Stefan Heinrich

Identification of micro parameters for discrete element simulation of agglomerates

The mechanical behaviour of solid particles like agglomerates, granules or crystals strongly depends on their micro structure, e.g. structural defects and porosity. In order to model the mechanical behaviour of these inhomogeneous media the discrete element method has been proven to be an appropriate tool. The model parameters used are typically micro parameters like bond stiffness, particle-particle contact stiffness, strength of the bonds. Due to the lack of general methods for a direct micro parameter determination, normally laborious parameter adaptation has to be done in order to fit experiment and simulation. In this contribution a systematic and automatic way for parameter adaptation using real experiments is proposed. Due to the fact, that discrete element models are typically systems of differential equations of very high order, gradient based methods are not suitable. Hence, the focus will be on derivative free methods.

Particle dynamics in the fluidized bed: Magnetic particle tracking and discrete particle modelling

In this contribution, the particle dynamics and the granular flow in a lab-scaled rotor granulator system (fluid bed rotor processor) are investigated on the scale of individual particles. The numerical approach is based on a Discrete Element Method (DEM) coupled with three-dimensional Computational Fluid Dynamics (CFD) for the gas phase. In this work a novel non-intrusive particle tracking technique, the Magnetic Particle Tracking (MPT) has been used to study the complex granular flow in rotor granulators. The technique allows a simultaneously and non-intrusivedescription of the translational as well as the rotational movement of a tracer particle in dense granular flow. The focus is on the analysis of the particle rotation behaviour at different process conditions.

Numerical estimation of the restitution coefficient for dry and wet agglomerates

In this contribution a novel simulation tool, which is able to predict the agglomerate deformation and breakage during different loading conditions, was developed. This simulation system is based on the Discrete Element Method (DEM). For a better understanding of the soft, non-elastic deformation behaviour of wet and dry agglomerates, the models of liquid and solid bridges have been implemented in the DEM to perform a detailed simulation. As a result, the dependency of the restitution coefficient on the viscosity of the binder, impact velocity and agglomerate size and shape were obtained.

Novel multiscale simulation environment for modeling of fluidized bed granulation

In this contribution the architecture of a novel simulation environment, which has been developedfor the multiscale modeling of fluidized bed spray granulation, is presented. The novel environment describes the granulation process on four different time and length scales. On the one hand, it allows to predict dynamics of the global production process, whereby, on the other hand, material properties can be considered.