Effect of the Rotating Reference Frame Size for Simulating a Mixing Straight-Blade Impeller in a Baffled Stirred Tank.

Concha-Gómez, Aarón D. De La; Ramírez-Muńoz, J.; Márquez-Baños, Valaur E.; Haro, C.; Alonso-Gómez, A.R.

doi:10.24275/uam/izt/dcbi/revmexingquim/2019v18n3/delaconcha

Cited by 10 publications

(6 citation statements)

References 33 publications

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“…Deviations in the flow field prediction dependent on the rotating reference frame size have been reported in several studies [22,40,41], leading to the general conclusion to enlarge the dimension of the rotating part toward a region where the flow variables' gradient is low to reduce numerical errors due to interpolation inaccuracies in transferring the results between both domains. Some authors suggest locating the interface between the rotating and stationary frame 0.5 impeller radius from the impeller tip, whereas others recommend a ratio of 1.5 [21,40]. For this study, a D-ratio between 1.5 and 2.0 is considered appropriate, as higher RRF diameters would place the interface of the RRF too close to the baffles, where too-high velocity gradients exist.…”

Section: Steady State Simulationsmentioning

confidence: 99%

Validation of Novel Lattice Boltzmann Large Eddy Simulations (LB LES) for Equipment Characterization in Biopharma

et al. 2021

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Detailed process and equipment knowledge is crucial for the successful production of biopharmaceuticals. An essential part is the characterization of equipment for which Computational Fluid Dynamics (CFD) is an important tool. While the steady, Reynolds-averaged Navier–Stokes (RANS) k − ε approach has been extensively reviewed in the literature and may be used for fast equipment characterization in terms of power number determination, transient schemes have to be further investigated and validated to gain more detailed insights into flow patterns because they are the method of choice for mixing time simulations. Due to the availability of commercial solvers, such as M-Star CFD, Lattice Boltzmann simulations have recently become popular in the industry, as they are easy to set up and require relatively low computing power. However, extensive validation studies for transient Lattice Boltzmann Large Eddy Simulations (LB LES) are still missing. In this study, transient LB LES were applied to simulate a 3 L bioreactor system. The results were compared to novel 4D particle tracking (4D PTV) experiments, which resolve the motion of thousands of passive tracer particles on their journey through the bioreactor. Steady simulations for the determination of the power number followed a structured workflow, including grid studies and rotating reference frame volume studies, resulting in high prediction accuracy with less than 11% deviation, compared to experimental data. Likewise, deviations for the transient simulations were less than 10% after computational demand was reduced as a result of prior grid studies. The time averaged flow fields from LB LES were in good accordance with the novel 4D PTV data. Moreover, 4D PTV data enabled the validation of transient flow structures by analyzing Lagrangian particle trajectories. This enables a more detailed determination of mixing times and mass transfer as well as local exposure times of local velocity and shear stress peaks. For the purpose of standardization of common industry CFD models, steady RANS simulations for the 3 L vessel were included in this study as well.

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Section: Steady State Simulationsmentioning

confidence: 99%

Validation of Novel Lattice Boltzmann Large Eddy Simulations (LB LES) for Equipment Characterization in Biopharma

et al. 2021

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“…The dependency of turbulent models on numerical consideration for agitated vessels with impeller has been faced only in a very limited number of research studies. Due to technical limitations in the past, mixers were usually solved with low grid resolutions [145,271,272]. The recent availability of very powerful clusters and multi-core workstations allows the conduction of systematic research studies on the evaluation of the numerical error with respect to the models' assumptions and approximations.…”

Section: Cfd Models Any Turbulence In Rotary Mixersmentioning

confidence: 99%

“…Other researchers set the zones interface at the axial location about 0.5 radius above and below impeller, while the radial distance was set at 1.5 impeller radius [67]. In [272], the authors evaluated four various cylindrical zones around the impeller by varying axial (in the range 0.62 R up to 1.27 R) and radial (in the range 1.11 R up to 1.43 R) distance from the impeller. The researchers conclude that in order to perform reliable CFD simulation, the rotating zone has to include the locations where the flow motion shifts from accelerating to decelerating.…”

Section: Impeller Rotation Modellingmentioning

confidence: 99%

“…In [269], it has been found that at the very low Reynolds number MRF interface location has no significant impact in the results, but it starts to play a significant role when the Reynolds number raises above 29.4. According to various studies [67,269,272,300] the size of the rotating domain dependents on the fluid flow regime and for higher Reynolds number RRF has to be enlarged. Authors also found that numerical results for velocity vector and power number are more sensitive to the size of the rotating reference frame than to the mesh resolution.…”

Section: Impeller Rotation Modellingmentioning

confidence: 99%

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A General Review of the Current Development of Mechanically Agitated Vessels

