炼钢过程气-固混合喷射动力学特性研究

Study on the dynamic characteristics of gas-solid mixed injection in steelmaking process

气-固喷射技术改变了传统冶金物料加入方法,粉气流通常以高速射流的形式射入熔池内部,不仅能够高效供给冶金反应介质,也可以大幅度强化熔池搅拌,为冶炼创造良好的热力学、动力学条件。建立了气-固混合喷射数值模拟模型,通过气-固混合喷射冷态试验进行验证;分析了炼钢过程气-固混合喷射的动力学特性。结果表明,采用气-固混合可有效提高射流核心段长度,降低气流速度的衰减。同时,喷粉速率的增大会导致气-固混合射流的粉气流速度逐步降低,射流核心段长度增加,且射流后半段粉气流速度衰减速度降低;粉剂粒度的增加会导致喷嘴出口气体速度最大值增加,粉粒的最大速度降低,射流核心段气体速度与粉剂速度间的差距加大。

Gas-solid injection technology has changed the traditional method of adding materials in metallurgy. Gas-solid flow is usually injected into the molten pool by high-speed jet,which can not only efficiently supply metallurgical reaction medium,but also greatly strengthen the molten pool stirring,creating good thermodynamic and dynamic conditions for smelting. A numerical simulation model of gas-solid mixture injection was established,which was verified by the cold state experiment of gas-solid mixture injection. Then,the dynamic characteristics of gas-solid mixture injection in steel-making process was analyzed. The results showed that the gas-solid mixture injection could effectively increase the length of the core section and reduce the velocity decay rate. Meanwhile,with the increase of powder injection rate,the velocity of powder gas flow in gas-solid mixed jet decreased gradually,the length of jet core section increased,and the velocity attenuation speed of powder gas flow in the second half of jet decreased. The increase of powder particle size would lead to the increase of maximum gas velocity at nozzle outlet and decrease of maximum velocity of powder particle,and the gap between gas velocity and powder velocity in core section of jet increased.