A Numerical Study of Entrainment Mechanism in Axisymmetric Annular Gas-Liquid Flow

Han, Huawei; Gabriel, Kamiel

doi:10.1115/1.2427078

Cited by 33 publications

(11 citation statements)

References 16 publications

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“…The study showed good predictions of the pressure gradient, film thickness, and shear stress. The authors noted the significant contribution of wave crests to the entrainment process, which was also observed by Han and Gabriel (2007), Han (2005).…”

Section: Introductionsupporting

confidence: 56%

“…According to the results, the authors concluded that laminar flow existed in the substrate region, while turbulent flow dominated the disturbance wave region. Han and Gabriel (2007) and Han (2005) conducted a CFD numerical simulation of annular flow in order to study the phenomena of liquid entrainment and the effect of disturbance waves on its progression. The one-fluid model with the VOF method implemented in the commercial software Fluent 6.18 was utilized with the RNG turbulence k-ε model.…”

Section: Introductionmentioning

confidence: 99%

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CFD modeling of liquid film reversal of two-phase flow in vertical pipes

Hussein

Al–Sarkhi

Badr

et al. 2019

J Petrol Explor Prod Technol

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The phenomenon of two-phase flows is characterized by its wide range of presence in nature and industrial applications. In gas and oil production, the simultaneous two-phase flow of gases and liquids often occurs in gas wells. The produced gases flow rate decreases over the years until reaching a critical flow rate when they lose their ability to lift the associated liquids upward and the liquid film reverses direction, which triggers liquid loading. Liquid loading causes the produced liquids to accumulate in the bottom of the wellbore, which causes a high back pressure that reduces the well production rate till production is ceased eventually. The critical gas velocity exists in the churn flow regime which is mainly characterized by the oscillatory behavior of the liquids flow field. This study employs CFD techniques to model the churn flow in a 3-inchdiameter vertical pipe near the critical gas flow rate for different liquid flow rates. This work utilizes the two-fluid Eulerian model along with the RNG (Re-Normalization Group) k-ε turbulence model to investigate the behavior of the flow field in a two-dimensional axisymmetric computational domain. Simulations were carried out using the commercial software ANSYS Fluent 18.2 with air and water as the two working fluids. The model results showed a good agreement with the experimental data and proved the mesh and time independence of the model. Oscillatory behaviors of the liquid film flow rate, shear stress, and pressure were observed along with the formation of interfacial waves. Detailed information about the velocity, shear stress, and pressure behaviors is presented. Accordingly, recommendations are suggested for future considerations.

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Section: Introductionsupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

CFD modeling of liquid film reversal of two-phase flow in vertical pipes

Hussein

Al–Sarkhi

Badr

et al. 2019

J Petrol Explor Prod Technol

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show abstract

“…Because of the challenges in determining the interface dynamics, a simple wave shape or even a smooth gas-liquid interface was used in many of the solution models. Han and Gabriel [196][197][198][199] modelled the gas core flow in a typical annular flow with the simplified flow in the liquid film region. Van der Meulen [18] simulated the droplet behaviour and droplet trajectory in gas-liquid flows in vertical pipes using Star-CD.…”

Section: Numerical Simulationmentioning

confidence: 99%

Two-Phase Annular Flow in Vertical Pipes: A Critical Review of Current Research Techniques and Progress

Xue¹,

Stewart

Kelly

et al. 2022

Water

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Two-phase annular flow in vertical pipes is one of the most common and important flow regimes in fluid mechanics, particularly in the field of building drainage systems where discharges to the vertical pipe are random and the flow is unsteady. With the development of experimental techniques and analytical methods, the understanding of the fundamental mechanism of the annular two-phase flow has been significantly advanced, such as liquid film development, evolution of the disturbance wave, and droplet entrainment mechanism. Despite the hundreds of papers published so far, the mechanism of annular flow remains incompletely understood. Therefore, this paper summarizes the research on two-phase annular flow in vertical pipes mainly in the last two decades. The review is mainly divided into two parts, i.e., the investigation methodologies and the advancement of knowledge. Different experimental techniques and numerical simulations are compared to highlight their advantages and challenges. Advanced underpinning physics of the mechanism is summarized in several groups including the wavy liquid film, droplet behaviour, entrainment and void fraction. Challenges and recommendations are summarized based on the literature cited in this review.

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“…The gas core flow in a typical annular flow was modeled by Han (2005) and Han and Gabriel (2007). Similar to the works of Jayanti and Hewitt (1997), the effects of liquid film flow on the gas core were simplified and considered through the use of experimental correlations.…”

Section: Numerical Studies On Two-phase Flowsmentioning

confidence: 99%

Current status of CFD modeling of liquid loading phenomena in gas wells: a literature review

Adaze

Al–Sarkhi

Badr

et al. 2018

J Petrol Explor Prod Technol

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Two-phase (gas-liquid) flow in vertical pipes has been one of the interests of industrial applications such as power plants, nuclear reactors, boilers, gas well exploration and so on. One of the problems usually encountered in the gas well exploration industries is liquid loading: a condition where the gas velocity is not high enough to carry all the liquid generated in the gas wells. During normal operation, flow in the gas wells shows characteristics of annular flow regime. However, as the gas wells mature, the gas velocities reduce (below a critical value) and gradually lead to the onset of liquid loading (film reversal). At this point, flow in the gas well presents features of churn flow. Thus, during the film reversal point, the liquid film tends to increase in thickness and part of it starts to flow downwards. This paper first summarizes the available mechanistic and numerical models related to liquid loading and then reviews the application of CFD techniques to liquid loading modeling in vertical pipes. Most of the methodologies discussed here focus on annular and churn flow due to the limited information on the application of CFD techniques to liquid loading modeling and the onset of film reversal occurs during the transition from annular flow to churn flow which can lead to liquid loading as observed experimentally by many researchers. It was concluded from the available literature related to liquid loading that a detailed understanding of the fluid flow behavior during liquid loading is not yet fully available and prediction methods of this phenomenon are still rather incipient. Directions for good CFD modeling of these important phenomena are presented in the present paper.

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A Numerical Study of Entrainment Mechanism in Axisymmetric Annular Gas-Liquid Flow

Cited by 33 publications

References 16 publications

CFD modeling of liquid film reversal of two-phase flow in vertical pipes

CFD modeling of liquid film reversal of two-phase flow in vertical pipes

Two-Phase Annular Flow in Vertical Pipes: A Critical Review of Current Research Techniques and Progress

Current status of CFD modeling of liquid loading phenomena in gas wells: a literature review

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