Horizontal Slug Flow: A Comparison of Existing Theories

1990 ◽  
Vol 112 (1) ◽  
pp. 74-83 ◽  
Author(s):  
E. Kordyban
Keyword(s):  
Experimental Data ◽  
Slug Flow ◽  
Wave Motion ◽  
Phase Flow ◽  
Bernoulli Equation ◽  
Helmholtz Instability ◽  
Two Phase ◽  
Motion Equations ◽  
The Waves ◽  
Number Of Authors

Over the last twenty years a number of papers have appeared in literature concerning the transition to slug flow in horizontal two-phase flow. The theories proposed in these papers are described, and compared to each other and to results of experiments. It is found that most writers accept that the transition is due to Kelvin-Helmholtz instability of the waves, but if this is studied on the basis of wave motion equations, the transition is found to be dependent on wavelength which contradicts experimental data. A number of authors look at this instability by studying the Bernoulli equation, but this does not predict the wave height. Various approaches are taken by the authors to determine this quantity.

scholarly journals Slug Flow Hydrodynamics Modeling for Gas–Liquid Two-Phase Flow in a Pipe

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 533
Author(s):  
Huishu Liu ◽  
Jimiao Duan ◽  
Kecheng Gu ◽  
Jiang Li ◽  
Hao Yan ◽  
...  
Keyword(s):  
Experimental Data ◽  
Slug Flow ◽  
Two Phase Flow ◽  
Close Contact ◽  
Liquid Droplet ◽  
Flow Patterns ◽  
Phase Flow ◽  
Interface Model ◽  
Two Phase ◽  
Model Calculations

Gas–liquid flow in a pipeline is a very common. Slug two-phase flow is dominated in the case of slightly upward flow (+0.25°) and considered to be the comprehensive flow configuration, and can be in close contact with all the other flow patterns. The models of different flow patterns can be unified. Precise prediction of the slug flow is crucial for proper design and operation. In this paper, we develop hydrodynamics unified modeling for gas–liquid two-phase slug flow, and the bubble and droplet entrainment is optimized. For the important parameters (wall and interfacial friction factors, slug translational velocity and average slug length), the correlations of these parameters are optimized. Furthermore, the related parameters for liquid droplet and gas bubble entrainment are given. Accounting for the gas–liquid interface shape, hydrodynamics models, i.e., the flat interface model (FIM) and the double interface model (DIM), of liquid film in the slug body are applied and compared with the experimental data. The calculated results show that the predictions for the liquid holdup and pressure gradient of the DIM agree with experimental data better than those of the FIM. A comparison between the available experimental results and Zhang’s model calculations shows that the DIM model correctly describes the slug dynamics in gas–liquid pipe flow.

Pressure Drop of Horizontal Air–Water Slug Flow in Different Configurations of Corrugated Pipes

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Ana Luiza B. Santana ◽  
Moisés A. Marcelino Neto ◽  
Rigoberto E. M. Morales
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Industrial Application ◽  
Slug Flow ◽  
Phase Flow ◽  
Dynamic Changes ◽  
Two Phase ◽  
Pressure Drops ◽  
Flow Pressure ◽  
Increased Pressure

Abstract Corrugated pipes (CP) have regularly shaped and spaced cavities on their internal walls that can induce dynamic changes in the flow, such as increased pressure drops. Offshore petroleum production pipelines are an example of an industrial application of CPs, known as flexible lines. Slug flow is the most challenging flow pattern in those lines due to its complex hydrodynamics. A number of previous studies proposed correlations to predict the two-phase flow pressure drops in smooth pipes (SPs). However, limited researches have evaluated the pressure drops associated with liquid–gas slug flow in CPs. In this work, experiments to analyze the pressure drops in horizontal air–water slug flow under different configurations of CPs were carried out. The tests were performed in three different CP internal diameters (IDs) (26, 40, and 50 mm) with different cavity widths (1.2, 1.6, and 2.0 mm). The effects of the internal diameters and the cavity widths on the pressure drops associated with slug flow were analyzed. Results demonstrated that the pressure drops increase with increasing cavity widths. The experimental data were fitted and a pressure drop correlation using the concept of multiplier factor was proposed. Comparisons between predictions and the experimental data proved to be within ±10% accuracy.

