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Abstract

In recent years, Horizontal Direct Chill (HDC) casting has gained popularity as a method for processing primary aluminum. In an attempt to further develop the knowledge and understanding necessary to enhance HDC casting capabilities in industry and improve its economic viability, a coupled thermal-fluid flow model of T-ingot casting has been developed. The model, developed using the commercial computational fluid dynamics software, ANSYS CFX-10.0, predicts the temperature and flow fields which occur during aluminum T-ingot HDC casting under steady-state operational conditions. Buoyancy, turbulence, solidification effects including flow damping and latent heat release, and boundary conditions were accounted for using methods that represent the physics occurring in the industrial process. Predictions for HDC T-ingot casting of pure and foundry (alloy A356) aluminum were compared to measurements made on industrially cast ingots. The measurements conducted included: drained sump profiles (6 in total), secondary dendrite arm spacings (SDAS), and location of macrostructure features. In all cases, the predictions matched the measurements well, providing confidence in the model and the methodology used. Throughout development of the model, sensitivity to modelling methodology as well as process and numerical parameters were explored. To simplify comparison, an extensive analysis was conducted by varying single features of a baseline model to show the importance of the modelling methodologies and process parameters.