Drag model for coupled cfd-dem simulations of non-spherical particles

Abstract

The production and handling of non-spherical granular products plays an important role in many industries. It is often necessary to consider the real particle shape of the real particles as an essential prerequisite for modeling these processes reliably. This work presents a new approach for approximating the drag coefficient of non-spherical particles during simulation. This is based on the representation of the particle shape as a clump of multiple spheres, as it is often used in the Discrete Element Method (DEM). The paper describes the calculation of the drag coefficient based on the arrangement of the spheres within the clump depending on the Reynolds number and the flow direction. Numerical simulations of the flow around regularly-and irregularly shaped particles, as well as experiments in a wind tunnel, are used as the basis of model development. The new drag model is able to describe the drag coefficient for irregularly shaped particles within a wide range of Reynolds numbers. It has been implemented in the toolbox CFDEM® coupling. The new drag model is tested within CFD-DEM simulations of particle behavior in a spouted bed.