamics: Construction And Application Of Unified Gas-kinetic Schemes written by Kun Xu and published by World Scientific. This book was released on 2014-12-23 with total page 335 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational fluid dynamics (CFD) studies the flow motion in a discretized space. Its basic scale resolved is the mesh size and time step. The CFD algorithm can be constructed through a direct modeling of flow motion in such a space. This book presents the principle of direct modeling for the CFD algorithm development, and the construction unified gas-kinetic scheme (UGKS). The UGKS accurately captures the gas evolution from rarefied to continuum flows. Numerically it provides a continuous spectrum of governing equation in the whole flow regimes.
Book Synopsis Flow Regime Transitions for Vertical Upward Gas Liquid Flow by :
Download or read book Flow Regime Transitions for Vertical Upward Gas Liquid Flow written by and published by . This book was released on 1977 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Towards a Predictive Model to Reproduce Flow Regime Transitions in Gas-liquid Flows with Neptune CFD by : Emmanuel Vianney Kuidjo Kuidjo
Download or read book Towards a Predictive Model to Reproduce Flow Regime Transitions in Gas-liquid Flows with Neptune CFD written by Emmanuel Vianney Kuidjo Kuidjo and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In nuclear reactors, several regimes of gas-liquid flows may occur with some transitions between them. The main challenges associated with simulating these transitions in 3D CFD codes are associated with deformable interfaces of different sizes, accounting for coalescence and breakup interactions between gas structures and developing flow regime independent closure relations. This work aims at modelling and simulating the hydrodynamics of adiabatic gas-liquid flows thanks to a three-field two-fluid model in Neptune CFD. In a first step, a model with one continuous liquid field and two dispersed gas fields for small and large bubbles is used to simulate cap and churn flows with a void fraction up to 0.5 and a focus is put on the interfacial area prediction. In a second step, the second dispersed field is replaced by a hybrid continuous/dispersed field representing both large bubbles and continuous gas regions. The model is validated on several flow regimes in large diameter pipes and in confined rectangular channels.
Book Synopsis Two-Phase Flow, Boiling, and Condensation by : S. Mostafa Ghiaasiaan
Download or read book Two-Phase Flow, Boiling, and Condensation written by S. Mostafa Ghiaasiaan and published by Cambridge University Press. This book was released on 2017-01-11 with total page 1322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing a comprehensive introduction to the fundamentals and applications of flow and heat transfer in conventional and miniature systems, this fully enhanced and updated edition covers all the topics essential for graduate courses on two-phase flow, boiling, and condensation. Beginning with a concise review of single-phase flow fundamentals and interfacial phenomena, detailed and clear discussion is provided on a range of topics, including two-phase hydrodynamics and flow regimes, mathematical modeling of gas-liquid two-phase flows, pool and flow boiling, flow and boiling in mini and microchannels, external and internal-flow condensation with and without noncondensables, condensation in small flow passages, and two-phase choked flow. Numerous solved examples and end-of-chapter problems that include many common design problems likely to be encountered by students, make this an essential text for graduate students. With up-to-date detail on the most recent research trends and practical applications, it is also an ideal reference for professionals and researchers in mechanical, nuclear, and chemical engineering.
Book Synopsis The Development of Multidimensional Two-fluid Modeling Capabilities by :
Download or read book The Development of Multidimensional Two-fluid Modeling Capabilities written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A fundamental problem in gas/liquid two-phase flow is the prediction of flow regime. Important macroscopic parameters such as pressure drop, wall heat transfer rate and critical heat flux (CHF) depend on the topology of the interface and the distribution of gas and liquid across the channel. The normal means of treating flow regimes is through a flow regime map, where a point in parameter space is assigned a flow regime, and the analysis proceeds based on models for the type of flow regime that is then appropriate. However, flow regime maps, and the models based on them do not work over a broad range of flows; indeed, the very concept of flow regime is limited in application to the particular geometry and range of conditions for which the flow regime map was developed. In addition, flow regime maps are not valid for transient conditions. The authors are developing a model for two-phase flow that is capable of describing the range of flow regimes observed in vertical pipe flow without reliance on a flow regime map. The model is capable of describing both steady and transient flows over a wide range of conditions, and consists of multidimensional equations of balance of mass, energy, and momentum for four fields; namely, continuous gas (cg), continuous liquid (cl), dispersed gas, or bubbles (dg), and dispersed liquid, or droplets (dl). To see that the four-field model is capable of predicting how given fluxes of gas and liquid distribute themselves in pipe or channel flow, consider the schematic of different flow regimes in figure 1. By describing the transverse distribution of bubbles and droplets being carried in continuous liquid and gas, respectively, most fundamental features of flow regimes can be captured. In addition, the local nature of the model requires distributed sources of mass and momentum for each field.
