A new Euler-Lagrange model of steel melt flows including dispersed secondary phases in continuous-casting tundishes is presented. The system of fundamental equations for the flow field is closed by different turbulence models. The calculation of tundish flows and a comparison with experimental results show that the flow fields of the steel melt and the behaviour of the dispersed secondary phases in the melt are described adequately by the model. However, the quality of the results for the dispersed phase depends essentially on the choice of turbulence model. Criteria for deciding which turbulence model is best suited for a specific flow situation are suggested. These criteria are deduced from investigations of different tundish flows.