Translational velocities of elongated bubbles in continuous slug flow

Hout, R. van; Barnea, Dvora; Shemer, Lev

doi:10.1016/s0301-9322(02)00027-7

Cited by 84 publications

(50 citation statements)

References 22 publications

(38 reference statements)

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“…The higher translational velocity is related to the higher frequency shown in the PSD plot in Figure 3 and the higher overall liquid holdup in the pipe for the air-silicone oil. This finding is in agreement with Van Hout et al [8], who found that the drift velocity for continuous slug flow is enhanced by the dispersed bubbles in the liquid slug body. Similarly, Hills and Darton [20] found considerable enhancement in the velocity of large bubbles in bubble swarms.…”

Section: Translational Velocitysupporting

confidence: 93%

“…Nicklin et al [6] established a correlation for translational velocity of Taylor bubbles in moving liquid while White and Beardmore [7] used dimensionless groups to account for the combined effect of several variables, including fluid properties. Later developments in instrumentation have allowed researchers to look further at the two-phase flow; Van Hout et al [8] measured the translational velocity of elongated bubbles in continuous slug flow, Hassan et al [9] studied two-phase flow field and 3D structures in bubbly flow using particle image velocimetry (PIV). However, no effect of physical properties has been reported.…”

Section: Introductionmentioning

confidence: 99%

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Effects of physical properties on the behaviour of Taylor bubbles

Hernández-Pérez

Abdulkareem

Azzopardi

2009

Computational Methods in Multiphase Flow V

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Gas-liquid flow in vertical pipes, which is important in oil/gas wells and the risers from sea bed completions to FPSOs, was investigated to determine the effects of physical properties on the characteristics of the mixture such as void fraction, structure frequency and velocity as well as the shape of 3D structures. These are difficult to visualise using conventional optical techniques because even if the pipe wall is transparent, near-wall bubbles would mask the flow deep in the pipe. Therefore, more sophisticated methods are required. Two advanced wire mesh sensors (WMS) were used and the two-phase mixtures employed were air-water and air-silicone oil.The effect of fluid properties is accounted for in terms of the Morton number. It was found that the flow pattern is affected by the fluid properties as the results revealed that contrary to what is commonly assumed when modelling pipe flow, the flow is not symmetric, with a lot of distortion, which is even higher for the air-silicone oil mixture.

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Section: Translational Velocitysupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Effects of physical properties on the behaviour of Taylor bubbles

Hernández-Pérez

Abdulkareem

Azzopardi

2009

Computational Methods in Multiphase Flow V

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“…Although these methods can be applied to some extent in continuous slug flow experiments (see e.g. van Hout et al, 2002b), much more detailed measurements can be carried out for the ''clean'' conditions of controlled bubble injection.…”

Section: Discussionmentioning

confidence: 99%

“…The value of C therefore equals approximately 1.2 for fully developed turbulent flow and 2.0 for fully developed laminar flow. The drift velocity U d depends on the inclination angle b, and has a maximum for 40 < b < 60° (Zukoski, 1966;Bendiksen, 1984;Fabre and Lin e e, 1992;van Hout et al, 2002b). Furthermore, U d increases with decreasing surface tension parameter R ¼ 4r=Dq gD 2 (Zukoski, 1966), where g is the gravitational constant, D the pipe diameter, r the surface tension and Dq the density difference between the liquid and the gas phases.…”

Section: Continuous Slug Flowmentioning

confidence: 99%

Hydrodynamic and statistical parameters of slug flow

Shemer

2003

International Journal of Heat and Fluid Flow

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In two-phase slug flow pattern, the bulk of the gas is trapped inside large bubbles that are separated by liquid slugs, which may contain small dispersed bubbles. The unsteady nature of slug flow makes the prediction of pressure drop and heat and mass transfer a difficult task. Earlier models that deal with steady slug flow assume constant lengths and shapes of liquid slugs and elongated bubbles, as well as a constant elongated bubble propagation velocity. However, due to the intrinsically irregular character of slug flow, statistical means are required for its proper description. Variation of the flow parameters along the pipes of various diameters and inclinations may strongly affect the resulting flow pattern and should thus be taken into account in modeling the flow. The development of slug flow along the pipe is mainly governed by the interaction between consecutive elongated bubbles. To gain a better insight into the mechanisms that govern slug flow evolution along pipes, experiments with controlled injection of consecutive elongated bubbles were performed in recent years. Due to the complexity of both the continuous slug flow and the liquid flow around injected bubbles, sophisticated experimental methods are required. The latest works regarding the hydrodynamic and statistics of naturally occurring continuous slug flow in pipes, as well as the results of experiments with controlled injection of elongated bubbles are reviewed. It is demonstrated how the information obtained in the controlled experiments can be applied to improve the performance of slug flow and slug tracking models.

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“…Directly below this region, is the wake zone of about 1 -10 pipe diameter long [17]. It is a cluster of bubbles which is said to contain the vortex according to [35]. There is a linear increase in the length of the liquid swelling and wake zone with increase in superficial gas velocity but with less effect with superficial liquid velocity.…”

Section: Slug Flow Structure In Bubble Columnmentioning

confidence: 99%