Use of PIV to measure turbulence modulation in a high throughput stirred vessel with the addition of high Stokes number particles for both up- and down-pumping configurations

Gabriele, A.; Tsoligkas, AN; Kings, Iain; Simmons, Mark

doi:10.1016/j.ces.2011.08.007

Cited by 42 publications

(31 citation statements)

References 25 publications

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“…At 8% overall solids volume fraction, the peak level in the contour plot of dimensionless TKE is 0.046, in the single‐phase case it is 0.065. The presence of particles weakening the turbulence intensities is in a good agreement with results of Unadkat et al and Gabriele et al…”

Section: Resultssupporting

confidence: 91%

“…As for investigations about the flow field, laser‐based optical imaging techniques such as Laser Doppler Anemometry (LDA) and Particle Image Velocimetry (PIV) are the most widely used. In applying these techniques to solid‐liquid systems, a main limiting factor is the solids concentration which—in the studies referred to here—was less than 1% by volume .…”

Section: Introductionmentioning

confidence: 99%

“…With the same continuous and dispersed phases, Virdung et al also measured the velocities of both phases up to 1.5% solids by volume using PIV combined with image analysis to separate the particles and liquid in their camera frames. Gabriele et al used p‐cymene and PMMA spheres as the continuous and dispersed phases, respectively, to investigate the turbulence properties of the fluid in a high throughput stirred vessel for both up‐pumping and down‐pumping configurations by PIV with up to 5% (by volume) particles. Kohnen et al used a mixture of oil (Pharma 5, DEA) and a light protective liquid (Eusolex, Merck) to match the refractive index of the particles (Duran glass).…”

Section: Introductionmentioning

confidence: 99%

“…However, the size of the particles as well as the resolution of velocity vectors in most investigations are less than or equal to one millimeter, which means that the flow field around the particles is not resolved by the experiments. In the study by Gabriele et al, the diameter of the particles was 1.5 mm whereas the velocity vectors resolution was 171 μm with the minimum interrogation area of 16 × 16 pixels and 50% overlap. As a result, there are about eight vectors over the diameter of the particles.…”

Section: Introductionmentioning

confidence: 99%

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Particle‐resolved PIV experiments of solid‐liquid mixing in a turbulent stirred tank

Gao

et al. 2017

AIChE Journal

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Particle Image Velocimetry (PIV) experiments on turbulent solid-liquid stirred tank flow with careful refractive index matching of the two phases have been performed. The spatial resolution of the PIV data is finer than the size of the spherical, uniformly sized solid particles, thereby providing insight in the flow around individual particles. The impeller is a down-pumping pitch-blade turbine. The impeller-based Reynolds number has been fixed to Re 5 10 4 . Overall solids volume fractions up to 8% have been investigated. The PIV experiments are impeller-angle resolved, that is, conditioned on the angular position of the impeller. The two-phase systems are in partially suspended states with an inhomogeneous distribution of solids: high solids loadings near the bottom and near the outer walls of the tank, much less solids in the bulk of the tank. The liquid velocity fields show very strong phase coupling effects with the particles increasingly attenuating the overall circulation patterns as well as the liquid velocity fluctuation levels when the solids volume fraction is increased.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Particle‐resolved PIV experiments of solid‐liquid mixing in a turbulent stirred tank

Gao

et al. 2017

AIChE Journal

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“…The tracer particles with a diameter of 10 μm were added to the distilled water to capture the flow patterns with the laser plane passing through the center of the shaft in all measurements. The maximum separation, dT max , is given as a function of the image magnification and the maximum velocity within the system .

true d T_{normalmax} = 0.25 L_{normalIA} M false/ U_{normaltip}

…”

Section: Computational and Experimental Approachmentioning

confidence: 99%

Quantitative Measurements of the Critical Impeller Speed for Solid‐Liquid Suspensions

Nienow

Alberini

2019

Chem Eng & Technol

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A quantitative methodology for particle suspension assessment is presented. A new parameter, f mov/tot , the ratio of the mean number of moving particles to the total number of particles, is introduced to evaluate the minimum speed required to just suspend solids. This approach is tested to investigate the impact of impeller clearance on the minimum impeller speed, N js , in a vessel when using a radial flow Rushton turbine. Flow patterns and power numbers obtained experimentally and computationally support the suspension findings. Image analysis is an appropriate method for determining N js . Lowering the impeller clearance reduces the speed required for particle suspension with a change of flow pattern from a radial discharge with two loops to a single loop scouring the vessel base. The power number also falls markedly at the two-to-one loop transition as does the strain rate near the base.

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Concentrated slurry formation via drawdown and incorporation of wettable solids in a mechanically agitated vessel

et al. 2018

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This article describes the effect of vessel configurations on the drawdown and incorporation of floating solids to prepare concentrated alumina slurries in stirred tanks. The impeller speed and power draw required to incorporate all dry powder within four seconds, N JI and P JI , are used to evaluate incorporation performance. The effect of impeller type is assessed, with pitched blade impellers proving to be the most effective across the full range of solid contents considered. At higher solids content the energy demand is shown to increase dramatically, with a 100-fold increase in energy required to add 1% w/w more solid at 50% by weight compared to 1% by weight. Analysis of impeller power numbers show this coincides with a transition from constant power number to a region where power number increases linearly with decreasing Reynolds number. Contrary to studies at low solids content, the presence of baffles is shown to inhibit drawdown.

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Use of PIV to measure turbulence modulation in a high throughput stirred vessel with the addition of high Stokes number particles for both up- and down-pumping configurations

Cited by 42 publications

References 25 publications

Particle‐resolved PIV experiments of solid‐liquid mixing in a turbulent stirred tank

Particle‐resolved PIV experiments of solid‐liquid mixing in a turbulent stirred tank

Quantitative Measurements of the Critical Impeller Speed for Solid‐Liquid Suspensions

Concentrated slurry formation via drawdown and incorporation of wettable solids in a mechanically agitated vessel

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