基于F曲线的中间包流场优化

Optimization of the tundish flow field based on F-curve

  • 摘要: 针对某厂三流异型坯中间包,建立了相似比为1∶2的水模型,使用F曲线对不同控流装置下的中间包流场特性进行分析与优化。实验内容包括原型控流装置、湍流抑制器无挡坝、湍流抑制器加挡坝组合。结果表明,原型中间包中部水口存在短路流,水口间流动的差异性较大,可能导致三个铸流的铸坯温度和洁净度不均匀,进而发生同炉次各铸坯质量稳定性差的问题。采用湍流抑制器无挡坝控流装置,湍流抑制器导流孔夹角为60°时,短路流出现在中部;导流孔夹角为86°时,无短路流,各流一致性变好;导流孔夹角为110°时,两侧水口出现短路流,各流一致性优于前两个角度。中间包的各流一致性与死区比例并无相关性,一致性良好的中间包流场,其死区比例并不一定小。优化后的中间包湍流抑制器导流孔夹角为110°,挡坝距离中间包中心2400 mm,中间包内无短路流,1#、2#水口一致性最佳,死区由17.89 %减小到9.67 %,减小率为11.25 %,F曲线标准差最大值由0.3减小到0.016。

     

    Abstract: The water model with a similarity ratio of 1∶2 was established for a three-strand beam blank tundish. The molten steel flowing character was researched in different flow control devices by using the F-curve, and the flow field of the tundish was optimized. The volume fractions of dead region, plug flow and well-mixed flow are calculated. The standard deviation of the stagnation time of 1, 2 and 3 flow and the maximum value of standard deviation function of F-curve were used to evaluate the dispersion of each flow. Three cases were considered during the experiments, i.e, prototype flow control device, turbulence inhibitor without dams combination, turbulence inhibitor and dams combination. The results show that short circuit flow exists in the middle nozzle of the prototype tundish, and poor consistency between nozzles, which may lead to the uneven temperature and cleanness of the three-strand beam blanks, leading to different quality of different beam blanks in one heat. Using the turbulence inhibitor without dams combination, the short circuit flow appears in the middle of tundish with the angle of diversion holes being 60°. When the angle is 86°, there is no short circuit flow, and the consistency between strands becomes better. When the angle is 110°, the short circuit flow appears in the two sides of the tundish nozzle with the best consistency between strands. There is no correlation between the consistency of the tundish strands and the dead volume fraction. When the consistency of the tundish strands is good, the dead volume fraction may not be small. After optimization, the angle of the diversion hole of the tundish turbulence inhibitor is 110°, the dam is 2400 mm away from the tundish center. There is no short-circuit flow, the consistency of 1# and 2# nozzles is the best, the dead volume fraction is reduced to 9.67% from 17.89%, and the reduction rate is 11.25%. The maximum standard deviation of the F-curve is reduced to 0.016 from 0.3.

     

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