Developing Mechanistic Understanding of Granular Behaviour in Complex Moving Geometry using the Discrete Element Method. Part A: Measurement and Reconstruction of Turbula (R) Mixer Motion using Positron Emission Particle Tracking

In this work the complex motion of the Turbula (R) mixer has been measured by Multiple-Positron Emission Particle Tracking (Multiple PEPT) in order to set-up a DEM numerical model. Positron emitting radioactive tracers were attached to three of the pivot bearings on the shaft of the mixer to enable the rotation and translation of the mixer chamber to be tracked in the PEPT camera. The measured movement was mathematically reconstructed and imported into DEM in order to apply the same movement to the modelled vessel. The three-dimensional motion of particles in a vessel located in the Turbula mixer was then calculated using Discrete Element Modelling (DEM). The DEM code used in this work is a commercially available package provided by DEM-Solutions (EDEM). Good qualitative agreements have been found between the DEM simulations and experimental data from the literature for the degree of segregation in bi-disperse particle mixtures at long mixing times.