Download or read book Numerical Simulation of Slug Flow in Horizontal Pipes and Comparison with Slug Frequency Prediction Methods from Literature written by Florian Webner and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical simulation of twophase slug flow in horizontal and nearly horizontal pipes written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Escoamentos bifásicos no regime de golfadas são caracterizados pelaalternância de pacotes de líquido e grandes bolhas de gás na tubulação, sendoassociados a altas perdas de carga, além de trazer uma indesejada intermitênciaaos escoamentos. O desenvolvimento do regime de golfadas em tubulaçõeshorizontais se dá a partir do escoamento estratificado em decorrência de doisfatores: do crescimento natural de pequenas perturbações (por um mecanismo deinstabilidade do tipo Kelvin-Helmholtz) ou devido à acumulação de líquidocausada por mudanças de inclinação no perfil do duto. O presente trabalhoconsiste da simulação numérica do surgimento das golfadas em ambas assituações descritas acima, assim como do subseqüente desenvolvimento doescoamento neste padrão para um regime estatisticamente permanente. Aprevisão do escoamento é obtida utilizando-se uma formulação unidimensionalbaseada no Modelo de Dois Fluidos. Parâmetros médios das golfadas(comprimento, velocidade e freqüência) são comparados com estudos numéricose experimentais da literatura, obtendo-se uma concordância bastante satisfatória, especialmente dada a simplicidade de uma formulação unidimensional.
Download or read book Numerical Simulation of Two phase Gas liquid Flows in Inclined and Vertical Pipelines written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The present thesis describes the advances made in modelling two-phase flows in inclined pipes using a transient one-dimensional approach. The research is a developement of an existing numerical methodology, capable of simulating stratified and slugging two-phase flows in horizontal or inclined single pipes. The aim of the present work is to extend the capabilities of the approach in order (i) to account for the effect of the pipe topography in the numerical solution of the two-fluid model, and (ii) to simulate vertical bubbly twophase flows at various pressures in large diameter pipes, and (iii) to model stratified and terrain-induced slugging in two-phase flow pipelines made of several uphill, downhill and level sections. A transient compressible two-fluid model based on the one-dimensional form of the mass and momentum conservation equations for the gas and liquid phases, is developed to predict those flow configurations. The wall to fluid and the interphase interactions are accounted for by constitutive relations which are flow regime dependent. The conservation equations are discretized using a finite volume method. An algorithm is created to enable simulations on pipelines made of several sections, and account for the effect of the topography in the simulations. The methodology is applied to the compressible model in order to evaluate the robustness and accuracy of the numerical schemes, especially for the high-resolution Advection Upwinding Splitting Method (AUSM) associated to the compressible model. It also assesses the ability of the method to predict three physical flow regimes, namely stratified, bubbly and terrain-induced slug flows. The terrain-induced slugging study is performed on a slightly inclined ("1.5°) V-section system. The use of hydrodynamic slug correlations for hilly-terrain slugging is discussed. It shows to be conclusive with a good agreement with experimental measurements obtained for slug frequency and slug length predictions. Mechanisms.
Download or read book Slug Flow Simulation in Inclined Pipes written by Seungyong Chang and published by . This book was released on 1993 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stochastic Tools in Turbulence written by John L. Lumley and published by Courier Corporation. This book was released on 2007-01-01 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: This accessible treatment offers the mathematical tools for describing and solving problems related to stochastic vector fields. Advanced undergraduates and graduate students will find its use of generalized functions a relatively simple method of resolving mathematical questions. It will prove a valuable reference for applied mathematicians and professionals in the fields of aerospace, chemical, civil, and nuclear engineering. The author, Professor Emeritus of Engineering at Cornell University, starts with a survey of probability distributions and densities and proceeds to examinations of moments, characteristic functions, and the Gaussian distribution; random functions; and random processes in more dimensions. Extensive appendixes—which include information on Fourier transforms, tensors, generalized functions, and invariant theory—contribute toward making this volume mathematically self-contained.
