Numerical Modelling of the Effect of Cooling Conditions and Mould Size during Solidification of Al-4.5%Cu Alloy in Static Casting Process

Abstract

Mathematical developments and computer simulation have greatly aided the modern day study of solidification phenomena. This work presents a numerical modelling of the effect of cooling conditions and mould size during solidification of Al-Cu eutectic binary alloy in static casting process. The numerical method adopted for the current work is the finite volume method and the mathematical problem was formulated according to the classic continuum energy conservation equation for the transient solidification problems. The latent heat evolution was accounted for using the modified source-based method. The boundary conditions included all the modes of heat transfer between the solidifying system and its surrounding. Two cases were simulated to study the effect of cooling conditions and mould size on the solidification system. In case I, a Dirichlet boundary condition with a known temperature (373 K) value was imposed on the bottom of the mould surface. An adiabatic condition was imposed on the bottom of the mould in case II. It was observed that the different boundary conditions and mould sizes have significant influence on the rate and pattern of solidification. Cooling curve results and temperature contours from these models showed reasonable deviations due to various cooling conditions and mould sizes. Larger thermal and solid fraction layers were predicted for the case II with slower cooling rate. It was also observed that temperature distribution along the horizontal distance within the casting increases monotonically as mould size was increased.