Gas Void Fraction Measurement in Two-Phase Gas/Liquid Slug Flow Using Acoustic Emission Technology

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
S. Al-lababidi ◽  
A. Addali ◽  
H. Yeung ◽  
D. Mba ◽  
F. Khan
Keyword(s):  
Acoustic Emission ◽  
Flow Regime ◽  
Void Fraction ◽  
Slug Flow ◽  
Chemical Engineering ◽  
Oil And Gas ◽  
Gas Production ◽  
Engineering Industry ◽  
Two Phase ◽  
Gas Void Fraction

The gas-liquid two-phase slug flow regime phenomenon is commonly encountered in the chemical engineering industry, particularly in oil and gas production transportation pipelines. Slug flow regime normally occurs for a range of pipe inclinations, and gas and liquid flowrates. A pipeline operating in the slug flow regime creates high fluctuations in gas and liquid flowrates at the outlet. Therefore, the monitoring of slugs and the measurement of their characteristics, such as the gas void fraction, are necessary to minimize the disruption of downstream process facilities. In this paper, a correlation between gas void fraction, absolute acoustic emission energy, and slug velocities in a two-phase air/water flow regime was developed using an acoustic emission technique. It is demonstrated that the gas void fraction can be determined by measurement of acoustic emission.

The Effect of Inclination on Flow Regime Boundaries and Slug Flow Characteristics

1989 ◽  
Vol 111 (3) ◽  
pp. 181-186 ◽  
Author(s):  
D. G. Wood
Keyword(s):  
Flow Regime ◽  
Slug Flow ◽  
Oil And Gas ◽  
Production Systems ◽  
Flow Characteristics ◽  
Gas Production ◽  
Research Centre ◽  
Test Rig ◽  
Oil And Gas Production ◽  
Capital Costs

Multiphase schemes for oil and gas production systems are becoming more common as the development of marginal fields necessitates a reduction in capital costs. Prediction of flow regime within these pipelines and the characteristics of the flow, especially within the slugging regime, is required in order to design the pipeline and the downstream separation and processing facilities. Test rig studies have been carried out at BP’s Sunbury Research Centre on the effect of small changes in pipeline inclination on both the flow regime and the characteristics of slug flow. Results from tests on a 2-in. rig are quoted.

Investigation of Slug Flow Structure in Terms of Flow Regime Transition in Co-Current Two-Phase Flow

2017 ◽  
Author(s):  
Muhao Zhang ◽  
Liang-ming PAN ◽  
Peng Ju ◽  
Mamoru Ishii
Keyword(s):  
Turbulent Flow ◽  
Flow Regime ◽  
Void Fraction ◽  
Slug Flow ◽  
Transition Process ◽  
Phase Flow ◽  
Regime Transition ◽  
Two Phase ◽  
Flow Regime Transition ◽  
Wake Effects

In order to investigate the structure parameters evolution characteristics during flow regime transition process in slug flow, the vertical upward slug flow experiment in a wide range of liquid superficial velocity (0.03 < jl < 1.6 m/s) were conducted in a tubular test section with the inside diameter of 25.4 mm. Impedance void meters were employed to measure the void fraction of separated two parts corresponding to Taylor bubble and liquid slug. The present research studied the evolution of length ratio and void fraction in slug unit by keeping the liquid superficial velocity constant while increasing gas flow rate. New structure of slug unit in strong relation with transition process was observed. In specific, it was realized that the proportion of such special structure unit played an important role in transition from slug flow to churn-turbulent flow. The existing transition criteria from slug flow to churn-turbulent flow in upward two-phase flow (entrance effects model, flooding model, wake effects model, bubble coalescence model and Helmholtz instability model) were compared with the experimental identified results obtained by a new objective flow regime identification method, ReliefF-FCM algorithm. The results indicate that the transition model based on the wake effects could be the most appropriate choice to describe the mechanism of transition from slug flow to churn-turbulent flow in present experimental conditions.

