scholarly journals Mixing of Bi-Dispersed Milli-Beads in a Rotary Drum. Mechanical Segregation Analyzed by Lab-Scale Experiments and DEM Simulation

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1166
Author(s):  
Aline Mesnier ◽  
Roman Peczalski ◽  
Guilhem Mollon ◽  
Séverine Vessot-Crastes
Keyword(s):  
Discrete Element ◽  
Front Side ◽  
Discrete Elements ◽  
Simulation Data ◽  
Segregation Index ◽  
Dem Simulation ◽  
Rotary Drum ◽  
Horizontal Drum ◽  
Dem Model ◽  
Discrete Elements Method

Mechanical flow and segregation phenomena within a bed composed of milli-metric size spherical beads rotated in a horizontal drum were investigated. The beads population was bi-dispersed, with two kinds of binary (half by half) compositions: a bi-size bed with two different sizes and a bi-density bed with two different densities. The distributions of the beads were observed optically on the front side of the bed by means of a lab-scale drum prototype. Different numbers and lengths of peripheral straight baffles were tested as well as different drum filling ratios. The photographical data were processed to obtain the front layer mechanical segregation index. This experimental index was compared to the simulated one, obtained by means of commercial discrete element software EDEM. The simulations were corroborated by the experiments provided that the friction coefficients of the discrete elements method (DEM) model were correctly adjusted. The global segregation index was also calculated from simulation data for all considered cases and its values were lower and less sensitive to baffles’ configurations than those for the front layer.

scholarly journals Mechanical and thermal segregation of milli-beads during contact heating in a rotary drum. DEM modeling and simulation.

2018 ◽  
Author(s):  
Aline Mesnier ◽  
Maroua Rouabah ◽  
C. Cogné ◽  
Roman Peczalski ◽  
Séverine Vessot-Crastes ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Standard Deviation ◽  
Operating Conditions ◽  
Contact Heat ◽  
Segregation Index ◽  
Dem Simulation ◽  
Contact Heating ◽  
Particulate Solid ◽  
Rotary Drum ◽  
Horizontal Drum

The flow mechanics and heat transfer phenomena within a bed of milli-metric size spherical beads rotated and heated by contact in a horizontal drum were simulated by means of commercial discrete element software EDEM. Mono-dispersed and bi-dispersed beds (two particle sizes or two particle densities) were considered. The mechanical segregation index (standard deviation of local bed compositions) and the thermal segregation index (standard deviation of beads temperatures) were calculated for the different types of bed and same operating conditions. The thermal segregation was found to be enhanced by mechanical segregation and was much stronger for bi-dispersed beds than for monodispersed one.   Keywords: rotating drum; particulate solid; segregation; contact heat transfer; DEM simulation. 

A CUBIC ARRANGED SPHERICAL DISCRETE ELEMENT MODEL

2014 ◽  
Vol 11 (05) ◽  
pp. 1350102 ◽  
Author(s):  
WEI GAO ◽  
YUANQIANG TAN ◽  
MENGYAN ZANG
Keyword(s):  
Strain Energy ◽  
Element Model ◽  
Discrete Element ◽  
Discrete Element Model ◽  
Laminated Plate ◽  
Discrete Elements ◽  
Elastic Continuum ◽  
Vibration Process ◽  
Spring Constants ◽  
Dem Model

A 3D discrete element model (DEM model) named cubic arranged discrete element model is proposed. The model treats the interaction between two connective discrete elements as an equivalent "beam" element. The spring constants between two connective elements are obtained based on the equivalence of strain energy stored in a unit volume of elastic continuum. Following that, the discrete element model proposed and its algorithm are implemented into the in-house developed code. To test the accuracy of the DEM model and its algorithm, the vibration process of the block, a homogeneous plate and laminated plate under impact loading are simulated in elastic range. By comparing the results with that calculated by using LS-DYNA, it is found that they agree with each other very well. The accuracy of the DEM model and its algorithm proposed in this paper is proved.

Study of the Effect of Liquid on Mixing Process for Size-Type Binary Particulate Systems by DEM Simulation

2011 ◽  
Vol 317-319 ◽  
pp. 2047-2050
Author(s):  
Hong Li Gao ◽  
You Chuan Chen
Keyword(s):  
Discrete Element Method ◽  
Liquid Bridge ◽  
Discrete Element ◽  
Mixing Process ◽  
Dem Simulation ◽  
Segregation Process ◽  
Size Type ◽  
Simulation Results ◽  
Horizontal Drum ◽  
Particulate Systems

The discrete-element method(DEM) was employed to simulate the mixing and segregation process for size-type binary particulate systems in a rotating horizontal drum for dry particulate systems and wet particulate systems. The effect of interstitial liquid on the mixing and segregation process were studied. The simulation results showed that the liquid bridge between particles play an important role in mixing and segregation process, as a result, segregation may be mitigated and mixing may be enhanced. To assess the accuracy of the simulation result, some comparisons were made with the experimental results in the literature.

scholarly journals A 3D DEM Model for Air Sparging Technology in the Saturated Granular Soils

