Modelling of turbulent flow, heat transfer and solidification in a twin-roll caster

A computational modelling study has been undertaken for analysing the complex turbulent melt flow, involving convective and conductive heat transfer in the melt pool and the solidifying mushy-region within the wedge-shaped region of a vertical twin-roll stainless steel caster.;An essential feature of the model is the incorporation of the body-fitted curvilinear coordinate transformation method for correctly modelling the arbitrary shaped region of the caster in the presence of non-isothermal solidification. The model can also treat an obstacle such as a submerged nozzle within the domain. The dendritic columnar solidification of molten metal has been modelled through the implementation of the enthalpy-porosity technique. The transformed curvilinear momentum and energy transport equations were suitably non-dimensionalized and later solved for the physical variables, using a control-volume finite difference scheme. The pressure-velocity coupling of the momentum equations were resolved through a modification of the well-established SIMPLER algorithm.;In the absence of such previous studies for stainless steel, either mathematical or experimental, comparisons have been made of the present model with the experimental work carried out within Nippon Steel Corporation as well as with experimental studies of a similar system for a tin-lead alloy. Predictions based on the present model are in good agreement with experimental results.;Various parametric studies have been carried out for the important variables of the twin-roll casting system, and their effects on the turbulent velocity fields, temperature distributions within the melt, solidification profiles and the extent of the mushy region, have been predicted. The present results lead to many suggestions for the design of twin-roll casting systems.