Study On Optimization Of Flow Control Devices In Eight-Strand Tundish

As a vital link in the continuous casting process, tundish metallurgy's principal function is to adjust the condition of the fluid flow by settings of flow control devices, with purposes of the temperature of the molten steel more uniform and the removal effect of non-metallic inclusions better. Therefore, lots of researchers explored the flow and control of the molten steel in tundishes, adopting experimental methods such as mathematical simulation and water modeling.This paper makes research on an eight-strand tundish in a steel plant. The methods of physical modeling and mathematical simulation are adopted to analyze and study the flow control devices in tundishes systematically and quantitatively, then to optimize these devices."Stimulate-response"experimental technique is applied in the physical modeling with a standard deviation as an evaluation index, to analyze the average residence time of the molten steel in tundishes with different kinds of flow control devices. The dead zone volume(Vp),mixed volume(Vm)and plug flow volume(Vd)in tundishes are also carried out by using the model of metallurgical reactor. The k-εtwo-equation model is introduced in the mathematical simulation and the commercial software PHOENICS is used to calculate the three-dimensional flow field in tundishes. And we analyze the effect on the fields caused by different flow control devices such as dams, impact plates, baffles and guide holes, and discuss the feature of the molten steel flow, the distributions of temperature and streamline between pre-and post these settings.According to the results, the conclusions are as follows. When the narrow and long rectangular tundish is without flow control devices, the molten steel starting from the entry nozzle runs forward 3# nozzle, then 4# nozzle from 1# and 2# nozzles. An inevitable result is that a greater difference in residence time and casting temperature may occur, influencing the quality of slabs directly. For the better production, the flow control devices of the tundish need to be designed reasonably.In the condition of the optimization of flow control devices with an impact zone added into the tundish, it improves the flow proprieties and extends the time in which the flow enters into the 1# and 2# nozzles, making the residence time of each nozzle tend to be uniform. The flow through a number of recirculation zones is in favor of the uniform of compositions and temperature and also is beneficial to the removal of inclusions. Calculations shows that each outlet's temperature of the molten steel keeps from 1495℃to 1498℃, with a bit of temperature difference except the impact zone. The flow proprieties of the four nozzles are similar and the response time, the residence time and the peak value are almost the same. The dead zone volume in the tundish accounts for only 5.6%.The optimization of flow control devices can not result in the slag entrapment, increase the sequence rate of the tundish and improve the quality of slabs.