Analysis of rapid flow of particles down and from an inclined chute using small scale experiments and discrete element simulation

Abstract

In blast furnaces with bell-less charging systems, the particles enter the furnace from a hopper and are distributed on the burden surface by a rotating chute. The velocity distribution of the particles in the chute is known to affect the burden distribution and particle segregation on the burden surface. This paper investigates by simulating the translational and rotational velocity distributions of uniform spherical particles for the simplified cases where they are discharged from a hopper into a non-rotating chute set at different angles with respect to the vertical plane. The simulations, which are based on the discrete element method, are partly validated by small scale experiments, where particle velocities are estimated from observed trajectories of the particle stream leaving the chute, as well as by sampling particles in boxes to estimate the width of the stream. The simulated translational and rotational velocity distributions at different cross-sections of the chute for different tilting angles are also reported and discussed. The results show that the average velocity at the chute tip depends only on the chute angle for the bulk of the material flow. The angular velocity distribution of the particles along the cross-section of the chute exhibits a V shaped profile, while the opposite holds true for the translational velocity distribution. As the particles flow down the chute, both velocity distributions become more uniform.

Keywords:

• Granular particles
• Chute
• Blast furnace
• Velocity distribution
• Discrete element method
• Burden distribution

The work was carried out within the Finnish Metals and Engineering Competence Cluster and its Energy and Lifecycle Efficient Metal Processes programme. We gratefully acknowledge the financial support from Tekes and participating companies. The DEM simulations and analysis were conducted using EDEM 2·2·1 and 2·3·1 particle simulation software provided by DEM Solutions Ltd, Edinburgh, Scotland, UK.