scholarly journals COMPARISON OF THE CRUSHED MATERIAL MOVEMENT MODEL IN THE BODY OF A VERTICAL CENTRIFUGAL MILL

2021 ◽  
Vol 13 (1) ◽  
pp. 119-124
Author(s):  
David MINASYAN ◽  
◽  
Alana ELOEVA ◽  
Sergey NAZAROV ◽  
Pavel SKVORTSOV ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Hydrodynamic Model ◽  
Initial Velocity ◽  
Bulk Material ◽  
Discrete Element ◽  
The Body ◽  
Crushed Material ◽  
Centrifugal Mill ◽  
Bulk Medium ◽  
Element Method

Introduction. Improving the performance, increasing productivity, reducing the metal consumption of grinding equipment and other mining machines is usually a very expensive process. It requires a large amount of development work, the production of prototype machines, and a large amount of experimental research. In this regard, one of the most important tasks is to simulate the movement of bulk material in operations for processing minerals in various equipment. In such modeling, the discrete element method (DEM) is widely used. The purpose of the research is to compare the models of the movement of the crushed material in the body of a vertical centrifugal mill. Research methodology The motion of the bulk medium in a vertical centrifugal mill was modeled using two models. In the first model, the cylindrical body of the centrifugal mill was assumed to be stationary, and on its surface and on the entire surface of the rotor, conditions were set for the absence of a relative speed of movement of the crushed material. In the second model, a hydrodynamic model was used to describe the motion of a granular material as a viscous incompressible liquid with a compression ratio that depends on the pres-sure. In this model, the viscosity coefficient is represented as consisting of two terms: a constant (analogous to dynamic viscosity) and an excess pressure over hydrostatic pressure. Research results It is established that both models give the same character of the movement of the material in the mill body. It is determined that the absolute velocity of the material movement near the walls and near the mill rotor is approximately the same for both models, but in the data obtained using the hydrodynamic model, as the material moves away from the walls and the rotor, it slows down more than for the model using the discrete element method. It is revealed that the absolute velocity of the material movement near the walls and at the axis of the mill rotor is approximately the same for both models, but in the data obtained using the hydrodynamic model, as it moves away from the walls and the rotor, the material slows down significantly more than for the model using the discrete element method. Based on the simulation results, it can be concluded that for a more accurate simulation of the processes occurring during the rapid movement of bulk material in the grinding equipment, it is preferable to use a model using the discrete element method. It is advisable to use the hydrodynamic model for conducting a large number of search dawns or as a predicate model that will allow you to quickly set the initial velocity values for particles in a model using the discrete element method. Conclusions 1. A hydrodynamic model of the motion of a bulk medium in a vertical centrifugal mill, represented as a viscous incompressible liquid with a compression coefficient depending on the pressure has been developed. 2. It is established that for a more correct simulation of the processes occurring during the rapid movement of bulk material in the grinding equipment, it is preferable to use a model using the discrete element method. At the same time, it is advisable to use the hydrodynamic model for conducting a large number of search calculations or as a predicate model that will allow you to quickly set the initial velocity values for particles in a model using the discrete element method.

Design modification of iron ore bearing transfer chute using discrete element method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Saprativ Basu ◽  
Arijit Chakrabarty ◽  
Samik Nag ◽  
Kishore Behera ◽  
Brati Bandyopadhyay ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Iron Ore ◽  
Bulk Material ◽  
Flow Behavior ◽  
Material Model ◽  
Discrete Element ◽  
Content Type ◽  
Iron Ore Fines ◽  
Cohesive Materials ◽  
Element Method

Purpose The dryer feed chute of the pellet plant plays an important role in the pelletizing process. The chute discharges sticky and moist iron ore fines (<1 mm) to the inline rotary dryer for further processing. Since the inception of the installation of the dryer feed chute, the poor flowability of the feed materials has caused severe problems such as blockages and excessive wear of chute liners. This leads to high maintenance costs and reduced lifetime of the liner materials. Constant housekeeping is needed for maintaining the chute and reliable operation. The purpose of this study is to redesign the dryer feed chute to overcome the above challenges. Design/methodology/approach The discrete element method (DEM) has been used to model the flow of cohesive materials through the transfer chute. Physical experiments have been performed to understand the most severe flow conditions. A DEM material model is also developed for replicating the worst-case material condition. After identifying the key problem areas, concept designs were proposed and simulated to assess the design improvements to increase the reliability of chute operation. Findings Flow simulations correlated well with the existing flow behavior of the iron ore fines inside the chute. The location of the problematic areas has been validated with that of the previously installed chute. Subsequently, design modifications have been proposed. This includes modification of deflector plate and change in slope and cross-section of the chute. DEM simulations and analysis were conducted after incorporating these design changes. A comparison in the average velocity of particle and force on chute wall shows a significant improvement using the proposed design. Originality/value Method to calibrate DEM material model was found to provide accurate prediction and modeling of the flow behavior of bulk material through the real transfer chute. DEM provided greater insight into the performance of the chute especially modeling cohesive materials. DEM is a valuable design tool to assist chute designers troubleshoot and verify chute designs. DEM provides a greater ability to model and assess chute wear. This technique can help in achieving a scientific understanding of the flow properties of bulk solids through transfer chute, hence eliminate challenges, ensuring reliable, uninterrupted and profitable plant operation. This paper strongly advocates the use of calibrated DEM methodology in designing bulk material handling equipment.

