Numerical simulation of transient power consumption characteristics in an unbaffled stirred tank

Li, Liangchao; Ke-feng, Xiang; Xiang, Baoqiang

doi:10.1007/s11696-020-01115-3

Cited by 5 publications

(4 citation statements)

References 31 publications

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“…A few studies have covered the underlying mixing dynamics within an unbaffled stirred vessel (Busciglio, Grisafi, Scargiali, & Brucato, 2014). Some of them are devoted to the laminar regime (Guadarrama-Pérez et al, 2020;Lamberto, Alvarez, & Muzzio, 1999) and a few more deal with the turbulence regime (Glover & Fitzpatrick, 2007;Li, Wang, Feng, & Gu, 2017;Li, Xiang, & Xiang, 2020;Martínez-de Jesús, Ramírez-Muñoz, García-Cortés, & Cota, 2018). For instance, Li et al (2017) coupled a volume-of-fluid method to a Reynolds stress model to capture the gas-liquid interface and turbulent flow agitated by pitched blade turbines where the interface deflection reached the impeller hub.…”

Section: Introductionmentioning

confidence: 99%

The transition to aeration in turbulent two-phase mixing in stirred vessels

Kahouadji

Liang

Valdés

et al. 2022

Flow

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We consider the mixing dynamics of an air–liquid system driven by the rotation of a pitched blade turbine (PBT) inside an open, cylindrical tank. To examine the flow and interfacial dynamics, we use a highly parallelised implementation of a hybrid front-tracking/level-set method that employs a domain-decomposition parallelisation strategy. Our numerical technique is designed to capture faithfully complex interfacial deformation, and changes of topology, including interface rupture and dispersed phase coalescence. As shown via transient, a three-dimensional (3-D) LES (large eddy simulation) using a Smagorinsky–Lilly turbulence model, the impeller induces the formation of primary vortices that arise in many idealised rotating flows as well as several secondary vortical structures resembling Kelvin–Helmholtz, vortex breakdown, blade tip vortices and end-wall corner vortices. As the rotation rate increases, a transition to ‘aeration’ is observed when the interface reaches the rotating blades leading to the entrainment of air bubbles into the viscous fluid and the creation of a bubbly, rotating, free surface flow. The mechanisms underlying the aeration transition are probed as are the routes leading to it, which are shown to exhibit a strong dependence on flow history.

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Section: Introductionmentioning

confidence: 99%

The transition to aeration in turbulent two-phase mixing in stirred vessels

Kahouadji

Liang

Valdés

et al. 2022

Flow

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“…Numerous CFD techniques have been used to study reactors with baffles, which is not the situation for unbaffled reactors. A few uses of CFD in unbaffled reactors are accessible in the works [24][25][26]. Some are offered to the laminar regime unbaffled reactors [24].…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamics Analysis of Mixing Process in Fermenter

Novia Novia,

Jerry Hardian,

Richard Sepriyadi Osman

et al. 2023

ARFMTS

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The perfect mixing process ensures the ideal substrate conditions for microorganisms to live to produce ethanol in the fermenter. The critical factors that affect the mixing process are the agitation speed, baffle configuration, and the impeller type. The Computational Fluid Dynamics (CFD) software can make the study of fermenter hydrodynamics more convenient due to the cost savings of expensive apparatus and less time-consuming. This study aimed to examine the hydrodynamic characteristics of a fermenter using the ANSYS FLUENT 2021 R1 software and its validation. The hydrodynamics of the mixing process in the dual-pitched blade impeller bioethanol fermenter in agitation speeds of 200 to 1000 RPM and the effect of baffles were observed by simulation and experimentally. The realizable k-epsilon turbulence model and the Eulerian volume of fluid mixture multiphase model were used in this CFD simulation. The simulation results were relatively close to the experimental with similar flow patterns and low mixing time error, which is 7.9% on average. The results show that the higher the agitation speed, the higher the torque, power, and shear stress. The increasing agitation speed caused the lower mixing time. A faster mixing time was obtained in the fermenter with no baffle configuration.

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“…For instance, ref. [9] presented numerical simulations to investigate transient power consumption characteristics in a stirred tank without baffles. The transient power number was analyzed based on the predicted impeller torque.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study and Geometric Investigation of the Influence of Rectangular Baffles over the Mixture of Turbulent Flows into Stirred Tanks

et al. 2022

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The present work aims to define strategies for numerical simulation of the mixture of turbulent flows in a stirred tank with a low computational effort, and to investigate the influence of the geometry of four rectangular baffles on the problem of performance. Two computational models based on momentum source and sliding mesh are validated by comparison with experimental results from the literature. For both models, the time-averaged conservation equations of mass, momentum and transport of the mixture are solved using the finite volume method (FVM) (FLUENT® v.14.5). The standard k–ε model is used for closure of turbulence. Concerning the geometrical investigation, constructal design is employed to define the search space, degrees of freedom and performance indicators of the problem. More precisely, seven configurations with different width/length (L/B) ratios for the rectangular baffles are studied and compared with an unbaffled case. The momentum source model leads to valid results and significantly reduces the computational effort in comparison with the sliding mesh model. Concerning the design, the results indicate that the case without baffles creates the highest magnitude of turbulence kinetic energy, but poorly distributes it along the domain. The best configuration, (L/B)o = 1.0, leads to a mixture performance nearly two times superior than the case without baffles.

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Numerical simulation of transient power consumption characteristics in an unbaffled stirred tank

Cited by 5 publications

References 31 publications

The transition to aeration in turbulent two-phase mixing in stirred vessels

The transition to aeration in turbulent two-phase mixing in stirred vessels

Hydrodynamics Analysis of Mixing Process in Fermenter

Numerical Study and Geometric Investigation of the Influence of Rectangular Baffles over the Mixture of Turbulent Flows into Stirred Tanks

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