Numerical predictions of the shape and size of the raceway zone in a blast furnace

Abstract

A 3D transient numerical model has been developed to predict the shape and size of the raceway zone created by the force of the blast air injected through the tuyeres in the coke bed of a blast furnace. The model is based on the solution of conservation equations of both gas and solid phases as interpenetrating continua on an Eulerian-Eulerian frame of reference. A modified k-e model has been adopted for gas phase turbulence including gas–coke turbulent interaction. The solid phase is characterized by the solid pressure, bulk viscosity and shear viscosity, which are evaluated by applying kinetic theory to granular flows. The influences of the air blast velocity, granular properties of the coke phase, and tuyere diameter on the shape and size of the raceway zone have been predicted by numerical simulations and described using semi-empirical relations. The effect of the cohesive zone on the raceway geometry is also taken into account. The trends of the derived results are compared with experimental data reported by various researchers with reasonable agreement.