方坯连铸结晶器内表面流速与卷渣行为模拟

针对中小断面方坯侧分水口浇铸技术，以实际180 mm×240 mm断面方坯连铸结晶器为原型，基于相似原理，采用1：1的物理模型，比较了直通型和侧分旋流型水口浇注时在不同拉速和浸入深度下的结晶器内自由表面流速和渣层状态。结果表明：相同的浸入深度和拉速下，旋流型水口浇注时结晶器内各测点表面流速比直通型水口大；在实验条件下，直通型水口表面流速为0.010～0.023 m/s，旋流型水口为0.010～0.055 m/s，拉速和浸入深度对旋流型水口表面流速的影响较直通型水口显著；此外，采用旋流水口时结晶器的渣层波动要比采用直通型水口时频繁，拉速1.0 m/min、浸入深度120 mm时，其渣层波动适宜，钢渣界面活跃且无卷渣和裸钢现象发生，此时两测点的表面流速分别为0.028和0.032 m/s，是较适宜的工艺条件。

Surface flow velocity and slag entrapment behavior modelling in a billet continuous casting mold

For the side-port nozzle casting technology of middle-small section billet，the free surface flow velocity and slag entrapment behavior of fluid in a 180 mm×240 mm billet continuous casting mould using single-port straight nozzle and four-port swirling nozzle casting，respectively，were investigated with 1：1 water model，based on the similarity principle. The results show that the surface flow velocity of fluid in the mold using swirling nozzle is larger than using the straight one at the same immersion depth and casting speed. The surface flow velocity of fluid using straight nozzle is in the range of 0.010～0.023 m/s，while it is 0.010～0.055 m/s using swirling nozzle at the given experiment conditions. The casting speed and immersion depth affect the surface flow velocity of fluid in the mold with swirling nozzle more obviously. Moreover，the fluctuation of slag layer is more frequent for the swirling nozzle than for the straight one. At the casting speed of 1.0m/min and the immersion depth of 120 mm，the slag layer fluctuates properly and the slag-steel interface keeps active. There’s no slag entrapped into the fluid and no simulated metal fluid exposed in the air.