Numerical Simulation On The Flame Envelope Of Coherent Jet Oxygen Lance

Coherent jet is a kind of new blowing oxygen technology. Because of its extralonger jet stream than the common one，it attracts most of the attention from theconcerned experts in the world. The coherent jet oxygen lance in EAF has beenintroduced to many steel mills in China. But theoretic research of this technology inBOF is still immature. Now most researches of coherent jet oxygen lance areconcentrated in the cold state jet characteristics, but researches on the thermal stateaccompanying gas are little. So we research the flame envelope by numericalsimulation methods. It can provide the basis for the design optimization andproduction operations.In this paper, a steel120t BOF coherent jet oxygen lance for the study, creationof a physical model, the choice of a suitable mathematical model, basic research ofcoherent jet and influence of different structural parameters and process parameters onthe flame envelope length by numerical simulation. The results show that:（1）Coherent jet can entrainment little ambient gas, keep initial diameter andvelocity in a long distance and increase the length of potential core area obviously.（2）Under the same conditions, with the molecular weight of accompany gasdecreases, it can strengthen the protection of primary oxygen jet, entrainment littleambient gas and slow down decay.（3）Structural parameters affecting the flame envelope length include fuel holewidth, spacing and angle of fuel hole and vice oxygen hole. As fuel hole widthincreases, the flame envelope length increasing. As spacing of fuel hole and viceoxygen hole decreases, the flame envelope length increasing. The angle of fuel holeand vice oxygen hole has little influence to diffusion combustion, so the flameenvelope length is the same.（4）Process parameters affecting the flame envelope length include fuelcomponents, accompanying pressure, environment temperature, amount of fuel andvice oxygen. As heating value of gas，accompanying pressure and environmenttemperature increases, the flame envelope length increasing. As the amount of fuelincreases, the flame envelope length increasing, but as the amount of vice oxygenincreases, the flame envelope length is the same. So the amount of fuel is the mainfactors to influence the flame envelope length.