Three-Dimensional Modeling of Direct Chill Caster with Partial Porous Plate

A three-dimensional control-volume-based finite difference code is developed to simulate a vertical direct chill casting process for aluminum alloy AA-1050. The rectangular slab caster is fitted with a porous plate occupying 50% of the width of the ingot and is placed near the top in the central region. The turbulence in the liquid sump is modeled employing a popular version of the low Reynolds number kappa-epsilon model. The enthalpy-porosity technique is used to solve the coupled melt flow and solidification heat transfer problem. To model the porous plate, the Brinkman-Forchheimer extended Darcy equation is considered. The code is first verified with the available experimental solidification profile data for a direct chill caster of a rolling ingot AA-3104. The effects of casting speed and heat transfer coefficient at the metal-mold contact region on solidification characteristics are investigated. By varying the latent heat of solidification of the said alloy, sensitivity analysis is also carried out. The temperature and velocity profiles, along with the solid shell thickness, sump depth, mushy thickness, and local surface heat flux, are presented and discussed. All results reported here are new and have direct industrial significance.