CFD Model Study of a New Four-Port Submerged Entry Nozzle for Decreasing the Turbulence in Slab Casting Mold

In recent years, the continuous casting process in which molten metal is constantly cast into semifinished shapes has been widely adopted in the steel and nonferrous metal producing industry, mainly due to its economic advantages associated with increased yields and the elimination of intermediate processing steps. Turbulent flow in submerged entrance nozzle and mold of continuous casting is associated with costly failure such as the entrainment of slag inclusions and the formation of surface defects. A number of previously studies have analyzed the flow. A CFD model study has done to decrease the turbulence within the mold by developing a 4-port submerged entry nozzle in comparison with conventional 2-port submerged entry nozzle. VOF (volume of fluid) simulation study has been done to find out the effect of turbulence within mold on slag metal interaction, level fluctuation, and risk of breakout. In all the cases the performance of new 4-port SEN over 2-port SEN has been compared by plotting graph. 1. Introduction Steel maker around the world is emphasized to increase the production rate to cope with the global demand of steel in coming decade. Simultaneously the supply of quality steel is demanding by customer. But to meet this stringent demand is very difficult as production machine has certain drawbacks and limitations. One of these drawbacks is creation of turbulence within mold during casting of steel at high casting speed. The submerged entry nozzle (SEN) with two bifurcated ports is commonly applied in slab continuous casting. As the source of the flow, the SEN decides on the steel flow pattern in the mold. For unreasonable nozzle design, impingement of hot liquid metal with high momentum against the solidifying shell can contribute to shell thinning and costly breakout as well as large surface fluctuation [1]. Scientists have been interested in the fluid flow that is observed in the mold during continuous casting because the flow pattern affects the inner and the surface quality of the steel slab to a great extent. Figure 1(a) shows the basic phenomenon produced in the mold during the continuous casting. The flow pattern depends on the structure of the submerged entry nozzle (SEN) and other relative parameters. On the one hand, a calm and smooth mold level assists the uniform formation of the strand shell in circumferential direction and reduces the thermomechanical stresses in the strand shell. It also allows the homogeneous intake of casting powder into the lubrication gap between the strand shell and the mold wall and this, in turn, is