Turbulence Modulation by Particles in Models of Flash Furnace Jets

Flow predictions based on three different two-way coupling models of gas-particle turbulent interaction are compared for confined jets within the context of modelling flash furnace flows. Particle diameters of 50 and 200 µm at mass fractions ranging from about 0.3 to 3.0 are considered. Isothermal jets with (a) a dominant primary (central) stream, analogous to that in a single entry flash furnace shaft, and (b) a dominant secondary stream, typical of a double-entry flash furnace shaft, are simulated numerically. Differences between the model predictions increased with particle loading and decreased with increased particle size when the primary stream dominates. However, extremely large differences between the predictions were obtained when the secondary inlet stream dominates, highlighting the need for experimental velocity data in such cases. Preferential concentration of particles is suggested as a factor limiting the validity of conventional turbulence models for double-entry flash furnace flows.