Discrete-element method application to mixing and segregation model in industrial blending system

2004 ◽  
Vol 19 (2) ◽  
pp. 623-627 ◽  
Author(s):  
Kenji Yamane
Keyword(s):  
Discrete Element Method ◽  
Axial Direction ◽  
Discrete Element ◽  
Rotating Cylinder ◽  
Pharmaceutical Products ◽  
Particle Migration ◽  
Interesting Phenomenon ◽  
Radial Segregation ◽  
Pharmaceutical Industries ◽  
Element Method

In the pharmaceutical industries, mixing is a critical process. Pharmaceutical products consist of various components, including active ingredient and excipient. After mixing, we should get a homogeneous mixture to ensure the quality of the final products, such as tablets or capsules. For that reason, segregation is an unwanted phenomena in the mixing process. In this study, discrete-element method (DEM) was applied to investigate the mechanism of segregation in a rotating cylinder; basic equipment for powder mixing. In addition, segregation of particles in a rotating cylinder is a very interesting phenomenon and has captured the curiosity of not only industrial engineers, but also physicists. DEM can simulate segregation in a rotating cylinder three-dimensionally. In particular, radial segregation, which was quickly observed, was quantified by computing the granular temperature of the system. Furthermore, particle migration in axial direction, which may be the source of axial segregation, was also shown by the DEM simulation.

Dem Application to Mixing and Segregation Model in Industrial Blending System

2000 ◽  
Vol 627 ◽  
Author(s):  
Kenji Yamane
Keyword(s):  
Industrial Application ◽  
Granular Flows ◽  
Industrial Process ◽  
Axial Direction ◽  
Rotating Cylinder ◽  
Particle Migration ◽  
Basic Study ◽  
Dem Simulation ◽  
Radial Segregation ◽  
Pharmaceutical Industries

ABSTRACTTo predict the motion of powders and grains is important in pharmaceutical industries. Many pharmaceutical engineers have studied granular flows related to powder mixing. In this study, DEM (Discrete Element Method) approach is presented as an industrial application to investigate the behavior of granular flows. The granular motion in a rotating cylinder was focused on the basic study of DEM for industrial application. Rotating cylinder is a fundamental system for commercial blenders widely used in many industrial process. In addition, segregation of particles in a rotating cylinder is very interesting phenomena. Not only industrial engineers but also physicists research this segregation mechanism. DEM simulation showed radial segregation of two different size particles in a rotating cylinder. From the viewpoint of calculated granular temperature, radial segregation system was analyzed. Particle migration in axial direction, which is the source for axial segregation, was also shown by DEM simulation.

scholarly journals Analysis of particle dynamics in a pin mill by Discrete Element Method

2021 ◽  
Vol 249 ◽  
pp. 07010
Author(s):  
Wei Pin Goh ◽  
Mojtaba Ghadiri
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Particle Dynamics ◽  
Operating Conditions ◽  
Impact Testing ◽  
Process Conditions ◽  
Pharmaceutical Industries ◽  
Element Method

Milling is an important process for tailoring the particle size distribution for enhanced attributes, such as dissolution, content uniformity, tableting, etc., especially for active pharmaceutical ingredients and excipients in pharmaceutical industries. Milling performance of particulate solids depends on the equipment operating conditions (geometry, process conditions and input energy etc.) as well as material properties (particle size, shape, and mechanical properties, such as Young’s modulus, hardness and fracture toughness). In this paper the particle dynamics in a pin mill is analysed using Discrete Element Method (DEM), combined with a novel approach for assessing particle breakability by single particle impact testing. A sensitivity analysis is carried out addressing the effect of the milling conditions (rotational speed and feed particle flow rate), accounting for feed mechanical properties on the breakage behaviour of the particles. Particle collision energy spectra are calculated and shown to have a distribution with the upper tail end being close to the maximum energy associated with the collision with the rings. Breakage is primarily due to collisions with the rings, except for large particles that are comparable in size with the gap between the rings, nipping is also a contributory breakage mechanism.

scholarly journals Modeling Water-Induced Base Particle Migration in Loaded Granular Filters Using Discrete Element Method

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1976
Author(s):  
Gang Zhang ◽  
Jahanzaib Israr ◽  
Wenguo Ma ◽  
Hongyu Wang
Keyword(s):  
Discrete Element Method ◽  
Stress Reduction ◽  
Limit Equilibrium ◽  
Discrete Element ◽  
Particle Migration ◽  
Retention Capacity ◽  
Effective Stresses ◽  
Proposed Model ◽  
Granular Filters ◽  
Element Method

Results are reported from a series of filtration tests simulated using coupled computational fluid dynamics and the discrete element method (CCFD-DEM) to investigate the factors controlling the mechanism of base particle erosion and their subsequent capture in loaded granular filters. Apart from geometrical factors such as particle and void sizes, the filter effectiveness was found to be controlled by the magnitudes of the hydraulic gradients and the effective stresses. The results of numerical simulations revealed that the base soils exhibit significant stress reduction that reduces further due to seepage, and the base particles migrate into the filter, bearing very low effective stresses (i.e., localized piping in base soil). Based on the limit equilibrium of hydraulic and mechanical constraints, a linear hydromechanical model has been proposed that governs the migration and capture of base particles in the filter (i.e., filter effectiveness avoiding piping) for cases simulated in this study. Nevertheless, the proposed model agrees closely with the simulation results of this study and those adopted from other published works, thereby showing a reasonable possibility of using the proposed model as a measure of retention capacity of loaded protective filters.

scholarly journals Discrete element method investigation of the milling characteristic in a rice mill

2022 ◽  
Vol 13 (1) ◽  
pp. 15-22
Author(s):  
Yan Zhang ◽  
Quan Han ◽  
Chunlin Xun ◽  
Gongtan Zhang
Keyword(s):  
Discrete Element Method ◽  
Milling Time ◽  
Axial Direction ◽  
Discrete Element ◽  
Milling Process ◽  
Particle Collisions ◽  
Left Hand ◽  
Rice Grains ◽  
Milling Performance ◽  
Element Method

Abstract. A milling chamber consisting of a rice sieve and a rotating roller plays critical roles in modulating the milling performance of rice grains. However, the mechanism of how the geometries of the rice sieve and rotating roller affect the particle collisions and the interaction time remains not fully understood. Our experimental results show that the milling degree and rate of broken rice of the octagonal rice sieve are largest among the hexagonal sieve, octagonal sieve, and circular sieve. Through the discrete element method, we illustrate that the peak milling degree at the octagonal sieve is attributed to the competition between the decreasing force and increasing milling time with the increase in edges. In addition, the geometries of the convex ribs of the rotating roller are investigated to optimize the structure of the milling chamber. In the left-hand spiral or right-hand spiral of the convex ribs, the rice particles are accumulated in the inlet or outlet regions, respectively, which leads to an uneven milling degree in the axial direction. The uniformity of a milling process can be promoted by increasing the number of convex ribs, which will reduce the milling degree on the other hand.

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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