Solid-liquid suspension in a stirred tank driven by an eccentric-shaft: Electrical resistance tomography measurement

Yang, Fengli; Zhang, Cuixun; Sun, Haiyao; Liu, Wenping

doi:10.1016/j.powtec.2022.117943

Cited by 5 publications

(4 citation statements)

References 77 publications

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“…As w increases, the dispersion of particles in the stirred tank becomes faster. This is due to the fact that a larger w induces strong shear and turbulence effects that drive the particles to be suspended and dispersed quickly; this phenomenon is also demonstrated in Yang et al’s work . As shown in Figure b, σ fluctuates within a certain range at different w when t > 2.5 s. Also, the fluctuation of σ is much higher for 500 rpm.…”

Section: Results and Discussionsupporting

confidence: 61%

“…This is due to the fact that a larger w induces strong shear and turbulence effects that drive the particles to be suspended and dispersed quickly; this phenomenon is also demonstrated in Yang et al's work. 47 As shown in Figure 13b, σ fluctuates within a certain range at different w when t > 2.5 s. Also, the fluctuation of σ is much higher for 500 rpm. This is because when the particle distribution in the stirred tank reaches a pseudosteady state, the vortex continues to become larger at high rotation speed, the height of the liquid level rises, and the centrifugal force on the particles is enhanced, resulting in the particles being thrown to the boundary of the stirred tank, as shown in Figure 13c.…”

Section: Fluid Flowmentioning

confidence: 75%

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Discrete Element Method–Volume of Fluid Simulation of Drawdown and Dispersion for Floating Particles in Stirred Tanks: Influences of Impeller Parameters

Li,

Zhang,

et al. 2024

Ind. Eng. Chem. Res.

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Exploring the drawdown and dispersion behaviors of particles in stirred tanks can provide insights and valuable references for optimizing the design of equipment and improving the efficiency of the stirring process. In this article, the kinetic behaviors of drawdown and dispersion of floating particles in the stirred tank were simulated by the DEM-VOF (discrete element method−volume of fluid) model. The influences of impeller parameters (blade number n, rotation speed w, eccentric distance l, and off-bottom clearance h) on the granular characteristics (particle distribution, coupling force, total force, and translational/rotational kinetic energies), fluid dynamics (fluid velocity and turbulent kinetic energy), and gas−liquid free surface were investigated. The results show that the drawdown process of floating particles can be divided into the pull-down stage, dispersion stage, and cycle stage. With the increase in n, w, l, or h, the duration of the pull-down stage decreases, while the duration of the cycle stage increases. Due to the vortex effect and turbulent motion in the stirred tank, both the particle characteristics and flow dynamics change with the impeller parameters. Besides, large n or w, small l, and moderate h result in the deeper gas−liquid free surface.

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Section: Results and Discussionsupporting

confidence: 61%

Section: Fluid Flowmentioning

confidence: 75%

Discrete Element Method–Volume of Fluid Simulation of Drawdown and Dispersion for Floating Particles in Stirred Tanks: Influences of Impeller Parameters

Li,

Zhang,

et al. 2024

Ind. Eng. Chem. Res.

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“…Gao et al [22] explored chaotic mixing using an impeller rotating periodically. In their study, they focused on the effect of placing the impeller eccentrically inside the stirred tank on many parameters inside the tank [23]- [28]. The design of the impeller, depending on the type of application, must strike a balance between two parameters, for example, the power consumption and the mixing efficiency or mixing time.…”

Section: Introductionmentioning

confidence: 99%

Study the effect of a new design of a twisted impeller blade on the vortexes formation and power consumption using a centric and eccentric stirred tank experimentally and numerically

