Experimental Study of the Transient Flow in a Coiled Pipe Using PIV

Brito, Moisés; Sanches, Pedro; Ferreira, Renata Marques; Covas, Dídia

doi:10.1061/(asce)hy.1943-7900.0001253

Cited by 6 publications

(6 citation statements)

References 35 publications

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“…The output laser beam is green with wavelength of 532 nm. This system is described in Ferreira [16]; Ricardo et al [34]; Brito et al [7]. A charged coupled device (CCD) Flowsense 2M camera, commercialized by Dantec, with a resolution of 1600 × 1200 pix 2 was positioned perpendicularly to the laser sheet in both layouts.…”

Section: Instrumentationmentioning

confidence: 99%

“…A charged coupled device (CCD) Flowsense 2M camera, commercialized by Dantec, with a resolution of 1600 × 1200 pix 2 was positioned perpendicularly to the laser sheet in both layouts. The PIV system was operated with a maximum sample frequency of 15 Hz and a time between two consecutive laser pulses of 500 s. The synchronization between the PIV system and gate was performed using an external trigger connected to the gate and PIV timer box [7]. Polyamid particles with nominal diameter of 50 m and specific density of 1.03 were used as tracer particles.…”

Section: Instrumentationmentioning

confidence: 99%

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LES validation of lock-exchange density currents interacting with an emergent bluff obstacle

et al. 2022

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We address the capability of large eddy simulation (LES) to predict the physics of density currents interacting with bluff obstacles. Most density currents of interest in engineering and geophysical applications interact with obstacles or topographic features. Validating LES solutions in these contexts is crucial to establish it as a trusted tool. We thus propose a validation effort based on simple geometries that nonetheless pose challenges common to more complex systems, including boundary layer separation and convective instabilities. We focus on lock-exchange gravity currents in the slumping phase interacting with an emergent vertical circular cylinder. Our main investment was in ensuring that the comparison of experimental data and numerical results include, at least, the velocity and the density fields , and derived quantities (e.g., second order moments). Measurements of both density and velocity fields were performed in the side and plan views for cylinder Reynolds numbers, Re d , in the range 1300 to 3475. It was found that the LES accurately predicts the temporal evolution of the current front position. The computed front velocity exhibits a maximum relative error less than 8%. A good agreement between the LES and the experimental size and shape of the current head, and billows was found. The overall features upstream the cylinder, including a reflected wave, adverse pressure gradient and backflow, and downstream the cylinder, including the backflow, wake and the formation of a new head are well reproduced by LES. The agreement between the LES and the experimental time-space evolution of current spanwise-and depth-averaged density contours and the instantaneous velocity fields are not affected by Re d .

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Section: Instrumentationmentioning

confidence: 99%

Section: Instrumentationmentioning

confidence: 99%

LES validation of lock-exchange density currents interacting with an emergent bluff obstacle

et al. 2022

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“…Flow fields in curved tubes were already visualized via holographic particle tracking 9, 2D and 3D particle image velocimetry (PIV) 14–18, and magnetic resonance imaging (MRI) 19, 20. Recently, Kováts et al applied laser‐induced fluorescence to visualize concentration fields of a fluorescent dye at different angles of revolution 21.…”

Section: Introductionmentioning

confidence: 99%

X‐Ray‐Based Tomographic Imaging for the Investigation of Laminar Mixing in Capillaries

2022

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Micro-computed tomography is a promising non-invasive imaging technology that offers high spatial resolution without requiring optical access. This opens the opportunity to analyze concentration fields in mixing equipment in 3D. To demonstrate the potential of the methodology, laminar mixing in helically coiled capillaries is investigated by tracking the radial distribution of potassium iodide along the main flow direction. Dean flow can be observed in the helically coiled capillaries, which intensifies with Reynolds number and decreasing effect of gravity.

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“…Especially non-invasive imaging approaches promise great insights and are crucial for the validation of numerical simulations [24]. Flow profiles were already visualized in curved tubes using magnetic resonance imaging (MRI) [14,25], digital holographic particle tracking velocimetry [12], and 2D and 3D particle image velocimetry (PIV) [24,[26][27][28][29]. In this perspective paper, Xray micro-computed tomography (X-µCT) is applied to visualize 3D concentration profiles of iodide (I − ) in an HCT.…”

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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Experimental Study of the Transient Flow in a Coiled Pipe Using PIV

Cited by 6 publications

References 35 publications

LES validation of lock-exchange density currents interacting with an emergent bluff obstacle

LES validation of lock-exchange density currents interacting with an emergent bluff obstacle

X‐Ray‐Based Tomographic Imaging for the Investigation of Laminar Mixing in Capillaries

3D investigations of microscale mixing in helically coiled capillaries

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