Jaszczur

Młynarczykowska

2020

Processes

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The mixing process in a mechanically agitated vessel is a widespread phenomenon which plays an important role among industrial processes. In that process, one of the crucial parameters, the mixing efficiency, depends on a large number of geometrical factors, as well as process parameters and complex interactions between the phases which are still not well understood. In the last decade, large progress has been made in optimisation, construction and numerical and experimental analysis of mechanically agitated vessels. In this review, the current state in this field has been presented. It shows that advanced computational fluid dynamic techniques for multiphase flow analysis with reactions and modern experimental techniques can be used with success to analyse in detail mixing features in liquid-liquid, gas-liquid, solid-liquid and in more than two-phase flows. The objective is to show the most important research recently carried out.

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“…A pesar de la alta precisión de los métodos no estacionarios su costo computacional es muy elevado, una alternativa son los métodos estacionarios en los cuales el impulsor se mantiene estático en la simulación y el campo de velocidades en rotación puede ser aproximado usando los siguientes enfoques (Joshi et al, 2011): condiciones de Frontera de Impulsor (IBC, Impeller Boundary Condition), termino Fuente (SS, Source-Sink approach), o marcos de referencia múltiples (MRF, Multiple Reference Frame). Este último ha sido ampliamente estudiado y aplicado en numerosos trabajos, (Jaworski and Dudczak, 1998;Bujalski et al, 2002;Ramírez-Gómez et al, 2015;De La Concha-Gómez et al, 2019) mostrando que es capaz de proporcionar resultados comparables a los obtenidos en enfoques como el SM pero con un tiempo de cómputo de un orden de magnitud menor (Oshinowo et al, 1999), con la limitante de que la interacción con los bafles o demás piezas estáticas sea baja (Oshinowo et al, 2000).…”

Section: Modelo De Múltiples Marcos De Referencia (Mrf)unclassified

Estudio hidrodinámico de tanques agitados para la producción de recubrimiento blanco base agua

Mendoza¹,

Pamela²

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In the present work, a university-industry linkage project was carried out in which the hydrodynamic performance of three existing impellers in agitated tanks in a Paint manufacturing plant of the company Axalta Coating Systems is compared. These are 45 ° inclined four vane impeller (PBT4), 35 ° inclined six vane impeller (PBT6), and Chemineer type curved tip three inclined vane high efficient impeller (HE3). For this, Computational Fluid Dynamics and experimental measurements of power consumption were used. The study was carried out in a 4-liter cylindrical tank operating in a turbulent regime (Reynolds numbers greater than 14,000) using two types of fluids; water and white coating like Newtonian fluid and slimming fluid. In all the simulations and experimental validations, geometric similarity was maintained with the existing conditions in the plant. An analysis of mesh independence was carried out, comparing meshes with an increase of twice the number of elements, in which the one with the least variability of the hydrodynamic properties with respect to the previous one was chosen. Once the independent mesh was obtained, the speed fields, the dependence of the power numbers (NP) and pumping numbers (NQ) of each of the impellers under study were obtained at different operating conditions similar to those existing in the plant. It was found that in turbulent regime for both Newtonian and non-Newtonian fluid, the power number is higher for the PBT4 impeller and the lower for the PBT6. For both fluids, the pumping number was higher for the PBT4 impeller and the lowest was obtained for the PBT6. The mixing effectiveness ratio (NQ/NP) that was found is that Chemineer's HE3 impeller has the highest value for Newtonian fluid, while for non-Newtonian fluid, the values are very similar for PBT4 and HE3 impellers. For the specific case study of this work, it was concluded that for the homogenization of a white coating manufactured in the company Axalta Coating Systems using the PBT4 and HE3 impellers they would have a very similar performance, while the PBT6 impeller would have the worst performance. Considering that the PBT4 impeller is a general purpose agitator and can be used in a large number of applications, and furthermore, it is easier to manufacture and its cost is lower, the PBT4 agitator would have a better performance than the HE3 impeller.

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Effect of the Rotating Reference Frame Size for Simulating a Mixing Straight-Blade Impeller in a Baffled Stirred Tank.

Abstract: Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo intemperizados en suelos y sedimentos (Biodegradation modeling of sludge bioreactors of total petroleum hydrocarbons weathering in soil and sediments)

Cited by 10 publications

References 33 publications

Validation of Novel Lattice Boltzmann Large Eddy Simulations (LB LES) for Equipment Characterization in Biopharma

Validation of Novel Lattice Boltzmann Large Eddy Simulations (LB LES) for Equipment Characterization in Biopharma

A General Review of the Current Development of Mechanically Agitated Vessels

Estudio hidrodinámico de tanques agitados para la producción de recubrimiento blanco base agua

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