Mathematical simulation of the influence of buoyancy forces on the molten steel flow in a continuous casting Tundish

Buoyancy effects on the fluid flow patterns of molten steel in a tundish of a continuous slab caster were mathematically simulated. Thermal responses of step-input temperatures in steel for different flow rates were predicted. The molten steel velocity profiles were determined for these temperature and flow rate variations. The importance of natural flow convection was established through a dimensionless number given by the ratio Gr/Re². Buoyancy forces proved to be as important as inertial forces, especially in the extremes of the tundish. The simulations indicated that these forces increase the residence time of the molten steel in the tundish, flowing near the slag layer, allowing more time for the non-metallic inclusions to be captured; also, that the turbulence inhibiting device helps to redirect the flow towards the top free surface. It is shown that this device helps to decrease turbulence near the entry zone and has a dumping effect on the temperature step inputs allowing better control of the casting temperature. The traditional flow control devices like weirs and dams were not as effective as the turbulence inhibitor.