浸入式水口倾角对宽幅连铸结晶器内流动行为的影响

浸入式水口出口角度影响射流的动能损失,进而影响结晶器内的流动行为.建立了比例为1 ∶ 4的水模型,在模型拉速为0.425 m/min、水口浸入深度为40 mm的条件下,借助粒子图像测速技术研究了浸入式水口出口倾角为0°和+5°对宽幅连铸结晶器内流动行为的影响.结果表明,0°和+5°水口条件下,射流在模型内的流动方式有很...

Influence of outlet angle for submerged entry nozzle on fluid flow in a wide slab casting mold

The outlet angle of submerged entry nozzle affects the kinetic energy loss of jet,then affects the flow behavior in the mold. A 1∶4 scale water model of slab mold was built. The influence of 0° and +5° nozzles on the flow behavior in wide slab casting mold was studied using particle image velocimetry under the condition that pulling rate was 0.425 m/min and nozzle immersion depth was 40 mm. The results show that there is a big difference in jet morphology between 0° and +5° nozzle. When the angle is 0°,the jet flow is relatively concentrated and spread slowly,it will spread to the wide surface in the direction of thickness when it reaches the narrow surface. However,at +5°,the jet has a process of upward impact and back again,and the expansion range of jet is larger than that of the 0° nozzle. This will make more jets impact the wide surface before reach the narrow front(which can reach the wide surface within 0.3 s). It means that the molten steel scours dendrite at the front of solidification for wide surface more greatly in actual production,which is not conducive to the growth of slab shell. When the liquid steel flows through +5° nozzle,it first impacts the bottom of nozzle in the direction of gravity,and then returns +5° to shoot from the nozzle. In this process, the kinetic energy loss of liquid steel is greater than 0° nozzle. In addition, the liquid steel flows through a longer distance in the wide-width mold than in the ordinary mold,so the kinetic energy is lost more. This is disadvantageous to the melting of slag and affecting the continuous casting. Comparing the flow fields of the center section,1/4 section and section close to the wide surface under 0° and +5°,the closer to the wide face the velocity of the whole flow field is smaller. At the angle of 0°,the velocity decreases from 0.103 m/s in the central plane to 0.042 m/s in the wide face,and it decreases from 0.097 m/s to 0.066 m/s in the angle of +5°. The symmetrical and asymmetric flow patterns in the mold under 0° and +5° conditions were analyzed. At 0°,86% of the flow states are symmetrical and 14% are asymmetric,while 69% of the flow states are symmetric and 31% are asymmetric at +5°.