The main purpose of the present work was to validate the numerical model for the pulse-step liquid steel alloying method using a physical simulator that enables the observation and recording of phenomena occurring during the continuous steel casting process. The facility under investigation was a single-nozzle tundish equipped with a dam. To physical trials the glass water model was made on a scale of 2:5. For the mathematical description of turbulence during liquid steel alloying process, the k-ε and k-ω models were employed in the simulations. Based on the computer simulations and physical trials carried out, alloy addition behaviour and mixing curves for different tundish alloy addition feeding positions were obtained. The change in the location of alloy addition feeding to the liquid steel had an effect on the process of alloy addition spread in the liquid steel bulk and on the mixing time.