Based on prototype of 150 t ladle

the effect of diameter of immersed cylinder inserting in ladle (50 ~ 130 mm)

inserting depth (30 ~ 150 mm) and bottom blowing gas rate (0. 03 -0.48 m

3

/h) on mixing time of liquid and amplitude of liquid level has been studied by using geometry similarity ratio 1 ： 7 water model. Results show that with increasing immersed cylinder diameter and inserting depth

the amplitude of liquid level decreases; with increasing bottom gas blowing rate the amplitude of liquid level raises ； in condition without inserting immersed cylinder the critical gas blowing rate for non-occurring slag entrapment is 0. 09 m

3

/h and mixing time is 10 s; in condition of inserting immersed cylinder with diameter 130 mm and inserting depth 90 m

m

the critical gas blowing rate for non-occurring slag entrapment is 0. 30 m

3

/h and shortest mixing time is 4 s. It is obtained by test data regression analysis that for 150 t ladle the relation between liquid mixing time U with bottom gas blowing rate Q

'

immersed cylinder diameter d' and inserting depth is t

'

=2.69 +0.017 9 d

'

+ 0.011 2 h'—0.425 Q'.