Comparison of three types of swirling generators in coarse particle pneumatic conveying using CFD-DEM simulation

Abstract

The present investigation aims at developing a gas and particle flow model based on CFD-DEM coupling for three types of swirling generators. Grid and time size dependence tests were performed to validate the numerical model; the prediction ability of the model was confirmed through comparison with experimental data. Detailed studies of certain parameters (including the fluid pattern, swirling number and pressure drop) were based on the CFD method for the three-lobed, rifle and internal spiral vanes swirling generator pipelines. These studies were performed using dimensionless forms and numerical simulations. The peak regions of the axial velocity for the three-lobed and internal spiral vanes pipes have obvious asymmetrical patterns that rotate quasi-periodically downstream; the three-lobed pipe generates the largest swirl number and decays the fastest. In addition, quantitative calculations using the CFD-DEM coupling model, which include the particle distribution and the pneumatic conveying efficiency, suggest that the three-lobed swirling generator is suitable for the preliminary conveying stage and that the internal spiral structure in this work is a favorable option for swirling pneumatic conveying systems for coarse particles.