Potent turbulence model for the computation of temperature distribution and eddy viscosity ratio in a horizontal direct-chill casting

Abstract

The present study investigates the performance of selected turbulence models to predict the temperature distribution and eddy viscosity ratio in a horizontal direct-chill casting. The turbulence models include the velocity variance–elliptic relaxation ($\overline{v^2}-f$), the kinetic energy-specific dissipation rate shear stress transport (k-ω SST), standard kinetic energy dissipation rate (k-ε), and its modern variants of the Realizable and the Renormalization group (RNG). The predicted results indicate that the $\overline{v^2}-f$ turbulence model majorly has a faster drop in the temperature within the mold region and decay of the eddy viscosity ratio within the slurry zone than other turbulence models. The second turbulence model of choice that has closed performance with the $\overline{v^2}-f$ is the k-ω SST. The reason for the improved heat transfer in the above-mentioned models was that they have an additional turbulent term in the energy equation that is called turbulent heat fluxes which promotes heat transfer rate as the flow strongly mixed during the solidification process. Therefore, $\overline{v^2}-f$ and k-ω SST turbulent heat fluxes strongly mixed more with the flow than the other turbulence models, thereby promoting fast temperature and eddy viscosity ratio drop.