Drawdown of floating solids in stirred tanks: Scale-up study using CFD modeling

Waghmare, Yogesh; Falk, Rick; Graham, Lisa; Koganti, Venkat

doi:10.1016/j.ijpharm.2011.05.039

Cited by 20 publications

(9 citation statements)

References 20 publications

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“…It determined the critical state when stagnant floating particles at the liquid surface just disappear within 1–2 s. Some scholars used computer‐aided optical methods or electrical resistance tomography to analyze the distribution of particles . Additionally, other scholars investigated the drawdown and dispersing of floating particles by simulation …”

Section: Introductionmentioning

confidence: 99%

“…[16,17] Additionally, other scholars investigated the drawdown and dispersing of floating particles by simulation. [16,[18][19][20] Although the above-mentioned references analyzed the effects of different factors on the solid-liquid mixing of floating particles, they all adopted water as the liquid phase and took no account of the influence of the material viscosity. In fact, viscous materials are common in most actual productions, like tank stripping of cis-polybutadiene rubber and recovering yellow phosphorous tail gas to produce formic acid.…”

Section: Introductionmentioning

confidence: 99%

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Experimental study on the mixing and dispersing of floating particles in viscous system

et al. 2016

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The effects of baffle configuration, impeller type, impeller diameter ratio, and immersion depth on the critical drawdown speed and power of floating particles were investigated by experiment, and the advantageous stirred vessel was determined on the basis of the low energy consumption principle. Furthermore, the effects of system viscosity, mean solid concentration, and particle size on the dispersing characteristic of floating particles were also researched with the advantageous stirred vessel. The results show that, (1) when the stirred vessel is equipped with a single baffle, the critical drawdown speed and power of floating particles are lower than those of others. (2) Among the propeller, six flat‐blade disc turbine (Rushton), and six 45° pitched‐blade turbine (PBT‐6), the Rushton turbine has the lowest critical drawdown speed, and the down‐pumping propeller (TXL) has the lowest critical drawdown power. (3) The critical drawdown speed and power are lower with a larger impeller diameter and a smaller immersion depth. (4) The critical drawdown speed and power increase with increasing system viscosity, mean solid concentration, and particle size. The experimental results provide useful guidelines for the advantageous design of the stirred vessel used for the dispersing of floating particles in a viscous system.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental study on the mixing and dispersing of floating particles in viscous system

et al. 2016

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“…Hence, the effect of the boundary condition for the solid phase was quite limited. In fact, most research on the simulation of solid-liquid mixing adopted the noslip boundary condition on the wall for the solid phase instead of the partial-slip boundary condition (Fan et al, 2005;Hosseini et al, 2010;Qiao et al, 2014;Tamburini et al, 2012;Waghmare et al, 2011). In the remaining sections of this paper, the partial-slip boundary condition with a specularity coefficient of 0 was adopted as the wall condition for the solid phase.…”

Section: Effect Of Boundary Condition For the Solid Phasementioning

confidence: 99%

“…However, literature on the numerical simulation of the mixing and dispersing of floating particles is relatively scarce. Waghmare et al (2011) developed a semi-empirical correlation to predict the drawdown rate of floating particles through a conjunction of simulation and experimental measurement. The drawdown rate is correlated to the mean liquid velocity of the free surface.…”

Section: Introductionmentioning

confidence: 99%

CFD simulation of the mixing and dispersing of floating particles in a viscous system

Liu

Zheng

Chen

et al. 2017

Braz. J. Chem. Eng.

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Based on the Gidaspow model, the distributions of velocity, turbulence intensity, and solid concentration in stirred vessels equipped with a down-pumping propeller (TXL), a six flat-blade disc turbine (Rushton), or a downpumping six 45° pitched-blade turbine (PBTD-6) in a viscous system were simulated. The power curve of the TXL propeller and the dimensionless solid concentrations of one sampling point in the vessel at different agitation speeds were obtained by simulation and experiment, which were in good agreement with each other. The results showed that: (1) both the tangential velocity and turbulence intensity on the liquid surface caused by a Rushton turbine were the highest of the three conditions at the same agitation speed; (2) the turbulence intensity on the azimuth of 90° behind the baffle near the shaft on the liquid surface was relatively larger than that in other regions; (3) the uniformity of solid concentration distribution in the stirred vessel equipped with a Rushton or PBTD-6 turbine was better than that with a TXL impeller at the same agitation speed.

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“…The drawdown of floating particles in stirred tanks was recently investigated by using the E-L approach (Waghmare et al, 2011) as well as the E-E approach (Chen et al, 2012). Kresta (2008, 2009) …”

Section: Particle Shape and Typementioning

confidence: 99%

Models and Applications for Simulating Turbulent Solid–Liquid Suspensions in Stirred Tanks

Derksen

Gao

2015

J. Chem. Eng. Japan / JCEJ

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Solid-liquid suspensions in stirred tanks are common unit operations in many process industries. The complex ow characteristics of these systems, such as two-phase turbulence and interphase interaction, make the corresponding numerical simulations complicated and challenging. This paper presents a review of models dealing with the continuous and discrete phases of solid-liquid suspensions and summarizes the applications for simulating related ow phenomena, including velocity and turbulence components, solids concentration, just-suspended speed, cloud height, optimization of geometrical parameters, and particle shape and type. Perspectives concerning di erent modeling approaches are presented, and the Eulerian-Lagrangian approach with resolved particles is highlighted to address the underlying suspension mechanisms in stirred tanks.

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Drawdown of floating solids in stirred tanks: Scale-up study using CFD modeling

Cited by 20 publications

References 20 publications

Experimental study on the mixing and dispersing of floating particles in viscous system

Experimental study on the mixing and dispersing of floating particles in viscous system

CFD simulation of the mixing and dispersing of floating particles in a viscous system

Models and Applications for Simulating Turbulent Solid–Liquid Suspensions in Stirred Tanks

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Drawdown of floating solids in stirred tanks: Scale-up study using CFD modeling

Cited by 20 publications

References 20 publications

Experimental study on the mixing and dispersing of floating particles in viscous system

Experimental study on the mixing and dispersing of floating particles in viscous system

CFD simulation of the mixing and dispersing of floating particles in a viscous system

Models and Applications for Simulating Turbulent Solid&#x2013;Liquid Suspensions in Stirred Tanks

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Models and Applications for Simulating Turbulent Solid–Liquid Suspensions in Stirred Tanks