A mathematical model of a top blown converter, which was based on a physical model of a 30 t vessel, was developed in this study. A simplified model consisting of the converter was used in the mathematical simulation. With the simplified model, it is possible to run a large number of tracer calculations within a short time, compared to solving for the entire flow evolution each time. A cavity depth and radius comparison has been done between the physical model and the mathematical model, which showed a good relative difference of 2.5% and 6.1% for the cavity depth and radius, respectively. The velocity change in the bath of the converter was monitored by setting several monitoring points in the physical model. A fully developed flow field was assumed to occur when the fluctuations in these points were small or periodic. It took approximately 25 s to get a developed flow field. In addition, the predicted mixing time showed a good relative difference of 2.8% in comparison to the experimental data.