Industrial Direct Chill Slab Caster of Tin Bronze (C903) Using a Porous Filter in the Hot-Top

A 3D computational fluid dynamics (CFD) modeling study has been carried out for the tin bronze (C903) slab of industrial size in a vertical direct chill caster. The melt is delivered from the top across the entire cross section of the caster. An insulated hot-top is considered above the 80-mm mold to control the melt level in the mold. A porous filter is considered in the hot-top region of the mold to arrest the incoming inclusions and homogenize the flow into the mold. The melt flow through the porous filter is modeled on the basis of the Brinkmann–Forchheimer-extended non-Darcy model. Results are obtained for four casting speeds varying from 40 to 100 mm/min. The metal–mold contact region, as well as the convective heat transfer coefficient at the mold wall, is also varied. In addition to the above, the Darcy number for the porous media is also changed. All parametric studies are performed for a fixed inlet melt superheat of 62 °C. The results are presented pictorially in the form of temperature and velocity fields. The sump depth, mushy region thickness, solid shell thickness (ST) at the exit of the mold, and axial temperature profiles are also presented and correlated with the casting speed through regression analysis.