Multiphase CFD Modelling of Mineral Separators Performance: Validation Against Tomography Data

Vakamalla, Teja Reddy; Vadlakonda, Balraju; K, Aketi V A; Mangadoddy, Narasimha

doi:10.1007/s12666-016-0995-4

Cited by 25 publications

(11 citation statements)

References 41 publications

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“…An increase in viscosity should decrease the tangential velocity, particularly in the forced vortex region, which can affect the air core formation . The effect of viscosity on hydrocyclone performance has been confirmed by CFD modelling, and some researchers have found that better predictions are obtained when viscosity is corrected by including a fines fraction in the model . The approach in those studies was that viscosity changes with both solids and fine contents, and Narasimha et al explained that although some slurries are shear thinning slurries (non‐Newtonian), at high shear rates slurry behaviour can be approximated to a Newtonian fluid, as it has been observed that the shear rates inside hydrocyclones are usually more than 100 s −1 .…”

Section: Rheology In Mineral Processing Unit Operationsmentioning

confidence: 95%

Slurry rheology in mineral processing unit operations: A critical review

2019

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Knowledge of slurry rheology in mineral processing is essential for the optimization of wet-grinding, dewatering, transport, and tailings management and it is becoming important in flotation due to the increasing need to process complex ores with a high clay mineral content. Slurries of these ores often display complex rheological behaviour even at low solids concentration, and traditional rheology measurements in mineral processing, such as yield stress and apparent viscosities, may not provide the critical information needed for process optimization. The objective of this paper is to provide a comprehensive review of some of the previous rheology studies performed at the bench, pilot plant, and industrial scale for different unit operations and to discuss the potential for alternative rheology measurements to provide a better insight into colloidal particle interactions in slurries with clay minerals. Firstly, the fundamentals of slurry rheology and the influence of colloidal particles are presented. Secondly, rheology measurements for suspensions are described briefly. Thirdly, a review of rheology studies in grinding, classification, flotation, dewatering, and tailings management is done, outlining possible ways of determining types of particle associations in slurries. Finally, recommendations for future research directions are provided.

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Section: Rheology In Mineral Processing Unit Operationsmentioning

confidence: 95%

Slurry rheology in mineral processing unit operations: A critical review

2019

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“…Knowledge of the air core shape and size are important to analyse and understand the air core behaviour in cyclones. It is reported that the percent feed solids strongly influence the size of the air core by decreasing the size as solids percent increase . This phenomenon is believed as a result of viscosity effect on the air core diameter .…”

Section: Resultsmentioning

confidence: 99%

The dynamic behaviour of a large‐scale 250‐mm hydrocyclone: A CFD study

Vakamalla

Mangadoddy

2019

Asia-Pacific J Chem Eng

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The fluctuating feed solid contents usually cause instationarities in industrial hydrocyclone separation. This demands a controlling mechanism for stabilizing the separation effect. Understanding the transitional/dynamic behaviour is necessary to design such control mechanisms. In this context, the present paper is aimed to understand the dynamic behaviour of a large-scale 250-mm hydrocyclone in terms of air core development and solid concentration distributions using the modified mixture model coupled with large eddy simulation turbulence model. Numerically predicted two-phase flow field data is validated against laser Doppler velocimetry data at two axial positions. A close agreement is found between the modified mixture model predicted particle classification curve and experimental data. Longer residence time is observed with near cut size particle compared to the and fine size particles. Further, the analysis of the equilibrium radius of different solid particles inside the cyclone in the presence of turbulence is compared with the classical Kelsall experiments and observed that the classification of particles influenced by both the turbulent dispersion and the centrifugal force. Finally, the effect of feed solids concentration (10-50 wt%) on the hydrocyclone performance and particle segregation is also undertaken in this study.

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“…Detailed information about this rheological model can be found in Narasimha et al 46 The modified ASM model with the aforementioned additional corrections accurately predicted the hydrocyclone and dense medium cyclone performance up to intermediate solids content. 10,17,24,47 3. NUMERICAL MODELING Figure 1 displays the grids of different cyclone geometries used for numerical studies.…”

Section: Methodsmentioning

confidence: 99%

Comprehensive Dense Slurry CFD Model for Performance Evaluation of Industrial Hydrocyclones

Vakamalla

Mangadoddy

2021

Ind. Eng. Chem. Res.

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In most mineral processing industries, hydrocyclone separators are operated at high feed solids content in the comminution circuits. Computational fluid dynamic (CFD) models developed so far are unable to predict the accurate classification behavior at high feed solid loadings. The dense slurry CFD model adopts algebraic slip mixture (ASM) model corrected with shear lift and hindered settling velocity-based drag forces to account for fluid–particle interactions and granular flow options for particle–particle interactions. The slurry rheology is modeled with a fine fraction-corrected Newtonian viscosity model. This model is utilized for running the multiphase simulations in five hydrocyclones (75–381 mm) at different design and operating conditions for the feed solids content varying between 0 and 65% by weight. Turbulence is modeled using the large Eddy simulation (LES) model. The results are analyzed in terms of air core diameter, water split, solid split, cut size, and sharpness of separation. In 75 and 250 mm hydrocyclones, the modified ASM model can predict accurate performance characteristics, including fine and coarse particle misplacement up to 30 wt % feed solids. Slight deviations are observed in the fine fraction recovery for the 50 wt % and higher feed solids content. Further, the same model is tested to predict the roping phenomena in a 381 mm hydrocyclone.

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Multiphase CFD Modelling of Mineral Separators Performance: Validation Against Tomography Data

Cited by 25 publications

References 41 publications

Slurry rheology in mineral processing unit operations: A critical review

Slurry rheology in mineral processing unit operations: A critical review

The dynamic behaviour of a large‐scale 250‐mm hydrocyclone: A CFD study

Comprehensive Dense Slurry CFD Model for Performance Evaluation of Industrial Hydrocyclones

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