The paper reports the results of studies on the validation of a numerical model of theflow of liquid steel through the tundish used for continuous casting of steel. Thefacility under investigation is a single-nozzle tundish designed for casting concastslabs. For the description of the turbulence of steel flow through the tundish, thek-ε, RNG k-ε and Realizable k-ε turbulence model wereadopted. Computer simulations of liquid steel flow were performed using the commercialprogram Ansys-Fluent®.For the validation of the numerical model and verification of the hydrodynamic conditionsoccurring in the examined tundish furniture variants, obtained from the computersimulations, a physical model of the tundish was employed. During laboratory testssimulating the process of steel flowing through the tundish, E and F-type RTD (ResidenceTime Distribution) curves were recorded, which were then juxtaposed with results obtainedfrom computer simulations. In order to obtain a complete hydrodynamic picture in thetundish furniture variants tested, the computer simulations were performed for bothisothermal and non-isothermal conditions.