A comprehensive numerical model was developed for the simulation of near-netshape continuous casting processes. The model, incorporating features such as generalized coordinates, multi-grid additive correction solver and a low-Reynolds number κ-ε turbulence model, solves for two and three-dimensional transport phenomena in the presence of solidification. The pressure-momentum coupling is handled using a hybrid of the SIMPLER and SIMPLEC algorithms, along with a total enthalpy formulation for the energy equation. All governing equations are discretized over a fixed computational grid incorporating, with a single set of equations, the solid, liquid and solid/liquid regions of the cast.

Several industrial processes are investigated with particular emphasis on continuous near-net-shape casting using twin-belt and rotary-strip casters. In particular a parametric study into the influence of process parameters on the solidification front and cooling rates in a twin-belt caster was conducted. Results of the investigation indicate that the response of the solidification front is strongly dependent upon heat transfer conditions and belt speed, and that accurate heat transfer data at the mould boundaries are necessary for reliable predictions. Cooling rates were found to be highly sensitive to changes in the heat transfer conditions along the belt, especially for the initial solid layers of the cast while the inner regions of the cast were much less sensitive. In another study the influence of air-gap formation, and cast movement, were investigated for the rotarystrip caster. For this study results indicate that significant reductions in cooling will occur Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. with the formation of even small air-gaps and the possibility of reheating of the inner core of the cast due to shifting. Both the reduced cooling and shifting of the cast enhance the possibility of molten breakout at the caster exit.

The interaction of turbulence, solidification, and boundary conditions in the entrance region of moving mould casters, such as the twin-belt and rotary-strip casters, are also investigated. Results suggest that significant turbulence levels only persist for a short distance into the mould, and exist in conjunction with low levels of solid fraction along the mould walls. The simultaneous presence of significant turbulence levels and low solid fraction may lead to surface quality problems in the final cast. A modification to the generalized turbulence damping mechanism for the low-Reynolds number turbulence model utilized provides good results in modelling the effects of a moving solidification front on turbulence.

Final consideration is given to a three-dimensional analysis of heat transfer, turbulent fluid flow, and inclusion behaviour in a rotary-strip caster. Results highlight the importance of heat transfer effects in the third-dimension and the essentially two-dimensional nature of the turbulent flow. Significant variations in cooling over the major heat transfer surfaces were found to exist, resulting from the particular design of the caster under consideration. Segregation of inclusion particles was found to be reduced due to the high degree of curvature of the rotary caster.