CFD simulation of flow and mixing characteristics in a stirred tank agitated by improved disc turbines

Jia, Zhuotai; Xu, Lele; Duan, Xiaoxia; Mao, Zai‐Sha; Zhang, Qinghua; Yang, Chao

doi:10.1016/j.cjche.2022.05.017

Cited by 14 publications

(10 citation statements)

References 33 publications

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“…The predicted ungassed power number against experimental data of the three turbine impellers is plotted as a function of Re in Figure . Our previous study has found that both improved impellers have lower power consumption with Re ranging from 3.95 × 10 4 to 11.88 × 10 4 under the ungassed condition, as shown in Figure . It is noted that compared to PDT ( N p = 1.46), the value of N p for SFPDT ( N p = 1.34) and SPDT ( N p = 0.95) decreased by 9 and 34%, respectively.…”

Section: Resultsmentioning

confidence: 88%

“…Validation of the CFD predicted power number with experimental data (single phase, N = 2–6 r·s –1 ).…”

Section: Resultsmentioning

confidence: 99%

“…Figure shows the geometric structures of PDT, SPDT, and SFPDT. More geometry details can be found in our previous work . All turbine impellers rotate in a counter-clockwise direction (the concave surface of the blade pushing the fluid).…”

Section: Methodsmentioning

confidence: 99%

“…The standard k-ε model was used for the single-phase simulation, while other setting details can be found in our previous study . The steady-state Reynolds-averaging formulation of the Eulerian–Eulerian two-fluid model equations was adopted to describe the gas–liquid flow behavior in an aerated vessel as follows which was solved for each phase consecutively in a coupled way.…”

Section: Numerical Approachmentioning

confidence: 99%

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Experimental and Numerical Investigation of the Characteristics of Novel Disc Turbines in Aerated Stirred Tanks

Jia

Zhang

Guo

et al. 2023

Ind. Eng. Chem. Res.

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In this work, the gas dispersion and transport characteristics of three different disc turbines, namely, parabolic disc turbine (PDT), novel swept-back parabolic disc turbine (SPDT), and staggered fan-shaped parabolic disc turbine (SFPDT), are characterized by experiments and two-fluid model/RANS simulations. The physical explanation of the superior power characteristics of SFPDT and SPDT is elaborated using the pressure distribution and drag force coefficient on a blade surface. Gas−liquid performance parameters such as critical dispersion speed, relative power demand (RPD), and volumetric mass transfer coefficient are assessed under different conditions. The results show that SFPDT and SPDT can produce smaller flow separation regions and trailing vortices, resulting in smaller gas cavities under aeration conditions. SFPDT has the lowest critical dispersion speed under a high flow rate, while SPDT consumes the least power. Both SFPDT and SPDT exert roughly 7% higher gassed power input than PDT under aeration conditions and have higher efficiency on gas−liquid mass transfer than PDT. Moreover, empirical correlations from experimental data for SFPDT and SPDT are presented to provide a reference to the design of industrial stirred tanks.

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Section: Resultsmentioning

confidence: 88%

“…Validation of the CFD predicted power number with experimental data (single phase, N = 2–6 r·s –1 ).…”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Numerical Approachmentioning

confidence: 99%

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Experimental and Numerical Investigation of the Characteristics of Novel Disc Turbines in Aerated Stirred Tanks

Jia

Zhang

Guo

et al. 2023

Ind. Eng. Chem. Res.

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“…Stirred tanks are usually involved in various industrial operations such as mixing, heat transfer, mass transfer, and chemical reactions, − and widely used in metallurgy, pharmaceutical, wastewater treatment, and polymer engineering. − As an essential accessory of the stirred tank, the baffle is installed to avoid the formation of surface vortex caused by the centrifugal force generated by the rotating stirrer, so that the circumferential flow colliding with the baffle is turned into axial flow upward or downward to strengthen effectively the mixing without changing the blade type and operating conditions . Baffles increase axial and radial circulation of the liquid in the tank and improve the overall flow of the liquid compared to an unbaffled stirred tank. , …”

Section: Introductionmentioning

confidence: 99%

Enhancement of Macromixing Performance of a Stirred Tank with a Novel V-Shaped Punched Baffle

Jia

Guo

et al. 2023

Ind. Eng. Chem. Res.

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A V-shaped punched baffle (VSPB) is developed to enhance fluid mixing in a stirred tank by producing impinging jet streams from face-to-face holes. Macromixing experiments and computational fluid dynamics (CFD) simulations are conducted with water and 0.5 wt % hydroxyethyl cellulose (HEC) solution as fluid to compare the performance of a standard baffle (SB), standard punched baffle (SPB) and VSPB. The experimental results show that the mixing time of VSPB is reduced by a maximum of 23 and 14.7% compared with those of SB and SPB at low speeds, respectively. With increasing stirring speed, the mixing time of all three baffles tends to be the same, but the power consumption of VSPB is less than that of SB and SPB with a Rushton turbine (RT). The simulation results show that the punched baffle can significantly increase the tangential velocity and turbulent kinetic energy of the fluid in the baffle region. Moreover, tiny vortices are at the back side of the punched baffles when the fluid is water. However, for a HEC solution, the flow field near the tank wall becomes disordered due to shear action caused by baffles and forms irregular vortices.

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Computational Fluid Dynamics

Paschedag¹

2023

Ullmann's Encyclopedia of Industrial Chemistry

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CFD simulation of flow and mixing characteristics in a stirred tank agitated by improved disc turbines

Cited by 14 publications

References 33 publications

Experimental and Numerical Investigation of the Characteristics of Novel Disc Turbines in Aerated Stirred Tanks

Experimental and Numerical Investigation of the Characteristics of Novel Disc Turbines in Aerated Stirred Tanks

Enhancement of Macromixing Performance of a Stirred Tank with a Novel V-Shaped Punched Baffle

Computational Fluid Dynamics

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