Modeling of 3-D turbulent transport phenomena and solidification of a direct chill caster fitted with a metallic-foam-plated combo bag.

The 3-D numerically simulated steady state results of an industrial size vertical Direct Chill (DC) slab caster fitted with a metallic-foam-plated combo bag melt distributor for AA-1050 aluminum alloy are reported. The turbulence in the melt and the mushy region solidification of the alloy are modeled through the popular low Reynolds number κ – ε model of Launder and Sharma and the enthalpy-porosity scheme, respectively. The transport of melt through the foam is modeled using the Brinkman–Forchheimer extended Darcy equation. The verification of the numerical model is performed by comparing the predicted and measured solidification front for AA-3104 rolling ingot reported in the literature. The inlet melt superheat and the porosity of the metallic foam of the combo-bag were kept fixed at 32 °C and 0.9, respectively. Parametric studies are carried out by varying two important parameters of the process, viz., the casting speed and the heat transfer coefficient (HTC) at the metal-mold contact region. Specifically, the casting speed and the HTC are varied from 40 to 100 mm/min and from 750 to 3000 W/(m 2 -K), respectively. With the increase of the casting speed, the solidification process is delayed while the solid-shell thickness increased with the increase of the HTC. The predicted results are presented for the solid-shell thickness, the sump depth, the mushy thickness, the surface temperature as well as the non-dimensional turbulent viscosity contours. In addition the temperature fields and velocity profiles with streamlines are also provided. [ABSTRACT FROM AUTHOR]