Contribution to the Large Eddy Simulation of Flows in Electromagnetic Stirrers for Continuous Casting

Abstract

A numerical study in cylindrical coordinates of the statistically steady turbulent flow in a laboratory setup for modeling the rotational inductive stirring in continuous casting of round strands is presented using the large eddy simulation method. For simulation of the velocity increase in the flow-mechanically stable layers the turbulent viscosity of the Smagorinsky model is reduced by a term depending on the r-derivative of the angular momentum, which characterize the stability. The explicit discretization scheme is applied for the time integration with implicit calculation of the diffusive terms in the azimuthal direction in order to obtain a greater maximal admissible time step. On the z-axis unique interpolated velocity values are used in the finite difference equations. The pressure Poisson equation is solved applying the fast Fourier transform and a supplementary pressure gradient is introduced to vanish the axial flow rate resulted by the use of axial periodic boundary conditions. Comparisons with experimental data show good agreements for both mean velocity and flow statistics.