Flow Behaviour of Ultrafine Cohesive Powder: View from Inside

Abstract Discrete element method (DEM) simulations will be presented with respect to modelling the standardised shear testers like Jenike shear cell or biaxial box. The main impact is made on modelling the flow behaviour of commercially widely used ultratine cohesive powders (TiOz, CaC03) and the influence of hysteretic contact models describing the microscopic particle-particle interaction behaviour with the load-dependent contact adhesion. The atomic force microscope (AFMFbased measurements of adhesion and friction forces between two particles are used to verify the contact behaviour on the micro-level. Therefore, the macroscopic dynamic behaviour of cohesive powder flow can be "microscopically " investigated and understood. Reference experiments with the Jenike shear cell coupled with volumetric strain measurements by triangulating laser displacement sensors will be shown and discussed as well. Comparison will be made between the simulations and experiments