The shape and motion of gas bubbles in a liquid flowing through a thin annulus

Abstract

We study the shape and motion of gas bubbles in a liquid flowing through a horizontal or slightly inclined thin annulus. Experimental data show that in the horizontal annulus, bubbles develop a unique ‘tadpole-like’ shape with a semi-circular cap and a highly stretched tail. As the annulus is inclined, the bubble tail tends to vanish, resulting in a significant decrease of bubble length. To model the bubble evolution, the thin annulus is conceptualised as a ‘Hele-Shaw’ cell in a curvilinear space. The three-dimensional flow within the cell is represented by a gap-averaged, two-dimensional model, which achieved a close match to the experimental data. The numerical model is further used to investigate the effects of gap thickness and pipe diameter on the bubble behaviour. The mechanism for the semi-circular cap formation is interpreted based on an analogous irrotational flow field around a circular cylinder, based on which a theoretical solution to the bubble velocity is derived. The bubble motion and cap geometry is mainly controlled by the gravitational component perpendicular to the flow direction. The bubble elongation in the horizontal annulus is caused by the buoyancy that moves the bubble to the top of the annulus. However, as the annulus is inclined, the gravitational component parallel to the flow direction becomes important, causing bubble separation at the tail and reduction in bubble length.

A control volume finite element method for three‐dimensional three‐phase flows

“…In this article, we build upon our novel interface‐capturing method and balanced‐force interfacial tension algorithm, from two‐dimensional (2D) two‐phase flow modeling with interfacial tension and adaptive unstructured meshes and 2D three‐phase flow modeling without interfacial tension to 3D three‐phase flow modeling with interfacial tension. The main novelty of the present article is the coupling of interface capturing and interfacial tension on adaptive unstructured meshes for 3D three‐phase flow problems, whereas most previous studies focused on two‐phase flows.…”

Modelling the reservoir-to-tubing pressure drop imposed by multiple autonomous inflow control devices installed in a single completion joint in a horizontal well

“…3) associated with a distorted gravity field ( Fig. 3c) (see (Lei et al, 2018) for the derivation details) by averaging across the annulus gap. Fig.…”

“…The derived gap-averaged governing equations are presented in the following subsection. The validity of this 2-D representation was determined by comparing the flow patterns it predicts with those seen in experiments (Lei et al 2018). More details can also be found in the supplementary material.…”

“…We use state-of-the-art, high resolution numerical modelling techniques to capture the detailed physics and dynamics of multiphase flow in the inner annulus of a completion joint mounted with one or two AICD(s). Earlier work has shown that our numerical modelling techniques can capture the dynamics of multiphase flow in thin annuli, through comparison with experiments (Lei et al, 2018). The model is used to explore a range of relevant flow conditions with different flow rates and phase volume fractions and allows us to determine the pressure drop from the annulus to the tubing across one or two AICD(s).…”

Dynamics of rising bubbles in initially quiescent liquids that are later on disturbed by falling drops

“…The observations conclude that the upward co-current tends to elongate the bubble, while the downward co-current makes the bubble flatter and shorter. A series of experimental and numerical studies were carried out in Kurimoto et al [11], Fershtman et al [12], Lei et al [13], Nogueira et al [14], Magnini et al [15], Tomiyama et al [16], Mirsandi et al [17] and Abishek et al [18] in order to understand the shape and dynamics of bubbles in flowing liquids. As observed in Abishek et al [18], the dynamics of an air bubble rising in a vertical tube under steady and pulsatile co-current flow is studied by using OpenFOAM-2.1.…”