Modeling methods for gravity flow of granular solids in silos

Golshan, Shahab; Zarghami, Reza; Saleh, Khashayar

doi:10.1515/revce-2019-0003

Cited by 7 publications

(8 citation statements)

References 165 publications

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“…In some cases it was noticed that the granular flow can be seen as occurring through an effective cross-sectional area reduced with respect to the actual area due to the effect of the grains size, in which case the corresponding formula is the Hagen-Beverloo,ṁ ∼ (D − kd) 5/2 , where k is a dimensionless constant of order unity [1,5]. In the context of numerical simulations, discrete and continuum modeling of silos discharge has also validated the Hagen and Hagen-Beverloo phenomenological correlations for flat-bottomed silos [6][7][8].…”

Section: Introductionmentioning

confidence: 94%

“…valid for horizontally elongated slots. Conversely, a series expansion when W/D 1 yields f (W/D) → (W/D) 1/2 , and consequently, in this limit, relationship (8) has the form…”

Section: Rectangular Orifices and Slotsmentioning

confidence: 99%

“…corresponding to vertically elongated slots. Asymptotic relationships ( 10) and ( 11) actually represent very different limits but both of them are embraced by the single relationship (8) or, in summary, by the fundamental formula (6).…”

Section: Rectangular Orifices and Slotsmentioning

confidence: 99%

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Granular flow through vertical slots: analysis of a general formula

et al. 2021

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Currently, very little is known about reliable phenomelogical correlations to estimate the gravity-driven mass flow rate, of dry non-cohesive granular material, outflowing from thin thickness slots in vertical sidewalls of rectangular silos. Here, we validate a simple and general formula that fits pretty well data published elsewhere, including the cases of vertically and horizontally elongated slots.

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Section: Introductionmentioning

confidence: 94%

“…valid for horizontally elongated slots. Conversely, a series expansion when W/D 1 yields f (W/D) → (W/D) 1/2 , and consequently, in this limit, relationship (8) has the form…”

Section: Rectangular Orifices and Slotsmentioning

confidence: 99%

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Granular flow through vertical slots: analysis of a general formula

et al. 2021

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“…There are two common approaches in the numerical modelling of granular flows, continuum models (Eulerian) and discrete models (Lagrangian). The continuum models, in which a constitutive model describes the relation between stresses and strains, ignore the discrete essence of granular systems and therefore suffer from multiple limitations, for instance in calculating solids holdup [4].…”

Section: Introductionmentioning

confidence: 99%

Lethe-DEM : An open-source parallel discrete element solver with load balancing

Golshan¹,

Münch²,

Gassmöller³

et al. 2021

Preprint

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Approximately 75% of the raw material and 50% of the products in the chemical industry are granular materials. The Discrete Element Method (DEM) provides detailed insights of phenomena at particle scale and it is therefore often used for modeling granular materials. However, because DEM tracks the motion and contact of individual particles separately, its computational cost increases nonlinearly O(n p log(n p )) -O(n 2 p ) depending on the algorithm) with the number of particles (n p ). In this article, we introduce a new open-source parallel DEM software with load balancing: Lethe-DEM. Lethe-DEM, a module of Lethe, consists of solvers for two-dimensional and three-dimensional DEM simulations. Loadbalancing allows Lethe-DEM to significantly increase the parallel efficiency by ≈ 25 − 70% depending on the granular simulation. We explain the fundamental modules of Lethe-DEM, its software architecture, and the governing equations. Furthermore, we verify Lethe-DEM with several tests including analytical solutions and comparison with other software. Comparisons with experiments in a flat-bottomed silo, wedge-shaped silo, and rotating drum validate Lethe-DEM. We investigate the strong and weak scaling of Lethe-DEM with 1 ≤ n c ≤ 192 and 32 ≤ n c ≤ 320 processes, respectively, with and without load-balancing. The strong-scaling analysis is performed on the wedge-shaped silo and rotating drum simulations, while for the weak-scaling analysis, we use a dam break simulation. The best scalability of Lethe-DEM is obtained in the range of 5000 ≤ n p /n c ≤ 15 000. Finally, we demonstrate that large scale simulations can be carried out with Lethe-DEM using the simulation of a three-dimensional

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“…[ 3,4 ] In DEM, simulations are performed at the particle scale, which increases the accuracy and breadth of physical phenomena that can be analyzed, though at the cost of higher computational time. [ 5 ] As a result, several studies were performed to study granular mixing using DEM.…”

Section: Introductionmentioning

confidence: 99%

Insights into granular mixing in vertical ribbon mixers

Golshan

Blais

2021

Can J Chem Eng

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In this research, granular mixing in vertical ribbon mixers was studied by means of discrete element method (DEM) simulations. Time‐averaged velocity distributions, granular mixing, mean square displacement of tracer particles, diffusion coefficients, and Peclet number in axial and azimuthal directions were used to find the flow pattern of particles and the dominant mixing mechanisms. Strong azimuthal motion of particles was observed, and it was found that by decreasing the height in the mixer, this azimuthal motion becomes stronger. The effects of rotating speed, fill level, and filling method were studied on the quality of mixing, where the quality of mixing was assessed using relative SD mixing index. It was found that by increasing the rotation speed from ωs = 60 rpm‐120 rpm, the mixing quality improves in a linear trend. Decreasing the fill level from 12 cm‐11 cm did not change the mixing quality, while with further decrease of the fill level to 10 cm, the mixing quality was improved. The mixing quality was also much better when the powder was inserted side‐to‐side instead of in axial layers.

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Modeling methods for gravity flow of granular solids in silos

Cited by 7 publications

References 165 publications

Granular flow through vertical slots: analysis of a general formula

Granular flow through vertical slots: analysis of a general formula

Lethe-DEM : An open-source parallel discrete element solver with load balancing

Insights into granular mixing in vertical ribbon mixers

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