2022 ◽  
Vol 9 ◽  
Author(s):  
Kai Wu ◽  
Zan Li ◽  
Zhibin Liu ◽  
Songyu Liu
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Discrete Element ◽  
Solid Particles ◽  
Air Sparging ◽  
Dem Simulation ◽  
Drag Forces ◽  
Novel Approach ◽  
Element Simulation ◽  
Dem Model

This work provides a three-dimensional discrete element simulation (DEM) model to study the air sparging technology. The simulations have taken into account the multi-phases of bubble (gas) - fluid (water) - soil (solid) particles. Bubbles are treated as discrete individual particles, with buoyancy and drag forces applied to bubbles and soil particles. The trajectory of each discrete bubble particle can be tracked using the discrete element model. It is found that the diffusion of the whole bubble is inverted conical though the motion behavior of a single bubble particle is random. Furthermore, the distribution of the radius of influence (ROI) is not uniform. The bubbles become more concentrated as in the center of the inverted cone. The number of bubbles dissipated from the water surface is normally distributed. The DEM simulation is a novel approach to studying air sparging technology that can provide us a deeper insight into bubble migration at the microscopic level.

scholarly journals Applications of Discrete Element Method in the Research of Agricultural Machinery: A Review

Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 425
Author(s):  
Hongbo Zhao ◽  
Yuxiang Huang ◽  
Zhengdao Liu ◽  
Wenzheng Liu ◽  
Zhiqi Zheng
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Agricultural Machinery ◽  
Design And Optimization ◽  
Design Of Agricultural Machinery ◽  
Agricultural Materials ◽  
Operational Processes ◽  
Dem Model ◽  
Agricultural Machines ◽  
Element Method

As a promising and convenient numerical calculation approach, the discrete element method (DEM) has been increasingly adopted in the research of agricultural machinery. DEM is capable of monitoring and recording the dynamic and mechanical behavior of agricultural materials in the operational process of agricultural machinery, from both a macro-perspective and micro-perspective; which has been a tremendous help for the design and optimization of agricultural machines and their components. This paper reviewed the application research status of DEM in two aspects: First is the DEM model establishment of common agricultural materials such as soil, crop seed, and straw, etc. The other is the simulation of typical operational processes of agricultural machines or their components, such as rotary tillage, subsoiling, soil compaction, furrow opening, seed and fertilizer metering, crop harvesting, and so on. Finally, we evaluate the development prospects of the application of research on the DEM in agricultural machinery, and look forward to promoting its application in the field of the optimization and design of agricultural machinery.

scholarly journals Discrete element method approach to modelling VPP dampers

2018 ◽  
Vol 157 ◽  
pp. 02014
Author(s):  
Pawel Chodkiewicz ◽  
Jakub Lengiewicz ◽  
Robert Zalewski
Keyword(s):  
Discrete Element Method ◽  
Granular Medium ◽  
Discrete Element ◽  
Modeling And Analysis ◽  
Novel Approach ◽  
Particle Dampers ◽  
Pressure Boundary Conditions ◽  
Dem Model ◽  
Method Approach ◽  
Element Method

In this paper, we present a novel approach to modeling and analysis of Vacuum Packed Particle dampers (VPP dampers) with the use of Discrete Element Method (DEM). VPP dampers are composed of loose granular medium encapsulated in a hermetic envelope, with controlled pressure inside the envelope. By changing the level of underpressure inside the envelope, one can control mechanical properties of the system. The main novelty of the DEM model proposed in this paper is the method to treat special (pressure) boundary conditions at the envelope. The model has been implemented within the open-source Yade DEM software. Preliminary results are presented and discussed in the paper. The qualitative agreement with experimental results has been achieved.

scholarly journals DECM: A Discrete Element for Multiscale Modeling of Composite Materials Using the Cell Method

2020 ◽  
Author(s):  
Elena Ferretti
Keyword(s):  
Composite Materials ◽  
Multiscale Modeling ◽  
Static Solution ◽  
Discrete Element ◽  
Shear Loading ◽  
Relaxation Techniques ◽  
Discrete Elements ◽  
Cell Method ◽  
Finite Displacements ◽  
Complete Detachment

This paper presents a new numerical method for multiscale modeling of composite materials. The new numerical model, called DECM, consists in a DEM (Discrete Element Method) approach of the Cell Method (CM) and combines the main features of both the DEM and the CM. In particular, it offers the same degree of detail as the CM, on the microscale, and manages the discrete elements individually such as the DEM—allowing finite displacements and rotations—on the macroscale. Moreover, the DECM is able to activate crack propagation until complete detachment and automatically recognizes new contacts. Unlike other DEM approaches for modeling failure mechanisms in continuous media, the DECM does not require prior knowledge of the failure position. Furthermore, the DECM solves the problems in the space domain directly. Therefore, it does not require any dynamic relaxation techniques to obtain the static solution. For the sake of example, the paper shows the results offered by the DECM for axial and shear loading of a composite two-dimensional domain with periodic round inclusions. The paper also offers some insights into how the inclusions modify the stress field in composite continua.

