基于环境温度的转炉旋流氧枪射流分析

Analysis of converter twist oxygen lance jet based on ambient temperature

为探究旋流氧枪自由射流特性,建立了0°、6°、12°和18°旋流氧枪自由射流几何模型,分析了不同旋流氧枪炼钢温度下的旋流特性、射流速度和动压分布。发现与0°旋流氧枪相比,6°、12°和18°旋流氧枪射流速度和动压衰减较快,且旋流角越大,射流衰减越快。而6°旋流氧枪与12°和18°旋流氧枪相比,射流速度和动压衰减较慢,在保证合适冲击深度和冲击面积的同时,使熔池产生一定的旋转运动。基于此,建立了6°旋流氧枪和转炉气-渣-金多相流几何模型,分析了环境温度变化对6°旋流氧枪冲击特性和熔池速度分布的影响,发现环境温度从300 K升高到1873 K,冲击半径从1.25 m增至1.78 m,而冲击深度仅从0.119 m增至0.132 m。环境温度升高,钢液面处高速区面积增大,死区和低速区面积减小;在熔池较浅处,环境温度升高,熔池死区面积减小,高速区面积增大,以熔池深度0.3 m为例,环境温度从300 K升高到1873 K,死区面积由0.41 m^(2)减小至0.17 m^(2),高速区面积由9.35 m^(2)增至9.76 m^(2);在熔池深处,底吹射流起主导作用,环境温度对熔池速度分布影响较小,不同速度区域面积相差较小。研究结果可以为旋流氧枪工业应用提供理论指导。

In order to investigate the free jet characteristics of the twist oxygen lance,the free jet geometric models of 0°,6°,12°and 18°twist oxygen lances were established.The twist characteristics,jet velocity and dynamic pressure distribution of twist oxygen lances with different twist angles at steelmaking temperature were studied.It was found that the jet velocity and dynamic pressure decay was faster in 6°,12°and 18°twist oxygen lances compared to 0°twist oxygen lance,and the larger the twist angle,the faster the jet decay.Compared with 12°and 18°twist oxygen lances,the jet velocity and dynamic pressure decayed slowly when 6°twist oxygen lance was used.While ensuring the appropriate impact depth and impact area,the molten bath produced certain rotational motion.Based on this,a geometric model of gas-slag-metal multiphase flow of 6°twist oxygen lance and converter was established.The influence of ambient temperature change on the impact characteristics of 6°twist oxygen lance and the velocity distribution of molten bath was studied.It was found that when the ambient temperature increased from 300 K to 1873 K,the impact radius increased from 1.25 m to 1.78 m,and the impact depth only increased from 0.119 m to 0.132 m.As the ambient temperature increased,the area of high-speed zone at the molten steel surface increased and the area of dead zone and low-speed zone decreased.In the shallower part of molten bath,the area of dead zone decreased and the area of high-speed zone increased as the ambient temperature increased.Taking the molten bath depth of 0.3 m as an example,the ambient temperature increased from 300 K to 1873 K,the dead zone area decreased from 0.41 m^(2) to 0.17 m^(2) and the high-speed zone increased from 9.35 m^(2) to 9.76 m^(2).In the deeper part of molten bath,the bottom-blowing jet played dominant role and the ambient temperature had weaker effect on the molten bath velocity distribution,with smaller difference in the area of different speed zones.The research results can provide theoretical guidance for the industrial application of twist oxygen lance.