Study On Optimization Of Three-Strand T-Type Tundish Configuration In Liquid Steel Continuous-Casting

The fluid flow in a three-strand T type tundish was studied and optimized with physical and numerical simulation in this research, and an optimum tundish configuration was obtained. According to the principle of similarity, a three-strand T type tundish model was set up to experiment in laboratory with 1:2.5 scale from the three-strand T type tundish prototype. The mathematical model describing the flow phenomena in the tundish was established from the continuity equation, momentum equation, k-s turbulent kinetic energy model and energy equation. The FLUENT commercial software was used to numerically calculate the inclusion removal, flow and temperature fields in different tundish configurations.Fluid flow was unreasonable with the original tundish configuration. The peak concentration time was short, and the plug flow zone volume was small in the original tundish configuration. The dead zone volume was large in the tundish. The fraction of dead zone volume was more than 30%. It made the effective volume of the tundish decrease by one third, which was not effective to promote floating and removal of the inclusion from liquid steel. The fluid scouring effect to the front wall of the tundish with the original configuration was serious.For the original flow control devices were unreasonable, new turbulence inhibitors and baffles bearing diversion holes with different shapes and sizes were designed. Flow characteristics of fluid in the tundish indicated that the square turbulence inhibitor was better. The fluid flow path was changed by using the optimal baffle and the fluid scouring effect to the front wall of the tundish was avoided. The trend of the fluid flow was toward the molten steel surface from the optimum baffles. In scheme 6, the fractions of dead volume were 15.4% and 16.6%, which decreased by 49.2% and 49.8% compared with the original tundish configuration, respectively. The fluid flow in the original scheme, scheme 6 and scheme14 tundish configurations were studied with mathematical simulation. Fluid flow was disorder with the original tundish configuration. The trend of the fluid flow toward the molten steel surface was not obvious and the fluid scoured the front wall of the original tundish. The flow field was changed obviously and the fluid scouring effect to the wall of the tundish was avoided in the optimal tundish configuration. A large circuit flow area was formed close to the free surface.The results of the temperature field indicated that the temperature distribution was unreasonable in the original tundish configuration. There was large temperature gradient along the flow direction, and the lowest temperature was small. The biggest temperature difference reached 35 K. The lowest temperature was increased and the biggest temperature difference was decreased in the optimal tundish configuration. The temperature distribution was reasonable. The biggest temperature difference dropped 8 K in scheme 6.The floating and removal of inclusions in the original scheme and the two optimization schemes were simulated. The removal rate of the inclusions with small size was lower in the original tundish configuration. The trajectory of the inclusions was changed and the removal rate of the inclusions with small size was improved in the two optimization schemes. For inclusions from 10 to 50μm, the removal rate of the inclusions was increased by 11.8% on average.