Salho,

Hamzah

2024

Preprint

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Vortex formation in stirred tanks is one of the problems facing many stirred tank designers. The current study depicts experimentally and numerically the effect of changing the impeller structure and its location in a twisted shape on the shape of the vortex, energy consumption, flow patterns, and turbulent kinetic energy. Numerically, the finite volume method was used, the mathematical model used the Volume of Fluid to simulate the free surface between air and water, and the mathematical model (k- ε ) was used to simulate turbulent flow. Rotational speeds of the impeller of different values between (150-450 RPM) were applied, noting the effect of changing the location of the impeller experimentally and numerically on the flow parameters and other parameters. The current study showed that the rate of deviation in the values of torque and energy consumption between the numerical and practical studies is relatively acceptable in addition to the convergence in the shape of the vortex. The results obtained showed that the shape and location of the impeller affect the shape of the vortex, and changing the rotation speed affects the growth and depth of the vortex. The study also showed that the amount of torque for the un-baffled stirred tank is less than that for the eccentric stirred tank, depending on the rotation speed. For example, at the rotation speed (350RPM) it was (0.034 N.m) and at the same speed, it was (0.093 N.m) for the eccentric location. The study also showed a comparison of flow patterns between the central and eccentric locations of the impeller.

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“…Electrical resistant tomography (ERT) is also a non-invasive measurement technique commonly used in the field of solid-liquid mixing. For example, Yang et al (2012) used ERT to obtain concentration data during agitation and studied the particle suspension performance of the proposed eccentric shaft agitation and two-half angular blade agitator. Mishra and Ein-Mozaffari (2016) used ERT to obtain solid-liquid mixing plane signals, reconstruct chromatographic images, evaluate the distribution of solid particles, and study the mixing performance of the Maxblend impeller in solid-liquid mixing (Mishra and Ein-Mozaffari, 2016).…”

Section: Introductionmentioning

confidence: 99%

Measurement of solid–liquid mixing quality by using a uniform design method based on image analysis

Yang

Wang

et al. 2023

Front. Energy Res.

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Solid–liquid mixing has been a common industrial process operation. The measurement of solid–liquid mixing quality can help improve the efficiency of related industrial processes, but there is still a lack of an intuitive, accurate, and simple measurement method. As an important indicator to evaluate the solid–liquid mixing quality, the degree of solid suspension and the uniformity of solid distribution are directly related to mass transfer and reaction efficiency. Therefore, it is necessary to study the solid suspension and distribution in a solid–liquid system. In this work, the solid suspension and distribution of a solid–liquid system composed of glass beads–water stirred by the impeller are studied experimentally via digital image processing combined with statistical analysis. Specifically, images of solid–liquid mixing are first obtained using a camera and digitally processed. The area ratio of the solid in the image is proposed to reflect the degree of solid suspension, and the modified L2-star discrepancy (MD) is then used to quantify the uniformity of the solid distribution. Then, the solid–liquid mixing quality can be characterized by combining the area ratio and solid distribution. The feasibility of this method was proved by qualitative analysis of the solid–liquid mixing state and comparison with known studies. In addition, the effects of various stirring factors on the solid distribution were studied and discussed by using the proposed method. The results show that the method proposed in this paper can measure the quality of the solid–liquid mixing state more directly and is effective and accurate. Furthermore, it was used to find the best experimental parameters in this work. This method is also simpler and cheaper than many other methods. It is of great significance to improve the efficiency of chemical and metallurgical and other industrial processes.

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Solid-liquid suspension in a stirred tank driven by an eccentric-shaft: Electrical resistance tomography measurement

Cited by 5 publications

References 77 publications

Discrete Element Method–Volume of Fluid Simulation of Drawdown and Dispersion for Floating Particles in Stirred Tanks: Influences of Impeller Parameters

Discrete Element Method–Volume of Fluid Simulation of Drawdown and Dispersion for Floating Particles in Stirred Tanks: Influences of Impeller Parameters

Study the effect of a new design of a twisted impeller blade on the vortexes formation and power consumption using a centric and eccentric stirred tank experimentally and numerically

Measurement of solid–liquid mixing quality by using a uniform design method based on image analysis

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