Simulation test on interaction between jet flow and bath in 180 t top and bottom combined blowing converter has been carried out by a water model with geometric similarity ratio 1:10 to study the effect of gas flow rate (38 ~42 m

3

/h) on mixing time with optimum lance position (150 mm) and the effect of coherent jet flow lance position (40 ~ 150 mm) on mixing time at optimum top lance flow rate (39 m

3

/h). Results show that the stirring effect in bath by coherent jet flow oxygen lance is the same as that by top and bottom combined blowing and if the coherent jet flow oxygen lance shall be applied in converter

the bottom system of top and bottom combined blowing converter could be canceled to simplify converter structure and increase converter lining life.