Discrete Element Method for Modeling Penetration

2004 ◽  
Author(s):  
Federico A. Tavarez ◽  
Michael E. Plesha
Keyword(s):  
Discrete Element Method ◽  
Solid Phase ◽  
Bulk Material ◽  
Discrete Element ◽  
Test Problems ◽  
Careful Study ◽  
Specific Test ◽  
Element Size ◽  
Seamless Transition ◽  
Element Method

The Discrete Element Method (DEM) discretizes a material using rigid elements of simple shape. Each element interacts with neighboring elements through appropriate interaction laws. The number of elements is typically large and is limited by computer speed. The method has seen widespread applications to modeling particulate media and more recently to modeling solids such as concrete, ceramic, and metal. For problems with severe damage, DEM offers a number of attractive features over continuum based numerical methods, with the primary feature being a seamless transition from solid phase to particulate phase. This study illustrates the potential of DEM for modeling penetration and briefly points out its numerous advantages. A weakness of DEM is that its convergence properties are not understood. The crucial question is whether convergence is obtained as DEM element size vanishes in the limit of model refinement. The major focus of our investigation will be a careful study of convergence for modeling the degradation of a solid into fragments. Our results show that indeed convergence is obtained in several specific test problems. Moreover, elastic interelement stiffness and damping properties were proven to be particle size-independent. However, convergence in material failure due to crack growth is obtained only if the interparticle potentials are properly constructed as functions of DEM element size and bulk material properties such as elastic modulus and fracture toughness.

Co-simulation framework of discrete element method and multibody dynamics models

2018 ◽  
Vol 35 (3) ◽  
pp. 1481-1499 ◽  
Author(s):  
Stef Lommen ◽  
Gabriel Lodewijks ◽  
Dingena L. Schott
Keyword(s):  
Discrete Element Method ◽  
Multibody Dynamics ◽  
Material Handling ◽  
Bulk Material ◽  
Discrete Element ◽  
Particulate Material ◽  
Content Type ◽  
Position Data ◽  
The Stability ◽  
Element Method

Purpose Bulk material-handling equipment development can be accelerated and is less expensive when testing of virtual prototypes can be adopted. However, often the complexity of the interaction between particulate material and handling equipment cannot be handled by a single computational solver. This paper aims to establish a framework for the development, verification and application of a co-simulation of discrete element method (DEM) and multibody dynamics (MBD). Design/methodology/approach The two methods have been coupled in two directions, which consists of coupling the load data on the geometry from DEM to MBD and the position data from MBD to DEM. The coupling has been validated thoroughly in several scenarios, and the stability and robustness have been investigated. Findings All tests clearly demonstrated that the co-simulation is successful in predicting particle–equipment interaction. Examples are provided describing the effects of a coupling that is too tight, as well as a coupling that is too loose. A guideline has been developed for achieving stable and efficient co-simulations. Originality/value This framework shows how to achieve realistic co-simulations of particulate material and equipment interaction of a dynamic nature.

scholarly journals Calibration of bulk material model in Discrete Element Method on example of perlite D18-D

2019 ◽  
Vol 21 (2) ◽  
pp. 351-357
Author(s):  
Bolesław Karwat ◽  
Ryszard Machnik ◽  
Jerzy Niedźwiedzki ◽  
Magdalena Nogaj ◽  
Piotr Rubacha ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Bulk Material ◽  
Material Model ◽  
Discrete Element ◽  
Element Method

scholarly journals Research of the polymer granules shape and size influence on their tribological properties

