According to the prototype of a 100 t ladle at steelworks and based on geometric similarity principle

a water model with model and prototype ratio 1:3.5 is established. The effect of different blowing position of single nozzle and double nozzles corresponding real gas blowing rate 31 L/min to 237 L/min on conditions of slag entrapment has been tested. It is found that the critical slag entrapment blowing gas rate for the original blowing position ( about distance from ladle center 0.45R) single nozzle

position distance from center of ladle 0.6R single nozzle

original blowing position ( about 0.45R) double nozzles and position distance from center of ladle 0.6R double nozzles gas blowing is respectively 113

93

31 and 82 L/min

therefore during real refining process it is available to using single nozzle blowing for soft gas blow

ing and to using double nozzles blowing for alloying stage. By regression analysis the relation formula between diameter of single nozzle blowing exposed areaand bottom gas blowing rate Q/(L

·

min

-1

) is D =43.333Q +47.5

as 0.6 ＜ Q ＜ 4.6.