Effect of particle shape in grinding mills using a GPU based DEM code.

The reduction of raw materials into particulate form using grinding mills is an energy and cost intensive task. Optimization of grinding processes is not trivial as obtaining information on the dynamics of media in the mill via experimental means is extremely difficult due to the harsh environment inside, thus computational modeling is the most feasible option to obtain information on the dynamics of the media. However the computational cost of modeling each particle is high, resulting in the shape of the media being approximated by simple shapes and in most cases a reduction in the size of the mill. Even with these simplifications typical simulations take many weeks to months to complete making it unfeasible for quick design prototyping and process optimization. In the last decade the Graphical Processor Unit (GPU) has enabled large scale simulations of tens of millions of spheres in ball mills using the Blaze-DEM GPU code. Recently this code was expanded to provide detailed contact detection for polyhedra using the volume overlap method which is the most accurate approach amongst commercial and academic codes. In this study we firstly validate the code against experiment for polyhedral both as well as spherical particles. We then perform a number of simulations to study the effect of particle shape, in particular angularity and aspect ratio. We clearly demonstrate the importance of accurate particle shape representation in mill simulations by comparing charge profile, power draw and force network for various polyhedra approximations against spheres