Mathematical And Physical Simulation Of Interface Behavior Between Two Parameter Oxygen Lance And Molten Pool

The top-blowing oxygen lance is an important equipment in the oxygen converter steelmaking process.It plays the role of slagging,oxygen supply,decarburization and molten pool stirring during the converter smelting process.Studying the impact morphology and splash behavior of the gas-liquid interface has guiding significance for the impact strength,splash rate,and slag splash protection of the converter smelting process.At present,a large amount of literature on the influence of top-blowing oxygen lances to the molten pool was focused on single-parameter such as nozzles angle and flow ratio,there are few researches on the effect of multi-parameter to the liquid bath,especially the coupling effect of angle and flow of the oxygen lance.Based on the similarity principle and dimensional analysis theory,a water model experiment platform with a reduced ratio of 1:7 was established for a 260t converter.The focus was on the analysis of the impact cavity size and furnace wall of the double-parameter oxygen lance with different nozzle inclination angles and flow ratios.The characteristics of splashing on furnace wall and furnace mouth were analyzed in detail and were compared with that of the traditional oxygen lance.Based on that,a two-dimensional,incompressible,non-isothermal CFD mathematical model was established,and key parameters such as gas-liquid interface morphology,splashing mechanism,and molten pool flow field were studied.The main conclusions obtained are as follows:(1)Compared with the traditional oxygen lance,the impact cavity formed by the double-parameter oxygen lance was deeper at a lower lance position.While at a higher lance position,the cavity formed by the double-parameter oxygen lance was shallower for its better jet independence.The depth of impact crater of the 9 dual parameter oxygen lance is 8.9%lower to 1.3%higher than that of the traditional6-hole oxygen lance,and the diameter of impact crater is 1%-9%higher than that of the traditional 6-hole oxygen lance under the condition of H/de=40 and Q=75m~3/h,.The depth of the impact cavity is mainly affected by the ratio of the main hole angle and the flow rate,and the diameter of the impact cavity is mainly determined by the ratio of the secondary hole angle and the flow rate.(2)The distribution of the splashing on the inner wall of the double-parameter oxygen lance is different from that of the traditional oxygen lance.The traditional oxygen lance has the largest splashing in the middle of the nozzles,while for the double-parameter oxygen lance,the largest splashing is at the position directly opposite the large nozzles.Under the same flow rate,the traditional oxygen lance caused the largest splash when H/de=35,while the double-parameter oxygen lance caused the largest splash when H/de=40.The double-parameter oxygen lance has a certain degree of splash resistance due to the poor jet coalescence effect.(3)There are two main reasons for liquid splashing when the airflow impacts the liquid surface.One reason is that the liquid on the surface of the molten pool is subjected to the shearing force of the reflected airflow,which causes splashing when the high-speed gas jet collides with the liquid,and the other is the surface wave splash caused by the impact of the wall surface during the transfer process.(4)From the view of the flow field in the converter,the area of the“dead zone”reaches the minimum within a short time during the blowing process,and the area of the“dead zone”increases with the increase of blowing time.The traditional structure of the oxygen lance will form a“dead zone”at the bottom of the converter,the small dead zone formed by the double-parameter oxygen lance moves cyclically from the direction of the secondary hole to the direction of the main hole.