A novel approach for modelling impermeable bonded-particle-structures in resolved CFD-DEM

The numerical modelling of a 3-component system – consisting of a fluid flow, particles and a multi-dimensional, non-rigid material that can deform under the influence of the particles and the fluid - is highly complex. Such a system can be modelled with high numerical effort using a resolved CFD-DEM simulation. While the particles and the fluid are represented in such a simulation with the DEM respectively CFD, the bonded particle method (BPM) can be used for modelling the flexible material in the DEM. However, the volume occupied by the bonds are usually not taken into account in the coupled CFD-DEM, so that a flow through the modelled material is possible. Therefore, a method is introduced adapting the void fraction calculation to account for the volume represented by the bonds, followed by a validation of its functionality and suitability for the representation of flexible materials in flows. For this purpose, the flow around a fixed cylinder and a fixed sphere is modelled using the introduced method and compared with the results of a CFD simulation, demonstrating the applicability. Furthermore, a comparison of the modelled drag force with a mechanistic calculated drag force shows good agreements. Finally, an example is used to show that the method presented is suitable for modelling the deformation of a material in a fluid flow. • New Approach for considering bonds in resolved CFD-DEM simulation is introduced. • Comparison of the method with CFD simulations and mechanistic drag forces show good agreements. • Possibility to model a deformation of a flexible bonded structure in a flow field is demonstrated.