Influence of Operating Parameters on Raceway Properties in a Model Blast Furnace Using a Two-Fluid Model

In the lower part of an ironmaking blast furnace, a hot air jet is injected horizontally into a bed of coke particles, forming a void zone, called a "raceway". In this paper, two-fluid gas-solid modeling is used to study the influence of various operational parameters on the size and shape of the raceway (void zone). The model employs state-of-the-art closure relations to describe solid-phase stress, which then incorporates frictional forces based on soil mechanics, and k-epsilon equations to describe gas-phase stress. The results show that raceway size and shape depend on jet velocity, outlet pressure, particle size, bed height, height of the jet inlet and the particle downward extraction rate. The influence of jet injection angle, domain geometry, and initial porosity on the raceway properties are found to be insignificant for the investigated range, although changing initial porosity suggests a small degree of hysteresis.