Download or read book Petroleum Abstracts Literature and Patents written by and published by . This book was released on 1989 with total page 1528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Slug Flow Models in Horizontal Pipes written by Carlos Alfredo Daza and published by . This book was released on 1990 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Simulation of Slug Flow with High Viscosity Liquid written by Yat Ho Nicholas Hor and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of Taylor Bubbles in Vertical and Inclined Slug Flow Using Multiphase CFD with Level Set written by Enrique Lizarraga-García and published by . This book was released on 2016 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Slug flow commonly occurs in gas and oil systems. Current predictive methods are based on mechanistic models, which require the use of closure relations to complement the conservation equations to predict integral flow parameters such as liquid holdup (or void fraction) and pressure gradient. These closure relations are typically developed either empirically or from semi-empirical models assuming idealized geometry of the interface, thus they carry the highest uncertainties in the mechanistic models. In this work, sensitivity analysis has determined that Taylor bubble velocity in slug flow is one such closure relation which significantly affects the calculation of these parameters. The main objective is to develop a unified higher-fidelity closure relation for Taylor bubble velocity. Here, we employ a novel approach to overcome the experimental limitations: validated 3D Computational Multiphase Fluid Dynamics (CMFD) with Interface Tracking Methods (ITMs) where the interface is tracked with a Level-Set method implemented in the commercial code TransAT®. In the literature, the Taylor bubble velocity is modeled based on two different contributions: (i) the drift velocity, i.e., the velocity of propagation of a Taylor bubble in stagnant liquid, and (ii) the liquid flow contribution. Here, we first analyze the dynamics of Taylor bubbles in stagnant liquid by generating a large numerical database that covers the most ample range of fluid properties and pipe inclination angles explored to date (Eo [epsilon] [10, 700], Mo [epsilon] [1 . 10-6, 5 . 103], and [theta] [epsilon] [0°, 90°]). A unified Taylor bubble velocity correlation, proposed for use as a slug flow closure relation in the mechanistic model, is derived from that database. The new correlation predicts the numerical database with 8.6% absolute average relative error and a coefficient of determination R2 = 0.97, and other available experimental data with 13.0% absolute average relative error and R2 = 0.84. By comparison, the second best correlation reports absolute average relative errors of 120% and 37%, and R2 = 0.40 and 0.17, respectively. Furthermore, two key assumptions made in the CMFD simulations are justified with simulations and experiments: (i) the lubricating liquid film formed above the bubble as the pipe inclines with respect to the horizontal does not breakup, i.e., the gas phase never touches the pipe wall and triple line is not formed; and (ii) the Taylor bubble length does not affect its dynamics in inclined pipes. To verify the robustness of the first assumption, the gravity-induced film drainage is analytically modeled and experimentally validated. From this model, a criterion to avoid film breakup is obtained, which holds in the simulations performed. The second assumption is validated with both experiments and simulations. Finally, simulations of Taylor bubbles in upward and downward fluid flow in vertical and inclined pipes are performed, from where it is concluded that an improvement of the current velocity prediction models is needed. In particular, Taylor bubbles in vertical downward flow where the bubble becomes non-axisymmetric at high enough liquid flows are remarkably ill-predicted by current correlations.
Download or read book Fundamentals of Multiphase Flow written by Christopher E. Brennen and published by Cambridge University Press. This book was released on 2005-04-18 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Publisher Description
Download or read book An Experimental and Numerical Investigation of Two phase Slug Flow in a Vertical Tube written by Julio Manuel Mendes DeJesus and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The multi-dimensional liquid velocity field and interfacial configuration of Taylor bubbles rising in stagnant kerosene in a vertical 25.6 mm I.D. pipe was investigated experimentally with a non-intrusive flow visualization technique based on photochromic dye activation, and numerically using a computer program for incompressible flows with free surfaces. The experimental results show that a change in flow direction of the liquid occurred at the nose of the Taylor bubble. From the nose, the liquid film accelerated downwards as the velocity profile became characteristic of developing falling film flow. At the tail, the liquid film penetrated into the wake creating vortices of different sizes. The film penetration distance in the wake region was not proportional to the film velocity, and therefore the bubble length. Within 1 to 1.5 tube diameters (26-38 mm) below the tail of the Taylor bubble, the vortices rapidly decayed and the liquid near the wall returned to essentially a stagnant state. However, small vortices in the bulk fluid remained visible up to 100 mm behind the Taylor bubble. An analysis of the flow revealed the liquid film surrounding the neatly cylindrical portion of the Taylor bubble to be approximately one-dimensional, whereas near the nose and in the wake it was highly two-dimensional. Furthermore, the velocity in the wake region was determined to be qualitatively similar for different runs. A simple predictive procedure for estimating the radially averaged streamwise film velocity and Taylor bubble shape concluded that the boundary-layer development at the pipe wall only influenced the falling film velocity. The numerical simulation of the Taylor bubble flow was conducted using the volume-of-fluid approach. However, the range of physical property values that yielded stable numerical results for the inertia-controlled rise of the bubble was severely limited, due to significant stability problems. The Taylor bubble shape was well predicted and velocity profiles in the liquid surrounding the Taylor bubble were computed with partial success for the first time in comparison with measured results. The flow in the wake was only qualitatively similar to the experimental data.
