Application of fluorescent PIV and digital image analysis to measure turbulence properties of solid–liquid stirred suspensions

Unadkat, Heema; Rielly, Chris D.; Hargrave, Graham K.; Nagy, Zoltán K.

doi:10.1016/j.cherd.2008.11.011

Cited by 62 publications

(51 citation statements)

References 29 publications

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“…As shown in Figure 12, low to moderate solid concentrations up to 10 wt % seem to cause a small reduction in Fl (L) , which is not compensated for by the simultaneous increase in Fl (1) and Fl (2) (mainly due to the local rise in c 1 and c 2 ); thus, the total flow number, Fl, diminishes from 0.86 to 0.77. At higher solid concentrations above 20 wt %, the approximately linear increase in Fl (1) and Fl (2) fails to counterbalance the steep reduction in Fl (L) caused by the presence of solid particles, consequently leading to a substantial fall in Fl.…”

Section: Global Indices For Multi-phase Mixingmentioning

confidence: 89%

“…At higher solid concentrations above 20 wt %, the approximately linear increase in Fl (1) and Fl (2) fails to counterbalance the steep reduction in Fl (L) caused by the presence of solid particles, consequently leading to a substantial fall in Fl. Overall, Fl incurs a reduction of $20% when X rises from 0 to 40 wt %.…”

Section: Global Indices For Multi-phase Mixingmentioning

confidence: 90%

“…The advent of powerful measurement and modeling techniques in recent years has re-energized interest in this field and more effort is increasingly being devoted to try and fully understand the mechanisms behind particle suspension and distribution. [1][2][3][4] Among the various flow visualization techniques, laser Doppler velocimetry (LDV) and particle image velocimetry (PIV) have become the most reliable to examine the complex nature of the flow fields in optically transparent singlephase systems. [5][6][7] Application to multi-phase studies, however, has been restricted to extremely dilute suspensions as these techniques fail completely in dense systems which are opaque.…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7] Application to multi-phase studies, however, has been restricted to extremely dilute suspensions as these techniques fail completely in dense systems which are opaque. 1 One of the important aspects in the local description of multi-phase or multi-component mixtures is the measurement of phase distribution, which has remained a challenge. Attempts at local measurements in these systems have been mainly limited to the measurement of mean axial solidconcentration profiles at relatively low concentrations, using a single vertical conductivity or capacitance probe traverse or a withdrawal technique.…”

Section: Introductionmentioning

confidence: 99%

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Mixing of dense binary suspensions: Multi‐component hydrodynamics and spatial phase distribution by PEPT

Guida¹,

Nienow²,

Barigou³

2010

AIChE Journal

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The three-component flow field and spatial phase distribution of binary mixtures of glass particles suspended in water in a stirred vessel have been resolved using positron emission particle tracking (PEPT). The Lagrangian flow data provided by the technique have been converted to give a detailed Eulerian description of each of the three phase components of the flow generated by a pitched blade turbine. For the first time, it has been possible to determine the full 3D velocity and concentration fields of the liquid phase and both the solid components within opaque dense slurries of this type containing up to 40 wt % solids. Spatial distributions of local time-averaged slip velocity have also been obtained for each solid component showing wide variations. The detailed PEPT measurements have enabled the solids mass balance and the mass continuity of the three phase components to be accurately verified throughout the vessel.

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Section: Global Indices For Multi-phase Mixingmentioning

confidence: 89%

Section: Global Indices For Multi-phase Mixingmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mixing of dense binary suspensions: Multi‐component hydrodynamics and spatial phase distribution by PEPT

Guida¹,

Nienow²,

Barigou³

2010

AIChE Journal

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“…In the last few decades, many engineers have recognised the importance of biological processes ranging from coastal protection (mangroves, salt marshes seagrasses) to better understanding of floc dynamics and structure (Wheatland et al 2017) and the ETDC cycle. However, particle-flow interactions are complex and are being addressed by theoretical (Violeau 2012) and practical advances (Unadkat et al 2009) and there are other issues in terms of revealing the complexity of turbulence structures in flow and their effects on particle behaviour that also requires advances in understanding and should be a rich vein of cooperative research. While early progress was hindered by the lack of suitable methodologies to apply to natural systems, an initial reluctance to bring the field into the laboratory and a lack of desire or resources to simulate the natural environment has now changed, and there is now an increasing emphasis on Bin situ^work (Andersen et al 2010) and combined Bfield and laboratory^ Parsons et al 2016;Schmidt et al 2016) and Bempirical and modelling^work (Orvain et al 2006).…”

Section: The Paradigm Shift Concerning Biota In Sediment Researchmentioning

confidence: 99%

Form, function and physics: the ecology of biogenic stabilisation

et al. 2018

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Purpose The objective of this work is to better understand the role that biological mediation plays in the behaviour of fine sediments. This research is supported by developments in ecological theory recognising organisms as Becosystem engineers^and associated discussion of Bniche construction^, suggesting an evolutionary role for habitat modification by biological action. In addition, there is acknowledgement from engineering disciplines that something is missing from fine sediment transport predictions. Materials and methods Advances in technology continue to improve our ability to examine the small-scale 2D processes with large-scale effects in natural environments. Advanced molecular tools can be combined with state-of-the-art field and laboratory techniques to allow the discrimination of microbial biodiversity and the examination of their metabolic contribution to ecosystem function. This in turn can be related to highly resolved measurements and visualisation of flow dynamics. Results and discussion Recent laboratory and field work have led to a paradigm shift whereby hydraulic research has to embrace biology and biogeochemistry to unravel the highly complex issues around on fine sediment dynamics. Examples are provided illustrating traditional and more recent approaches including using multiple stressors in fully factorial designs in both the laboratory and the field to highlight the complexity of the interaction between biology and sediment dynamics in time and space. The next phase is likely to rely on advances in molecular analysis, metagenomics and metabolomics, to assess the functional role of microbial assemblages in sediment behaviour, including the nature and rate of polymer production by bacteria, the mechanism of their influence on sediment behaviour. Conclusions To fully understand how aquatic habitats will adjust to environmental change and to support the provision of various ecosystem services, we require a holistic approach. We must consider all aspects that control the distribution of sediment and the erosion-transport-deposition-consolidation cycle including biological and chemical processes, not just the physical. In particular, the role of microbial assemblages is now recognised as a significant factor deserving greater attention across disciplines.

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