Abstract: In order to reduce the defect such as comer crack of rectangular bloom and breakout to increase the quality of bloom, the study of optimization of mould flow field by changing nozzle angle of submerged nozzle has been carried out. The numerical simulation of liquid flow and solidification coupling process in mould for 150 mm x 380 mm rectangular bloom has been performed by using Fluent software to get the effect of nozzle angel (15°-30°) on surface flow rate, surface turbulent kinetic energy and impact depth. Results show that with increasing nozzle angle the average surface flow rate decreases, the impact depth increases being favourable to stabilize the liquid surface ； but with increasing nozzle angle, the liquid surface fluctuation is small, it is unfavourable to stirring liquid and removing inclusions in steel, and in this case the circle round region in lower part of mould is too low and the bloom shell is thinning easily forming breakout ； to sum up it is obtained that the suitable nozzle angle for 150 mm X 380 mm bloom casting is 25°. Application results obtain that the total inclusion numbers with using optimized nozzle decrease by 36%.

Key words: 150 mm x380 mm Rectangular Casting Bloom, Nozzle Angle, Mould, Flow Field, Numerical Simulation

摘要： 为减少矩形坯角裂、漏钢等缺陷,提高铸坯质量,进行改变浸入式水口出口倾角角度以优化结晶器流场的研究。通过Fluent软件,对150 mm×380 mm矩形坯结晶器钢液流动和凝固耦合过程进行数值模拟,得出水口倾角（15°~30°）对表面流速、表面湍动能和冲击深度的影响。结果表明,随水口倾角增加,平均表面流速下降,冲击深度增加,有利于稳定液面;但随倾角增加,液面波动小,不利于钢液搅拌和夹杂物去除,下部回旋区过低,坯壳变薄,容易产生漏钢;综合得出,150 mm×380 mm铸坯的水口倾角宜为25°。应用结果得出使用优化水口后,铸坯中夹杂物总数减少36%。

关键词: 150 mmx380 mm矩形坯, 水口倾角, 结晶器, 流场, 数值模拟