Numerical Simulation of Pneumatic Conveying in a Horizontal Pipe

Abstract

A numerical simulation was attempted for pneumatic conveying of solids in a horizontal pipe. Trajectories of individual particles were calculated using equations of motion. In this simulation, the fluid drag, lift force due to particle rotation and torque on the rotating particles were taken into consideration. The friction loss due to collision of particles with a pipe wall was also calculated using impulsive equations. The pressure drop due to the presence of particles was obtained from the fluid drag acting on the particles through the momentum theorem. To avoid sliding motion of particles on a pipe bottom wall, a model of abnormal bouncing was newly proposed. Several parameters concerning the abnormal bouncing were determined empirically. It was found that the particle flow predicted by the present simulation agreed with measurements regarding particle distribution, pressure drop and particle velocities including angular velocities. In addition, this method was applied to find the effects of particle size, pipe diameter, particle density and so forth. Since particle diffusion due to the air turbulence was neglected in this analysis, the case of fine particles was not investigated.