Mixing in a tank stirred by a Rushton turbine at a low clearance

Ochieng, Aoyi; Onyango, Maurice S.; Kumar, Anil; Kiriamiti, Kirimi; Musonge, Paul

doi:10.1016/j.cep.2007.01.034

Cited by 63 publications

(42 citation statements)

References 18 publications

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“…8,51,52 Experimental validation of the simulations It has consistently been shown over the years that in a stirred tank, the best prediction is obtained for the axial velocity component and the worst prediction is obtained for the kinetic energy dissipation rate. 6,7,14 In addition, the same authors have reported that better prediction is obtained in the regions of high turbulence, such as the impeller region. Generally, there is a mismatch between the experimental and simulation results in the wall region.…”

Section: Validation Of Simulation Results and Scale Upmentioning

confidence: 96%

“…Baffles change the flow patterns by converting part of the circumferential and radial velocity components into the axial velocity component. 6,14 This enhances the axial circulation of the fluid, and at the same time introduces loops in the vicinity of the baffles. These loops can be suppressed by an increased upward current induced by a draft tube.…”

Section: Bafflesmentioning

confidence: 99%

“…21 More recently, a lightning type of impeller (Mixtec HA735) was used to study mixing time. 14 In some systems, more than one impeller may be required to provide efficient mixing. Multiple impellers are used in tanks with a high aspect ratio, where a single impeller may not generate momentum high enough to overcome the hydrostatic head.…”

Section: Impeller Typesmentioning

confidence: 99%

“…13 A large number of hydrodynamic studies has been conducted using these standard configurations and it recently has been shown that mixing can be improved with non-standard tank configurations. 10,14 In a single-impeller stirred tank, the fluid flow in the lower part of the tank is largely dependent on the interaction between the downward stream and the tank bottom, which results in the generation of an upward jet. This jet is an important feature in a mixing tank and has attracted attention, especially with regards to solid-liquid mixing.…”

mentioning

confidence: 99%

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Experimental measurement and computational fluid dynamics simulation of mixing in a stirred tank: a review

Ochieng

Kiriamiti

2010

S Afr J Sci

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Section: Validation Of Simulation Results and Scale Upmentioning

confidence: 96%

Section: Bafflesmentioning

confidence: 99%

Section: Impeller Typesmentioning

confidence: 99%

mentioning

confidence: 99%

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Experimental measurement and computational fluid dynamics simulation of mixing in a stirred tank: a review

Ochieng

Kiriamiti

2010

S Afr J Sci

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“…Using ANSYS FLUENT v15. 4.to solve the continuity and momentum equations incorporating the RNG K-ε turbulence model with the standard wall function available in Fluent. The multiple frames of reference (MFR) model is used for impeller modeling.…”

mentioning

confidence: 99%

Effect of Impeller Rotational Speed on Flow Behavior in Fully Baffled Mixing Tank.

rasool¹,

Ahmad²,

Hamad³

2017

IJAR

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fluid flow in mixing tank, mixing, Retreat Curve impeller This paper reports the results of numerical study undertaken to investigate the effect of impeller rotational speed on velocity field in mixing tank. The hydrodynamic of the flow in standard mixing tank generated by retreat curve 3-blaed impellers, (radial flow) is studied. Using ANSYS FLUENT v15.4.to solve the continuity and momentum equations incorporating the RNG K-ε turbulence model with the standard wall function available in Fluent. The multiple frames of reference (MFR) model is used for impeller modeling. The results show that the velocity fluctuated increased with the rotational speed. …………………………………………………………………………………………………….... Introduction:-Mixing tanks is one of the techniques that is widely used and play a significant role in industrial processes to homogenize the mixture of two or more fluids/solids by using rotating impeller. The better understanding of the fluids behavior in mixing vessel may improve the performance of impeller and the mixing process. Means e.g. the main aims of using missing is to improve the mass and heat transfer and to generate a homogenized mixture to minimize the settling of the particles at the bottom of the tank. A summary of some recent published works in the literature is given below. et. al. 2008) [5] Investigated the hydrodynamics in mixing tank by CFD simulation. Two models were used to determine the dissipation rate and its distribution in mixing vessel. Three dimensional simulations using the commercial CFD code FLENT 6.2.16 based on the Unsteady Reynolds Averaged NaiverStokes equations (URANS) model and Large Eddy simulation (LES) model was used (Zadghaffari et. al. 2008)[6] Studied the flow field, power and mixing time in mixing tank agitated by a double Rushton turbine. It was observed that a considerable reduction in mixing time can be achieved by increasing impeller rotation speed and reasonable agreement between the simulation and experimental results were obtained. The comparisons pointed the advantages Corresponding Author:-Adnan A. Abdul rasool. Address:-A: mech. Eng. Dept, college of engineering, al-mustansiriya university, Baghdad, Iraq.

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Detached eddy simulation on the turbulent flow in a stirred tank

et al. 2011

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A detached eddy simulation (DES), a large‐eddy simulation (LES), and a k‐ε‐based Reynolds averaged Navier‐Stokes (RANS) calculation on the single phase turbulent flow in a fully baffled stirred tank, agitated by a Rushton turbine is presented. The DES used here is based on the Spalart‐Allmaras turbulence model solved on a grid containing about a million control volumes. The standard k‐ε and LES were considered here for comparison purposes. Predictions of the impeller‐angle‐resolved and time‐averaged turbulent flow have been evaluated and compared with data from laser doppler anemometry measurements. The effects of the turbulence model on the predictions of the mean velocity components and the turbulent kinetic energy are most pronounced in the (highly anisotropic) trailing vortex core region, with specifically DES performing well. The LES—that was performed on the same grid as the DES—appears to lack resolution in the boundary layers on the surface of the impeller. The findings suggest that DES provides a more accurate prediction of the features of the turbulent flows in a stirred tank compared with RANS‐based models and at the same time alleviates resolution requirements of LES close to walls. © 2011 American Institute of Chemical Engineers AIChE J, 58: 3224–3241, 2012

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Mixing in a tank stirred by a Rushton turbine at a low clearance

Cited by 63 publications

References 18 publications

Experimental measurement and computational fluid dynamics simulation of mixing in a stirred tank: a review

Experimental measurement and computational fluid dynamics simulation of mixing in a stirred tank: a review

Effect of Impeller Rotational Speed on Flow Behavior in Fully Baffled Mixing Tank.

Detached eddy simulation on the turbulent flow in a stirred tank

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