Research on the Air-Water Flow Regime and Characteristics in Rectangular Channel

2021 ◽  
Author(s):  
Qingche He ◽  
Liangming Pan ◽  
Luteng Zhang ◽  
Meiyue Yan ◽  
Wangtao Xu
Keyword(s):  
Flow Regime ◽  
Void Fraction ◽  
Slug Flow ◽  
Clustering Algorithm ◽  
Two Phase Flow ◽  
Rectangular Channel ◽  
Interfacial Structure ◽  
Phase Flow ◽  
Two Phase ◽  
Rectangular Channels

Abstract Two-phase Flow is widely involved in reactor design and is directly relevant to reactor safety. However, the flow regime in narrow rectangular channels still needs further study because it has a considerable difference from tube and bundle channels. To investigate the two-phase flow regime and interfacial structure characteristics, the air-water experiment with an adiabatic vertical channel of 4 × 66 × 1800, 6 × 66 × 1800 mm have been conducted under atmosphere pressure condition. The impedance void meter was used to measure the global void fraction in narrow rectangular channels. A high-speed camera was used to record the profiles of the flow regime. The flow regime was identified by the random forest clustering algorithm based on a training sample. The profiles of different parameters, including void fraction, pressure loss at Z/D = 150, were analyzed in this paper. Furthermore, based on the parameters’ distribution, the regime transition criteria in narrow rectangular channels were discussed. It is shown that the transition from bubble to slug flow always occurred when the average void fraction is 0.17–0.2. The transition value is 0.57–0.62 when the slug Flow changes to the churn-turbulent Flow and 0.78–0.8 from churn-turbulent to annular Flow. The constant used in the Lockhart-Martinelli correlation is found to calculate the frictional pressure drop in a rectangular channel. Furthermore, the drift-model applied to the rectangular channel is verified.

Void Fraction, Pressure Drop, and Flow Pattern Behavior for Two-Phase Non-Newtonian Slug Flow

2021 ◽  
Author(s):  
Faraj Ben Rajeb ◽  
Syed Imtiaz ◽  
Yan Zhang ◽  
Amer Aborig ◽  
Mohamed M. Awad ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Flow Regime ◽  
Void Fraction ◽  
Slug Flow ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Intermittent Flow ◽  
Phase Flow ◽  
Two Phase

Abstract Slug flow is one of the most common flow patterns in non-Newtonian two-phase flow in pipes. It is a very common occurrence in gas-liquid two-phase flow in the pipe. Usually, it is an unfavorable flow pattern due to its unsteady nature, intermittency as well as high pressure drop. The differences between slug flow and elongated bubble flow are not clear because usually these two types of flow combined under one flow category. In general, these two-phase flow regimes are commonly defined as intermittent flow. In the present study, pressure gradient, and wave behavior in slug flow have been investigated depending on experimental work. In addition, void fraction has been estimated regarding available superficial liquid and gas velocities. The experimental records of superficial velocities of gas and liquid for slug flow and other flow patterns is used to create flow regime map for the gas non-Newtonian flow system. The effect of investigated flow regime velocities for non-Newtonian/gas flow on pressure drop and void fraction is reported. Pressure drop has been discovered to be reduced in slug flow more than other flow patterns due to high shear thinning behavior.

Numerical simulation of two-phase flow regime in horizontal pipeline and its validation

2018 ◽  
Vol 28 (6) ◽  
pp. 1279-1314 ◽  
Author(s):  
Sam Ban ◽  
William Pao ◽  
Mohammad Shakir Nasif
Keyword(s):  
Flow Regime ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Gas Production ◽  
Liquid Holdup ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Oil And Gas Production ◽  
Content Type ◽  
The Difference

Purpose The purpose of this paper is to investigate oil-gas slug formation in horizontal straight pipe and its associated pressure gradient, slug liquid holdup and slug frequency. Design/methodology/approach The abrupt change in gas/liquid velocities, which causes transition of flow patterns, was analyzed using incompressible volume of fluid method to capture the dynamic gas-liquid interface. The validity of present model and its methodology was validated using Baker’s flow regime chart for 3.15 inches diameter horizontal pipe and with existing experimental data to ensure its correctness. Findings The present paper proposes simplified correlations for liquid holdup and slug frequency by comparison with numerous existing models. The paper also identified correlations that can be used in operational oil and gas industry and several outlier models that may not be applicable. Research limitations/implications The correlation may be limited to the range of material properties used in this paper. Practical implications Numerically derived liquid holdup and holdup frequency agreed reasonably with the experimentally derived correlations. Social implications The models could be used to design pipeline and piping systems for oil and gas production. Originality/value The paper simulated all the seven flow regimes with superior results compared to existing methodology. New correlations derived numerically are compared to published experimental correlations to understand the difference between models.

