# The Development of an Optimized Impact Pad for a Six-Strand Tundish Using CFD Simulations
## 4 Evaluation and Discussion
### Flow Characteristic Evaluation  
The visual evaluation of the flow characteristics based on vectors, contours, and streamlines was carried out in three planes: the YZ plane (a cross-section)--Plane 1, the XZ plane--Plane 2, and the XZ plane--Plane 3 (coming through the outlets) (Figure 9).  
The tracer flow pattern observed at 20 s, based on contour visualization in the ZY plane (Plane 1), is presented in Figure 10. The comparison between configurations allowed for clear differentiation in flow behavior as a result of the applied impact pad design. In the K configuration, the flow pattern resembled a typical plug flow, which may lead to the exposure of the molten steel surface and contribute to the formation of the so-called slag \"red eye\" phenomenon. In contrast, the SP-K2 configuration exhibited a notable redirection of flow toward the upper frontal region of the tundish. This redistribution supports a more uniform dispersion of molten steel throughout the tundish volume, enhancing the overall efficiency of space utilization. The SP-K4 configuration further modified the flow by promoting partial dispersion throughout the tundish while simultaneously directing part of the flow along the axis of the ladle shroud.  
Figure 10: Tracer distribution with the K (**a**), SP-K2 (**b**), and SP-K4 (**c**) configurations in Plane 1.  
Figure 9: Analyzed planes and outlet designations in the simulation model.  
The observation of the tracer flowing through the XZ plane (Plane 2) revealed that it was necessary to prevent a short-circuit flow primarily at the CS3 outlet. It was achieved with both analyzed configurations--SP-K2 and SP-K4 (Figure 11).  
The visualization of the tracer flow patterns at 80 s shows certain differences between the SP-K2 and SP-K4 configurations as well as a more even distribution across the whole-tundish volume (Figure 12).  
The observation of the flow patterns in Plane 3 revealed that the tracer only flew in the upper section of the inflow area with the K configuration. This phenomenon might cause increased erosion of the lining in the slag line area (Figure 13).  
Figure 11: Tracer distribution with the K (**a**), SP-K2 (**b**), and SP-K4 (**c**) configurations in Plane 2.  
Figure 12: Tracer distribution with the K (**a**), SP-K2 (**b**), and SP-K4 (**c**) configurations in Plane 2 at 80 s.  
Flow behavior near the tundish walls can be effectively analyzed using vector fields, which reveal both the direction and magnitude of molten steel movement. This approach provides insights into potential erosion intensity caused by flow acting on the working lining. From the vector analysis corresponding to the K configuration, it was determined that the upper central region of the tundish particularly close to the ladle shroud is subjected to the highest stress and is therefore most susceptible to wear. In contrast, under the SP-K2 and SP-K4 configurations, the region exhibiting the greatest stress concentration was located in the rear section of the tundish, specifically behind the ladle shroud, as illustrated in Figure 14.  
The cross-section of Plane 2 shows the flow vectors in the analyzed configurations (Figure 15), with visible differences in the flow across the entire tundish volume.  
Figure 14: Fluid flow direction with the K (**a**), SP-K2 (**b**), and SP-K4 (**c**) configurations in the tundish in Plane 1.  
Figure 13: Washing off the upper inflow section of the tundish in the slag line area.