CFD-DEM simulation of raceway formation in an ironmaking blast furnace

This paper presents a CFD-DEM study of gas-solid flow in the raceway region in an ironmaking blast furnace (BF). In the simulation, 120,000 spherical particles are packed into a full-scale 2D slot BF geometry. Gas is injected into the geometry via tuyeres, generating raceways in different sizes and shapes under different conditions. It is observed that the raceway characteristics are much more complex under the full-scale BF than those observed under the laboratory scale in the literature. Three kinds of raceways can be identified: anti-clockwise circulating raceway, clockwise circulating raceway, and plumelike raceway. The results are analysed in terms of solid flow patterns, and flow and force structures of particles. The simulation has a good agreement with the observed in physical experiments in terms of two contrary circulating gas vortexes located upon and below tuyeres during raceway formation. Moreover, it is also indicated that operational variables have significant effect on one of the gas vortexes, which becomes the main circulating gas flow stream and determines the gas circulating direction.