Download or read book Analysis of Annular Two phase Flow with Liquid Entrainment written by Mohamed Abdelfatah Abolfadl and published by . This book was released on 1984 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Annular Two Phase Flow written by Geoffrey Hewitt and published by Elsevier. This book was released on 2013-10-22 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Analysis of Various Types of Two phase Annular Flow written by S. Levy and published by . This book was released on 1963 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Analytical Study of Liquid Entrainment in Two phase Annular Flow written by Henry Aloysius Putre and published by . This book was released on 1964 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiphase Flow Dynamics 2 written by Nikolay Ivanov Kolev and published by Springer Science & Business Media. This book was released on 2005-08-15 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multi-phase flows are part of our natural environment such as tornadoes, typhoons, air and water pollution and volcanic activities as well as part of industrial technology such as power plants, combustion engines, propulsion systems, or chemical and biological industry. The industrial use of multi-phase systems requires analytical and numerical strategies for predicting their behavior. In its third extended edition this book contains theory, methods and practical experience for describing complex transient multi-phase processes in arbitrary geometrical configurations. This book provides a systematic presentation of the theory and practice of numerical multi-phase fluid dynamics. In the present second volume the mechanical and thermal interactions in multiphase dynamics are provided. This third edition includes various updates, extensions, improvements and corrections.

Download or read book Study of Liquid Entrainment Rates in Annular Two phase Flow Through Smooth and Rifled Tubes written by Robert Hong-Leung Chiang and published by . This book was released on 1986 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modelling and Experimentation in Two Phase Flow written by Volfango Bertola and published by Springer. This book was released on 2014-05-04 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Stability of Two phase Annular Flow in a Vertical Pipe written by Stephen Jarvis and published by . This book was released on 1965 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Study of Liquid Entrainment in Annular Co current Two phase Fluid Flow written by Andrew Field Fritzlen and published by . This book was released on 1951 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental and Analytical Investigation of Entrainment Rates for Downward Annular Mist Two phase Flow in Pipes and Downstream of a Localized Contraction written by Kim Ann Shollenberger and published by . This book was released on 1994 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Two phase Flow and Heat Transfer written by Graham B. Wallis and published by . This book was released on 1967 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Pipe Diameter on Horizontal Annular Two phase Flow written by Lawrence Robert Williams and published by . This book was released on 1990 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Two Phase Flow in Complex Systems written by Salomon Levy and published by John Wiley & Sons. This book was released on 1999-08-02 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mehrphasige Strömungen spielen in etlichen Industriezweigen, besonders der Luft- und Raumfahrt und der Energieerzeugung, eine zentrale Rolle. Derart komplexe Strömungsvorgänge sind extrem schwer vorauszuberechnen, zu analysieren und zu testen. Wertvolle Hilfestellungen, die für reale technische Situationen gedacht sind, gibt dieser Band, der auch Quelltexte einschlägiger Computerprogramme enthält. (07/99)

Download or read book The correlation of liquid entrainment fraction and entrainment rate in annular two phase flow written by P. B. Whalley and published by . This book was released on 1978 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Development of a Comprehensive Annular Flow Modeling Package for Two phase Three field Transient Safety Analysis Codes written by Jeffrey W. Lane and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The annular two-phase flow regime is important to several applications and most notably the safety analysis of nuclear reactors. Such analyses require an accurate prediction of the phenomena associated with this regime, including the pressure gradient as well as the distribution of liquid and the interfield rate of exchange between the film and dispersed droplet fields. In general, the nuclear industry uses transient safety analysis codes, such as COBRA-TF, to predict phenomena of interest for various reactor accident scenarios and ensure the safe design of the system. COBRA-TF is a best-estimate thermal-hydraulic analysis tool developed for Light Water Reactors (LWR) and the primary feature of COBRA-TF is that it provides a three-field representation of two-phase flow (vapor/non-condensable gases, continuous liquid or films, and dispersed liquid or droplets). This representation is regarded as the most physically accurate approach for analyzing situations where liquid can coexist in both continuous and discrete forms, as is the case for annular-mist and counter-current flow situations, since substantial differences can exist in the velocity and flow direction for these two fields. The prediction of annular flow situations requires a variety of constitutive relationships to describe the mass, momentum, and energy exchange that occurs between the flow fields and provide closure to the set of momentum equations. An initial assessment of the predictive capability of COBRA-TF indicated that the modeling package that was used in the baseline version of the code did not provide adequate predictions when a variety of annular flow experiments were