Numerical modelling of the rise of Taylor bubbles through a change in pipe diameter

Ambrose, Stephen E.; Lowndes, I.S.; Hargreaves, David; Azzopardi, B.J.

doi:10.1016/j.compfluid.2017.01.023

Cited by 15 publications

(10 citation statements)

References 20 publications

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“…The public domain Java image processing program ImageJ 1.4.3.67 was used to calculate the bubble size (area) and to monitor size changes during each experiment. Some of the experiment results were published without our knowledge or consent by Ambrose et al ().…”

Section: Methodsmentioning

confidence: 99%

“…We note that a detailed investigation of slug stability at inverse viscosity above 1,000 is not the main purpose of this study and that more work is needed to reliably predict stable slug sizes in this regime. The 2‐D geometry of the experimental and numerical setups is not well suited for resolving nonlinear, inertial effects, and a 3‐D approach as in Ambrose et al () would be more suitable. That being said, slug breakup rising through straight conduits in the inertial regime has also been observed in previous experiments (e.g., James et al, , ; Pringle et al, ) and in simulations (e.g., Ambrose et al, ; Suckale, Hager, et al, ; Suckale et al, ).…”

Section: Ramifications For Lava Lake Degassingmentioning

confidence: 99%

“…The 2‐D geometry of the experimental and numerical setups is not well suited for resolving nonlinear, inertial effects, and a 3‐D approach as in Ambrose et al () would be more suitable. That being said, slug breakup rising through straight conduits in the inertial regime has also been observed in previous experiments (e.g., James et al, , ; Pringle et al, ) and in simulations (e.g., Ambrose et al, ; Suckale, Hager, et al, ; Suckale et al, ). The results of these studies are consistent with the present study results in the sense that those results showed more pronounced breakup in the inertial regime (James et al, ) and in noticing that geometry is not necessarily the main controlling factor in this regime.…”

Section: Ramifications For Lava Lake Degassingmentioning

confidence: 99%

“…Previous studies have demonstrated that conduit geometry may play an important role in modulating the rise of large gas slugs (e.g., Ambrose et al, 2017;James et al, 2006;Pioli et al, 2009). James et al (2006) performed experiments of slug ascent through vertical tubes with a smooth change in the diameter.…”

Section: Introductionmentioning

confidence: 99%

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Slug Stability in Flaring Geometries and Ramifications for Lava Lake Degassing

et al. 2018

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Long‐lived, persistently active lava lakes are rare but have been studied extensively because they may provide a natural laboratory for studying magmatic convection in basaltic and other low‐viscosity volcanoes. However, lava lakes differ from other volcanic systems in various ways, particularly geometry: the presence of the lava lake requires a sudden and significant flaring of the conduit. The goal of this paper is to advance our understanding of the effect that a sudden increase in the conduit width has on the stability of large gas slugs and bubbles ascending from the plumbing system. We investigate this question by linking analog laboratory experiments to direct numerical simulations in two dimensions. We find that the rapid change in the geometry associated with the transition from the conduit to the lava lake causes large gas slugs to break up. The nondimensional regime over which we observe the breakup depends sensitively on the flare angle of the lava lake and the importance of inertial effects in the flow, implying that degassing‐related eruptive activity at open‐system volcanoes is sensitive to the upper conduit and lake geometries. Applying this idea to the likely geometries and viscosities of actual lava lakes, our study suggests that all lava lakes except Erebus fall well within the regime where large gas slugs are prone to breakup.

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Section: Methodsmentioning

confidence: 99%

Section: Ramifications For Lava Lake Degassingmentioning

confidence: 99%

Section: Ramifications For Lava Lake Degassingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Slug Stability in Flaring Geometries and Ramifications for Lava Lake Degassing

et al. 2018

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“…These fluidic elements can be found in chemical reactors, gas-lift in oil wells, petrochemical plants, natural gas transportation in subsea pipelines, and power generation units [1]. As an example, the splitting of Taylor bubbles into two daughter bubbles, being caused by the passage through an expansion, is still scarcely studied experimentally [2], and there are only two published computational works of Taylor bubbles rising through expansions in pipe diameter [3,4]. Taylor bubbles/droplets are long and wide bullet-shaped entities-occupying almost all the cross section of a channel-that appear in one of the most frequent multiphase flow patterns, named slug flow.…”

Section: Introductionmentioning

confidence: 99%

Review on Microbubbles and Microdroplets Flowing through Microfluidic Geometrical Elements

et al. 2020

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Two-phase flows are found in several industrial systems/applications, including boilers and condensers, which are used in power generation or refrigeration, steam generators, oil/gas extraction wells and refineries, flame stabilizers, safety valves, among many others. The structure of these flows is complex, and it is largely governed by the extent of interphase interactions. In the last two decades, due to a large development of microfabrication technologies, many microstructured devices involving several elements (constrictions, contractions, expansions, obstacles, or T-junctions) have been designed and manufactured. The pursuit for innovation in two-phase flows in these elements require an understanding and control of the behaviour of bubble/droplet flow. The need to systematize the most relevant studies that involve these issues constitutes the motivation for this review. In the present work, literature addressing gas-liquid and liquid-liquid flows, with Newtonian and non-Newtonian fluids, and covering theoretical, experimental, and numerical approaches, is reviewed. Particular focus is given to the deformation, coalescence, and breakup mechanisms when bubbles and droplets pass through the aforementioned microfluidic elements.Micromachines 2020, 11, 201 2 of 22 droplets through a sudden/gradual expansion/contraction, several numerical and experimental works considered the flow through horizontal pipes, but they are mainly focused on pressure drop [6][7][8][9].The heat and mass transfer can be significantly enhanced in a microsystem due to the high surface volume ratio. Currently, bubble/droplet-based microfluidics has been successfully applied in chemical and biological analysis [10,11], the synthesis of advanced materials [12], sample pretreatment [13], and the encapsulation of cells [14]. Droplets are liquid entities that flow in a immiscible liquid continuous phase, and bubbles are gas entities also flowing in a liquid fluid. The use of droplets as microreactors presents a lot of advantages when compared with single-phase microfluidics, such as: confinement of reactants or prevention of longitudinal dispersion, and cross contamination between samples [15]. The reduction of unwanted adhesion/absorption of the material confined in droplets at the microchannel walls, the possibility of varying, in each droplet the physicochemical conditions under which chemical or biological process develop, and the facilitated heat/mass transport due to the fast mixing promoted by droplets are other benefits [15,16]. The use of bubbles might be interesting to produce contrast agents in medical applications [17], as a source of reactants in the gas phase to promote reactions in liquid or solid (i.e., microchannel wall) phases [18], and to study in vitro gas embolisms [19].Microfluidic devices (length scales lower than one millimeter) comprise microfluidic elements, analogous to their macroscale counterparts, to transport and distribute fluids, to promote mixing, reaction, and mass transfer. In the case of multiphase flows, ...

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