ON THE NUMERICAL COMPUTATION OF TURBULENT FLUID-FLOW IN CAS STEELMAKING OPERATIONS

Mathematical modelling of turbulent fluid flow in the composition adjustment by sealed (CAS) argon bubbling steelmaking operation has been reassessed. Toward this end, a quasi-single phase calculation procedure embodying the standard coefficient two-equation k - epsilon turbulence model of Launder and Spalding has been applied. It is shown that numerically predicted flow patterns in the CAS reactor vessel depend strongly on (i) numerical grid distribution in the flow domain and (ii) appropriate modelling of turbulence parameters in the vicinity of the baffle wall. Provided a sufficiently fine grid is used for the numerical solution together with customary wall functions for flow and turbulence parameters (at the baffle wall as well as at the vessel side wall and bottom surface), quasi-single phase modelling procedure embodying standard coefficients for the k - epsilon model produces estimates of flow variables, which are very similar to those derived via the PHOENICS-based Eulerian two fluid computational procedure. Present predictions compare reasonably well with experimental measurements reported previously by the present authors.