Wide-ranging survey on the laminar flow of individual Taylor bubbles rising through stagnant Newtonian liquids

Araújo, J.D.P.; Miranda, J. M.; Pinto, A.M.F.R.; Campos, J.B.L.M.

doi:10.1016/j.ijmultiphaseflow.2012.03.007

Cited by 77 publications

(62 citation statements)

References 36 publications

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“…The focus of the present study is the magnitude of the film that exists in liquid-liquid slug flow regimes. Numerous researchers have completed numerical, (Araujo et al, 2012;Heil, 2001;Taha and Cui, 2004) and experimental, (Grimes et al, 2007;Irandoust and Andersson, 1989;Jovanovic et al, 2010) analysis of the deposition of the liquid film on the capillary wall. Some of these works have resulted in the development of a number of models to estimate the magnitude of the film; the details of the most referenced of these are listed in Table 1.…”

Section: Introductionmentioning

confidence: 99%

Film thickness measurements in liquid–liquid slug flow regimes

Eain

Egan

Punch

2013

International Journal of Heat and Fluid Flow

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a b s t r a c tAt present there is significant interest in the development of small scale medical diagnostic equipment. These devices offer faster processing times and require smaller sample volumes than equivalent macro scale systems. Although significant attention has been focused upon their outputs, little attention has been devoted to the detailed fluid mechanics that govern the flow mechanisms within these devices. Conventionally, the samples in these small scale devices are segmented into distinct discrete droplets or slugs which are suspended in an organic carrier phase. Separating these slugs from the channel wall is a very thin film of the organic carrier phase.The magnitude of this film is the focus of the present study and the effects of sample slug length and carrier phase fluidic properties on the film are examined over a range of Capillary numbers. A non-intrusive optical technique was used to capture images of the flow from which the magnitude of the film was determined.The experimental results show that the film is not constant along the length of the slug; however above a threshold value for slug length, a region of constant film thickness exists. When compared with existing correlations in the literature, the experimental data showed reasonable agreement with the Bretherton model when the Capillary number was calculated based on the mean two phase flow velocity. However, significant differences were observed when the Capillary number was redefined to account for the mean velocity at the liquid interface, i.e., the mean slug velocity.Analysis of the experimental data revealed that it fell into two distinct flow regimes; a visco-capillary regime and a visco-inertial regime. A modified Taylor expression is presented to estimate the magnitude of the film for flows in the visco-capillary regime while a new model is put forward, based on Capillary and Weber numbers, for flows in the visco-inertial regime. Overall, this study provides some novel insights into parameters, such as aqueous slug length and carrier phase fluidic properties, that affect the thickness of the film in liquid-liquid slug flow regimes.

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Section: Introductionmentioning

confidence: 99%

Film thickness measurements in liquid–liquid slug flow regimes

Eain

Egan

Punch

2013

International Journal of Heat and Fluid Flow

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“…CFD studies such as Taha and Cui (2004) and Araujo et al (2012) have produced Taylor bubbles with the rise velocity agreeing with that predicted by Dumitrescu (1943). These studies use an approach in which the Taylor bubble is held at a constant position by having walls move vertically downwards around it.…”

Section: Introductionmentioning

confidence: 71%

“…In recent years, CFD studies using the volume of fluid (VOF) multiphase model have replicated observations from experimental studies such as bubble rise rate and wake behavior (Araujo, Miranda, Pinto, and Campos, 2012;James et al, 2008;Ndinisa, Wiley, and Fletcher, 2005;Taha and Cui, 2004). Other interface reconstruction schemes have been used to model the gas-liquid interface.…”

Section: Introductionmentioning

confidence: 82%

Numerical modeling of oscillating Taylor bubbles

Ambrose

Hargreaves

Lowndes

2016

Engineering Applications of Computational Fluid Mechanics

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In this study, computational fluid dynamics (CFD) modeling is used to simulate Taylor bubbles rising in vertical pipes. Experiments indicate that in large diameter (0.29 m) pipes for an air-water system, the bubbles can rise in a oscillatory manner, depending on the method of air injection. The CFD models are able to capture this oscillatory behavior because the air phase is modeled as a compressible ideal gas. Insights into the flow field ahead and behind the bubble during contraction and expansion are shown. For a bubble with an initial pressure equal to the hydrostatic pressure at its nose, no oscillations are seen in the bubble as it rises. If the initial pressure in the bubble is set less than or greater than the hydrostatic pressure then the length of the bubble oscillates with an amplitude that depends on the magnitude of the initial bubble pressure relative to the hydrostatic pressure. The frequency of the oscillations is inversely proportional to the square root of the head of water above the bubble and so the frequency increases as the bubble approaches the water surface. The predicted frequency also depends inversely on the square root of the average bubble length, in agreement with experimental observations and an analytical model that is also presented. In this model, a viscous damping term due to the presence of a Stokes boundary layer for the oscillating cases is introduced for the first time and used to assess the effect on the oscillations of increasing the liquid viscosity by several orders of magnitude. ARTICLE HISTORY

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“…Previously, in literature a bubble wake was investigated in detail in [2]. The wake length was estimated as (16 ÷ 30)D. Later, according to [9], the length increased up to 50D.…”

Section: Resultsmentioning

confidence: 99%

Wall shear stress from a single almost spherical and a Taylor bubbles in laminar upward tube flow

Timkin

Gorelik

2017

MATEC Web Conf.

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Abstract. An experimental electrodiffusional technique with eight double probes is used to detect perturbation the wall shear stress caused by a single bubble in laminar upward tube flow. A small almost spherical and different length Taylor bubbles are considered. The shear stress perturbations by bubbles have a complex structure. It is possible to define three components of perturbation caused by a small bubble. The perturbation by Taylor bubble contains only two components due to the main flow symmetry around the bubble. An unexpectedly long shear stress pulsations zone is registered behind the bubbles.

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Wide-ranging survey on the laminar flow of individual Taylor bubbles rising through stagnant Newtonian liquids

Cited by 77 publications

References 36 publications

Film thickness measurements in liquid–liquid slug flow regimes

Film thickness measurements in liquid–liquid slug flow regimes

Numerical modeling of oscillating Taylor bubbles

Wall shear stress from a single almost spherical and a Taylor bubbles in laminar upward tube flow

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