Two-Phase Flow-Induced Forces on Bends in Small Scale Tubes

2009 ◽  
Author(s):  
Marcos F. Cargnelutti ◽  
Stefan P. C. Belfroid ◽  
Wouter Schiferli
Keyword(s):  
Experimental Data ◽  
Slug Flow ◽  
Structural Integrity ◽  
Two Phase Flow ◽  
Small Scale ◽  
Phase Flow ◽  
Mechanical Forces ◽  
Two Phase ◽  
Or Efficiency ◽  
Flow Induced Vibrations

Two-phase flow occurs in many situations in industry. Under certain circumstances, this can be the source of flow-induced vibrations. The forces generated can be sufficiently large to affect the performance or efficiency of an industrial device. At worst, the mechanical forces that arise may endanger structural integrity. Thus, it is important to take these forces into account in designing industrial machinery to avoid problems during operation. Although the occurrence of such forces is well-known, not much is known about their magnitudes. Unfortunately, the amount of experimental data available in literature is rather limited. This paper describes an investigation into the forces in a two-phase flow in a 6mm pipe containing a bend. The results are analyzed based on flow regime and bend configuration. Finally, a simple model is proposed to predict the forces generated by slug flow.

Mechanism of Slug Formation in Horizontal Two-Phase Flow

1970 ◽  
Vol 92 (4) ◽  
pp. 857-864 ◽  
Author(s):  
E. S. Kordyban ◽  
T. Ranov
Keyword(s):  
Theoretical Prediction ◽  
Surface Waves ◽  
Flow Pattern ◽  
Slug Flow ◽  
Wave Amplitude ◽  
Experimental Results ◽  
Phase Flow ◽  
Helmholtz Instability ◽  
Two Phase ◽  
Good Agreement

It is proposed in this work that the transition to slug flow occurs due to Kelvin-Helmholtz instability, which, in this case, is enhanced by the proximity of the upper wall and becomes wave-amplitude dependent. Since the surface waves possess a limiting amplitude, the transition can be predicted by examining whether the highest possible waves are unstable. The theoretical prediction is in good agreement with the authors’ experimental results. It also agrees reasonably well with Baker’s and Schicht’s flow pattern charts for strictly horizontal channels, but it exhibits large differences when the channels deviate somewhat from the horizontal.

On Instabilities in Horizontal Two-Phase Flow

1994 ◽  
Vol 59 (12) ◽  
pp. 2595-2603
Author(s):  
Lothar Ebner ◽  
Marie Fialová
Keyword(s):  
Differential Equation ◽  
Flow Regime ◽  
Slug Flow ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Annular Flows ◽  
Flow Regime Maps

Two regions of instabilities in horizontal two-phase flow were detected. The first was found in the transition from slug to annular flow, the second between stratified and slug flow. The existence of oscillations between the slug and annular flows can explain the differences in the limitation of the slug flow in flow regime maps proposed by different authors. Coexistence of these two regimes is similar to bistable behaviour of some differential equation solutions.

scholarly journals Experimental data for the slug two-phase flow characteristics in horizontal pipeline

Data in Brief ◽  
2018 ◽  
Vol 16 ◽  
pp. 527-530 ◽  
Author(s):  
Abdalellah O. Mohmmed ◽  
Mohammad S. Nasif ◽  
Hussain H. Al-Kayiem
Keyword(s):  
Experimental Data ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Two Phase

scholarly journals Investigation of representing hysteresis in macroscopic models of two-phase flow in porous media using intermediate scale experimental data

2017 ◽  
Vol 53 (1) ◽  
pp. 199-221 ◽  
Author(s):  
Abdullah Cihan ◽  
Jens Birkholzer ◽  
Luca Trevisan ◽  
Ana Gonzalez-Nicolas ◽  
Tissa Illangasekare
Keyword(s):  
Experimental Data ◽  
Porous Media ◽  
Two Phase Flow ◽  
Flow In Porous Media ◽  
Phase Flow ◽  
Two Phase ◽  
Intermediate Scale ◽  
Macroscopic Models

