Hydrodynamics characterization of the Maxblend impeller

Iranshahi, Arash; Devals, Christophe; Heniche, Mourad; Fradette, Louis; Tanguy, Philippe A.; Takenaka, Katsuhide

doi:10.1016/j.ces.2007.03.031

Cited by 58 publications

(61 citation statements)

References 18 publications

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“…It is believed that the large-diameter close-clearance impellers, such as helical-ribbon and anchor impellers, give rise to good mixing in the entire mixing vessels for such applications [7,8]. In laminar mixing of highly viscous fluids, the mixing is obtained by a sequence of stretching, folding and breaking mechanisms and not by highly energetic eddies, which makes the design of an optimal mixing device very challenging [9]. The anchor impellers have been widely used in the chemical industry for the mixing of non-Newtonian fluids [10,11].…”

Section: Introductionmentioning

confidence: 99%

CFD Investigation of the Mixing of Yield‐Pseudoplastic Fluids with Anchor Impellers

Prajapati

Ein‐Mozaffari

2009

Chem Eng & Technol

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The study was carried out to simulate the 3D flow domain in the mixing of pseudoplastic fluids possessing yield stress with anchor impellers, using a computational fluid dynamics (CFD) package. The multiple reference frames (MRF) technique was employed to model the rotation of the impellers. The rheology of the fluid was approximated using the Herschel-Bulkley model. To validate the model, the CFD results for the power consumption were compared to the experimental data. After the flow fields were calculated, the simulations for tracer homogenization were performed to simulate the mixing time. The effects of impeller speed, fluid rheology, and impeller geometry on power consumption, mixing time, and flow pattern were explored. The optimum values of c/D (impeller clearance to tank diameter) and w/D (impeller blade width to tank diameter) ratios were determined on the basis of minimum mixing time.

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Section: Introductionmentioning

confidence: 99%

CFD Investigation of the Mixing of Yield‐Pseudoplastic Fluids with Anchor Impellers

Prajapati

Ein‐Mozaffari

2009

Chem Eng & Technol

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“…The details of the CFD methodology are discussed in Iranshahi et al . [4] Using the computed velocity field at Re = 40, the potential of dispersion of each design was evaluated using a cluster of 5000 tracers that was injected in the unmixed lower region (Fig. 2).…”

Section: Methodsmentioning

confidence: 99%

“…In particular, it was found by Iranshahi et al . [4] that two recirculation zones formed behind the bottom paddle in the laminar regime (Fig. 2).…”

Section: Introductionmentioning

confidence: 99%

Effect of the geometry on the performance of the Maxblend^™ impeller with viscous Newtonian fluids

Guntzburger

Fradette

Farhat

et al. 2009

Asia-Pacific J Chem Eng

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Experimental and numerical investigations have been carried out to assess the effect of the vessel geometry (number of baffles) and the shape of the Maxblend impeller (configuration of the bottom paddle and angle of the upper grid) with viscous Newtonian fluids in the laminar and lower turbulent mixing regimes. Two parameters have been explored namely the power consumption of the impeller and the mixing time. Videos of the discoloration process have also been taken to get access to the mixing patterns. A nominal 50-l vessel has been used in the experiments. The number of baffles has been varied from 1 to 4, and the bottom paddle has been modified by making openings to allow flow passage. Finally, the effect of using a straight grid in the upper part of the Maxblend has been studied under the same conditions. It is shown that the number of baffles does not have a significant effect on the power consumption, the mixing evolution, and the mixing time regardless of the flow regime. Making openings in the bottom paddle allows for the destruction of the segregated zones at the bottom of the tank at the expense of a very slight increase in power consumption and mixing time. Finally, the power and mixing time are both increased with a straight grid Maxblend.

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“…Iranshahi et al determined the power number of the agitator experimentally in a specific system using Maxblend impeller and pointed out that the value depends on the number of baffles, therefore, the geometry of the vessel [21]. However, finding the exact correlation between the power number and the geometry requires detailed inspection on that matter.…”

Section: Introductionmentioning

confidence: 99%

CFD Based Qualification of Mixing Efficiency of Stirred Vessels

Till

Molnár²,

Egedy

et al. 2018

Period. Polytech. Chem. Eng.

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In this work, we focus on the most crucial units in a chemical technology, the chemical reactors. Using a commercially available CFD software package, COMSOL Multiphysics, 3D mathematical models of a batch reactor with different impeller geometries have been investigated. The reasonable agreement between the experimental and simulation results indicates the validity of the developed CFD model. The effect of the impeller design, e. g. number of blades on the mixing efficiency is evaluated based on the simulation studies.The proposed measure to determine the energy efficiency of mixing (i. e. mixing index) is based on the calculated velocity field and energy usage. The information about the homogeneity of the mixed phase in the system can be extracted from the developed velocity field. Hence, we proposed histograms of velocity fluctuations on a logarithmic scale as an efficient tool to measure the achieved homogeneity of the phase in case of different impellers and rotational speeds. IntroductionDuring the last few decades, computational fluid dynamics (CFD) method has become a very powerful tool in the process industry primarily to analyse the hydrodynamic behavior. In general, CFD methods rely on the numerical solution of the Navier-Stokes equations, thus flow velocity, velocity magnitudes, and pressure values can be calculated in the geometric space investigated. A particularly significant benefit of the CFD simulators is that they can include entire apparatuses in three dimensions, regarding either single phase or multiphase systems [1,2]. This property of the CFD simulators makes them useful in a large number of research areas, including the study of mixing phenomena. Fluid mixing is a fundamental operation in the chemical process industry and the stirred tank or autoclave is a commonly used reactor type in many kinds of chemical technologies; therefore these systems are well described. Regardless, when it comes to design work, simple experimental correlations are still commonly used, e.g. Reynolds number, Froude number, power number or the Euler number which is derived from the previous ones. This approach has its limitations when it comes to the design of stirred vessels with complex internal structure.

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Hydrodynamics characterization of the Maxblend impeller

Cited by 58 publications

References 18 publications

CFD Investigation of the Mixing of Yield‐Pseudoplastic Fluids with Anchor Impellers

CFD Investigation of the Mixing of Yield‐Pseudoplastic Fluids with Anchor Impellers

Effect of the geometry on the performance of the Maxblend^™ impeller with viscous Newtonian fluids

CFD Based Qualification of Mixing Efficiency of Stirred Vessels

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Hydrodynamics characterization of the Maxblend impeller

Cited by 58 publications

References 18 publications

CFD Investigation of the Mixing of Yield‐Pseudoplastic Fluids with Anchor Impellers

CFD Investigation of the Mixing of Yield‐Pseudoplastic Fluids with Anchor Impellers

Effect of the geometry on the performance of the Maxblend™ impeller with viscous Newtonian fluids

CFD Based Qualification of Mixing Efficiency of Stirred Vessels

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Effect of the geometry on the performance of the Maxblend^™ impeller with viscous Newtonian fluids