Book Synopsis Flow Regime Transitions in Horizontal Gas-liquid Flow by : Pui-Yan Lin
Download or read book Flow Regime Transitions in Horizontal Gas-liquid Flow written by Pui-Yan Lin and published by . This book was released on 1985 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Hydrodynamics and Transport Processes of Inverse Bubbly Flow by : Subrata Kumar Majumder
Download or read book Hydrodynamics and Transport Processes of Inverse Bubbly Flow written by Subrata Kumar Majumder and published by Elsevier. This book was released on 2016-03-31 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrodynamics and Transport Processes of Inverse Bubbly Flow provides the science and fundamentals behind hydrodynamic characteristics, including flow regimes, gas entrainment, pressure drop, holdup and mixing characteristics, bubble size distribution, and the interfacial area of inverse bubble flow regimes. Special attention is given to mass and heat transfer. This book is an indispensable reference for researchers in academia and industry working in chemical and biochemical engineering. Hydrodynamics and Transport Processes of Inverse Bubbly Flow helps facilitate a better understanding of the phenomena of multiphase flow systems as used in chemical and biochemical industries. - A first book in the market dedicated to the hydrodynamics of inverse bubbly flows - Includes fundamentals of conventional and inverse bubble columns for different hydrodynamic parameters - Includes recommendations for future applications of bubble flows
Book Synopsis Mechanistic Study of Slug Formation and Evolution in High-viscosity-liquid/High-density-gas Multiphase Flows in Channels/pipes by : Sha Miao (Ph. D.)
Download or read book Mechanistic Study of Slug Formation and Evolution in High-viscosity-liquid/High-density-gas Multiphase Flows in Channels/pipes written by Sha Miao (Ph. D.) and published by . This book was released on 2018 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rapidly rising global energy demand coupled with dwindling conventional oil resources has pushed unconventional oil, such as heavy oil, to become one of the most important future energy resources. However, design and operation of pipelines to transport heavy-oil/gas flows have raised new challenges associated with remarkably different flow regime transitions compared to conventional low-viscosity-oil/low-density-gas flows. Many traditional flow regime models for these oil/gas flows result in O(1) prediction errors when applied to high-viscosity-oil/high-density-gas flows because they fail to account for the complex change in physics and scales that occur as the fluid properties substantially change. Therefore, understanding the mechanisms that cause flow-regime transition for these types of flows is of critical importance to the development of physics-based models allowing for the creation of more robust and cost effective designs. The work described in this thesis focuses on investigating the fundamental mechanisms governing the initial growth and nonlinear evolution of interfacial waves leading to slugging in concurrent high-viscosity (laminar) liquid/high-density(turbulent) gas two-phase flows in horizontal channels/pipes. We first develop a Fully-Coupled Immersed Flow (FCIF) solver for the three-dimensional simulation of fluid-fluid interaction by coupling two distinct flow solvers using an Immersed Boundary (IB) method. The FCIF solver captures dynamic interactions between two fluids with disparate flow properties, while retaining the desirable simplicity of non-boundary-conforming grids. For the application of slug development with turbulent gas and laminar liquid, we couple an IB-based unsteady Reynolds Averaged Navier Stokes (uRANS) simulator with a depth-integrated (long-wave) solver in FCIF. We perform a series of validations on this method. The results demonstrate that the FCIF solver effectively captures the essential physics of gas-liquid interaction and can serve as a useful tool for the mechanistic study of slug generation in two-phase gas/liquid flows in channels and pipes.
Book Synopsis Heat Transfer and Fluid Flow in Minichannels and Microchannels by : Satish Kandlikar
Download or read book Heat Transfer and Fluid Flow in Minichannels and Microchannels written by Satish Kandlikar and published by Elsevier. This book was released on 2006 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: &Quot;This book explores flow through passages with hydraulic diameters from about 1 [mu]m to 3 mm, covering the range of minichannels and microchannels. Design equations along with solved examples and practice problems are also included to serve the needs of practicing engineers and students in a graduate course."--BOOK JACKET.
