Experimental and DEM studies of velocity profiles and residence time distribution of non-spherical particles in silos

Golshan, Shahab; Esgandari, Behrad; Zarghami, Reza; Blais, Bruno; Saleh, Khashayar

doi:10.1016/j.powtec.2020.06.093

Cited by 17 publications

(13 citation statements)

References 38 publications

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“…Normally, the larger the half cone angle is, the more favorable the grain flow is [45]. The necessary condition for the formation of overall flow is that the half cone angle of the hopper θ is greater than θ max [46].…”

Section: Discussionmentioning

confidence: 99%

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Study on Periodic Pulsation Characteristics of Corn Grain in a Grain Cylinder during the Unloading Stage

Tang

et al. 2021

Foods

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The fluctuation effect of corn grain often occurs during the unloading stage. To accurately explore the periodic pulsation characteristics of corn grain during the unloading stage, a discrete model of corn grain was established, and the effectiveness of the discrete element method in simulating the corn grain unloading stage was verified by a 3D laser scanner and the “spherical particle filling method”. The grain cylinder was divided into six areas, and the periodic pulsation characteristics at different heights were explored through simulation tests. The results showed that the faster the average speed of corn grain changes in unit time, the more significant the periodic pulsation characteristics were as the height of grain unloading increased. The corn grain pulsateon in the grain cylinder exhibited gradual upward transmission and gradual amplification in the process of transmission. The average velocity decreased with increasing height. The direct cause of pulsation was the variation in the average stress between grain layers. Simulation analysis of grain unloading for different half cone angles of the grain cylinder was carried out. The change in corn grain average velocity over time in the area below 20 mm of the upper free surface was extracted. The results showed that the speed of the top corn grain increased with increasing the half cone angle, and the periodic pulsation phenomenon became more obvious with increasing the half cone angle at half cone angles of 30–65°. A half cone angle of 65–70° marked the critical state of corn grain flow changing from funnel flow to overall flow in the grain cylinder. This study provides a method for studying the periodic pulsation characteristics of different crops during the grain unloading stage and provides a technical reference for the safe design of grain unloading equipment.

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Section: Discussionmentioning

confidence: 99%

“…[45]. The necessary condition for the formation of overall flow is that the half cone angle of the hopper θ is greater than max θ [46]. max 90 (90…”

Section: Discussionmentioning

confidence: 99%

Study on Periodic Pulsation Characteristics of Corn Grain in a Grain Cylinder during the Unloading Stage

Tang

et al. 2021

Foods

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“…n p = 132 300 particles. Golshan et al [42] measured time-averaged particle velocity in a wedge-shaped silo using particle image velocimetry (PIV) and DEM. Table 5-b reports the DEM physical properties of this simulation [42].…”

Section: Wedge-shaped Silomentioning

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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“…In this regard, emerging works have recently made progress by implementing the postulates of the μ(I) rheology (MiDi 2004;Jop, Forterre & Pouliquen 2006) to characterize the granular flow in silos with a continuous description (Staron, Lagrée & Popinet 2012;Dunatunga & Kamrin 2015;Zhou et al 2017). In parallel to this, many investigations consisting of experiments and simulations using discrete methods continue to produce fruitful results, keeping the problem of silo flow under very active research (González-Montellano et al 2011;Benyamine et al 2014;Zhou, Ruyer & Aussillous 2015;Ashour et al 2017;Gella, Maza & Zuriguel 2017;Madrid, Asencio & Maza 2017;Stannarius et al 2019;Golshan et al 2020;Reddy, Kumar & Reddy 2021).…”

Section: Introductionmentioning

confidence: 99%

Granular internal dynamics in a silo discharged with a conveyor belt

2021

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The dynamics of granular media within a silo in which the grain velocities are controlled by a conveyor belt has been experimentally investigated. To this end, the building of coarse-grained field maps of different magnitudes has allowed a deep analysis of the flow properties as a function of two parameters: the orifice size and the belt velocity. First, the internal dynamics of the particles within the silo has been fully characterized by the solid fraction, the velocity of the particles and the kinetic stress. Then, the analysis of the vertical profiles of the same magnitude (plus the acceleration) has allowed connection of the internal dynamics with the flow rate. In particular, we show that the gamma parameter – which accounts for the integration of the normalized acceleration along the vertical direction – can successfully discriminate the kind of flow established within the silo (from the quasistatic regime to the free discharge) depending on the outlet size and belt velocity.

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Experimental and DEM studies of velocity profiles and residence time distribution of non-spherical particles in silos

Cited by 17 publications

References 38 publications

Study on Periodic Pulsation Characteristics of Corn Grain in a Grain Cylinder during the Unloading Stage

Study on Periodic Pulsation Characteristics of Corn Grain in a Grain Cylinder during the Unloading Stage

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

Granular internal dynamics in a silo discharged with a conveyor belt

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