SPRITE MRI of bubbly flow in a horizontal pipe

Sankey, Mark H.; Yang, Zhengtao; Gladden, Lynn F.; Johns, Michael L.; Lister, D. H.; Newling, Benedict

doi:10.1016/j.jmr.2009.01.034

Cited by 26 publications

(14 citation statements)

References 29 publications

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“…Engineering applications have spanned from reactors [11] and microfluidic devices [12] to filters [13] and rheology [14,15]. In addition, the ability of MRI to simultaneously probe flow and chemistry has allowed velocity fields in complex multi-phase flows [16][17][18] to be studied.…”

Section: Introductionmentioning

confidence: 99%

Accuracy of phase-contrast velocimetry in systems with skewed intravoxel velocity distributions

Vallatos

Al-Mubarak

Mullin

et al. 2018

Journal of Magnetic Resonance

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Phase contrast velocimetry (PCV) has been widely used to investigate flow properties in numerous systems. Several authors have reported errors in velocity measurements and have speculated on the sources, which have ranged from eddy current effects to acceleration artefacts. An often overlooked assumption in the theory of PCV, which may not be met in complex or unsteady flows, is that the intravoxel displacement distributions (propagators) are symmetric. Here, the effect of the higher moments of the displacement distribution (variance, skewness and kurtosis) on the accuracy of PCV is investigated experimentally and theoretically. Phase and propagator measurements are performed on tailored intravoxel distributions, achieved using a simple phantom combined with a single large voxel. Asymmetric distributions (Skewness ≠ 0) are shown to generate important phase measurement errors that lead to significant velocimetry errors. Simulations of the phase of the spin vector sum, based on experimentally measured propagators, are shown to quantitatively reproduce the relationship between measured phase and experimental parameters. These allow relating the observed velocimetry errors to a discrepancy between the average phase of intravoxel spins considered in PCV theory and the vector phase actually measured by a PFG experiment. A theoretical expression is derived for PCV velocimetry errors as a function of the moments of the displacement distribution. Positively skewed distributions result in an underestimation of the true mean velocity, while negatively skewed distributions result in an overestimation. The magnitude of these errors is shown to increase with the variance and decrease with the kurtosis of the intravoxel displacement distribution.

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Section: Introductionmentioning

confidence: 99%

Accuracy of phase-contrast velocimetry in systems with skewed intravoxel velocity distributions

Vallatos

Al-Mubarak

Mullin

et al. 2018

Journal of Magnetic Resonance

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show abstract

“…Once in the column gas forms discrete bubbles that rise due to their buoyancy and induce motion of the continuous liquid phase. 2006Ong, Gupta, Youssef, Al-dahhan, & Dudukovic, 2009;Patel & Thorat, 2008;Rabha, Schubert, & Wagner, 2013a,b;Rabha, Schubert, Wagner, Lucas, & Hampel, 2013;; and magnetic resonance imaging (MRI) (Daidzic, Schmidt, Hasan, & Altobelli, 2005;Sankey, Yang, et al, 2009;Tayler, Holland, Sederman, & Gladden, 2012a). These measurements have been used to explore a variety of characteristics of bubble column reactor performance.…”

Section: Fluid Phase Fraction Measurementsmentioning

confidence: 99%

Applications of tomography in bubble column and trickle bed reactors

Holland

2015

Industrial Tomography

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“…Whilst this particular study focused on the behaviour of single bubbles, initial data were also reported showing that this approach may enable us to explore how large-scale vortex chains are generated by the wake behaviour of individual bubbles in a swarm of bubbles. The SPRITE technique has also been used to measure average gas-liquid distributions and average velocities in horizontal bubbly flows [46]. The very short encoding times used by SPRITE make it an ideal technique for studying such dynamic systems with moving interfaces.…”

Section: Two-phase Flowsmentioning

confidence: 99%