双通道感应加热中间包的三维磁流热耦合模型

 结合感应加热的中间包冶金是当前提升特殊钢连铸洁净度和质量稳定性的前沿技术。针对大方坯连铸用T型六流中间包,利用流动-传热耦合模型研究了控流装置对具有双感应加热通道中间包冶金行为的影响,首先获得了不开启感应加热工况下中间包的优化控流结构;进而通过对该结构进行电磁-流动-传热耦合模拟,研究了感应加热的控流和热补偿作用。结果表明,通过提高加热通道高度并配合双挡坝结构可进一步改善流体流动状况、提高各流一致性。其中,在不开启感应加热时,优化后中间包较原型死区比例由31.4%降低为17.6%,活塞区比例由19.1%提高为39.1%,平均停留时间标准差由99.6减小到40.3 s。开启感应加热后,中间包内流场有显著变化,通道出口钢液具有明显的上升流,这将有利于夹杂物的上浮去除。开启感应加热30 min后较未开启感应加热时中间包各出口平均温度由1 798.1升高为1 827.3 K,这表明感应加热可有效补偿钢水浇注过程中的热损失。这一功能有利于实现低过热度恒温浇铸,从而也有助于提高中间包控制铸坯洁净度和铸态组织一致性的综合冶金效果。

Three-dimensional magneto-hydrothermal coupling model of twin-channel tundish with induction heating

Tundish metallurgy with induction heating is one of cutting-edge casting technologies for improving the cleanliness and quality stability of special steels. Based on the flow-heat transfer coupling model,the influence of the flow control device on the metallurgical behavior of the six-strand T-type twin-channel tundish was studied for bloom steel casting,and the optimized flow control structure of the tundish under the condition of without induction heating was obtained. Accordingly,the electromagnetic-flow-heat transfer coupling simulation of the structure was carried out to study the flow control and thermal compensation of induction heating. The results show that the fluid flow and the consistency of each strand flow can be improved by increasing the height of the channel with double dams. Without induction heating,compared to the prototype tundish,the proportion of dead zone ratio was decreased from 31.4% to 17.6%, the proportion of piston zone was increased from 19.1% to 39.1%, the standard deviation of average residence time was reduced from 99.6 to 40.3 s,and the consistency of each flow is significantly improved. After the induction heating is employed,the flow field in the tundish is more complicated and the molten steel at the outlet of the channel has an obvious upward flow,which prolongs the average residence time of the molten steel and facilitates the floating and removal of inclusions. After 30 min of induction heating,the average temperature of each outlet of the tundish increased from 1 798.1 to 1 827.2 K compared to the case without induction heating,indicating that induction heating can effectively compensate for the heat loss during the steel casting. This function is beneficial to conduct low superheat casting under a constant speed,which means an improved tundish metallurgical effect for both the steel cleanness and as-cast structure.