In this work, the fluid and particle dynamics in a rotor granulator system (fluid bed rotor processor) are investigated. The mathematical model is based on a three-dimensional Computational Fluid Dynamics (CFD) approach for the gas phase coupled with a Discrete Element Method (DEM). The physical properties and collision behaviour of test particles are investigated experimentally and incorporated in a viscoelastic particle contact model. The influence of several process parameters, e.g. air gap velocity and rotor speed, on the particle motion and collision behaviour is investigated. In order to check applicability and limitations of the simulation model, a novel non-intrusive Magnetic Particle Tracking (MPT) technique was used for the continuous measurement of the particle position and orientation of a single tracer particle. Thus particle trajectories as well as translational and angular velocities are obtained. The simulation model shows a good agreement with the experimental results. (C) 2012 Elsevier Ltd. All rights reserved.