MULTIPHASE FLOW MODELING OF EQUIAXED DENDRITIC SOLIDIFICATION WITH MELT CONVECTION

摘要

A Computational Fluid Dynamics model for simulation of equiaxed dendritic solidification with melt convection and crystal transport is developed. This multi-scale multiphase model accounts for transport phenomena on the macro- and the microscales of a solidifying alloy. It predicts nucleation and growth of equiaxed dendrites from a melt, and their transport in the melt. Thermo-solutal convection and remelting of crystals are also included in the multiphase model that is based on the work of Wang and Beckermann (Metall. Mater. Trans. 27 A, 1996, p. 2754). To verify the modeling results comparison to published experimental data were made (nucleation, growth and transport of equiaxed crystals from a cooled NH_4Cl-70wt%H_2O solution). It is shown that the predicted evolution of temperature and average bed height (due to crystal sedimentation) are in good agreement with the experimental results.