Transient Hydrodynamics and Free Surface Capture of an Under-Baffled Stirred Tank During Stopping

Torré, Jean-Philippe; Fletcher, David F.; Lasuye, Thierry; Xuereb, Catherine

doi:10.1205/cherd06174

Cited by 11 publications

(10 citation statements)

References 25 publications

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“…All simulations were carried out as single-phase simulations with a fixed surface. Multiphase simulations are highly computationally expensive because there are roughly twice as many equations to be solved as for a single-phase simulation and the convergence is slowed due to the complexity of the multiphase physics [34]. The influences of the free surface and the development of a deep vortex are neglected in the simulations of this study.…”

Section: Power Numbermentioning

confidence: 99%

Flow Field Analysis of Stirred Liquid‐Liquid Systems in Slim Reactors

Maaß¹,

Eppinger²,

Altwasser³

et al. 2011

Chem Eng & Technol

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Previous studies have shown the great potential, but also the great challenges, in handling slim reactors often used for polymerization reactions. Experiments and simulations were carried out in reactors with aspect-to-diameter ratios of up to 5, to test and to evaluate the mixing and dispersion efficiency for liquid-liquid systems of single-and multiple-stage impellers. Therefore, power consumption, mixing time and minimum dispersion speed were determined for five different stirrer types under turbulent conditions. It was found that the dimensionless mixing time is highly sensitive to the configuration of the impellers, with almost no dependency on the turbulent power number. Another focus was the analysis of the effect of the baffles. The influence of the baffle length in slim reactors on the mixing time and the macroscopic flow field was determined.

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Section: Power Numbermentioning

confidence: 99%

Flow Field Analysis of Stirred Liquid‐Liquid Systems in Slim Reactors

Maaß¹,

Eppinger²,

Altwasser³

et al. 2011

Chem Eng & Technol

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“…The transient volume of fluid (VOF) model is useful for tracking the shape of the free liquid surface (Marshall and Bakker, 2004). In stirred tank applications, the VOF method together with the RANS approach has been commonly used for predicting the steady‐state shape of the surface (Serra et al, 2001; Torré et al, 2007). However, using the RANS approach, the time and the spatial dynamics of the liquid flow in the stirred tank are averaged.…”

Section: Introductionmentioning

confidence: 99%

CFD simulation of free liquid surface motion in a pilot plant stirred tank

et al. 2011

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The Volume of Fluid method together with the Large Eddy Simulation technique for turbulence flow was used for CFD prediction of liquid flow and free liquid surface motion in a pilot plant cylindrical flat-bottomed stirred tank with an inner diameter of 1 m filled with tap water at room temperature. A pitched-blade (45 • ) down pumping impeller (diameter of 0.33 m) with six blades was used for stirring. The impeller speed was 180 rpm. For simulation of the impeller motion, the sliding mesh method was adopted. The CFD simulations of the flow field predicted a highly complex, multi-dimensional dynamic system exhibiting unstable, pseudo-stationary behaviour. The main advantage of this CFD simulation is the prediction of the velocity flow patterns and the free surface elevation/depression in the whole system at one time. The results for the location and dimensions of the free liquid surface fluctuation correspond well with an experimental investigation by a conductivity method.La méthode de volume de fluide avec la technique Large Eddy Simulation pour le flux de turbulence aété utilisée pour prédire la DFN du flux de liquide et du mouvement de la surface liquide libre dans la cuveà agitation cylindriqueà fond plat d'une usine pilote avec un diamètre interne de 1 m remplie d'eau du robinetà température ambiante. Un impulseurà pompage descendantà pales inclinées (45 • ) (diamètre of 0,33 m) avec six pales aété utilisé pour l'agitation. La vitesse de l'impulseurétait de 180 tr/min. Pour la simulation du mouvement de l'impulseur, la méthode des maillages glissants aété adoptée. Les simulations de la DFN du champ du flux ont prédit un système dynamique multidimensionnel très complexe qui affiche un comportement pseudo-immobile et instable. Le principal avantage de cette simulation de la DFN est la prédiction des modèles de la vitesse d'écoulement et l'élévation ou la dépression de la surface libre dans tout le système en même temps. Les résultats de l'emplacement et des dimensions de la fluctuation de la surface liquide libre correspondent bienà l'analyse expérimentale par une méthode de conductivité.

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“…[43][44][45][46] There were only few works to investigate the transient hydrodynamics in reactors during the stop stage of the whole process. 47 As can be seen in previous works, it is reasonable to comprehensively investigate the flow structures and hydrodynamics by experiments and numerical simulations because of their great significances on effective mixing. The selectivity and yield of reactions depend strongly on the hydrodynamics in STRs.…”

Section: Introductionmentioning

confidence: 97%

“…As for applications of various CFD methods in structure design and operational condition optimization for industrial reactors, most efforts have focused on the flow structures and hydrodynamics with emphasis on the influences of baffles, dual impellers, impeller clearance, and spacing . There were only few works to investigate the transient hydrodynamics in reactors during the stop stage of the whole process . As can be seen in previous works, it is reasonable to comprehensively investigate the flow structures and hydrodynamics by experiments and numerical simulations because of their great significances on effective mixing.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulations of hydrodynamics and concentration distribution in a stirred tank during startup stage for producing phenylboronic acid ester

Liu

Luo

2018

Asia-Pacific J Chem Eng

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In this work, a kinetic model of phenylboronic acid ester production process is firstly derived using the power law analysis based on experimental data and then combined with computational fluid dynamics models to simulate the concentration distributions of phenylmagnesium as reactant and phenylboronic acid ester as product during the stirred tank startup stage. Computational grid refinements as well as transient analysis are applied to confirm hydrodynamic and concentration results. Different factors including turbulent equations, wall functions, and rotational speed are investigated with different computational fluid dynamics methods to predict both the phenylmagnesium and phenylboronic acid ester concentration distributions. Simulation results show good agreements with experimental results, and thus, the diffusion and distribution of phenylmagnesium and phenylboronic acid ester inside the reactor can be successfully predicted. To achieve good mixing performance, high rotational speed should be provided with considering the balance between the mixing time and the energy consumption.

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Transient Hydrodynamics and Free Surface Capture of an Under-Baffled Stirred Tank During Stopping

Cited by 11 publications

References 25 publications

Flow Field Analysis of Stirred Liquid‐Liquid Systems in Slim Reactors

Flow Field Analysis of Stirred Liquid‐Liquid Systems in Slim Reactors

CFD simulation of free liquid surface motion in a pilot plant stirred tank

Numerical simulations of hydrodynamics and concentration distribution in a stirred tank during startup stage for producing phenylboronic acid ester

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