Optimising Computational Fluid Dynamic Conditions for Simulating Copper Vertical Casting

Abstract

A 2-D finite volume Computational Fluid Dynamic (CFD) model, using Ansys Fluent vR.1 of a vertically oriented upwards continuous casting (VUCC), was investigated for 8 mm, oxygen free copper (OFCu). The simulations enabled the mapping of the cast OFCu solidification front (SF) interface from liquid to solid. Optimisation of the simulation parameters were investigated which included mesh size and the Ansys specific ‘mushy zone’ constant (Amush), which is used to account for fluid flow dampening at SF within the model. Observations of the SF, the change in fluid volume in the die, the simulation convergence and the total simulation time, revealed that the optimised casting parameters were for mesh size 1×10-4 m and Amush 106 kg/m3s. These parameters were compared with the cast rod and highlighted qualitatively the relationship between grain growth direction and SF position during a casting pulse cycle.

Prediction of Periodic Centerline Porosity and Pulse Marks by CFD and Experimentation for Continuously Cast Copper

“…The software-specific parameters include the approximation for the dampening coefficient Amush occurring around the SF, the applied heat model (RANS k-x SST), and the mesh and time step optimizations. These parameters were optimized within [24] and mesh optimized within supplemental section A3, to give the closest approximation to the predicted SF behaviors for VUCC OFCu.…”

“…The casting settings influencing SF shape included the speed settings, the Marangoni flow which occurred at the liquid OFCu-graphite die interface, and the airgap approximation occurring after solidification due to shrinkage between the OFCu and graphite die. The Marangoni flow and the air gap approximation applied in this work were optimized in [1,24] and kept constant.…”

“…[1] Computational fluid dynamic (CFD) modeling provides prediction of heat and solidification during casting. [1] Recent CFD work by the authors [1,24] highlighted the validation and verification of a finite-volume model developed in commercial software Ansys Fluent and indicated its use for predicting the influence of casting motions on 8 mm VUCC OFCu solidification.…”