Measurement of Taylor bubble shape in square channel by microfocus X-ray computed tomography for investigation of mass transfer

Boden, Stephan; Haghnegahdar, Mohammadreza; Hampel, Uwe

doi:10.1016/j.flowmeasinst.2016.06.004

Cited by 22 publications

(5 citation statements)

References 12 publications

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“…Similar hydrodynamic investigations of Taylor flows 12, 13 have proven to be rotationally symmetric, providing a sufficiently long entrance length for the flow to develop. This condition cannot be met due to the height limitation in the horizontal bore MRI system.…”

Section: Resultsmentioning

confidence: 88%

“…These so‐called Taylor flows are the tool of choice for systematic studies when dealing with flow dynamics 5–9, mass transfer 10–12, and chemical reactions 13 within two‐phase flows. They are characterized by elongated, bullet‐shaped bubbles, the so‐called Taylor bubbles, moving along inside a capillary, with a well‐defined thin liquid film separating the bubble from the capillary wall.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic Resonance Imaging for Non‐invasive Study of Hydrodynamics Inside Gas‐Liquid Taylor Flows

et al. 2021

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Multiphase flows are of major importance in today's industrial processes as many products originate from gas‐liquid reactions. The hydrodynamics within the wake behind the bubbles is essential as product selectivity is determined by the residence times in these mixing zones. Magnetic resonance imaging (MRI) offers a wide range of options for the investigation of multiphase flows. Here, non‐invasive MRI flow measurements of buoyancy‐driven N2 Taylor bubbles, spatially fixed inside a countercurrent flow of water, are performed. An experimental setup is presented, enabling the generation of Taylor bubbles inside a horizontal bore MRI scanner. Furthermore, a suitable MRI sequence allowing a time‐dependent analysis of the present flow field is described. The obtained MRI results are qualitatively compared to PIV images acquired in the same setup.

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Section: Resultsmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Magnetic Resonance Imaging for Non‐invasive Study of Hydrodynamics Inside Gas‐Liquid Taylor Flows

et al. 2021

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“…In microfocus CT (µCT) applications, to obtain projections from different sides, the object of interest is usually rotated between a fixed source/detector pair. This was demonstrated for vertical multiphase flows such as cavitating nozzle flow (Lorenzi 2017) or Taylor bubbles (Boden et al 2017). However, horizontal two-phase flows cannot be rotated around the pipe axis.…”

Section: Introductionmentioning

confidence: 98%

Horizontal annular flow through orifice studied by X-ray microtomography

et al. 2020

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An X-ray microtomography (µCT) system was adapted so that 3D scans of fixed horizontal or vertical test sections can be performed. The mobile µCT system has been applied to measure the local, time-averaged volume fraction distribution of developing annular air-water flow in a horizontal pipe with µm spatial resolution. Based on the volume fraction data the liquid film thickness profile is computed and the accumulation, stripping and renewal of the annular liquid film at a circular orifice is studied. The development length of the annular flow downstream of the orifice is evaluated based on the integral volume fraction and the change of the film thickness profile along the pipe axis. Both parameters give a consistent result, indicating that liquid film renewal can be judged based on integral measurement techniques in this case. Further, the detailed 3D data enables the validation of computational fluid dynamics codes based on phase-averaged variables such as the Euler-Euler approach. Graphic abstract

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“…X-µCT is non-invasive and offers high spatial resolutions without requiring optical access [30,31]. Even though X-ray based computed tomography has already been successfully applied for the characterization of processes on a larger scale, among others [32][33][34][35][36][37], studies concerning its extension to the mini-or microscale are limited [31] and only very few studies concern the X-ray based investigation of mass transfer related problems [38][39][40]. Nonetheless, the proposed methodology offers great potential in gaining deeper knowledge about local radial mixing in HCTs, which is crucial for controlling reactions and their selectivity.…”

Section: Introductionmentioning

confidence: 99%

3D investigations of microscale mixing in helically coiled capillaries

2021

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In capillary reactors, improving radial mixing and narrowing the residence time distribution is of great importance for high selectivity and reaction performance. A well-known approach is inducing secondary flow patterns by coiling the capillary around a cylinder. To increase understanding of transport phenomena in helically coiled capillaries non-invasive 3D imaging approaches are required. In this perspective paper, we introduce X-ray-based micro-computed tomography for the investigation of dispersion of iodide in a helically coiled tube. The methodology presented here allows for the direct evaluation of radial concentration fields. By varying Dean number $$Dn$$ D n and modified torsion parameter $${T}^{*}$$ T ∗ , the effect of torsion and curvature on the radial concentration profile can be identified. Detailed knowledge of local radial mixing in helically coiled capillaries will help the precise prediction of reaction progress and selectivity. Graphical abstract

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Measurement of Taylor bubble shape in square channel by microfocus X-ray computed tomography for investigation of mass transfer

Cited by 22 publications

References 12 publications

Magnetic Resonance Imaging for Non‐invasive Study of Hydrodynamics Inside Gas‐Liquid Taylor Flows

Magnetic Resonance Imaging for Non‐invasive Study of Hydrodynamics Inside Gas‐Liquid Taylor Flows

Horizontal annular flow through orifice studied by X-ray microtomography

3D investigations of microscale mixing in helically coiled capillaries

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