Numerical and Physical Modelling of Steel Flow in a One-strand Continuous Casting Tundish

Constantly increasing customers demands for the production of high and very high-quality steels, promote the intensive technological development of their production. Since the dominating method of global steel production is continuous casting, the tundish has become very important metallurgical unit. Nowadays, tundish is not only a storage vessel which guaranty the continuous casting of steel, but it become an additional metallurgical stage where other operation are performed. These operations are for example control of melt temperature, composition and melt flow control to promote non metallic inclusion separation. The melt flow is the key factor to control the inclusions flotation. Investigations of steel flow or inclusions separation process at the industrial plant are nearly impossible because of the high temperature and a lack of optical accessibility. For this reason the investigations are performed with physical modelling and numerical simulations. Investigations with water models are already well known and widely applied 1-4 . Water can be used to model liquid steel because the kinematic viscosities of both fluids are similar ( st.1536°C = 8,26·10 -7 m/s, w.20°C = 10,0·10 -7 m/s). So far tundish water models were used for qualify as well as quantify investigations. Flow visualisation and measurements of the residence time distributions, transient zone, influence of different flow control devices on steel flow, or particle separation are the examples. Physical models are often combined with mathematical model since the accuracy of the numerical simulation in describing investigated phenomena is validated with water model experimental results. A large number of tundish flow and particle separation studies have been performed with using mathematical modelling as well 5-7 . An extensive development of numerical studies is an effect of dynamic development of the computers computational power parallel with development of computational codes. In mathematical modelling, the fluid flow is described by the Reynolds Averaged Navier-Stokes equations (RANS) and turbulence model. The results of physical and numerical modelling presented in this article are carried out to investigate the steel flow in a one-strand tundish for steady-state casting conditions. First, Laser-Doppler Anemometry (LDA) measurements of the flow field of a 1:3-scale water model of the tundish are carried out. Then, the results are used to validate the numerical model used to predict an isothermal water flow in a tundish model. Properly validated numerical model is used for modelling steel flow in the industrial plant tundish.