scholarly journals Calibration of the Discrete Element Method Parameters in Living Juvenile Manila Clam (Ruditapes philippinarum) and Seeding Verification

2021 ◽  
Vol 3 (4) ◽  
pp. 894-906
Author(s):  
Hangqi Li ◽  
Guochen Zhang ◽  
Xiuchen Li ◽  
Hanbing Zhang ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Discrete Element Method ◽  
Static Friction ◽  
Discrete Element ◽  
Rolling Friction ◽  
Manila Clam ◽  
Average Error ◽  
Verification Test ◽  
Dem Model ◽  
Element Method

The Manila Clam is an important economic shellfish in China’s seafood industry. In order to improve the design of juvenile Manila Clam seeding equipment, a juvenile clam discrete element method (DEM) particle shape was established, which is based on 3D scanning and EDEM software. The DEM contact parameters of clam-stainless steel, and clam-acrylic were calibrated by combining direct measurements and test simulations (slope sliding and dropping). Then, clam DEM simulation and realistic seeding tests were carried out on a seeding wheel at different rotational speeds. The accuracy of the calibrated clam DEM model was evaluated in a clam seeding verification test by comparing the average error of the variation coefficient between the realistic and simulated seeding tests. The results showed that: (a) the static friction coefficients of clam-acrylic and clam-stainless steel were 0.31 and 0.23, respectively; (b) the restitution coefficients of clam-clam, clam-acrylic, and clam-stainless steel were 0.32, 0.48, and 0.32, respectively. Furthermore, the results of the static repose angle from response surface tests showed that when the contact wall was acrylic, the coefficient rolling friction and static friction of clam-clam were 0.17 and 1.12, respectively, and the coefficient rolling friction of clam-acrylic was 0.20. When the contact wall was formed of stainless steel, the coefficient rolling friction and static friction of clam-clam were 0.33 and 1.25, respectively, and the coefficient rolling friction of clam-stainless steel was 0.20. The results of the verification test showed that the average error between the realistic and simulated value was <5.00%. Following up from these results, the clam DEM model was applied in a clam seeding simulation.

Simulation of Uniaxial Compression for Flexible Fibers of Wheat Straw Using the Discrete Element Method

2021 ◽  
Vol 64 (6) ◽  
pp. 2025-2034
Author(s):  
Matthew W Schramm ◽  
Mehari Z. Tekeste ◽  
Brian L Steward
Keyword(s):  
Discrete Element Method ◽  
Wheat Straw ◽  
Young’S Modulus ◽  
Uniaxial Compression ◽  
Material Properties ◽  
Young's Modulus ◽  
Discrete Element ◽  
Flexible Fibers ◽  
Dem Model ◽  
Element Method

HighlightsSimulation of uniaxial compression was performed with flexible fibers modeled in DEM.Bond-specific DEM parameters were found to be sensitive in uniaxial compression.A calibration technique that is not plunger-dependent is shown and validated.Abstract. To accurately simulate a discrete element method (DEM) model, the material properties must be calibrated to reproduce bulk material behavior. In this study, a method was developed to calibrate DEM parameters for bulk fibrous materials using uniaxial compression. Wheat straw was cut to 100.2 mm lengths. A 227 mm diameter cylindrical container was loosely filled with the cut straw. The material was pre-compressed to 1 kPa. A plunger (50, 150, or 225 mm diameter) was then lowered onto the compressed straw at a rate of 15 mm s-1. This experimental procedure was simulated using a DEM model for different material properties to generate a simulated design of experiment (DOE). The simulated plunger had a travel rate of 40 mm s-1. The contact Young’s modulus, bond Young’s modulus, and particle-to-particle friction DEM parameters were found to be statistically significant in the prediction of normal forces on the plunger in the uniaxial compression test. The DEM calibration procedure was used to approximate the mean laboratory results of wheat straw compression with root mean square (RMS) percent errors of 3.77%, 3.02%, and 13.90% for the 50, 150, and 225 mm plungers, respectively. Keywords: Calibration, DEM, DOE, Flexible DEM particle, Uniaxial compression, Wheat straw.

scholarly journals Analysis of the Effect of Ventilation Bars on the Packing Structure of Sinter Bed by DEM Simulation

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3836
Author(s):  
Shingo Ishihara ◽  
Kizuku Kushimoto ◽  
Junya Kano
Keyword(s):  
Shear Flow ◽  
Discrete Element Method ◽  
Adhesion Force ◽  
Sinter Machine ◽  
Discrete Element ◽  
Angle Of Repose ◽  
Dem Simulation ◽  
Packing Structure ◽  
Experimental Values ◽  
Simulation Parameters

The effect of ventilation bars on the porosity of a sinter bed charged on a sinter machine was investigated. The behavior of the sinter feed was calculated by discrete element method (DEM) simulation. By taking into account the adhesion force, the sinter feed in the wet state was represented and the simulation parameters were determined to reproduce the experimental values of the angle of repose. The porosity of the sinter bed was calculated, and the mechanism of the formation of the packing structure and the cause of the distribution of porosity in each region were clarified. As a result, it is shown that in the case of shear flow, the higher the powder pressure during flow, the higher the porosity.

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