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In Discrete Element Method (DEM) simulations the choice of appropriate contact parameters is significant to obtain reasonable results. Particularly, for the determination of DEM parameters for non-spherical particles a general straightforward procedure is not available. Therefore, in a first step of the investigation here, methods to obtain the friction and restitution coefficients experimentally for single particles (Polyoxymethylene (POM) spheres and quartz gravel) will be introduced. In the following, these predetermined DEM coefficients are used as initial values for the adjustment of bulk simulations to respective experiments. In the DEM simulations, the quartz gravel particles are represented by non-spherical particles approximated by clustered spheres. The best fit approximation of the non-spherical particles is performed automatically by a genetic algorithm. In order to optimize the sliding and rolling friction coefficients for DEM simulations, the static and dynamic angle of repose are determined from granular piles obtained by slump tests and rotating drum experiments, respectively. Additionally, a vibrating plate is used to obtain the dynamic bed height which is mainly influenced by the coefficient of restitution. The adjustment of the results of the bulk simulations to the experiments is conducted automatically by an optimization tool based on a genetic algorithm. The obtained contact parameters are later used to perform batch-screening DEM simulations and lead to accurate results. This underlines the applicability of the in parts automated strategy to obtain DEM parameters for particulate processes like screening.

Phenomena related to sieving of non‐spherical particles are investigated numerically in two batch apparatuses and on a horizontally aligned continuous sieve by particle‐based simulation approaches in the framework of the discrete element method. The feed material is approximated by complex‐shaped particles composed of clustered spheres. Comparisons are made with regard to the passage through the screen as well as the segregation and transportation on the screen. Results for passage are compared to data from literature, where simulations with spherical particles were performed of a laboratory‐scale sieve operated with non‐spherical quarry rock particles. Additionally, variations in screen inclination are investigated. Experimental results are matched by the simulations. A distinctive influence of particle shape on flow rates and residence times is identified.

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In a wide field of applications, screening is required to separate bulk materials according to their particle sizes. Due to environmental, material or process related effects, particles frequently prevail in moist conditions, which is not preferred due to attractive forces altering the screening efficiency, but often not preventable. As for the design of dry screening processes detailed particle-based simulation approaches like the discrete element method (DEM) and phenomenological models are available, a step towards meeting the requirements for real particle systems under moist conditions is made. Therefore, batch screening under the influence of moisture is investigated experimentally and by using DEM simulations involving different sized polyoxymethylene and glass spheres. For this purpose, a DEM code is extended to calculate forces caused by liquid bridges, forming out between particles or walls close to each other under moist conditions. Thereby, the bridge formation and rupture and the liquid distribution are considered. First, the DEM framework is validated against experiments by monitoring the capillary and viscous force acting on two liquid bridge contact partners. Further extensive validations are performed by comparing the fraction retained over time and the final liquid distribution for discontinuous screening under the influence of various amounts of liquid for different mechanical agitations in experiments and simulations. Finally, the detailed liquid distribution over time in the DEM simulations is examined and general conclusions are drawn. The overall aim is to use the framework and the respective data, to extend phenomenological process models for screening under moist conditions in subsequent studies.