The swirling radial jet

Kolář, V.; Filip, Petr; Curev, A. G.

doi:10.1007/bf00389269

Cited by 13 publications

(3 citation statements)

References 3 publications

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“…Based on a unique coordinate transformation which was basically developed for the laminar case, these equations can be further reduced to the basic turbulent radial‐jet equations with no swirl in a direction tangent to a cylinder of radius “ e ”,

true(r, θ, z true) \to true(\sqrt{r^{2} - e^{2}}, z true)

. The cylinder radius is determined by the asymptotic ratio of the radial to angular momentum flux in the radial direction …”

Section: Theoretical Approachmentioning

confidence: 99%

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Semianalytical characterization of turbulence from radial impellers, with experimental and numerical validation

et al. 2015

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Based on conventional turbulent jet theory and the general theoretical framework of scalar dispersion in turbulent shear flows, a novel formulation of the radial impeller's jet in stirred tanks is introduced. Whereas previous studies considered the impeller's jet as developed, it is now comprised of two separate spatial regions along the radial axis: the zone of flow establishment (ZFE) and the zone of established flow (ZEF). This formulation is accompanied with semi‐analytical expressions for the prediction of turbulent key parameters including the random part of k and ε in the ZFE. The new theoretical framework is validated both with laser Doppler anemometry measurements and with 3‐D numerical simulations using the standard k−ε turbulent model. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1413–1426, 2015

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true(r, θ, z true) \to true(\sqrt{r^{2} - e^{2}}, z true)

. The cylinder radius is determined by the asymptotic ratio of the radial to angular momentum flux in the radial direction …”

Section: Theoretical Approachmentioning

confidence: 99%

“…This concept was further developed with time and has been applied for complex geometries such as stirred tanks . However, most of the models predict only the velocity field (e.g., the swirling‐radial‐jet model). In 1991, the swirling‐radial‐jet model was extended numerically to provide the

k

and

ε

turbulent parameters as well .…”

Section: Introductionmentioning

confidence: 99%

Semianalytical characterization of turbulence from radial impellers, with experimental and numerical validation

et al. 2015

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“…Various alternative models are used to incorporate the effect of the rotating turbine blades. In the ''Black-box Approach'' or the ''Impeller Boundary Condition'' (Harvey and Greaves, 1982;Kolář et al, 1982), steady state simulations are carried out by treating the impeller swept region as a black box whose surfaces either contains inlets and outlets for the flow generated by the impeller. The main advantage of the ''Impeller Boundary Condition'' approach is that both the grid and the boundary conditions are fixed in space.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of a fully baffled biological reactor: The differential circumferential averaging mixing plane approach

Dubey

Das

Panda

2006

Biotechnol. Bioeng.

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A modified mixing plane approach for steady state simulation of flow field in fully baffled biological reactor is presented and discussed. Without requiring any experimental input, this approach of dividing the vessel into suitable number of connected and disconnected zones; solving steady state equation separately in each zone and then transferring information between them, provides a computationally less intensive alternative for simulating the flow in the whole vessel. Impeller used is the standard Rushton Turbine positioned at mid-height of the reactor and simulations are carried out using standard k-epsilon turbulence model implemented in CFD code FLUENT. Meshing is done using tetrahedral elements such that mesh size gradually increases from the center to the periphery. Most of the previous simulation works present only a few aspects of the flow field with scant importance to the energy balance in the tank and near tip turbulence. In this work, complete model prediction for velocity field and turbulence parameters (near tip and in the bulk region) are validated by comparison with experimental data. As compared to previous simulation works, the results predicted by this "Differential circumferential averaging mixing plane approach" show a better qualitative and quantitative agreement with the published experimental data. A distribution of energy dissipation in various zones of vessel is presented. Also a qualitative picture of flow field and stagnant zones inside the reactor is presented and discussed. Comparison of flow characteristics for different number of baffles shows that for the present dimension of the vessel, five baffles gives maximum enhanced mixing.

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