Mathematical simulation of effects of flow control devices and buoyancy forces on molten steel flow and evolution of output temperatures in tundish

The effects of flow control devices and buoyancy forces on the melt flow in a large tundish have been mathematically simulated using a k-epsilon turbu lence model. Flow control devices included arrangements consisting of a pai r of weirs and a pair of dams, a turbulence inhibitor and a pair of dams, a nd only a turbulence inhibitor. Buoyancy forces were simulated using step i nputs of temperature and inputs of varying ladle stream temperature into th e tundish. It was found that with inputs of hot steel, flow control devices improve performance by driving the melt upwards through the action of buoy ancy forces. A bare tundish is less sensitive to buoyancy forces and shows greater thermal mixing than any other arrangement. Inputs of temperature st eps promote higher temperature gradients of liquid steel inside the vessel than inputs of varying ladle stream temperatures. A turbulence inhibitor de lays the thermal disturbance compared with a bare tundish or a tundish with a weir-dam arrangement. When using a turbulence inhibitor higher volume fr actions of melt obey a pluglike flow. The dimensionless quantity Gr/Re-2, w here Grand Re are the Grashof and Reynolds number respectively, quantifies buoyancy forces: high values indicate that buoyancy forces have more effect than inertial forces on fluid flow. When Gr/Re-2 < 5, buoyancy forces have no noticeable influence on fluid flow.