圆坯结晶器水口优化的模拟研究

以大圆坯结晶器为原型,采用数值模拟与物理模拟相结合的方法,分别研究了使用直通式水口和4孔旋转水口时该圆坯结晶器内钢液流场和温度场的分布情况,对比分析了2种水口的优劣。数值模拟和物理模拟结果表明,使用目前常用的直通型水口时钢水冲击深度大,易在弯月面处形成死区,不利于圆坯内部及表面质量的提高;4孔旋转水口比直通水口的钢液冲击深度浅,回旋区位置明显比直通水口更靠近自由液面,这将有利于夹杂物的上浮去除和热区中心的上移。温度场模拟结果显示,使用旋转水口时自由液面温度比直通型水口高14℃,更有利于结晶器内钢水过热耗散及保护渣的熔化,可防止液面结壳。

Simulation Study on Optimization of Nozzle Structure for Round Mould

Based on the prototype of the round mould in some plant, the methods of numerical simulation and water modeling were used to study the distribution of flow field and temperature field of molten steel in the mould when applying the single outlet SEN and a rotating nozzle with four outlets, then the results of these two kinds of nozzle were compared. Results show that the impact depth caused by the single outlet SEN used at present is larger, leading to a dead zone of steel at the meniscus of the mould which is detrimental to the surface and inner qualities of billet. With smaller impact depth, the flow from the optimized rotating nozzle outlet helps the vortex center move up, improving the inclusion removal and heat transfer. Numerical simulation results show that with rotating nozzle the temperature at fluid free surface is 14℃ higher than that with single outlet nozzle, implying better dissipation of steel superheat and melting of mould powder, then the slag crusting can be prevented.