连铸结晶器内偏流及漩涡卷渣的实验研究

连铸结晶器内的偏流和漩涡卷渣行为严重影响连铸坯的质量,因此建立了一套直弧型结晶器系统,研究了偏流和漩涡卷渣的运动规律.结果发现:偏流是由于流场自身的不稳定造成的,是时刻变化的;偏流发生在二冷区弯曲段附近.即使保证水口对中放置,结晶器上表面漩涡依然存在,多数情况下只有单个漩涡出现,其位置和大小是瞬变的.对称涡出现的机率较小,尺寸和强度较小,持续时间较短.同时考察了拉速、水口插入深度、滑动水口开度和中间包液位高度对偏流及其周期和漩涡卷渣的影响.

Experimental Studies on Asymmetrical Flow and Vortex Slag Entrapment in Continuous Casting Mold

The asymmetrical flow inside the mold and the slag entrapment induced by vortex at the top surface have great influences on the quality of continuous casting slab. One vertical-curved mold system was set to study the asymmetrical flow and slag entrapment behaviors. The results show that the asymmetrical flow in the mold is induced by the instability of the flow field itself and the flow pattern is not stationary but changed over frequently. The asymmetrical flow occurs near the bending section of the secondary cooling zone. Although the geometrical and operating conditions were made to be symmetric strictly， the vortex cannot be avoided. In the most cases， only one vortex took place and its size and position varies with time. The probability， size and strength of the symmetric vortex are very small and the durations is also short. Moreover， the effects of casting speed， gas injection rate， immersion depth of nozzle， slide gate opening， and liquid level height of tundish on the periodic asymmetrical flow and slag entrapment are analyzed.