simulated. As a result, the goal of the current study was to assemble a physically-based and self-consistent annular flow modeling package that is amenable to implementation in three-field analysis environments and accurately captures the variation in entrainment and interfacial drag within co-current and counter-current regimes over the pressure range of interest (atmospheric to 2000-psia). The constitutive relations available in the open-literature were assessed relative to the models employed in the modeling package that was applied in the baseline version of COBRA-TF. Where necessary, model upgrades were made in an effort to utilize the most appropriate models that are based on either the physics of the flow or developed from experimental data collected over the desired range of conditions. The models that were incorporated into the newly proposed modeling package were either based on those developed in previous studies or developed uniquely within the current study. It is important to note that the current study used COBRA-TF to provide the baseline modeling package as a means for comparison and as a vehicle for assessing the newly proposed modeling packages; however, the proposed packages are amenable to implementation into any other three-field analysis tool. The proposed modeling packages for co-current and counter-current annular flow are outlined in Chapters 4 and 5, respectively. The co-current modeling package: 1) applies an interfacial shear model that explicitly accounts for the presence of interfacial waves, 2) idealizes the structure of the interface in a manner that is consistent with both the interfacial shear model and other visual observations, 3) includes three mechanistic-based entrainment rate models (roll wave stripping, Kelvin-Helmholtz lifting, and liquid bridge breakup) that calculate a theoretical entrainment rate for a single wave based on the physical structures and controlling phenomena as they are currently understood for each mechanism, and 4) provides a functional relationship between the actual and theoretical entrainment rates based on comparisons to experimental data to account for any deficiencies that exist in the theoretical model. This methodology improves the physical basis of the modeling package while simultaneously leveraging the available experimental data to ensure the modeling package is able to accurately reflect the experimental data. Meanwhile, the three-field Counter-Current Flow Limitation (CCFL) model developed in the current study is based on an empirical model that has been shown to suitably correlate specific sets of data over a wide range of flow path dimensions and geometries. The resulting correlation provides a quantitative description of the experimentally determined flooding curve. The proposed model compares the flow conditions predicted by the code to the results of the user-specified CCFL correlation to determine if the standard set of momentum equations should be replaced with a newly developed set of CCFL momentum equations. The proposed model also provides appropriate entrainment rate models (pool and excess film) and necessary criterion to exit the model in a stable manner. In general, this approach provides flexibility to the code user and again leverages the available experimental data to improve the predictive capability of the code since a universal model has yet to be determined for this phenomenon. While not entirely mechanistic, this approach ensures the proper amount of liquid flow can penetrate these regions, which is preeminent to achieving accurate predictions of coolant and temperature distributions for Loss-of-Coolant Accident (LOCA) scenarios. Overall the development of this model is a unique aspect of the current study because of the explicit treatment of the entrained field, which previously suggested models did not consider because they were aimed at two-field analysis environments. The results of the current study indicate that the inclusion of these newly proposed modeling packages for both co-current and counter-current annular flow has provided increased accuracy in the predictions of phenomena that are of interest to reactor safety analyses. In particular, the mean relative error in entrained fraction was reduced from 20.2% (underprediction) to 4.5% (overprediction) and the mean relative error in axial pressure gradient was reduced from 108.2% to 7.6% (both overprediction) for co-current upward annular flow situations following the implementation of these packages into COBRA-TF and the code-to-data agreement of several different parameters within the counter-current flow regime was improved significantly. It was also shown that the proposed co-current annular modeling package: 1) provided reasonable estimates of a variety of more fundamental annular flow parameters such as wave spacing, velocity, and intermittency, and 2) was able to capture the general behavior within the developing flow region. Both these results provide confidence that the proposed modeling package reasonably reflects the underlying physics of the annular regime. Moreover, the current study is one of the few works that has examined the predictive capabilities of transient analysis codes within the developing, or non-equilibrium, annular flow region. The methodology employed in the current study is not meant to provide a final solution to this complex problem; however, given the importance of these phenomena to the safety analysis of various reactor accident scenarios and the abundance of available experimental data, it would be inopportune not to employ this modeling methodology and improve the predictive capabilities of three-field transient analysis codes until a more viable approach is ascertained. Regardless, the current study has both provided a functional modeling package that has presently improved the predictive capabilities of three-field analysis tools and established a new baseline for future research and model development activities in this area.

