CFD prediction of liquid homogenisation in a gas–liquid stirred tank

Jahoda, M.; Tomášková, L.; Moštěk, M.

doi:10.1016/j.cherd.2008.12.006

Cited by 69 publications

(29 citation statements)

References 19 publications

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“…The CFD-predicted mixing times have been in good agreement with the experimental data reported by some researchers [9,10], while in some other studies [11,12] they are up to two times longer than the measure ones. In the recent 3-5 years, studies on the macro-mixing in stirred tanks for either solid-liquid [13] or gas-liquid [14,15] two-phase flows using experimental or CFD methods have been performed, and the results obtained from the two methods are mostly in good agreement. This means that the macro-mixing process in the single-or two-phase stirred vessels could be well predicted by the CFD method.…”

Section: Introductionmentioning

confidence: 85%

Experimental and Numerical Studies of the Flow Field in a Stirred Tank Equipped with Multiple Side‐Entering Agitators

2011

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The flow field and the macro-mixing process in a stirred tank equipped with four side-entering agitators were investigated experimentally and numerically. Experiments were conducted using two-dimensional particle image velocimetry (PIV) measurements to characterize the flow field at different positions in the vessel. The computational fluid dynamics (CFD) simulation was performed by the software Fluent 6.3, using the standard k-e turbulent model and the multiple reference frame together with the sliding mesh technique. The macro-mixing process was also discussed using CFD and decolorization experiments. The effects of the tracer detection positions and some mounting parameters in the mixing system were discussed. The results show that the mixing process was dominated by the flow field pattern in the stirred tank. According to the mixing times under different conditions using CFD simulation, the mounting parameters including inclination angle, plunging length and mounting height of the shaft were optimized.

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Section: Introductionmentioning

confidence: 85%

Experimental and Numerical Studies of the Flow Field in a Stirred Tank Equipped with Multiple Side‐Entering Agitators

2011

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“…The MRF method simulates the flow for fixed position of the agitator relative to the vessel [25,26]. In this method the solution domain is divided into two regions, namely, inner and outer region.…”

Section: Cfd Simulationmentioning

confidence: 99%

Formation of pre-coating dynamic membrane on mesh filter by cross-flow filtration of PAC–water suspension in a bioreactor: experimental and modeling

Poostchi¹,

Bayat²,

Rezaei³

et al. 2014

Desalination and Water Treatment

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A B S T R A C TThis study presents a closed-loop process for forming pre-coated dynamic membrane used in membrane bioreactor. Powder-activated carbon (PAC) particles are suspended by using axial-flow agitator whilst simultaneously deposited upon the filter medium by cross-flow filtration. The revolution speed of agitator is varied in the range of 150-450 rpm. Computational fluid dynamic is used to calculate velocity and shear rate adjacent to membrane surface. The force balance of the particles considers the driving force of dynamic membrane formation, drag force due to negative pressure-driven of suction pump, lift force due to mechanical mixing, and adhesive force due to particle-particle interactions. The effect of two major terms including drag and lift forces on the porosity of dynamic membrane is systematically investigated. The lower drag force results in the higher porosity of dynamic membrane. The results also show that the denser dynamic membrane is formed when the lift force becomes lower. The porosity of dynamic membrane is ranged from 0.38 to 0.46 while the thickness of dynamic membrane is altered between 100 and 500 μm. A dimensionless immobilized parameter is derived to predict the formation of pre-coating dynamic membrane. The results obtained from modeling show that dynamic membranes formed at higher values of immobilization parameter have a more cohesive structure. The results obtained from the experiments and the model reveal that the thickness of 400 μm of PAC layer is considered as a stability threshold thereafter the structure of dynamic membrane becomes loose and unstable. The rejection capacity of dynamic membrane is also evaluated at different thicknesses by using Formazin solution. The results reveal that the turbidity of filtrate decreases with increasing the thickness of dynamic membrane. The results display that rejection capacity of pre-coating dynamic membrane is comparable to that of microfiltration membrane.

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“…The mathematical model equations are solved by Fluent 6.3 . To solve the governing partial differential equations for the conservation of mass, momentum, and scalars such as turbulence in integral form, a control‐volume technique and SIMPLE procedure were used.…”

Section: Vof Modelmentioning

confidence: 99%

Optimization of mixing parameters for a cold model system by CFD for aluminum matrix composites synthesis process

Sun

Liu

et al. 2016

Can J Chem Eng

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Stir casting process is the most important method in the aluminum matrix composites synthesis industry. In the stir casting process, the stability of the liquid aluminum surface and the highest shear force induced by the impellers are the two main factors for high quality of aluminum matrix composites synthesis. In this paper, a three‐dimensional CFD model validated on a water and air two‐phase flow system in a cold model was used to optimize the mixing string tank for aluminum matrix composites synthesis, coupling the volume of fluid (VOF) model, the k‐ϵ turbulence model, and the multiple reference frames (MRF) model. Important mixing parameters of the gas‐liquid two‐phase stirred tank such as rotation speed, type of baffles, and angle of rotating impellers were simulated and analyzed in detail. Varieties of speed were investigated to choose the best one. The best stirrer was chosen through analyzing the stability of liquid aluminum and shear force induced by impellers. The results showed that the optimal stirring speed was 180 rpm during studying the surface between liquid and gas. The best baffles with the lowest vortex were obtained through simulation, with dimensions of 50 mm × 20 mm × 350 mm. In order to get the lowest vortex between water and air and the strongest shear force, the blades should be installed at 15° with vertical direction.

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CFD prediction of liquid homogenisation in a gas–liquid stirred tank

Cited by 69 publications

References 19 publications

Experimental and Numerical Studies of the Flow Field in a Stirred Tank Equipped with Multiple Side‐Entering Agitators

Experimental and Numerical Studies of the Flow Field in a Stirred Tank Equipped with Multiple Side‐Entering Agitators

Formation of pre-coating dynamic membrane on mesh filter by cross-flow filtration of PAC–water suspension in a bioreactor: experimental and modeling

Optimization of mixing parameters for a cold model system by CFD for aluminum matrix composites synthesis process

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