Flow Characteristics Related to Liquid/liquid Mixing Pattern in an Impeller-stirred Vessel

Tanaka, Ryo; Uddin, Md. Azhar; Kato, Yoshiei

doi:10.2355/isijinternational.isijint-2017-619

Cited by 12 publications

(6 citation statements)

References 25 publications

(30 reference statements)

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“…The acrylic hemispherical vessel with an inner diameter of T (m) without baffles was surrounded by an acrylic cuboid vessel filled with tap water to decrease the optical refraction index. [33][34][35][36] Liquid was charged into the hemispherical vessel in order to become bath depth, H L (m) = (3/5)T. The off-bottom clearance, C (m), was defined as the distance between the impeller and vessel bottom. The shaft centre of the impeller was set on the central axis of the hemispherical vessel and the up-pumping impeller was used in this study.…”

Section: Visual Observationmentioning

confidence: 99%

Suspension pattern and rising height of sedimentary particles with low concentration in a mechanically stirred vessel

et al. 2020

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In this study, the effects of impeller rotation speed, off-bottom clearance, blade angle, types of solid and liquid, etc., on the suspension pattern of sedimentary particles and particle rise height in liquid were investigated with a hemispherical vessel without baffles under low particle concentration. The transition conditions of suspension pattern between regimes I and II, and regimes II and III, were observed visually, and their non-dimensional equations were expressed with an acceptable correlation by varying the above operation factors a great deal. Here, regime I is stagnation of particles on a vessel bottom, II is partial suspension, and III is complete suspension in liquid. The non-dimensional equation of the maximum particle rise height was also successfully obtained. The combination of the non-dimensional equations of transition and maximum particle rise height permitted us to determine the adequate solid/liquid mixing operation conditions without collision of particles with device parts.

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Section: Visual Observationmentioning

confidence: 99%

Suspension pattern and rising height of sedimentary particles with low concentration in a mechanically stirred vessel

et al. 2020

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“…To understand the effect of impeller design on the refining process and optimally conduct it in an industrial application, some studies have been done. [5][6][7][8][9][10][11][12][13][14][15][16][17][17][18][19][20][21][22][23][24][25][26][27][28] Visuri et al [20] have given a comprehensive review in hot metal desulfurization and particularly summarized the previous contributions and work in progress on KRs. Song et al [21] conducted a particle image velocimetry (PIV) measurement to investigate the flow pattern induced by a 30-degree pitched paddle impeller for an aluminum-melting furnace.…”

Section: Introductionmentioning

confidence: 99%

“…Later, they [25] further studied the mechanism of surface vortex formation by an axial-flow impeller used in aluminum industries and found that the axial-flow impeller gives rise to a steeply curved shape vortex core around the impeller shaft. Ryo et al [6] investigated the flow characteristics of the liquid/liquid mixing mode in a stirred tank using a four-blade impeller for hot metal pretreatment in steelmaking industries. The results show that the flow patterns can be classified into three types and depend on the rotational velocity, but the influence of impeller shape was not discussed.…”

Section: Introductionmentioning

confidence: 99%

Computational Investigation on Effect of Impeller Dimension on Fluid Flow and Interface Behavior for Kanbara Reactor Hot Metal Treatment

Shen

Guo

et al. 2021

steel research int.

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Kanbara Reactor (KR) is widely used for hot metal desulfurization pretreatment in the steelmaking industry. The configuration of its impeller plays a crucial role in the reactor performance, but its function is not fully understood. Herein, a 3D volume of fluid (VOF) model coupled with the sliding mesh technique is developed, and the performance of five impellers with different dimensions is investigated. After the test of grid dependency, the calibration of turbulent models, and the validation via experiments, the numerical model is applied to study the typical developing phenomena and the effect of impeller dimension on the fluid flow characteristics, mixing time, interface profile, and vortex core depth. The results show that the centrifugal discharging flow extruded by the rotating impeller creates a double‐recirculation flow pattern in the axial direction. When the aspect ratio χ of the impeller increases, the upper recirculating region is successively strengthened and enlarged. Furthermore, the mixing time as a function of impeller configuration exists a minimum value. Impeller III is the optimal configuration in the current study. In addition, the relationship between vortex core depth and χ is obtained, and the velocity of the gas–liquid interface increases with the increase in χ.

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“…The simulation of KRs involves the impeller motion, which requires specified numerical tactics. In the current study, the sliding mesh method (SMM) [24][25][26][27][28][29] is adapted, and full transient simulations are carried out using two grid zones (see Figure 1). Compared with other technologies used to numerically deal with the region motion, such as the multiple reference frame (MRF) method, there are no additional source terms inserted into the momentum equations, e.g., centrifugal, Coriolis, and Euler forces, but the mesh will be moving.…”

Section: Sliding Mesh Methods For Impeller Motionmentioning

confidence: 99%

Effects of Impeller Rotational Speed and Immersion Depth on Flow Pattern, Mixing and Interface Characteristics for Kanbara Reactors Using VOF-SMM Simulations

Shen³

et al. 2021

Metals

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The Kanbara Reactor (KR) is a primary desulfurization technology in the hot metal pretreatment refining process that is widely employed in the modern steelmaking industry. The operating parameters of KR impeller immersion depth (IID) and rotation speed (IRS) have a crucial impact on the process performance and the desulfurization effect. Still, their influences have not been fully understood. This study systematically investigated the effects of IID and IRS on the flow pattern, mixing behavior, vortex core depth, and free surface characteristics for KR processes based on a 3D Volume of Fluid (VOF) model coupled with the sliding mesh method (SMM). The model was validated via scale-down water model experiments and then applied to the KR process, and simulations found that IID and IRS have different impacts on the flow pattern. Specifically, the discharge flow location moves downward with IID increasing, but the discharge strength and mean velocity hardly changes. Comparatively, the rise of IRS significantly increases the mean velocity, but few changes occur to the discharge flow position. Increasing IRS improves bath hydrodynamics, strengthens recirculation, and efficiently shortens mixing time, but IID has a neglectable effect on these features. The minimum mixing time is 55 s at a maximum IRS of 260 rpm. Moreover, the vortex core depth and free surface velocity visibly increase with the increase of IRS. Comparatively, IID has a limited effect on the flow and mixing behavior but directly impacts the distribution of recirculation regions at the axial direction and the velocity gradient on the free surface at the radial direction. Furthermore, the correlation equations of these critical parameters as a function of the operating parameters were obtained. The results from this study may provide references for operating optimizations and industrial practices of KRs.

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Flow Characteristics Related to Liquid/liquid Mixing Pattern in an Impeller-stirred Vessel

Cited by 12 publications

References 25 publications

Suspension pattern and rising height of sedimentary particles with low concentration in a mechanically stirred vessel

Suspension pattern and rising height of sedimentary particles with low concentration in a mechanically stirred vessel

Computational Investigation on Effect of Impeller Dimension on Fluid Flow and Interface Behavior for Kanbara Reactor Hot Metal Treatment

Effects of Impeller Rotational Speed and Immersion Depth on Flow Pattern, Mixing and Interface Characteristics for Kanbara Reactors Using VOF-SMM Simulations

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