Abstract: Considering standard k~ε model， a CFD model of compressible oxygen jet was developed for BOF convertor topblown process. Jet behaviors inside and outside de Laval nozzle were simulated. Flow characteristics of oxygen jet on the condition of various operating pressures and ambient temperatures were investigated and shock waves of jet were expounded. The numerical simulation results showed that when the operating pressure is under the design pressure， the oblique shocks are formed from the nozzle corner and alternate between compression waves. When the operating pressure is beyond the design pressure， a fan of expanding wave is released from the nozzle corner and expansion and alternate between expansion and compression waves. Simultaneously， the numerical simulation also showed that the length of supersonic region of jet increases with the increased ambient temperature， but kinetic pressure of jet is not influenced. Finally， the quantitative relationship between the length of supersonic region of jet and operating pressure is obtained.

Key words: oxygen jet, de Laval nozzle, jet supersonic region length, convertor, numerical simulation