CFD–DEM investigation of gas-solid flow and wall erosion of vortex elbows conveying coarse particles

Vortex elbows are generally used to mitigate erosive wear while conveying fine particles. This paper presents a modified vortex elbow designed to handle coarse particles. Gas–solid flows and wall erosion of the modified vortex elbow are studied by the combined approach of discrete element model for particles and computational fluid dynamics for the gas phase. The validity of the model is first examined by comparing the predicted pressure drop and wall erosion with experimental measurements for a standard elbow. Then, via the model, the effects of particle size on the flow characteristics and elbow erosion of the modified vortex elbow are quantified and compared with those of the standard elbow. The results show that the vortex elbow decreases the maximum penetration ratio and total penetration depth for all the particle sizes considered. These effects become more significant for larger particles. The wall erosion is also elucidated using flow characteristics.