Numerical Study of Raceway Shape and Size in a Model Blast Furnace

Abstract

In ironmaking blast furnaces, hot air is injected through tuyeres to form a cavity, known as “raceway”. In this study, a three-dimensional transient numerical model has been developed to study the shape and size of the raceway in a packed particle bed. It is assumed that gas and solid (particle) phases are interpenetrating continuum in the model. Gas phase turbulence is described as a k-e dispersed model. Gas phase stress considers its effective viscosity. The solid phase constitutive relationship is expressed as solid stress that is characterized by solid pressure, bulk viscosity, kinetic viscosity, collisional viscosity, and frictional viscosity. The effects of blast velocity and injection angle on the raceway were studied. The results demonstrate when air is injected through the tuyere, the raceway size first increases, then decreases with time, and finally stabilizes. The raceway size increases with the increase of blast velocity. The raceway shape depends on the injection angle, and the surface area of the raceway is largest when the injection angle is 5°.