Discrete Element Method

Leitung:  P. Wriggers
Team:  B. Avci
Jahr:  2011

This project is concerned with the development of a discrete element method (DEM) code for the simulation of large particle systems in 3-D, where also complex moving boundary geometries can be taken into account. The DEM is a well established numerical method to simulate systems consisting of granular matter. Transport of particles via conveyor belts or screw conveyors, granular mixing, tumbling mills - these are just some examples of important particulate processes in industry sectors like mining, pharmaceutical and food industries. For such systems, the optimization of the design variables as well as the appropriate choice of the operating parameters is still a difficult and a challenging task. There are many parameters which have a significant impact on the performance ability of a system, e.g., the rotational speed of a screw conveyor, the grinding charge in a mill, the size and the shape of the lifters in a mill related to the grain size of the granular material, the filling degree of a mixer. Generally, most parameters are very difficult to understand and it is very expensive to measure the sensitivity of a system due to a change of some parameters. Regarding this, the DEM allows to simulate and to analyze the motion of the granular matter in a system for a wide range of different sets of parameter combinations. Moreover, in the experimental approach it is difficult and sometimes impossible to measure the quantities of the granular grains, whereas the DEM allows easily to monitor the position of each single grain, its velocities and also the contact forces to which the grains are subjected. Thus, applying the DEM for numerical studies of granular systems, accurate predictions can be obtained for granular industrial processes. It can contribute to the understanding and as a result to the optimization of these kind of complex engineering problems.

Horizontal transport of particles via a rotational screw conveyor

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Mixing of granular material in a rotating drum

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Granular flow through a hopper

     

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Insertion of a pile into granular media

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