Mechanism of fluid flow in a continuous casting tundish with different turbo-stoppers

The fluid flow in a continuous casting tundish affects the separation of non-metallic particles and the cleanliness of the steel. Today, laser-optical investigations of water models are state of the art and enable detailed information about the effect of baffles, i. e. dams, weirs and turbo-stoppers, on the flow. In this work 3D-LDA and 2D-DPIV-investigations for different turbo-stoppers in a water model on a scale of 1:1.7 of a 16 t single strand tundish are presented. Three circular turbo-stoppers are investigated. Detailed measurements of the mean velocity and turbulence intensity in the tundish with and without turbo-stopper are shown. With a suitable turbo-stopper geometry the recirculation area in the tundish centre and short-circuit flows along the side walls can be avoided and thus more favourable residence time distributions can be obtained. It is shown that the turbo-stopper produces higher turbulence in the inlet region of the tundish, which is spatially more limited, however, in relation to the flow without turbo-stopper. Thereby a more homogeneous flow is created at the discharge of the tundish with better conditions for the particle separation. The experimental data yield a good understanding of the flow phenomena in a tundish with turbo-stopper and are used as validating criterion for numerical simulations (Fluent 5.5) on the basis of the Reynolds equations. The turbulence modelling is based on a two-equation model (realizable k-epsilon model).