Bubble Motion Studies in a Countercurrent Flow Apparatus

Moo‐Young, Murray; Fulford, George D.; Cheyne, Ian M.

doi:10.1021/i160037a027

Cited by 15 publications

(5 citation statements)

References 7 publications

(8 reference statements)

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“…Turbulence intensity in the VS of the HWTF can reach 10% at maximum pump speed (~ 37 L/min); however, Moo‐Young et al . [], in a similar, low‐pressure device, noted little effect on expected air bubble shapes and rise velocities, the latter being a sensitive indicator of bubble hydrodynamics. Likewise, the design of the flow conditioning elements in the HWTF allows a bubble, drop, or particle of up to ~20 mm diameter to have sufficient freedom to permit a measure of natural hydrodynamics, in particular, lateral path and shape oscillations.…”

Section: Methodsmentioning

confidence: 97%

Dynamic morphology of gas hydrate on a methane bubble in water: Observations and new insights for hydrate film models

Warzinski

Lynn²,

Haljasmaa³

et al. 2014

Geophysical Research Letters

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Predicting the fate of subsea hydrocarbon gases escaping into seawater is complicated by potential formation of hydrate on rising bubbles that can enhance their survival in the water column, allowing gas to reach shallower depths and the atmosphere. The precise nature and influence of hydrate coatings on bubble hydrodynamics and dissolution is largely unknown. Here we present high-definition, experimental observations of complex surficial mechanisms governing methane bubble hydrate formation and dissociation during transit of a simulated oceanic water column that reveal a temporal progression of deep-sea controlling mechanisms. Synergistic feedbacks between bubble hydrodynamics, hydrate morphology, and coverage characteristics were discovered. Morphological changes on the bubble surface appear analogous to macroscale, sea ice processes, presenting new mechanistic insights. An inverse linear relationship between hydrate coverage and bubble dissolution rate is indicated. Understanding and incorporating these phenomena into bubble and bubble plume models will be necessary to accurately predict global greenhouse gas budgets for warming ocean scenarios and hydrocarbon transport from anthropogenic or natural deep-sea eruptions.

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Section: Methodsmentioning

confidence: 97%

Dynamic morphology of gas hydrate on a methane bubble in water: Observations and new insights for hydrate film models

Warzinski

Lynn²,

Haljasmaa³

et al. 2014

Geophysical Research Letters

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“…A few studies do exist where the authors examined the flow field around gas bubbles that are held axially stationary in downward flows in rigid tubes. Moo-Young, Fulford & Cheyne (1971) experimentally suspended small bubbles (0.11 6 λ 6 0.32) in a downward liquid turbulent flow with larger bubbles requiring higher suspension flow rates. Similarly, Kojima, Akehata & Shirai (1975) investigated the behaviour of bubbles of 0.04 6 λ 6 0.2 which were held stationary in downward turbulent flows.…”

Section: Introductionmentioning

confidence: 97%

Interfacial dynamics of stationary gas bubbles in flows in inclined tubes

Cavanagh¹,

Eckmann²

1999

J. Fluid Mech.

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We have experimentally examined the effects of bubble size (0.4 [les ] λ [les ] 2.0), inclination angle (0° [les ] α [les ] 90°), and tube material on suspended gas bubbles in flows in tubes for a range of Weber (0 [les ] We [les ] 3.6), Reynolds (0 [les ] Re [les ] 1200), and Froude (0 [les ] Frα [les ] 1) numbers. Flow rates and associated pressure differences which allow the suspension of bubbles in glass and acrylic tubes are measured. Due to contact angle hysteresis, bubbles which dry the tube wall (i.e. form a gas–solid interface) may remain suspended over a range of flows while non-drying bubbles remain stationary for a single flow rate depending on experimental conditions. Stationary bubbles increase the axial pressure gradient with larger bubbles and steeper inclination angles leading to the greatest increase in the pressure gradient. Both the suspension flow range and pressure difference modifications are strongly dependent upon gas/liquid/solid material interactions. Stronger contact forces, i.e. smaller spreading coefficients, cause dried bubbles in acrylic tubes to remain stationary over a wider range of suspension flows than bubbles in glass tubes. Bubble deformation is governed by the interaction of interfacial, contact, and flow-derived forces. This investigation reveals the importance of bubble size, tube inclination, and tube material on gas bubble suspension.

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“…It is apparent in fig.2 (d) that an irregular fluctuation behavior is clearly seen on the autocorrelation function. This can be explained by the fact that the signals induced by different turbulent bursting events at different instants are almost uncorrelated [21][22][23][24]. In leak detection practice, non-leak acoustic sources around the water pipelines are always inevitable, such as from machine vibrations in a factory.…”

Section: A Feature Description By Autocorrelation Functionmentioning

confidence: 99%

Information processing for leak detection on underground water supply pipelines

Yang

Wen

2010

Third International Workshop on Advanced Computational Intelligence

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In the correlation-based leak location, it is supposed that the correlative components in the spatially separately collected acoustic signals merely result from a leak or leaks. This is why a false leak location will be produced when there is a non-leak acoustic source occurring outside a pipeline. To void a false leak location, it is necessary to detect whether or not a real leak exists in the pipeline beforehand. The traditional methods can detect leak only when the leak signal and non-leak signal are not acquired by the vibration sensors in the pipeline simultaneously. However, in practice, the leak signal is always blurred with the non-leak signal, and they will be picked up by the vibration sensors simultaneously. In this case, the traditional detection methods are infeasible. In this paper, a new feature extraction and leak identification method using autocorrelation analysis and approximate entropy algorithm is proposed to detect leak in the presence of non-leak acoustic sources. Due to the ability to analyze the coherent structure of time series, the autocorrelation function is used to describe the self-similarity of the signal. And the autocorrelation function values for the delay τ larger than the signal correlation length, not the signal itself or its entire autocorrelation function, is used to extract or evaluate the self-similarity degree of the signal by the approximate entropy algorithm. A neural-network approach has been developed as a classifier, which uses the identified self-similarity degrees as the network inputs. The method has been employed to identify the leak signals in the presence of some non-leak sounds, and achieved a 93.8% correct detection rate.

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Bubble Motion Studies in a Countercurrent Flow Apparatus

Cited by 15 publications

References 7 publications

Dynamic morphology of gas hydrate on a methane bubble in water: Observations and new insights for hydrate film models

Dynamic morphology of gas hydrate on a methane bubble in water: Observations and new insights for hydrate film models

Interfacial dynamics of stationary gas bubbles in flows in inclined tubes

Information processing for leak detection on underground water supply pipelines

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