CFD-DEM modelling of hydraulic transport of coarse solids in vertical pipelines

Hydraulic transport of solids in pipelines is an important operation in industries such as metallurgy, mining and mineral processing. The hydraulic behaviour of the solids, i.e. velocity and concentration spatial distributions and pressure drop, in the conveyer pipes should be well understood as it results in developing of a set of correlations which are necessary for the design of hydraulic pipelines. Pipeline slurries exhibit a complex range of flow patterns, depending upon the physical properties of carrier fluid and transported solids, the superficial liquid velocity and concentration of slurry. Most of numerical, theoretical and experimental studies in the area of vertical lifting have been focused on the transportations of fine and medium size solids; and just a few research have been carried out on the vertical hydraulic conveying of coarse particles, particularly in terms of numerical studies. Therefore, in this work, a three-dimensional Discrete Element Model (DEM) and Computational Fluid Dynamics (CFD) are coupled to study the hydraulic transport of coarse solids in vertical conveyers with carrying fluid of water under different operation conditions. The model shows a good agreement with experimental observations both qualitatively and quantitatively, and it captures some specific phenomena related to the coarse particles such as the near-wall hydrodynamic lift force, which keeps the particles away the pipe wall.