Numerical simulation of oil-water two-phase flow in a horizontal duct with a Venturi flow meter

M Guilizzoni,L P M Colombo,G Sotgia,G Salvi

doi:10.1088/1742-6596/1224/1/012008

M Guilizzoni, L P M Colombo + Show 2 more

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https://doi.org/10.1088/1742-6596/1224/1/012008

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Abstract

The progressive depletion of on-shore and light-oil reserves is forcing an increased use of transitional and heavy oils, which implies new challenges both during the extraction and the transportation. Focusing on the latter, a technique to reduce the pressure drop is water injection in the oil stream to create the so-called core annular flow (CAF), a flow regime with an oil core enveloped in a water annulus wetting the pipe wall, so that the apparent viscosity of the mixture is considerably reduced. Behaviour of CAF in ducts with non-uniform sections is still under research. This work is devoted to a CFD investigation about the pressure drop, pressure gradients, velocity profiles and in situ volume fractions in a duct including a Venturi flow meter. Unsteady RANS simulations were carried out using the Volume-Of-Fluid interFoam solver of OpenFOAM. Numerical results were experimentally validated for oil superficial velocities in the range 0.25-0.75 m/s and water superficial velocities in the range 0.44-1.10 m/s and comparisons between different approaches and sensitivity analyses were performed. Satisfactory agreement was found for the pressure drop and pressure gradients, and also for the in situ volume fraction with respect to the predictions of the Arney correlation.

Highlights

A large majority of the world energy demand is nowadays still satisfied by oil, and since the last decades progressive depletion of on-shore and light-oil reserves forced an increased use of transitional and unconventional/heavy oils
This work is devoted to a Computational Fluid Dynamics (CFD) investigation about the pressure drop, pressure gradients, velocity profiles and in situ volume fractions in a duct including a Venturi flow meter
Among the possible solution to make it feasible, the creation of a peculiar two-phase flow pattern, in which the apparent viscosity is reduced, is at present under study and development [3]. Such a flow pattern is named Core Annular Flow (CAF): an oil core flows in the central part of the pipeline, while a “lubricating” water annulus wets the duct wall [4,5,6], reducing the wall shear stress and lowering the pressure drop

Summary

Introduction

A large majority of the world energy demand is nowadays still satisfied by oil, and since the last decades progressive depletion of on-shore and light-oil reserves forced an increased use of transitional and unconventional/heavy oils These are available in a larger total amount and in a higher number of countries, and pose new challenges. Among the possible solution to make it feasible, the creation of a peculiar two-phase flow pattern, in which the apparent viscosity is reduced, is at present under study and development [3] Such a flow pattern is named Core Annular Flow (CAF): an oil core flows in the central part of the pipeline, while a “lubricating” water annulus wets the duct wall [4,5,6], reducing the wall shear stress and lowering the pressure drop. The stability of Core Annular Flow in presence of variations in the pipeline (e.g. bends, changes in the cross-section, in-line measurement devices) is still under investigation

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