Experimental investigation on the bubble formation from needles with and without liquid co-flow

Muilwijk, Corné; Akker, H.E.A. van den

doi:10.1016/j.ces.2019.03.026

Cited by 27 publications

(19 citation statements)

References 54 publications

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“…In order to achieve the constant gas flow rate condition throughout the bubble formation process, the total pressure drop across the orifice needs to be sufficiently large compared to the pressure variations occurring during the bubble formation. Muilwijk and Van den Akker (2019) suggested that the constant laminar flow rate can be achieved when the non-dimensional orifice constant defined as: where approaches zero. Here, l cap and d cap are the length and the inner diameter of the capillary, respectively.…”

Section: Methodsmentioning

confidence: 99%

Influence of wetting conditions on bubble formation from a submerged orifice

et al. 2020

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The formation of gas bubbles by submerged orifices is a fundamental process encountered in various industrial applications. The dynamics of the contact line and the contact angle may have a significant influence on the detached bubble size depending on the wettability of the system. In this study, the influence of wetting conditions on the dynamics of bubble formation from a submerged orifice is investigated experimentally and numerically. The experiments are performed using a hydrophobic orifice plate and a series of ethanol-water solutions to vary the wettability where the key characteristics of the bubbles are measured using a high-speed, high-resolution camera. An extensive analysis on the influence of wetting conditions on the bubble size, bubble growth mechanism and the behavior of the contact line is given. Bubble growth stages, termed (1) hemispherical spreading, (2) cylindrical spreading, (3) critical growth and (4) necking, are identified based on key geometrical parameters of the bubble and relevant forces acting on the bubble during the growth. The experimental results show that the apparent contact angle varies in a complicated manner as the bubble grows due to the surface roughness and heterogeneity. The experimental findings are finally used to validate the local front reconstruction method with a contact angle model to account for the contact angle hysteresis observed in the experiments.

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Section: Methodsmentioning

confidence: 99%

Influence of wetting conditions on bubble formation from a submerged orifice

et al. 2020

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“…In this study, the size of the bubbles was small enough to avoid wobbling regime of bubble shape and we measured accurate 3-D bubble velocity fields. Similar to the experimental work performed by Muilwijk & Van den Akker (2019), co-flow due to water supply has the effect of separating bubbles from needles. An air compressor was used to supply air to the bubble generator, and the air flow rate was manipulated using a pressure regulator and a tachometer (Dwyer RMA-151).…”

Section: Experimental Set-upmentioning

confidence: 70%

“…A gas-liquid ejector can generate a local low-pressure region where high-energy dissipation occurs, producing very fine bubbles (Cramers & Beenackers 2001;Zheng et al 2010;Terasaka et al 2011;Aliyu et al 2018;Seo et al 2018). For bubbly jets with bubble generators, the co-flow suppresses the coalescence of bubbles near nozzles and accelerates bubble separation (Muilwijk & Van den Akker 2019). In this case, the plume spreading of the turbulent bubbly mixed jet can be governed by different physical processes from a classical bubble plume.…”

Section: Introductionmentioning

confidence: 99%

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Experimental study of turbulent bubbly jet. Part 1. Simultaneous measurement of three-dimensional velocity fields of bubbles and water

et al. 2022

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This study proposes a method for simultaneous measurements of time-resolved three-dimensional velocity fields of the dispersed and continuous phases of a turbulent bubbly jet at a low void fraction using Lagrangian particle tracking (LPT) velocimetry with the Shake-The-Box algorithm. Four high-speed cameras are used to acquire time series of images that include both bubbles and fluid tracer particles. Bubbles are firstly tracked using intensity differences between tracer particles and bubbles, then the bubble images are removed from the camera images and all tracer particles are tracked using the residual images. Subsequently, FlowFit interpolation is applied to the LPT results obtained by phase separation to investigate flow characteristics of a bubbly jet. The bubbly jet was divided into two regions along the vertical direction: jet-like and plume-like regions. Streamwise vortex structures of continuous phase were generated mainly by the rising bubbles. The Gaussian and top-hat velocity profiles matched well with the ensemble-averaged fluid and bubble velocities, respectively. The measured slip velocity in the radial direction was not constant but linearly increased. The classical assumption of self-similarity with Gaussian profiles for fluid velocity and bubble concentration is experimentally verified. The fluid volume flux and entrainment coefficient are obtained as a function of the slip velocity, void fraction, plume and bubble width based on three-dimensional measurements. We found that the classical integral theory agrees well with experiments in the plume region.

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“…A precise measurement of the bubble formation process is performed using a helium-neon laser as a light source using beam expansion and light amplification techniques. According to Muilwijk and Van den Akker [16] increasing fluid viscosity reduces the speed and acceleration of bubble rise. Research by Zähringer and Kováts [17] also note the relationship between bubble shape, bubble size, and liquid density and suggest that increasing viscosity or decreasing surface tension leads to much narrower bubble size distributions.…”

Section: Experimental Justificationmentioning

confidence: 99%

In-line measurement of multiphase flow viscosity

et al. 2022

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The transportation modes depend entirely on the viscosity of the oil. To date, none of the viscometric methods are able to provide measurements to meet all the requirements of oil flow, features of main oil pipelines, and trends in the oil industry, such as decarbonization and digitalization. The method of inline viscosity measurement of multiphase flow through a metal pipeline can be based on direct gamma ray measurement. It is stipulated by the ability of gamma-radiation to penetrate through the pipeline material without destroying it, as well as by the ability to work with flows containing free gas and the high capability to be introduced into automatic control systems. The authors consider the physical forces acting on the gas inclusions in the oil flow. They determine the physical dependence between the parameters determined by the radioisotope method and the viscosity of oil in the three-phase flow. These studies show good agreement with the work of other scientists. The prospect of further research will be to clarify the mathematical model of gas-oil flow, to increase the accuracy by reducing the number of assumptions made.

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Experimental investigation on the bubble formation from needles with and without liquid co-flow

Cited by 27 publications

References 54 publications

Influence of wetting conditions on bubble formation from a submerged orifice

Influence of wetting conditions on bubble formation from a submerged orifice

Experimental study of turbulent bubbly jet. Part 1. Simultaneous measurement of three-dimensional velocity fields of bubbles and water

In-line measurement of multiphase flow viscosity

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