Simulation Research On Flow Field Optimization And Inclusion Removal In Continuous Casting Tundish For Heavy Rail Steel

With the rapid development of high-speed railways in recent years,it is urgent and necessary for China to increase the output and quality of heavy rail steel.As an important multifunctional smelting container in the continuous casting process,the tundish has great significance for improving the purity of molten steel and the quality of the casting slab.In this work,it is aimed at the problems of instability of steel stream in the continuous casting process and inconsistent flaw detection of heavy rail steel in a steel plant.With its Five-strand T-type tundish as the research object,the fluid dynamics simulation software Fluent was used to numerically simulate three tundish structures with turbulence inhibitor,turbulence inhibitor+dam and weir,turbulence inhibitor+porous baffle wall.The optimal flow control scheme is determined by comparing the effects of different schemes and inclusion removal efficiency.?1?The numerical simulation results of the original tundish show that when the tundish is not provided with the flow control device,its flow field and temperature field are extremely uneven,the remote flow is bad,and the temperature and average residence time of molten steel at each nozzle are extremely different.?2?The numerical simulation study of the effect of tundish flow control was carried out by adding different turbulence inhibitors and a combination of turbulence inhibitor with dam and weir in the tundish.First,the simulation results of the two turbulence inhibitors show that the turbulence inhibitor is effective for improving the flow condition in the stream impact zone and reducing the impact of the inflow molten steel on the bottom and surface of the tundish.The round type is better than the square type.The volume of the dead zone has increased by 1.5%,and the minimum temperature of the tundish has increased by 10.2k.However,the tundish still has the problems of poor remote flow and significant differences in molten steel in each strand.Second,the simulation results of the“round turbulence inhibitor+four dam and weir schemes”show that setting the dam and weir did not achieve the desired flow control effect.The flow field and temperature field of tundish do not change significantly,and the previous flow problems still exist.?3?The numerical simulation of tundish flow control effect was studied using round turbulence inhibitor+porous baffle wall scheme.The improved holes opening plan of baffle wall was determined through orthogonal optimization design of holes opening and porous baffle wall structure.The test condition is set to a left inclination angle?₁=22°,a right inclination angle?₂=48°,an upward elevation angle?=30°,and an aperture d=70mm.The simulation results of the optimization scheme show that the uniformity of the flow field and temperature field of the tundish has been significantly improved,and the flow in each strand has become consistent.The maximum temperature difference of the tundish is 21k,and the maximum temperature difference of the three nozzles is only 1.7k.The dead zone volume is reduced by 10.0%compared to the original tundish,and the plug flow volume is increased by 14.2%.?4?Comparing the inclusion removal efficiency of different particle sizes of 10?m,30?m,50?m,70?m,and 90?m in the tundish,the results show that the round turbulence inhibitor+porous baffle wall has the highest inclusion removal efficiency under the four schemes.The removal efficiency of inclusions with smaller particle diameters of 10?m and 30?m was above 87%,which was significantly better than other schemes.The removal rate of inclusions with larger particle diameters of?50?m also remained above 95%.?5?According to the final simulation results of flow field optimization and inclusion removal efficiency,the best optimization combination of tundish structure is obtained:round turbulence inhibitor+porous baffle wall,and the optimal plan of baffle wall holes opening is left inclination angle?₁=22°,right inclination angle?₂=48°,upward elevation angle?=30°,aperture d=70mm.