连铸中间包水口吹氩对堵塞的影响数值模拟

Numerical Simulation of Influence of Argon Flowrate on Tundish Nozzle Clogging during Continuous Casting

摘要: 本文采用数值模拟方法，对水口吹氩量和水口开度影响水口沉积速率的规律作了分析研究。结果表明，吹氩量对水口内的压力存在较大的影响，压力在滑动水口处存在突降。使水口滑板处保持正压的吹氩量随着开度的减小而增大。水口开度从66.45%减小至42.82%时，使水口滑板处保持正压的吹氩量从10 L∙min⁻¹增加至25~30 L∙min⁻¹。吹氩量对水口内沉积速率的影响规律与滑板开度有关。大开度时，较小吹氩量2.5~5 L∙min⁻¹可以使沉积速率降至最低，但随着吹氩量进一步增大时，沉积速率反而增加，至最大值后再次下降。小开度时，随着吹氩量的增加，沉积速率均为下降趋势，但吹氩量大于15~20 L∙min⁻¹以后，增大吹氩量对降低沉积速率的效果并不明显。综合考虑吹气量对水口内压力和对沉积速率的影响，大开度下(>60%)合适的吹气量应为10 L∙min⁻¹。考虑大吹气量带来的危害，小开度下(<60%)合适的吹气量应为15~20 L∙min⁻¹。

Abstract: Influence of argon flowrate and slide gate opening ratio on deposition rate was researched by the method of numerical simulation. Flowrate of argon had influence markedly upon pressure in the nozzle, and the pressure dropped suddenly after molten steel flowing through the slide gate. To keep positive pressure at slide gate for avoiding inspiration of air, minimum flowrate of argon was increased from about 10 L∙min⁻¹ to 25~30 L∙min⁻¹ as slide gate opening ratio decreasing from 66.45%to 42.82% when casting speed was 1.2 m∙min⁻¹. Influence of argon flowrate on the deposition rate of alumina was related to the slide gate opening ratio. When the slide gate opening ratio was big, such as 66.45%, the deposition rate of alumina occurred maximum and minimum values as the argon flowrate increased step by step. When the opening ratio was small, such as 50.46% and 42.82%, the deposition rate of alumina was decreased all along as the argon flowrate increased, and the effect of argon flowrate on decreasing alumina deposition rate was not obvious when the argon flowrate was more than 15~20 L∙min⁻¹. Considering the influence of flowrate upon to static pressure in nozzle and deposition rate, the appropriate argon flowrate was 10 L∙min⁻¹ as big opening ratio of slide gate (>60%). Due to the disadvantage of high flowrate, the appropriate argon flowrate was 15~20 L∙min⁻¹ as small opening ratio (<60%).