Coarse-grained CFD-DEM simulation of elbow erosion induced by dilute gas-solid flow: A multi-level study

A coarse-grained (CG) approach, which can significantly facilitate large-scale modelling of particle systems, was proposed for predicting the surface erosion in an elbow pipe induced by dilute gas-particle flow. In the approach, the particle sizes and forces such as gas-particle interactions are scaled in terms of a CG ratio. A particle-level Shear Impact Energy Model (SIEM) is applied to calculate the erosion rate. The accuracy of the CG approach is evaluated extensively for different particle concentrations and tube diameters. The CG approach is found to work satisfactorily when suitable fluctuation velocities are used at the inlet of the tube. The reason is that the fluctuation velocities keep the kinetic energy of particles conservative within the elbow. An equation was provided for determining the magnitude of the fluctuation velocity in CG modelling of the elbow pipe and its universality is tested under different coarse-grained ratios and particle concentrations.