Experimental and numerical investigation of the effect of buoyancy force on solid flow

This paper presents an experimental and numerical study of solid flow under conditions related to an ironmaking blast furnace where the flow of particles is driven by the downward gravitational and upward buoyancy forces. Physical experiments were conducted with a water model and wooden balls. The results showed that the flow pattern and stagnant zone profile, strongly affected by the level of liquid and the position for solid discharging, are more complicated than those obtained when the gravitational force is the only driving force. Numerical experiments were performed by means of discrete element method that considers explicitly the key forces involved, including the gravitational, buoyancy, and various interparticle forces due to the collision and contact between particles. It was shown that the simulation model proposed can reproduce the experimental results well. The analysis of the numerical results indicates that the flow pattern observed under given conditions can be related to the packing and force structures. An attempt had also been made to simulate the solid flow in a blast furnace hearth.