Research of Swirling Flow Pneumatic Conveying System in a Horizontal Pipeline. 2nd Report. Particle Velocity and Concentration Profiles.

Abstract

Measurements of particle velocity and concentration profiles for a swirling flow pneumatic conveying system in a horizontal pipeline with a length of 13 m and an inner diameter of 80 mm have been made by photographic methods. Polyethylene and polyvinyl pellets, with mean diameters of 3. 1 mm and 4.3 mm, respectively, were transported as test particles. The initial swirl numbers were varied from 0.58 to 1.12, the mean air velocities from 9 m/s to 24 m/s and the solid-gas ratios from 0.8 to 3.0. It was found that in the acceleration region the mean particle velocity for the swirling flow pneumatic conveying system was higher than that for the axial flow pneumatic conveying system in the lower air velocity range and was lower in the higher air velocity range. The change of the mean particle velocity against the mean air velocity for the swirling flow pneumatic conveying system was smaller than that for the axial flow pneumatic conveying system. With swirling flow, the particle velocity profiles became uniform and the concentration profiles became symmetrical with respect to the pipe axis.