Analysis of Slug Frequency Correlations for Two-Phase Gas-Liquid Horizontal Slug Flow

2014 ◽  
Author(s):  
Manoella M. Antunes ◽  
Cristiane Cozin ◽  
Fausto A. A. Barbuto ◽  
Rigoberto E. M. Morales ◽  
Hendy T. Rodrigues
Keyword(s):  
Slug Flow ◽  
Oil And Gas ◽  
Transient Flow ◽  
Industrial Applications ◽  
Gas Production ◽  
Two Phase ◽  
Oil And Gas Production ◽  
One Dimensional ◽  
Flow Parameters ◽  
Two Fluid

Multiphase flows in pipelines show several flow patterns depending on the industrial applications where they appear. In oil and gas production, typical flow rates, geometries and the physical properties of the phases make slug flow to be the most common of all patterns. This kind of flow is characterized by an intermittent succession of an aerated liquid slug region and a long, turbulent gas bubble surrounded by a liquid film. Due to its complexity, slug flow modelling has been a challenge to many researchers over the last four decades. Presently, steady-state one-dimensional models based on the unit cell concept and more accurate physical representations based on either two-fluid or slug tracking models embedding transient flow capabilities are available. These models require closure relationships for predicting flow parameters. In the present work, a literature review on frequency correlations is presented. An analysis of the performance of those correlations with experimental data for horizontal slug flows was carried out and its results are presented.

Analysis of Numerical Simulation of Gas-Liquid Slug Flow Using Slug Tracking Model

2015 ◽  
Author(s):  
Stella C. P. Cavalli ◽  
Cristiane Cozin ◽  
Fausto A. A. Barbuto ◽  
Rigoberto E. M. Morales
Keyword(s):  
Slug Flow ◽  
Oil And Gas ◽  
Initial Conditions ◽  
Computational Simulation ◽  
Flow Simulation ◽  
Gas Production ◽  
Liquid Slug ◽  
Two Phase ◽  
Tracking Model ◽  
Slug Flows

The distribution of the interfaces in gas-liquid two-phase flows in pipes can assume several shapes. Amongst those shapes, the slug flow pattern stands out as the most common one and occurs quite often in oil and gas production due to the flow rates and geometries used. This pattern is characterized by the succession of the so-called unit cells, that is, a flow structure composed of an aerated liquid slug and an elongated bubble surrounded by a liquid film. Due to its complexity, the study and understanding of this pattern’s behaviour becomes very important. The main methodologies used to describe slug flows are the steady-state one-dimensional models, based on the slug unit concept, and the transient approach, which takes the flow intermittence into account. The slug tracking model is one such transient approach, which considers slugs and elongated bubbles as separated bodies and analyzes the evolution along the flow and the interaction between those bodies. Whenever this model is numerically implemented, its initial conditions are important parameters that affect the results. The goal of this article is to study the influence of the initial conditions on slug flow simulation using the slug tracking model. A computer program written in Fortran95 using a slug tracking model to provide the characteristic parameters of slug flows such as the bubble and slug lengths and void fraction in the bubble region was built and used. The results were compared to experimental data and showed the important role the initial conditions play on the computational simulation of slug flow.

Gas Void Fraction Prediction for Air-Water and Air-Oil Two-Phase Flows via Artificial Neural Network

2019 ◽  
Author(s):  
Tiago Ferreira Souza ◽  
Caio Araujo ◽  
Maurício Figueiredo ◽  
FLAVIO SILVA ◽  
Ana Maria Frattini Fileti
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Void Fraction ◽  
Two Phase Flows ◽  
Two Phase ◽  
Artificial Neural ◽  
Gas Void Fraction

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.

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