A Revised Coarse-Graining Approach for Simulation of Highly Poly-Disperse Granular Flows

Simulation of poly - disperse granular flow is required to model mixing and transport of lumpy materials through industrial components. The discrete element method (DEM) is widely used to model such flow systems. Therefore, it is an important tool for many industrial applications. But, it is computationally expensive for a large number of particles. To reduce the computation time, we have adopted an alternative coarse graining method by introducing a parcel approach consisting equal number of smaller particles. The choice of coarse grain ratio is non uniform in our model. This is beneficial compare to traditional uniform coarse grain model in terms of more flexibility to reduce number of particles. Hence, specially for the system, where large heterogeneity is involved in size distribution and therefore much higher number of small particles are used to meet a certain mass ratio, this method is more efficient. However, due to violating geometric similarity, this method does not reveal the correct particle segregation dynamics through the densely packed particle bed. Therefore, we have implemented a revised model introducing a correction parameter to measure contact diameter during collision between parcels containing small and the large particles. The results, when quantified with a reference DEM solution show fairly good agreement between the revision model and reference DEM simulations.