Jet penetrability

We calculate now the depth of penetration when the jet hits the bath surface at a distance x .Depth of penetration of an impinging jet (h) is

(9)

At x = 3m,  and increases to 0.46m when the distance x is decreased to 1.5m. This means that there will be shallow jet penetration in the bath at x=3 m, whereas at x=1.5m jet will penetrate deep into the bath.

Dimensionless flow rate number describes the effect of lance distance on the penetrability of jet.

Shallow jet penetration as obtained at higher lance distance is a “soft jet” as compared to deep penetrating jet as obtained at lower distance and is termed “hard jet”.

This would mean that a constant volume flow rate of oxygen supplied at constant pressure when discharged through a nozzle can be made to hit the bath “soft “and can be made progressively harder.

Thus method of oxygen supply in converter steelmaking practice i.e. through “free jet” is very effective in terms of physico- chemical reactions.

The effects induced by a reactive soft and hard jet impinging oxygen jet, when it hits the hot metal bath are given below.