(121e) Motion of Large Particles in a Horizontal Pneumatic Pipe

To find a saltation velocity of a single particle, the horizontal pneumatic conveying whose diameter ratio to pipe is 0.6 is examined. This type of conveying can be regarded as a capsule conveying. The inside diameter of pipeline is 10 mm and the length is 8.8m. We used two different ABS resin particles and a stainless steel particle. The particles are uniform and spherical whose diameter is 6 mm, and the densities are 1061, 2193, and 7958 kg/m³, respectively. We used the method of characteristics for airflow in this calculation. It is found that the particle conveying is possible even when the mean air velocity is smaller than the terminal settling velocity of particle, and that the dimensionless particle velocity for ABS particles, which is made dimensionless on the mean air velocity, increases with increase in air velocity and becomes almost constant when the air velocity exceeds the terminal velocity although the dimensionless velocity for stainless particle is almost constant. Furthermore, there is a maximum in the number of revolutions for each particle at which air velocity is larger for larger density particle. The calculation shows a good agreement with the experiment except for the steel particle.