Design And Structural Optimization Of High Maher Oxygen Lance Nozzle

The key technology of converter automatic steelmaking is oxygen lance control,and the structural characteristics and parameter settings of the original lance equipment have been difficult to adapt to the automatic steelmaking system,resulting in extremely unstable blowing process.Based on this,the high Mach number oxygen lance nozzle equipment was studied.Based on the theoretical analysis and the actual requirements of the steel plant,the key parameters were proposed and optimized,using numerical simulation and cold water simulation.The mutual verification method obtained the dependence of the jet characteristics of the high Mach number oxygen lance nozzle and the flow velocity distribution of the molten steel under different working conditions.In the subsequent practice of automatic steelmaking industry,combined with the variable pressure transformer process,the pressure application range of the high Mach number oxygen lance nozzle was fully applied,and the converter blowing process was more stable.The main research contents of the article are:1)Based on the actual conditions of automatic steelmaking in a steel plant in the north and the design principle of the oxygen lance nozzle,the design and calculation of the main parameters such as the throat diameter,the length of the expansion section and the inclination of the throat of the high Mach number oxygen lance nozzle are designed and studied.The high Mach number oxygen lance nozzle is designed to have an oxygen pressure of 1.1 MPa and an Mach number of 2.15.2)According to the actual data of the steel plant,several oxygen supply pressures and oxygen supply gun positions were selected,and the numerical simulation software Fluent was used to different the high Mach number oxygen gas nozzles.The oxygen supply pressure and the jet characteristics under different oxygen supply gun positions and the flow field effects of the impact weld pool were simulated.Then,based on the similarity between the model and the prototype geometry and the modified Froude criterion(Fr),the cold water simulation experiment was carried out,and the numerical simulation results were mutually verified.Research indicates:When Ma=2.0~2.3,the curve is stable,the design pressure changes moderately,and the operation stability is optimal.With the continuous increase of oxygen supply pressure,the Mach number of the oxygen jet of the high Mach oximeter and the jet parameters of the high-speed section length They are constantly increasing,and the impact on the molten pool is continuously enhanced,but the mutual interference between the jets is also increasing;When the high Mach number oxygen lance is larger than the designed oxygen supply pressure of 1.1 MPa,the impact diameter and the impact depth increase less;The highest Mach number oxygen lance has the highest impact depth between 1.6m and 2.2m,and the molten pool has the best mixing effect.At this time,the molten steel flow rate is more evenly distributed in the radial direction of the molten pool.The high-speed area accounts for a larger proportion,the mixing time is shorter,and the stirring effect of the molten steel at the bottom of the molten pool is the best.After designing and researching the high Mach number oxygen lance nozzle and applying it to automatic steelmaking production,combined with the variable gun pressure transformation process,the blasting during the blowing process is reduced from 8.2% to 3.2%,which is about 5% lower than before.The final slag TFe content decreased from 18.5% to 15.3%,and the slag splashing effect was significantly improved;During the smelting process,the blown gun position is increased by 100mm-200 mm compared with the previous one.Compared with the previous gun age,the furnace is increased by 100 furnaces,which greatly improves the life of the oxygen lance nozzle.Figure29;Table23;Reference 59.