A theoretical model for core-annular flow of a very viscous oil core and a water annulus through a horizontal pipe

Ooms, G.; Segal, A.; Wees, A.J. van der; Meerhoff, Ronald; Oliemans, R.V.A.

doi:10.1016/0301-9322(83)90059-9

Cited by 116 publications

(64 citation statements)

References 2 publications

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“…A steady eccentric core flow is feasible when the overall vertical components of the viscous forces are in a dynamic equilibrium with the buoyancy force (due to the density differential). Stabilizing hydrodynamic forces may evolve due to core eccentricity and interfacial waviness (Ooms et al, 1984, 1985, Oliemans and Ooms, 1986, Ooms and Poesio, 2003. The development of a wavy core interface is believed to be a necessary condition for core flow stabilization.…”

Section: Resultsmentioning

confidence: 99%

Liquid-Liquid Two-Phase Flow Systems

Brauner

2003

Modelling and Experimentation in Two-Phase Flow

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Section: Resultsmentioning

confidence: 99%

Liquid-Liquid Two-Phase Flow Systems

Brauner

2003

Modelling and Experimentation in Two-Phase Flow

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“…Relatively little attention has been given to the explanation of the levitation mechanism. Ooms and Beckers, 13 Ooms et al, 14 and Oliemans and Ooms 2 proposed a mechanism based on hydrodynamic lubrication theory. They showed that levitation could not take place without a hydrodynamic lifting action due to the waves present at the oil-water interface.…”

Section: Introductionmentioning

confidence: 99%

On the levitation force in horizontal core-annular flow with a large viscosity ratio and small density ratio

2013

Self Cite

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A numerical study has been made of horizontal core-annular flow: the flow of a high-viscosity liquid core surrounded by a low-viscosity liquid annular layer through a horizontal pipe. Special attention is paid to the question how the buoyancy force on the core, caused by a density difference between the core and the annular layer, is counterbalanced. The volume-of-fluid method is used to calculate the velocities and pressures in the two liquids. At the start of the calculation the core is in a concentric position. Thereafter the core starts to rise under the influence of buoyancy until it reaches an eccentric equilibrium position where the buoyancy force is counterbalanced by hydrodynamic forces generated by the movement of a wave at the core-annular interface with respect to the pipe wall. At high Reynolds number of the flow in the annular layer core levitation is due to inertial forces, whereas at low Reynolds number viscous (lubrication) forces are responsible for levitation. We carried out two types of calculation. In the first we assume the interface to be smooth (without wave) at the start of the calculation and study how the wave develops during the rising period of the core. In the second a wave is already present at the start of the calculation.

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“…The pioneer works of Russel and Charles 14 and Charles et al for horizontal pipes showed that this flow pattern occurs when the two liquids have similar densities and relatively small quantities of water are added. Ooms, 15 Ooms et al, 16 and Oliemans 17 showed that for the existence of the core-annular flow the annulus must be thin and there must be asymmetric interfacial waves. Joseph et al 18 and Feng et al 19 studied the hydrodynamic stability of two immiscible liquids flowing in a pipe, showing that the more viscous fluid must occupy most of the pipe's cross-section and that asymmetric interfacial waves might be responsible for the stabilization of the core phase.…”

Section: Introductionmentioning

confidence: 98%

Stability analysis of core‐annular flow and neutral stability wave number

Rodriguez

Bannwart

2007

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).A general transition criterion is proposed in order to locate the core-annular flow pattern in horizontal and vertical oil-water flows. It is based on a rigorous one-dimensional two-fluid model of liquid-liquid two-phase flow and considers the existence of critical interfacial wave numbers related to a non-negligible interfacial tension term to which the linear stability theory still applies. The viscous laminar-laminar flow problem is fully resolved and turbulence effects on the stability are analyzed through experimentally obtained shape factors. The proposed general transition criterion includes in its formulation the inviscid Kelvin-Helmholtz's discriminator. If a theoretical maximum wavelength is considered as a necessary condition for stability, a stability criterion in terms of the Eo¨tvo¨s number is achieved. Effects of interfacial tension, viscosity ratio, density difference, and shape factors on the stability of core-annular flow are analyzed in detail. The more complete modeling allowed for the analysis of the neutral-stability wave number and the results strongly suggest that the interfacial tension term plays an indispensable role in the correct prediction of the stable region of core-annular flow pattern. The incorporation of a theoretical minimum wavelength into the transition model produced significantly better results. The criterion predictions were compared with recent data from the literature and the agreement is encouraging.

show abstract

A theoretical model for core-annular flow of a very viscous oil core and a water annulus through a horizontal pipe

Cited by 116 publications

References 2 publications

Liquid-Liquid Two-Phase Flow Systems

Liquid-Liquid Two-Phase Flow Systems

On the levitation force in horizontal core-annular flow with a large viscosity ratio and small density ratio

Stability analysis of core‐annular flow and neutral stability wave number

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