Effect of Common Impurities on the Phase Behavior of Carbon-Dioxide-Rich Systems: Minimizing the Risk of Hydrate Formation and Two-Phase Flow

SPE Journal ◽  
2011 ◽  
Vol 16 (04) ◽  
pp. 921-930 ◽  
Author(s):  
Antonin Chapoy ◽  
Rod Burgass ◽  
Bahman Tohidi ◽  
J. Michael Austell ◽  
Charles Eickhoff
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Phase Behavior ◽  
Water Content ◽  
Thermodynamic Model ◽  
Two Phase Flow ◽  
Hydrate Formation ◽  
Experimental Methodology ◽  
Phase Flow ◽  
Two Phase

Summary Carbon dioxide (CO2) produced by carbon-capture processes is generally not pure and can contain impurities such as N2, H2, CO, H2 S, and water. The presence of these impurities could lead to challenging flow-assurance issues. The presence of water may result in ice or gas-hydrate formation and cause blockage. Reducing the water content is commonly required to reduce the potential for corrosion, but, for an offshore pipeline system, it is also used as a means of preventing gas-hydrate problems; however, there is little information on the dehydration requirements. Furthermore, the gaseous CO2-rich stream is generally compressed to be transported as liquid or dense-phase in order to avoid two-phase flow and increase in the density of the system. The presence of impurities will also change the system's bubblepoint pressure, hence affecting the compression requirement. The aim of this study is to evaluate the risk of hydrate formation in a CO2-rich stream and to study the phase behavior of CO2 in the presence of common impurities. An experimental methodology was developed for measuring water content in a CO2-rich phase in equilibrium with hydrates. The water content in equilibrium with hydrates at simulated pipeline conditions (e.g., 4°C and up to 190 bar) as well as after simulated choke conditions (e.g., at -2°C and approximately 50 bar) was measured for pure CO2 and a mixture of 2 mol% H2 and 98 mol% CO2. Bubblepoint measurements were also taken for this binary mixture for temperatures ranging from -20 to 25°C. A thermodynamic approach was employed to model the phase equilibria. The experimental data available in the literature on gas solubility in water in binary systems were used in tuning the binary interaction parameters (BIPs). The thermodynamic model was used to predict the phase behavior and the hydrate-dissociation conditions of various CO2-rich streams in the presence of free water and various levels of dehydration (250 and 500 ppm). The results are in good agreement with the available experimental data. The developed experimental methodology and thermodynamic model could provide the necessary data in determining the required dehydration level for CO2-rich systems, as well as minimum pipeline pressure required to avoid two-phase flow, hydrates, and water condensation.

Study of the 90° Elbows Performance as Phase Separators in an Air-Water Two-Phase Flow

2003 ◽  
Author(s):  
Valente Herna´ndez P. ◽  
Florencio Sa´nchez S. ◽  
Miguel Toledo V. ◽  
Georgiy Polupan
Keyword(s):  
Phase Separation ◽  
Slug Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Pressure Gradients ◽  
Two Phase ◽  
Branch Diameter ◽  
Independent Variables ◽  
Inclination Angles ◽  
Phase Separator

In order to observe the 90° elbows performance as phase separators in an air-water two-phase flow, experimental results for the phase split which occurs at a 90° branched elbow are presented. The branched elbow geometry was varied in order to have three (branch diameter / elbow diameter) ratios and three branch inclination angles. Also the pressure was monitored at different points of the elbow with ramification in order to examine the pressure drop effect. The flow pattern upstream was mainly slug flow. First, the analysis of the main independent variables effect, (superficial velocities, branch inclination angle, ratio of diameters and pressure gradients) was carried out, then a correlation for the phase split was developed and, finally a comparison was made with data of phase separation in T junctions obtained by Azzopardi [1] and Soliman [2], as a result, a better behavior as phase separator was found for the elbow.

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