CFD prediction of fluid flow and mixing in stirred tanks: Numerical issues about the RANS simulations

Coroneo, Mirella; Montante, Giuseppina Maria Rosa; Paglianti, Alessandro; Magelli, Franco

doi:10.1016/j.compchemeng.2010.12.007

Cited by 157 publications

(116 citation statements)

References 45 publications

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“…However, much finer grids than those that have been usually adopted so far for RANS simulations are obviously required for accurate prediction of the turbulent quantities. Coroneo et al (2011) also found that the influence of the discretisation scheme is critical. They compared the first order upwind, second order upwind and QUICK scheme.…”

Section: Introductionmentioning

confidence: 99%

“…It has been stated many times that the k-ε turbulence model underestimates the turbulent quantities, which results in underestimation of the power number computed from the integral of the turbulent dissipation rate. Coroneo et al (2011) tested four different computational grids ranging from 270,000 to 6.6 million cells on a single-phase system and concluded that the turbulent quantities prediction may be substantially improved by reducing the spatial discretisation size. In recent years, the traditional approach was to use computational meshes with less than half a million cells for the BSD modelling in stirred tanks.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

CFD Prediction of Gas-Liquid Flow in an Aerated Stirred Vessel Using the Population Balance Model

Kálal¹,

Jahoda²,

Fořt³

2014

Chemical and Process Engineering

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The main topic of this study is the experimental measurement and mathematical modelling of global gas hold-up and bubble size distribution in an aerated stirred vessel using the population balance method. The air-water system consisted of a mixing tank of diameter T = 0.29 m, which was equipped with a six-bladed Rushton turbine. Calculations were performed with CFD software CFX 14.5. Turbulent quantities were predicted using the standard k-ε turbulence model. Coalescence and breakup of bubbles were modelled using the homogeneous MUSIG method with 24 bubble size groups. To achieve a better prediction of the turbulent quantities, simulations were performed with much finer meshes than those that have been adopted so far for bubble size distribution modelling. Several different drag coefficient correlations were implemented in the solver, and their influence on the results was studied. Turbulent drag correction to reduce the bubble slip velocity proved to be essential to achieve agreement of the simulated gas distribution with experiments. To model the disintegration of bubbles, the widely adopted breakup model by Luo & Svendsen was used. However, its applicability was questioned.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

CFD Prediction of Gas-Liquid Flow in an Aerated Stirred Vessel Using the Population Balance Model

Kálal¹,

Jahoda²,

Fořt³

2014

Chemical and Process Engineering

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“…The height of the MRF is about 2.5 times the blade height (Oshinowoi et al, 2000), and the MRF diameter is equal to the median diameter between the blade tip and the baffle inner edge (Coronero et al, 2011). The MRF model with commonly used turbulence model is suitable for simulating flow parameters of velocity field near the impellers (Harvey et al, 1995).…”

Section: Cdf Simulationmentioning

confidence: 99%

A Study of CFD Simulations of the Flow Pattern in an Agitated System with a Pitched Blade Worn Turbine

Skočilas¹,

Fořt²,

Jirout³

2013

Chemical and Process Engineering

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This paper presents a numerical analysis of an agitated fully baffled cylindrical vessel with a down pumping four blade worn or unworn pitched blade impeller (α = 45° and 30°) under a turbulent flow regime. CFD simulations predict the pumping capacity of the system equipped by worn and unworn pitched blade impeller. Experimental data were taken from the authors' previous work and compared with results of numerical computations. A good agreement with experimental data was obtained. The ensemble-average mean velocity field with worn and unworn impellers was computed. It follows from the simulation results that the wear rate of the impeller blade has a significantly negative effect on the velocity distribution in an agitated liquid. The greater the destruction of the worn blade, the higher is the deformation of the velocity field around the rotating impeller, with a simultaneous decrease in impeller pumping capacity.

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“…Assuming three-dimensional viscous flow through the turbine, the continuity equation and the Navier-Stokes [17][18][19] equations were used for numerical simulation as follows:…”

Section: Turbulence Modelmentioning

confidence: 99%

Bidirectional Power Performance of a Tidal Unit with Unilateral and Double Guide Vanes

Yang

Zheng²,

Zhou

et al. 2013

Advances in Mechanical Engineering

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To improve the bidirectional power performance of a tidal unit, two designs were investigated. The use of unilateral or double guide vanes in a tubular tidal unit influences the performance of the hydraulic unit. Based on the N-S equations and the RNGturbulence model, the SIMPLEC algorithm was used for 3D steady-state numerical simulation of the entire turbine flow passage with unilateral and double guide vanes. The internal flow condition under positive and reverse power generation conditions was also analyzed. At the same time, the turbine, with a runner 1.6 m in diameter, was scaled down to 0.35 m diameter for model tests. The model tests were based on a multifunction hydromechanical test bench at Hohai University. The water head, discharge, and torque of the tubular turbine were, respectively, tested using a pressure difference sensor, electromagnetic flow meter, and torque meter under different guide-vane openings. The results show that turbine efficiency in the model test is slightly lower than that predicted by numerical simulation under the same conditions. However, the difference is not large. With double side guide vanes, although the efficiency of positive power generation decreased, the efficiency of reverse power generation is greatly improved.

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CFD prediction of fluid flow and mixing in stirred tanks: Numerical issues about the RANS simulations

Cited by 157 publications

References 45 publications

CFD Prediction of Gas-Liquid Flow in an Aerated Stirred Vessel Using the Population Balance Model

CFD Prediction of Gas-Liquid Flow in an Aerated Stirred Vessel Using the Population Balance Model

A Study of CFD Simulations of the Flow Pattern in an Agitated System with a Pitched Blade Worn Turbine

Bidirectional Power Performance of a Tidal Unit with Unilateral and Double Guide Vanes

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