板坯高拉速连铸台阶状水口的水模型研究

采用全比例水模型研究了一种用于板坯高拉速连铸的新型台阶状水口的流场、液面特征、液渣分布与流股特征。研究发现： 与原水口相比，使用该水口后结晶器内流场对称性更好；新水口在拉速2.4 m/min下平均波高最大值为 5.3 mm，比原水口最大值（6.4 mm）小17%，液位波动的FFT分析表明：新水口下液面波动频率集中在1.2 Hz (振幅为0.46 mm)，而原水口液面波动频率集中在1.1Hz，振幅0.7 mm；使用新水口在高拉速下结晶器的表面流速为0.28 m/s，比原水口(0.41 m/s)小32%，且自由液面波峰波谷差和液渣层裸露面积均小于原水口；水口作用机理分析表明：由于新水口台阶的混合作用，促使水口出口两侧流股对称性更好，更有利于稳定液面和减少卷渣。

Water model study on step-shaped submerged entry nozzle for high speed slab casting.

A full scale water model of continuous casting mold was built to investigate the fluid flow， level characteristics， mold flux profile and jet characteristics by a novel step-shaped submerged entry nozzle (SEN). The results show that this novel SEN shows better symmetrical fluid flow in the mold for high speed casting. In addition， the average level fluctuation of this SEN is 17% smaller than the traditional SEN； The FFT analysis of level fluctuation shows that the level fluctuation frequency is concentrated in about 1.2 Hz and the amplitude is 0.46 mm with the novel SEN， while the level fluctuation frequency is concentrated in about 1.1Hz and the amplitude is 0.7 mm with the traditional SEN；Furthermore， the surface velocity is 0.28 m·s－1 with the novel SEN at high speed casting， which is 32% smaller than that with traditional SEN (0.41 m·s－1)， Moreover， the level profile distance (wave peak-wave valley) and the exposed area of mold flux is much smaller than that of traditional SEN；The mechanism analysis shows that this new step-shaped SEN with its mix effect can improve the symmetry of jet velocity and thus prevent slag entrapment in the mold.