Download or read book A Method to Predict Liquid Entrainment Fraction and Quantify the Associated Uncertainty in Two Phase Annular Flow written by Md Azharul Islam and published by . This book was released on 2016 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phase Flow Rate Measurements of Annular Flows written by Qahtan Al-Yarubi and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the international oil and gas industry multiphase annular flow in pipelines and wells is extremely important, but not well understood. This thesis reports the development of an efficient and cheap method for measuring the phase flow rates in two phase annular and annular mist flow, in which the liquid phase is electrically conducting, using ultrasonic and conductance techniques. The method measures changes in the conductance of the liquid film formed during annular flow and uses these to calculate the volumetric and mass flow rates of the liquid film. The gas velocity in the core of the annular flow is measured using an ultrasonic technique. Combined with an entrainment model and the liquid film measurements described above, the ultrasonic technique enables the volumetric flow rate of the gas in the core and the volumetric and mass flow rates of entrained liquid droplets to be measured. This study was based on experimental work and the use of modelling techniques. The practical investigation comprised a series of experiments conducted on a purpose built flow loop in which the test section was a Perspex pipe of 50mm ID. The experimental work was limited to two-phase air-water flow. The flow loop was specifically designed to accommodate the different instruments and subsystems designed in this investigation including bespoke flow meters and a film extraction system. Most flow loop controls were automated using a MATLAB program. Reference measurement of the total water flow rate was made using a calibrated turbine flow meter and of the air flow rate using a calibrated rotameter. For the combined ultrasonic/conductance method investigated in this thesis, the velocity of the gas in the core was found using a novel Ultrasonic Flow Meter (USFM). The positioning and arrangement of the transducers have never been used previously. The flow velocity of the liquid film and the thickness of the film were measured using a novel Conductance Flow Meter (CFM). The CFM measured the liquid film thickness using novel wall conductance probes. By cross correlating the signals from a pair of such probes the film velocity was obtained. Good agreement of the experimental results obtained from the CFM and USFM with results published in the literature was found. Although not investigated experimentally in the work described in this thesis, annular flows encountered in the oil industry may contain a liquid phase comprising a mixture of oil and water. For such flows, the volume fractions of the oil and water can be measured using an automated bypass system developed during this project. The bypass system periodically extracts part of the liquid film, measures its density and then releases the sample back into the pipeline. The liquid phase volume fractions are determined from this density measurement which can be performed more than once per minute. An entrainment model was developed, which is required by the ultrasonic/conductance flow metering technique described in this thesis, in which the mass fraction of the liquid flowing as entrained droplets in the core can be determined from the liquid film thickness and velocity measurements. A mathematical model was also developed to describe the properties of the liquid film, such as liquid velocity profile within the film, and the model?s results were found to agree with the experimental results obtained during the project and also with previous work cited in the literature. The complexity of this latter model was reduced by making a number of simplifying assumptions, which are presented and discussed in the thesis, including the assumption that in annular flow there is a dynamic balance liquid entrainment and droplets being deposited back onto the film. The combination of the designed CFM and USFM with the bypass tube and the entrainment model offer the opportunity for a?wet gas? flow meter to be developed to measure two and three phase annular flows at relatively low cost and with enhanced accuracy. Such a device would have the advantage that it would by substantially smaller than systems using separators and it could even be retrofitted onto off-shore platforms. The integration of the subsystems developed in this project into a single system capable of giving on-line measurements of annular flow would be a major benefit to the author?s sponsor, Petroleum Development of Oman.