Flow correlations and transport behaviour of turbulent slurries in partially filled pipes

Cunliffe, Christopher; Dodds, Jonathan M.; Dennis, David

doi:10.1016/j.ces.2021.116465

Cited by 11 publications

(3 citation statements)

References 45 publications

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“…Very good agreement was observed between the computational and the experimental results. The effect of partially filled pipe on slurry transport was investigated experimentally by Cunliffe et al [46]. In this study, settling behaviours of slurries in partially filled pipelines was investigated and a correlation for predicting the settling rate of particles was developed based on the experimental data.…”

Section: Introductionmentioning

confidence: 99%

Implementation of a Model for Predicting the Size Distribution of Coal Particles in a Horizontal Fluid Pipeline

2023

jjmie

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In this study, a model for the prediction of coal particle gradation in horizontal fluid pipeline was developed. The intent of this study is to develop a model that can predict the coal particle gradations in horizontal coal-liquid slurry pipelines. A semiempirical model originally developed by Karabelas has been modified by applying the k-ε approach to model a dimensionless diffusivity, originally assumed to be constant. The mechanistic model developed shows that dimensionless diffusivity is a function of root mean square turbulent velocity fluctuations and many other parameters which include fluid velocity, pipe diameter, carrier fluid and suspended particles densities, particle size, and the efflux concentration. The modified model was compared with four different sets of experimental data and a CFD model, and was found to have overall good agreement. It was employed to analyze particle gradations and the results show that larger coal particles tend to drift to the pipe bed, leaving the upper section of the pipes for smaller particles. The results show that concentration profile of coal particles in single-sized homogenous slurry is different from that of the same particle concentration in multi-sized slurry flow for each particle size and the same efflux concentration. The modified model was applied to analyze the d50 concentration profile and the result shows that d50 concentration profile represents the actual profile accurately within low and moderate range of particle sizes in the slurry. The mechanistic model presented in this study will be useful for coal and other mining industries worldwide, for accurate prediction of concentration profiles and choice of particle sizes as well as flow velocity of slurry in horizontal pipelines to avoid deposition and clogging of particles along the pipeline, thereby reducing associated danger in the pipelines.

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Section: Introductionmentioning

confidence: 99%

Implementation of a Model for Predicting the Size Distribution of Coal Particles in a Horizontal Fluid Pipeline

2023

jjmie

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“…In such fields, an understanding of both the particle-scale and bulk-scale dynamics is fundamental to the ability to predict long-term eventualities, such as deposition, formation of agglomerates, and blockages. For instance, the nuclear waste processing industry must possess the ability to determine particle-fluid and particle-particle interaction processes that could lead to further complications in waste transport flows in order to guarantee safety and to optimize economic cost (Cunliffe et al, 2021). In such flows, which are often also turbulent due to the presence of high flow rates, knowledge surrounding turbulent dispersion and its effect on particle-particle collisions is paramount in foreseeing processing issues in current designs, as well as in enhancing the effectiveness of future systems.…”

Section: Introductionmentioning

confidence: 99%

Stokes number and coupling effects on particle interaction behavior in turbulent channel flows

Rupp,

Mortimer,

Fairweather

2023

Physics of Fluids

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The effects of Reynolds number (Reτ=180 and 300), particle Stokes number (St+=0.5, 50, and 92), and fluid–solid phase coupling level (one-way, two-way, and four-way) on particle behavior in turbulent channel flows has been investigated using direct numerical simulation and Lagrangian particle tracking. Previous studies have used all these levels of coupling, but in terms of those employing four-way coupling, no consideration is given as to how emergent phenomena due to collision dynamics within a flow affect the way in which particles impart feedback to the continuous phase. In the present work, we relate the particle–particle interaction to particle–fluid coupling, as well as in assessing its relation to the Stokes number. As the Reynolds number increases and the turbulent region narrows, fewer particles retain their velocity as they migrate to the wall-region leading to reduced streamwise velocity fluctuations and preferential concentration. It is also evident that low Stokes number particles are capable of minor wall-accumulation at Reτ=300. At this increased Reynolds number, four-way coupled simulations performed with moderate Stokes number particles (St+=50) are shown to diminish the effects of particle–fluid feedback, leading to similar fluid and particle statistics as the one-way coupled simulations. It is concluded that turbophoretic and preferential concentration effects are responsible for this phenomenon, since the increased collision rates due to larger concentrations of particles and velocity fluctuations in the wall-region correlate directly with the impact on the two-way coupling flow modifications. Analysis of the collision dynamics also indicates particles colliding with increased relative velocities and angles, which cause larger momentum transfer and directional redistribution, increasing and redirecting slip velocities. It is concluded that for midrange Stokes numbers, four-way coupling is imperative to increase simulation accuracy beyond that obtained assuming one-way coupling.

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“…In recent years, pipeline filling technology has been widely used while the mining depth has been gradually increased [1][2][3]. Therefore, both the rules of sedimentation and influence on the pipeline transportation must be determined [4][5][6]. The production capacity of a mine can be increased by selecting an appropriate technology of particle sedimentation, and avoiding pipe blocking to reduce the failure rates in mine pipelines [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Study and Analysis on the Influence Degree of Particle Settlement Factors in Pipe Transportation of Backfill Slurry

Wang

Gan

2021

Metals

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In this study, we developed a pipeline transport model to investigate the influence of particle sedimentation factors on slurry transportation through pipelines. The particle tracking module of the software was used to simulate the transport process, and the influences on the sedimentation rate were analyzed considering the slurry concentration, particle size, and flow velocity. The established model exhibited small calculation errors. In addition, the results revealed that the proposed model is reliable for calculating the degree of influence of various factors on particle sedimentation. The effect of the particle sedimentation rate on the pipeline slurry was explored considering the particle size, slurry concentration, and flow velocity. The sedimentation rate was positively related to particle size and adversely related to the slurry concentration and flow velocity. Indeed, study on the sedimentation rate requires considering a reasonable range of particle sizes, preparing a slurry with an appropriate concentration, and adjusting an appropriate flow velocity. Numerical simulations were performed using the filling data as the background for a sample mining area. The experimental results showed optimal slurry concentration and particle size of 60% and 25.25 µm, respectively.

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Flow correlations and transport behaviour of turbulent slurries in partially filled pipes

Cited by 11 publications

References 45 publications

Implementation of a Model for Predicting the Size Distribution of Coal Particles in a Horizontal Fluid Pipeline

Implementation of a Model for Predicting the Size Distribution of Coal Particles in a Horizontal Fluid Pipeline

Stokes number and coupling effects on particle interaction behavior in turbulent channel flows

Study and Analysis on the Influence Degree of Particle Settlement Factors in Pipe Transportation of Backfill Slurry

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