Abstract: The raceway plays a very important role in the blast furnace and COREX ironmaking processes and is also the basis of smooth operation of the furnaces. In order to describe its shape and size， a combined discrete element method (DEM) and computational fluid dynamics (CFD) model was developed. The particle porosity of raceway with bed height of 04m and gas blowing velocity of 1174m/s was obtained. When blowing time was 013s， some of particles which are nearby the gas inlet were blown away. The number of particles increased with the increased time. When blowing time was 019~021s， the raceway began to stabilize. The particle velocity inside and around raceway at different blast velocities was simulated. The results showed that the particles which are nearby the tuyere make circular cyclotron motion， and the raceway increases with the increased gas blowing velocity. When the gas velocities are 1174m/s and 1683m/s， the raceway is more stable. When the velocity is greater than 2190m/s， the raceway becomes unstable.

Key words: COREX melter gasifier, raceway, DEM, CFD, velocity of particles in raceway