Control of Two-Phase Flows During Startup Operations of Casting Sequences in a Billet Tundish

The startup operations of continuous casting sequences of steel in a 4-strand tundish, using three different turbulence inhibitors (TI), were investigated using a 1/3-scale water model in combination with numerical simulations through the volume of fluid model. The two-phase flow water–air is used to model the system, and the liquid steel–air and the liquid–gas interfaces are tracked by a donor–acceptor principle applied in the computational mesh. In the actual caster, one of the inhibitors releases the liquid steel with a sensible heat high enough to avoid freezing in the regions near the outer strands during the startup of the casting sequence. A second inhibitor improves the fluid flow control by yielding higher plug flow volume fractions. However, it promotes steel freezing in the outer strands. The analysis of the results lead to the design of the third TI with intermediate capability to control the steel flow, preventing steel freezing in the regions near the outer strands.