2020 ◽  
pp. 52-61
Author(s):  
V. M. Vytvytskyi ◽  
A. Ya. Karvatskyi ◽  
I. O. Mikulionok ◽  
O. L. Sokolskyi
Keyword(s):  
Discrete Element Method ◽  
Tribological Properties ◽  
Bulk Material ◽  
Viscoelastic Model ◽  
Discrete Element ◽  
Angle Of Repose ◽  
Calculation Results ◽  
Feeding Zone ◽  
Discrete Motion ◽  
Element Method

The use of a mathematical model of discrete motion of bulk material were justified for movement of polymer granules in the working channel of feeding zone of the screw extruder as a set of particles moving relative to each other based on the Discrete Element Method taking into account the influence of the shape and the size of polymer granules on their tribological properties on the example of the problem of forming the angle of repose. The study of the interaction among the granules of the following four polymers has been conducted: high-density polyeth-ylene of brand Marlex HHM 5502BN (HDPE), copolymer of ethylene with vinyl acetate (sevilene) of brand 11104-030(CEV), polystyrene of brand Denka Styrol MW-1-301 (PS), polyvinyl chloride of brand SorVyl G 2171/9005 11/01 (PVC), which are selected because they are widely used in industry and at the same time differ from each other in shape, size and physical and mechanical characteristics. The Hertz-Mindlin viscoelastic model was used to de-scribe the interaction between granules, which assumes that the sphere-shaped particles do not deform upon con-tact and overlap each other by a predetermined amount, forming a contact patch. The study was carried out in the EDEM software package. The calculation results for the formation of an angle of repose of natural methods and numerical experiment were given with the two approaches to modeling the shape of pellets were analyzed: the consideration in the form of granules in the form of spheres and in the form of multisphere, when the calculated shape of the pellets as close to real. The results of the calculations on the formation of the angle of repose prove that the discrete motion model of bulk material based on the discrete element method when using the form of gran-ules close to real better reproduces the behavior of bulk materials compared to spherical granules.

Numerical Simulation of Vibration Compacting Process on Hydrous Embankment by Discrete Element Method

2012 ◽  
Vol 594-597 ◽  
pp. 506-511
Author(s):  
Bao Tao Huang ◽  
Xin Yuan ◽  
Jie Zhou ◽  
Ding Liu
Keyword(s):  
Numerical Simulation ◽  
Discrete Element Method ◽  
Discrete Element ◽  
The Body ◽  
Coarse Grained ◽  
Material Parameters ◽  
Irregular Particle ◽  
Micro Particles ◽  
Simulation Results ◽  
Element Method

In this article, the discrete element method is used to investigate the coarse particle material close-grained space structure evolutionary process submitted to a vibrating compressive load. 2-D generation algorithm about irregular particle generation and particle contact interface generation was adopted. Irregular particles were randomly generated in the designated categories with this algorithm. The microcosmic material parameters are endowed to irregular particle and pore space. The microcosmic material parameters are also endowed to water. The irregular micro-particles close-grained process was been analyzed under vibrating compressive. The numerical simulation results demonstrate that the coarse-grained soil Irregular particles compacting effect of the simulation results with the actual theoretic situation in the basic line. The Irregular particles were whirligig and movement, location of the rearrangement as a whole to show the close-grained process. The use of discrete element method can be clearly informed that the simulation of the embankment particles in the body vibration. This research offers a new idea and continent method for compaction dense of hydrous embankment.

Discrete element method to model cracking for two layer systems

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 101-108
Author(s):  
Daniel Varney ◽  
Douglas Bousfield
Keyword(s):  
Discrete Element Method ◽  
Flexural Modulus ◽  
Single Layer ◽  
Discrete Element ◽  
Flexural Stress ◽  
Layer System ◽  
Three Point Bending ◽  
Moving Force ◽  
Coating Layers ◽  
Element Method

Cracking at the fold is a serious issue for many grades of coated paper and coated board. Some recent work has suggested methods to minimize this problem by using two or more coating layers of different properties. A discrete element method (DEM) has been used to model deformation events for single layer coating systems such as in-plain and out-of-plain tension, three-point bending, and a novel moving force picking simulation, but nothing has been reported related to multiple coating layers. In this paper, a DEM model has been expanded to predict the three-point bending response of a two-layer system. The main factors evaluated include the use of different binder systems in each layer and the ratio of the bottom and top layer weights. As in the past, the properties of the binder and the binder concentration are input parameters. The model can predict crack formation that is a function of these two sets of factors. In addition, the model can predict the flexural modulus, the maximum flexural stress, and the strain-at-failure. The predictions are qualitatively compared with experimental results reported in the literature.

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