Complex free surface flows for mould filling using centrifugal casting

A challenging application in the computational modelling of free-surface flows and interacting physical phenomena is in the context of centrifugal casting. The combination of complex rotating geometries, significant centrifugal forces and high velocity transient free surface flows, coupled with heat transfer and solidification yields a comprehensive problem. Obviously the objective in centrifugal casting is to capitalise on the resulting centrifugal forces to control the flow dynamics and reduce component defects. This contribution will describe the enhancements required to enable conventional free surface algorithms to capture the details of the flow during the filling stage of centrifugal casting in what are inevitably complex three dimensional geometries. The work described in this paper concentrates on resolving the fluid film formation at the early filling stages and the subsequent vortex formation. Validation of the above phenomena is a key issue; a series of water model experiments has been performed and recorded using high-speed video image capture. The objective was to validate and refine the computational model predictions using repeatable high quality experimental data, before application of the model in analysing full-scale centrifugal casting process. A number of key observations arise from this work that are not trivial to capture within the computational modelling tools; however, for the models to be useful in the analysing the full scale casting process, such physics must be reflected within their predictive capability.