Stress Tensor Measurements of Sheared Packings of Non-Spherical Particles*

In processing apparatus for dense gas-solid flows, the motion of the constituent particles is dictated by interactions with the ambient gas and inter-collisions with neighbouring particles. Typically, these particles are non-spherical in nature, such as the elongated biomass particles used in the production of biofuels in fluidised bed reactors. While experiments at both the laboratory and industrial scale can be used to study particle dynamics, information pertaining to particle contact neighbourhood and the inter-particle forces in the bulk are difficult to ascertain, thus necessitating a numerical approach.

We present a CFD-DEM approach to calculate particle forces and hence stress tensors in packings of elongated particles with varying packing fraction, mutual alignment and shear rates. The packings are subject to shear rates comparable to the deformations experienced by particles in real fluidised bed reactors. We also compare the stress tensors calculated with those for packings of spherical particles. Such calculations will prove valuable in the derivation of expressions relevant for industrial-scale simulations.