Modeling of cavern formation in yield stress fluids in stirred tanks

Xiao, Qi; Yang, Ning; Zhu, Jiahua; Guo, Liejin

doi:10.1002/aic.14470

Cited by 18 publications

(13 citation statements)

References 29 publications

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“…Xiao et al established an apple torus cavern model based on the torus model:

τ_{y} ((), S_{p} + {aS}_{v}) = ρ N^{2} D^{4} \sqrt{{N_{normalf}}^{2} + {(\frac{4 N_{p}}{3 π})}^{2}}

…”

Section: Cavern Model Analysismentioning

confidence: 99%

“…This model only considers the tangential effects and neglects the axial effects, so it is only suitable for the radial flow impellers. Xiao et al established an apple torus model based on the assumption that the circle center of the torus moves along the impeller as the cavern grows, which results in a prediction error at the upper section of the cavern.…”

Section: Introductionmentioning

confidence: 99%

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Formation of heart‐shaped cavern model in stirring pseudoplastic fluid with the impeller of perturbed six‐bend‐blade turbine

et al. 2019

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The cavern characteristics of xanthan gum solution stirred with the impeller of perturbed six‐bend‐blade turbine (6PBT impeller) were studied based on CFD laminar flow model. The heart‐shaped cavern model was presented for predicting the cavern development accurately, and the predicted results were made a contrastive analysis with that of other existing cavern models. Results showed that the calculated values agreed well with the data measured by PIV, which validated the laminar flow model. The correction coefficient k = 0.64 is more suitable to revise the characteristic parameter a in the equation of the heart‐shaped cavern model. As a result, the heart‐shaped model always keeps high prediction accuracy at the cavern boundary. The cavern boundary curves predicted by the heart‐shaped model are in good agreement with the results of CFD simulation, and the cavern development along the axial height can be also realistically exhibited. The heart‐shaped cavern model will contribute to increase the prediction accuracy of cavern development.

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“…Xiao et al established an apple torus cavern model based on the torus model:

τ_{y} ((), S_{p} + {aS}_{v}) = ρ N^{2} D^{4} \sqrt{{N_{normalf}}^{2} + {(\frac{4 N_{p}}{3 π})}^{2}}

…”

Section: Cavern Model Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Formation of heart‐shaped cavern model in stirring pseudoplastic fluid with the impeller of perturbed six‐bend‐blade turbine

et al. 2019

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“…Up to now, several researches have been conducted to study the cavern phenomenons of the pseudoplastic fluids . Amanullah et al used visualization technique to research the cavern formation through injecting Carbopol dye mixtures to the center region of the SCABA 3SHP1 impeller in stirring Carbopol 940 powder solution (a kind of high shear‐thinning fluid), and established the axial force model of the cavern.…”

Section: Introductionmentioning

confidence: 99%

Determination method of the cavern boundary viscosity in a stirred tank with pseudoplastic fluid

Luan

Wang

et al. 2020

AIChE Journal

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It is essential to predict the cavern boundary accurately for investigating the cavern characteristics and achieving efficient mixing of the pseudoplastic fluids. The distribution characteristics of apparent viscosity of xanthan gum solutions at different mass concentrations stirred by the impeller of perturbed six-bent-bladed turbine (6PBT impeller) were numerically investigated through the computational fluid dynamics (CFD) simulation based on laminar flow model. The determination method of the cavern boundary viscosity was presented, and the predicted results were compared with those of traditional velocity method. Results showed that the data of the power consumption predicted using CFD simulation agreed well with those measured by torque experiment, which validated the laminar flow model. The η a − γ curve changes from nearly horizontal straight line to the power function curve along the direction of center axis toward tank wall. As a result, the location of the transitional point can be determined as the cavern boundary, and the corresponding viscosity is the cavern boundary viscosity. The ratio of the cavern boundary viscosity and the fluid yield viscosity (η a /η y ) always remains approximately constant, that is, η a = 0:25η y at different speeds. Compared with the traditional velocity method, the boundary viscosity method can maintain its high accuracy for exhibiting the cavern boundary, and the predicted cavern size and development are always in good agreement with the CFD results free from the speed and the impeller type. So this work can provide a new way for accurately characterizing the cavern boundary. K E Y W O R D S boundary viscosity, cavern, numerical simulation, pseudoplastic fluid

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“…Wilkens et al [18] further developed an elliptical torus model considering only the tangential effects and neglecting the axial effects. Xiao et al [19] proposed an apple torus model to predict the cavern shape and size based on the assumption of the torus center moving along the impeller as the cavern is growing. It is obvious that these researches mainly focused on the formation of the different cavern models for describing better the cavern development.…”

Section: Introductionmentioning

confidence: 99%

Cavern Boundary Determination with Pseudoplastic Fluid Based on the Apparent Viscosity Method

et al. 2020

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The cavern characteristics of xanthan gum solutions stirred by impellers of a perturbed six‐bent‐bladed turbine (6PBT) were investigated numerically using computational fluid dynamics (CFD) with laminar flow model. The apparent viscosity method was proposed to determine the boundary of the cavern. The cavern sizes predicted by apparent viscosity were in good agreement with the calculated results, and this method was not influenced by speed and impeller configuration. However, the predicted results of the cavern by the traditional speed method usually displayed a great deviation, especially at high speed. Therefore, it is feasible to determine the cavern boundary with the apparent viscosity, i.e., 0.25 times the yield viscosity of a pseudoplastic fluid, as the unified standard.

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Modeling of cavern formation in yield stress fluids in stirred tanks

Cited by 18 publications

References 29 publications

Formation of heart‐shaped cavern model in stirring pseudoplastic fluid with the impeller of perturbed six‐bend‐blade turbine

Formation of heart‐shaped cavern model in stirring pseudoplastic fluid with the impeller of perturbed six‐bend‐blade turbine

Determination method of the cavern boundary viscosity in a stirred tank with pseudoplastic fluid

Cavern Boundary Determination with Pseudoplastic Fluid Based on the Apparent Viscosity Method

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