Transient Fluid Flow Phenomena in Continuous Casting Tundishes

摘要

The continuous casting tundish is used for all the continuous casting process and serves as a buffer and links the discontinuous process of the secondary metallurgy in the ladle with the continuous casting process in the mold. A modern day tundish is designed to perform various metallurgical operations such as inclusion removal, gas bubbling, alloying, modification of inclusions by calcium treatment, melt reheating, superheat control, and thermal homogenization, which is called "Tundish Metallurgy". Though the steel cleanliness in the tundish has been investigated through industrial trials, the operation conditions like the high temperature, the visual opacity of the molten steel, and the massive size of industrial tundish, retard any direct and elaborate industrial experimental investigation on the fluid flow phenomena in tundish. Water modeling is well used to investigated the fluid flow in tundish based on the fact of similar kinematic viscosity between the molten steel and water, the optimization results by water modeling, especially the results of inclusion removal, needs to be further proved before being used to industries due to the following unclear issues: 1) the big difference in the surface tension between the steel (σ_(steel)=1.89 N/m) and the water (σ_(water)=0.073 N/m), affecting the inclusion behavior very much; 2) how to accurately simulate inclusion motion and removal in tundish; and 3) How to mostly simultaneously satisfy several similarity criterions between the molten steel and the water model, such as Froude number similarity, Reynolds number similarity, and Weber number similarity if with gas bubbling, in order to let the water model results represent those in the real steel system.