Flow of Coarse Particles of Mixed Densities in a Vertical Upward Pneumatic Pipe

Abstract

The experimental and numerical investigations were done in a vertical pipeline 8.5m in height and with an inside diameter of 60mm. The densities of particles are 982kg/m³ and 2193kg/m³, respectively and both particles consist of spherical plastic balls 6mm in diameter. The profiles of particle velocity and number flux of particles were measured by using a high-speed video camera. Several cases were studied in which the particles of two different densities were mixed for different mixing ratios and in which the uniform density particles were used separately. It is found that the mean velocity of large density particles is increased due to the collision with the small density particles of higher velocity with an increasing feed rate of particles, and that the relative velocity between two different particles is almost constant above a certain number feed rate of particles, and that for a given particle feed rate the larger the mixing ratio of large density particles is, the smaller the relative velocity is. It is also found that the additional pressure loss can be predicted by our simulation.