Experiment and simulation analysis of the suspension behavior of large (5–30 mm) nonspherical particles in vertical pneumatic conveying

Abstract

The particle suspension velocity has a strong practical impact on pneumatic conveying systems. The barycenter and centroid of large nonspherical particles are not in the same point, and the particles rotate under the action of torque when the particles are subjected to an unbalanced force in the flow field. This rotation causes the vortexes or turbulence near the particles. The stirring effect of large particle is especially obvious and directly affects the particle suspension behavior. To investigate the suspension behavior of large (5–30 mm) nonspherical particles in vertical pneumatic conveying, the CFD-DEM coupling method is adopted to realize the coupling between the solid phase and the gas phase and establish the coupling simulation model between the nonspherical particles and flow field. The suspension velocity relations of three flow drag zones are calculated on the basis of the particle-size method and the relationships between the pipe diameter, particle shape, Reynolds number and fluid drag coefficient. It will help in designing and operation of pneumatic conveying systems. The dynamic characteristics of large nonspherical particles in the vertical flow field are analyzed according to the particle suspension experiment and simulation results. The experiment and simulation results show that the nonspherical particles rotate in the vertical flow field, which can reduce the required flow velocity of large nonspherical particles in vertical pneumatic conveying.