Influence of the contraction angle on the injection of large coal particles

Abstract

The CFD–DEM coupling numerical calculation and pneumatic conveying experiment were carried out on the injection of large coal particles. The influence of contraction angle on the flow field and coal particles was studied by the distribution of turbulent kinetic energy, instantaneous distribution of particles and trajectories of particles. The performance of injection was studied by injected particles, remaining particles and mass flux of particles. The results show that the center of turbulence is located in the top of the mixing section and constriction section. The particle collision frequency increases with the increase of the contraction angle, and the conveying state of coal particles changes from uniform flow to bottom flow. When the contraction angle is 12.5°, the injector has the maximum efficiency. Since the range of mass flux is less than 1%, 10°–15° can be regarded as the optimal contraction angle.