Transient Mold Fluid Flow with Well- and Mountain-Bottom Nozzles in Continuous Casting of Steel

Nozzle shape plays a key role in determining the flow pattern in the mold of the continuous- casting process under both steady-state and transient conditions. This work applies computational models and experiments with a one-third scale water model to characterize flow in the nozzle and mold to evaluate well-bottom and mountain-bottom nozzle performance. Velocities predicted with the three-dimensional k-epsilon turbulence model agree with both particle- image velocimetry and impeller measurements in the water model. The steady-state jet velocity and angle leaving the ports is similar for the two nozzle-bottom designs. However, the results show that nozzles with a mountain-shaped bottom are more susceptible to problems from asymmetric flow, low-frequency surface-flow variations, and excessive surface velocities. The same benefits of the well-bottom nozzle are predicted for flow in the steel caster.