Modelling of fluid flow phenomena during DC casting of aluminium alloys

In this paper, we will investigate two important phenomena, i.e. macrosegregation of solute, and the flow behaviour of oxide inclusions. Reliable calculations of macrosegregation during casting of alloys depend on accurate modelling of the associated physical mechanisms. In solving the solute concentration equation, the accuracy of the velocity field is of great concern. Several discretisation schemes for the convection terms are examined on their ability to correctly predict macrosegregation. The occurrence of oxides can give major problems during aluminium casting and processing. During transfer from conventional metal treatment systems to the casting station pick up of inclusions can occur. In our simulations, we have assessed quantitatively some of the upstream fluid flow effects in relation to filling behaviour of the DC mould cavity and number of inclusions trapped in the launder system. Results of numerical simulations of fluid flow with discrete particles of different mass and distribution are given.