Book Synopsis Numerical Modelling of Transient Gas-liquid Flows (application to Stratified & Slug Flow Regimes). by :
Download or read book Numerical Modelling of Transient Gas-liquid Flows (application to Stratified & Slug Flow Regimes). written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new methodology was developed for the numerical simulation of transient two-phase flow in pipes. The method combines high-resolution numerical solvers and adaptive mesh refinement (AMR) techniques, and can achieve an order of magnitude improvement in computational time compared to solvers using conventional uniform grids. After a thorough analysis of the mathematical models used to describe the complex behaviour of two-phase flows, the methodology was used with three specific models in order to evaluate the robustness and accuracy of the numerical schemes developed, and to assess the ability of these models to predict two physical flow regimes, namely stratified and slug flows. The first stage of the validation work was to examine the physical correlations required for an accurate modelling of the stratified smooth and wavy flow patterns, and a new combination of existing correlations for the wall and interfacial friction factors was suggested in order to properly predict the flow features of the experimental transient case investigated. The second and final phase of the work dealt with the complex and multi-dimensional nature of slug flow. This flow regime remains a major and expensive headache for oil producers, due to its unsteady nature and high-pressure drop. The irregular flow results in poor oil/water separation, limits production and can cause flaring. The modelling approached that was adopted here is based on the two-fluid model, which can theoretically follows each formed slug and predicts its evolution, growth and decay, as it moves along the pipe. However, the slug flow study, performed here through a test case above the Inviscid Kelvin-Helmholtz transition from stratified to slug flow, showed that the incompressible two-fluid model used is unable to accurately predict most of the features of this complex flow. Mechanisms such as the interfacial wave formation, the slug growth and propagation, although observed from the simulations, cannot be accuratel.
Book Synopsis Thermo-fluid Dynamics of Two-Phase Flow by : Mamoru Ishii
Download or read book Thermo-fluid Dynamics of Two-Phase Flow written by Mamoru Ishii and published by Springer Science & Business Media. This book was released on 2006-09-28 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book has been written for graduate students, scientists and engineers who need in-depth theoretical foundations to solve two-phase problems in various technological systems. Based on extensive research experiences 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 a variety of scenarios, including nuclear reactor transient and accident analysis, energy systems, power generation systems and even space propulsion.
Book Synopsis Development and Validation of a Multifield Model of Churn-Turbulent Gas/Liquid Flows by :
Download or read book Development and Validation of a Multifield Model of Churn-Turbulent Gas/Liquid Flows written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The accuracy of numerical predictions for gas/liquid two-phase flows using Computational Multiphase Fluid Dynamics (CMFD) methods strongly depends on the formulation of models governing the interaction between the continuous liquid field and bubbles of different sizes. The purpose of this paper is to develop, test and validate a multifield model of adiabatic gas/liquid flows at intermediate gas concentrations (e.g., churn-turbulent flow regime), in which multiple-size bubbles are divided into a specified number of groups, each representing a prescribed range of sizes. The proposed modeling concept uses transport equations for the continuous liquid field and for each bubble field. The overall model has been implemented in the NPHASE-CMFD computer code. The results of NPHASE-CMFD simulations have been validated against the experimental data from the TOPFLOW test facility. Also, a parametric analysis on the effect of various modeling assumptions has been performed.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 1572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Direct Numerical Simulations of Gas–Liquid Multiphase Flows by : Grétar Tryggvason
Download or read book Direct Numerical Simulations of Gas–Liquid Multiphase Flows written by Grétar Tryggvason and published by Cambridge University Press. This book was released on 2011-03-10 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurately predicting the behaviour of multiphase flows is a problem of immense industrial and scientific interest. Modern computers can now study the dynamics in great detail and these simulations yield unprecedented insight. This book provides a comprehensive introduction to direct numerical simulations of multiphase flows for researchers and graduate students. After a brief overview of the context and history the authors review the governing equations. A particular emphasis is placed on the 'one-fluid' formulation where a single set of equations is used to describe the entire flow field and interface terms are included as singularity distributions. Several applications are discussed, showing how direct numerical simulations have helped researchers advance both our understanding and our ability to make predictions. The final chapter gives an overview of recent studies of flows with relatively complex physics, such as mass transfer and chemical reactions, solidification and boiling, and includes extensive references to current work.
