Influence of contact parameters on Discrete Element method (DEM) simulations of flow from a hopper: Comparison with magnetic resonance imaging (MRI) measurements

Danczyk, Megan; Meaclem, Tom; Mehdizad, Maral; Clarke, Daniel; Galvosas, Petrik; Fullard, Luke; Holland, Daniel J.

doi:10.1016/j.powtec.2020.06.002

Cited by 21 publications

(11 citation statements)

References 46 publications

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“…Spatial maps of the time-averaged vertical velocity of particles were obtained using a slice selective Pulsed-Gradient Spin Echo (PGSE) imaging method [4]. Experiments were performed using a flow-encoding gradient with a maximum strength of 0.62 T m -1 and a width of 0.15 ms incremented in 9 steps.…”

Section: Experimental Set-upmentioning

confidence: 99%

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Quantitative measurement of hopper flow using MRI

et al. 2021

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To gain fundamental insight into granular flow behaviour, quantitative measurements of velocity and solid fraction are required. The aim of this study is to measure the solid fraction and velocity of 3D granular flows quantitively using a recently developed MRI method. Time-averaged spatial maps of the solid fraction and velocity are obtained for hoppers with wall angles of 30°, 60°, and 90°. From these maps, the mass flow rate of the material was calculated along the height of the hoppers. Excellent agreement was observed between the MRI and gravimetric mass flow rate measurements, confirming the quantitative nature of the measurements. The resulting solid fraction and velocity measurements provide insight into the dynamics of granular flow.

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Section: Experimental Set-upmentioning

confidence: 99%

“…MRI measurements of granular flow are mostly of velocity only [4]. The few solid fraction measurements that have been presented are either of static samples [5,6], or do not provide sufficient accuracy [7,8] to provide insight into the granular rheology.…”

Section: Introductionmentioning

confidence: 99%

Quantitative measurement of hopper flow using MRI

et al. 2021

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“…Gella et al [16] found that the relationship between the mass flow and the nature of contacts between beads, friction, or differences in kinetic energy per unit area is not trivial, and further research is necessary to clarify these questions. Numerical Processes 2021, 9, 1860 2 of 20 simulations of flow from a hopper conducted by Danczyk et al [17] showed high sensitivity of flow to contact parameters and the need for detailed local observations of the process for the validation of the computational technique.…”

Section: Introductionmentioning

confidence: 99%

“…The Beverloo law or other models based thereon facilitate a very good estimation of the mass flow rate of particles with various PSD and particle shapes [15,18]. However, the physical significance of some model parameters remains unknown or at least unclear [17]. The issue requires further investigations.…”

Section: Introductionmentioning

confidence: 99%

Discharge Flow of Spherical Particles from a Cylindrical Bin: Experiment and DEM Simulations

et al. 2021

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A series of the DEM simulations of the outflow of wooden spheres from a flat-bottomed container was reported, considering the maximum diameter to arrest the flow. Numerical simulations of the discharge process were performed, and the micro-mechanics of the discharged particles were described. The effect of the sliding friction coefficient between particles, rolling friction coefficient, and modulus of elasticity of particles on the clogging process was investigated. The results of the simulations of the mass flow rate of spheres have shown a fairly close agreement with the experimental results. The real particles of wood were not perfectly spherical, their properties were anisotropic, and their frictional properties were non-homogenously distributed on the surface. Nevertheless, these deviations from ideal conditions did not produce a considerable discrepancy in the results. No direct relationship between the interparticle friction and the clogging was found; however, a relationship between the stability of the dome formed at flow arrest and the rolling friction was observed. An increase in Young’s modulus of particles by two orders of magnitude did not affect the clogging process, but a slightly higher probability of clogging was found for softer particles.

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“…Liquid is present in many granular flows, including both natural [2] and industrial systems [3]. DEM simulations are able to model dry granular flow quite accurately [4], but are limited when describing systems containing small amounts of liquid [5]. A variety of contact models exist that describe wet particle collisions in the pendular regime, which include a capillary and viscous cohesive force for the liquid [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

An investigation of collisions of liquid coated particles

2021

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The presence of even small amounts of liquid between particles dramatically changes the dynamics of collisions. This study considers granular collisions between two particles coated with a thin layer of viscous liquid, such that the capillary number is high and viscous forces dominate. High-speed particle tracking velocimetry was used to experimentally study the collisions of two smooth spheres with and without liquid coatings. We then use these experiments to examine four theoretical models that describe the collisions. A key challenge when modelling viscous forces is that the force which is predicted as particles approach each other scales with the inverse of the distance, i.e. tends to infinity. Most existing models impose a limit to the viscous force. One recent model instead assumes a hard sphere collision. These fundamentally different approaches produce different rebound outcomes. A fair match between experiments and simulations was obtained when using the hard sphere collision model, but only if an empirically-fitted glass transition pressure model was used to describe the minimum approach distance.

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Influence of contact parameters on Discrete Element method (DEM) simulations of flow from a hopper: Comparison with magnetic resonance imaging (MRI) measurements

Cited by 21 publications

References 46 publications

Quantitative measurement of hopper flow using MRI

Quantitative measurement of hopper flow using MRI

Discharge Flow of Spherical Particles from a Cylindrical Bin: Experiment and DEM Simulations

An investigation of collisions of liquid coated particles

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