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D. Markauskas and H. Kruggel-Emden
surface (stratification), whereby particles smaller than the aperture size pass through
the screen openings depending on their shapes [8]. In addition, the transport of
the bulk material during the continuous screening process and various mechanical
excitations also influence the particle passage [9, 10].
For the design and optimization of apparatus-specific parameters as well as operational ones of a screening process under stationary conditions, various phenomenological process models are available. Some simple models, which are commonly
used in stationary process simulation packages, only consider the integral outcome
of the separation operation, while others represent the particle size separation temporally or spatially resolved. In addition, some of the models take the interacting
processes of stratification and the actual particle passage through the screen into
account. All phenomenological models have in common that they require a set of
empirical parameters, which are material, operation and apparatus-specific and are
usually determined from experimental investigations. In contrast, particle-based simulation methods such as the discrete element method (DEM), based on the work by
Cundall und Strack [11], provide detailed insights into the process of screening and
allow, after appropriate validations, the design and optimization of equipment as well
as of operating parameters. Up to now, only a few screening investigations addressed
systems of realistic particles of complex shape or under the influence of liquid.
Applications of the DEM with the aim to directly derive parameters for dynamic
phenomenological models for the process step screening were rarely carried out and
are yet not adequately accomplished.
That the DEM is capable after appropriate calibration to perform a benchmarking
of screening process models and can even address moist particles is shown in the
following. The data obtained from the DEM can thereafter be utilized to derive and
optimize novel process models which can then be utilized in solids process simulation
frameworks.
2 Discrete Element Method (DEM)
The discrete element method (DEM) first proposed by Cundall and Strack [11] as
well as Walton and Braun [12] is a particle-based simulation approach that provides
detailed insights into various processes and has become a common tool for modeling
particulate systems (see [13–16]). After validation, it offers the possibility to optimize
equipment and operating parameters without carrying out extensive experiments
before each study. By applying this method, the movement and interaction of each
individual particle within a considered computational domain can be represented and
tracked. Contact forces between the particles and the system environment as well as
possible additional forces resulting from the presence of liquid are used to determine
velocities, positions and spatial orientations of all particles contained in the system
using the Newton’s and Euler’s equations of motion.
D. Markauskas and H. Kruggel-Emden
surface (stratification), whereby particles smaller than the aperture size pass through
the screen openings depending on their shapes [8]. In addition, the transport of
the bulk material during the continuous screening process and various mechanical
excitations also influence the particle passage [9, 10].
For the design and optimization of apparatus-specific parameters as well as operational ones of a screening process under stationary conditions, various phenomenological process models are available. Some simple models, which are commonly
used in stationary process simulation packages, only consider the integral outcome
of the separation operation, while others represent the particle size separation temporally or spatially resolved. In addition, some of the models take the interacting
processes of stratification and the actual particle passage through the screen into
account. All phenomenological models have in common that they require a set of
empirical parameters, which are material, operation and apparatus-specific and are
usually determined from experimental investigations. In contrast, particle-based simulation methods such as the discrete element method (DEM), based on the work by
Cundall und Strack [11], provide detailed insights into the process of screening and
allow, after appropriate validations, the design and optimization of equipment as well
as of operating parameters. Up to now, only a few screening investigations addressed
systems of realistic particles of complex shape or under the influence of liquid.
Applications of the DEM with the aim to directly derive parameters for dynamic
phenomenological models for the process step screening were rarely carried out and
are yet not adequately accomplished.
That the DEM is capable after appropriate calibration to perform a benchmarking
of screening process models and can even address moist particles is shown in the
following. The data obtained from the DEM can thereafter be utilized to derive and
optimize novel process models which can then be utilized in solids process simulation
frameworks.
2 Discrete Element Method (DEM)
The discrete element method (DEM) first proposed by Cundall and Strack [11] as
well as Walton and Braun [12] is a particle-based simulation approach that provides
detailed insights into various processes and has become a common tool for modeling
particulate systems (see [13–16]). After validation, it offers the possibility to optimize
equipment and operating parameters without carrying out extensive experiments
before each study. By applying this method, the movement and interaction of each
individual particle within a considered computational domain can be represented and
tracked. Contact forces between the particles and the system environment as well as
possible additional forces resulting from the presence of liquid are used to determine
velocities, positions and spatial orientations of all particles contained in the system
using the Newton’s and Euler’s equations of motion.