X-ray-based assessment of the three-dimensional velocity of the liquid phase in a bubble column

Seeger, A.; Affeld, K.; Goubergrits, Leonid; Kertzscher, Ulrich; Wellnhofer, Ernst

doi:10.1007/s003480100273

Cited by 53 publications

(46 citation statements)

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“…The powerful laser-based techniques then fail. The liquid can only be probed for hydrodynamic information by hot-wires or via nuclear techniques [a radioactive particle or X-ray absorbers, as were recently employed by Seeger et al (2001), who turned their technique into a kind of PIV]. The bubble phase is even more difficult to probe.…”

Section: Final Remarksmentioning

confidence: 99%

Gravity-Driven Bubbly Flows

Mudde

2005

Annu. Rev. Fluid Mech.

160

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■ Abstract Gravity-driven bubbly flows are a specific class of flows, where all action is provided by gravity. An industrial example is formed by the so-called bubble column: a vertical cylinder filled with liquid through which bubbles flow that are introduced at the bottom of the cylinder. On the bubble scale, gravity gives rise to buoyancy of individual bubbles. On larger scales, gravity acts on nonuniformities in the spatial bubble distribution present in the bubbly mixture. The gravity-induced flow and flow structures can increase the inhomogeneity of the bubble distribution, leading to a turbulent flow. In this flow, specific scales are identified: a large-scale circulation with the liquid flowing upward in the center of the column and downward close to the wall. On the intermediate scale there are vortical structures; eddies of liquid, with a size on the order of the diameter of the column, that stir the liquid and radially transport the bubbles. On the small scale there is the local stirring of the bubbles. We describe the ideas developed over time and identify some open questions. We discuss the experimental findings on the turbulence generated, the stability of the flow, axial dispersion, and the similarities between bubble columns and air lifts. Especially for higher gas fractions, many questions still lack accurate answers. The lateral lift force in bubble swarms and the structure of the turbulence in the bubbly mixture are important examples of inadequately understood physical phenomena, providing many challenges for fundamental and applied research on bubbly flows.

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Section: Final Remarksmentioning

confidence: 99%

Gravity-Driven Bubbly Flows

Mudde

2005

Annu. Rev. Fluid Mech.

160

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“…The most common techniques include video image capturing combined with advanced image processing software, particle-image velocimetry (PIV), laser Doppler velocimetry (LDV), ultrasonic Doppler velocimetry (UDV) and X-ray based particle tracking velocimetry (XPTV) [8][9][10]. Most methods rely on inert particles with the same density as the liquid phase.…”

Section: Methods For Multi-fluid Flow Analysesmentioning

confidence: 99%

Modeling and simulation of the bubble-induced flow in wine fermentation vessels

Schmidt

Velten

2015

BIO Web of Conferences

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“…Seeger et al [13] developed an x-ray PIV system for chemical engineering experiments in a bubble column, whereas Lee & Kim [14] used a somewhat different implementation of x-ray PIV for small low-speed flows and later applied it to a simulated blood flow. The only known high-speed flow in which x-ray particle tracking was employed is that of Xiao et al [15], but the particle concentration in this case was very low.…”

Section: Literature Reviewmentioning

confidence: 99%

“…To penetrate the optically-dense medium, X-ray measurement techniques previously utilized for multiphase flows and high-energy physics were adapted to the uncommon difficulties of the present problem. It was determined that the continuous xray sources used in previous low-speed studies [13,14] could not provide adequate light in the microsecond timescales of interest. Alternatively, flash x-ray sources are able to provide intense beams that last tens of nanoseconds, essentially 'freezing' the flow in a similar fashion to laser diagnostic measurements in fluids experiments.…”

Section: The Flash X-ray Systemmentioning

confidence: 99%

Experimental characterization of energetic material dynamics for multiphase blast simulation.

Beresh¹,

Wagner²,

Kearney³

et al. 2011

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Currently there is a substantial lack of data for interactions of shock waves with particle fields having volume fractions residing between the dilute and granular regimes, which creates one of the largest sources of uncertainty in the simulation of energetic material detonation. To close this gap, a novel Multiphase Shock Tube has been constructed to drive a planar shock wave into a dense gassolid field of particles. A nearly spatially isotropic field of particles is generated in the test section by a gravity-fed method that results in a spanwise curtain of spherical 100-micron particles having a volume fraction of about 19%. Interactions with incident shock Mach numbers of 1.66, 1.92, and 2.02 were achieved. High-speed schlieren imaging simultaneous with high-frequency wall pressure measurements are used to reveal the complex wave structure associated with the interaction. Following incident shock impingement, transmitted and reflected shocks are observed, which lead to differences in particle drag across the streamwise dimension of the curtain. Shortly thereafter, the particle field begins to propagate downstream and spread. For all three Mach numbers tested, the energy and momentum fluxes in the induced flow far downstream are reduced about 30-40% by the presence of the particle field. X-Ray diagnostics have been developed to penetrate the opacity of the flow, revealing the concentrations throughout the particle field as it expands and spreads downstream with time. Furthermore, an X-Ray particle tracking velocimetry diagnostic has been demonstrated to be feasible for this flow, which can be used to follow the trajectory of tracer particles seeded into the curtain. Additional experiments on single spherical particles accelerated behind an incident shock 4 wave have shown that elevated particle drag coefficients can be attributed to increased compressibility rather than flow unsteadiness, clarifying confusing results from the historical database of shock tube experiments. The development of the Multiphase Shock Tube and associated diagnostic capabilities offers experimental capability to a previously inaccessible regime, which can provide unprecedented data concerning particle dynamics of dense gas-solid flows. 5

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X-ray-based assessment of the three-dimensional velocity of the liquid phase in a bubble column

Cited by 53 publications

References 0 publications

Gravity-Driven Bubbly Flows

Gravity-Driven Bubbly Flows

Modeling and simulation of the bubble-induced flow in wine fermentation vessels

Experimental characterization of energetic material dynamics for multiphase blast simulation.

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