Download or read book Slug Frequency in Horizontal Pipes written by Jochen Gier and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of slug flow in horizontal pipelines by the two fluid model written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Diversos processos práticos apresentam uma seqüência de diferentes configurações de escoamentos bifásicos, com diferentes padrões de escoamento. Dependendo das razões entre as velocidades superficiais do gás e do líquido, diferentes padrões de escoamento bifásico podem ser encontrados. O padrão de escoamento slug pode ser formado a partir do padrão estratificado, devido ao crescimento das instabilidades hidrodinâmicas ou devido às ondulações noterreno onde se instala a tubulação. O presente trabalho consiste na análise do escoamento bifásico no padrão slug, ao longo de tubulações horizontais, mediante a aplicaçãodo modelo de dois fluidos em sua forma transiente e unidimensional. Através de uma análise de estabilidade de Kelvin-Helmholtz para escoamento estratificado, estima-se a possível faixa de operação para a obtenção de um modelomatemático bem posto. Diferentes técnicas de discretização foram implementadas e testadas. Comparações com dados disponíveis na literatura foram realizadas.
Download or read book Prediction of Pressure Drop of Slug Flow in Vertical Pipes Using Mechanistic Model written by Mohamad Fakhrol Radzi Zulkefli and published by . This book was released on 2014 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the variability of flow pattern of gas liquid two-phase flow and complexity of flow mechanism,it is very difficult to seek a single model which is able to predict pressure drop and fit for any flow condition. when the existing model of two-phase flow pressure drop is used to predict the pressure of the conditions of producing gas well,a large error occurs.Therefore, it is necessary,based on the experimental data of gas-water two phase flow,to research the flow mechanism and discover the regular existing in the process of fluid property changing .On the basis of the current two-phase flow pressure drop model, it is important to explore modified pressure loss model applicable for producing gas well with water,to improve predictability of the pressure drop of gas wells,and to provide the theory and technology guidence for development of gas reservoir with water. Underbalanced drilling (UBD) has increased in recent years because of the many advantages associated with it. These include increase in the rate of penetration and reduction of lost circulation and formation damage. Drilling of deviated and horizontal wells also increased since recovery can be improved from a horizontal or a deviated well. The drilling of deviated wells using UBD method will reduce several drilling related problems such as hole cleaning and formation damage. Prediction of flow and pressure profiles while drilling underbalanced in such wells will help in designing and planning of the well. The aim of this research is to predict the pressure drop of slug flow in the certain pressure in vertical pipes using mechanistic model and to study the behavior of the flow profile in the drillstring and the annulus under UBD conditions through the use of mechanistic two phase flow models. Mechanistic two phase flow models is been used In this research to predict the liquid hold up for phase gas- liquid slug flow which is important for the accurate calculations of the pressure drop.In particular, its evaluation is important for the vertical pipes since the liquid hold up in the slug body is the main contributor to the hydrostatic pressure drop which quite significant for the verticals flows. Further development of mechanistic models has allowed accurate prediction of wellbore pressure. Many Underbalanced Drilling operations require the use of nitrified diesel as the drilling fluid.Thus two phase flow will exist both in the drill pipe and the annulus.
Download or read book Closure Relations of the One dimensional Two fluid Model for the Simulation of Slug Flows written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation and CFD Simulation of Slug Flow in Horizontal Channels written by and published by . This book was released on 2007 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanistic Models to Simulate Slug Flow in Horizontal and Vertical Pipes written by Fabio Robert Di Salvo and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
