Investigation of surface structures in two phase wavy pipe flow by utilizing X-ray tomography

Smith, Lisa; Kolaas, Jostein; Jensen, Atle; Sveen, Kristian

doi:10.1016/j.ijmultiphaseflow.2018.06.004

Cited by 6 publications

(3 citation statements)

References 28 publications

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“…The three-dimensionality of the wavefield (using the same two-phase flow loop) has previously been investigated by Strand (1993) and Smith et al. (2018). Strand (1993) used conductance wave probes at different cross-wise planes of the pipe and found that for the flow rates under investigation in the present work, the normalized cross-correlation between the centreline and off-axis surface elevation exceeded 0.85 everywhere in the pipe.…”

Section: Methodsmentioning

confidence: 94%

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Experimental investigation of intermittent airflow separation and microscale wave breaking in wavy two-phase pipe flow

2019

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We perform an experimental analysis of co-current, stratified wavy pipe flow, with the aim of investigating the effect of small scale wave breaking (microscale breaking) on the airflow. Particle image velocimetry is applied simultaneously in the gas and liquid phases. Active wave breaking is identified by high levels of vorticity on the leeward side of individual waves, and the statistics of the airflow above breaking and non-breaking waves are extracted from the gas-phase velocity fields. Keeping the liquid superficial velocity constant ($U_{sl}=0.1~\text{m}~\text{s}^{-1}$), we consider two experimental cases of different gas flow rates. The lowest flow rate ($U_{sg}=1.85~\text{m}~\text{s}^{-1}$) is slightly higher than the onset of microscale breaking, while the higher flow rate ($U_{sg}=2.20~\text{m}~\text{s}^{-1}$) is within the regime where wave breaking is observed to be frequent, and the root-mean-square interface elevation $\unicode[STIX]{x1D702}_{rms}$ is independent of gas flow rate. Results show that for the lowest gas flow rate considered, active wave breaking has a stabilizing effect on the airflow above the waves, reducing the sheltered region on the leeward side of the wave and the turbulence above the wave crest compared with non-breaking waves at similar steepness. At the higher gas flow rate the effect of active wave breaking is found to be small, and the main geometrical properties of the waves are found to dominate the evolution of the separated flow region.

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Section: Methodsmentioning

confidence: 94%

“…Smith et al. (2018) used X-ray tomography and found that the dominant wave components were well-described as two-dimensional for the flow rates of interest. Near the pipe walls the waves were observed to have a crescent shape, and slightly larger wave amplitudes were observed compared with the pipe centreline.…”

Section: Methodsmentioning

confidence: 99%

Experimental investigation of intermittent airflow separation and microscale wave breaking in wavy two-phase pipe flow

2019

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“…Therefore, thresholding of the image, although useful for analyzing the dissolution patterns, leads inevitably to the information loss, as partially dissolved region are either interpreted as fully dissolved or as undissolved. In order to measure the aperture variation in the experimental images, a calibration between the thickness profile of the plaster sample and the intensity profile of the photos is performed by an X-ray Thickness Gauging REX-CELL 4X from Flow Capture [43][44][45].…”

Section: Statistical Properties Of the Dissolution Patternsmentioning

confidence: 99%

Experimental Observation of Dissolution Finger Growth in Radial Geometry

Szymczak

Toussaint

et al. 2019

Front. Phys.

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Reaction-infiltration instability refers to the morphological instability of a reactive fluid front flowing in a soluble porous medium. This process is important for many naturally occurring phenomena, such as the weathering and diagenesis of rocks, dissolution in salt deposits and melt extraction from the mantle. This paper is focused on experiments on dissolution finger growth in radial geometries in an analog fracture. In the experiments, pure water dissolves a plaster sample forming one of the fracture walls in a Hele-Shaw cell with controlled injection rate and aperture. The flow is directed inwards to the center, and we observe the reaction-infiltration instability developing along the relatively long perimeter of the plaster. Our experimental results show a number of features consistent with the theoretical and numerical predictions on the finger growth dynamics such as screening and selection between the fingers. Statistical properties of the dissolved part evolution with time are also investigated.

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Tomographic X-ray particle tracking velocimetry

Mäkiharju

Dewanckele²,

Boone³

et al. 2021

Exp Fluids

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We investigate the feasibility of in-laboratory tomographic X-ray particle tracking velocimetry (TXPTV) and consider creeping flows with nearly density matched flow tracers. Specifically, in these proof-of-concept experiments we examined a Poiseuille flow, flow through porous media and a multiphase flow with a Taylor bubble. For a full 360$$^\circ$$ ∘ computed tomography (CT) scan we show that the specially selected 60 micron tracer particles could be imaged in less than 3 seconds with a signal-to-noise ratio between the tracers and the fluid of 2.5, sufficient to achieve proper volumetric segmentation at each time step. In the pipe flow, continuous Lagrangian particle trajectories were obtained, after which all the standard techniques used for PTV or PIV (taken at visible wave lengths) could also be employed for TXPTV data. And, with TXPTV we can examine flows inaccessible with visible wave lengths due to opaque media or numerous refractive interfaces. In the case of opaque porous media we were able to observe material accumulation and pore clogging, and for flow with Taylor bubble we can trace the particles and hence obtain velocities in the liquid film between the wall and bubble, with thickness of liquid film itself also simultaneously obtained from the volumetric reconstruction after segmentation. While improvements in scan speed are anticipated due to continuing improvements in CT system components, we show that for the flows examined even the presently available CT systems could yield quantitative flow data with the primary limitation being the quality of available flow tracers. Graphic abstract

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Investigation of surface structures in two phase wavy pipe flow by utilizing X-ray tomography

Cited by 6 publications

References 28 publications

Experimental investigation of intermittent airflow separation and microscale wave breaking in wavy two-phase pipe flow

Experimental investigation of intermittent airflow separation and microscale wave breaking in wavy two-phase pipe flow

Experimental Observation of Dissolution Finger Growth in Radial Geometry

Tomographic X-ray particle tracking velocimetry

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