Research On Simulation Of Structure Optimization In Channel-type Induction Heating Tundish

Continuous casting is the key link from steel smelting to solid-state billet production.Tundish is the last important transitional refractory container in the continuous casting production process.The tundish not only plays the basic role of storing and distributing molten steel,but also achieves the purpose of purifying molten steel and realizing constant temperature casting with low superheat.Furthermore,it improves the output and quality of products.In the actual production process,there is a large amount of heat loss at the initial stage of casting,tundish change and the end of casting.The resulting large temperature drop causes uneven temperature distribution inside the tundish,which seriously affects product quality.In response to the problems,metallurgical industry workers at home and abroad proposed the need of external heat supplementation and optimization of the internal flow field of the tundish.Meanwhile,the application of induction heating in the tundish provides the possibility to realize constant temperature casting with low superheat and improve the cleanliness of molten steel.Therefore,the channel-type tundish type which is convenient for the application of induction heating came into being.With the application of tundish induction heating,the influence of the internal non-isothermal state caused by tundish supplementary heating on the flow field has also attracted much attention.In order to study the influence of the internal structure of the channel-type induction heating tundish and the non-isothermal state on the flow field,which quantitatively studied the flow field distribution in tundish under non-isothermal state by numerical and physical simulation.It combined with Particle Image Velocimetry(PIV,hereafter)velocity measurement.Based on non-isothermal experiments,quantitative researches were carried out on the velocity field,vorticity field,Residence Time Distribution(RTD,hereafter)and other characterization parameters in the tundish.Combined with the numerical simulation process with reasonable non-isothermal assumptions,the influence of the non-isothermal state in the channel on the flow field in the tundish was explored.Finally,this thesis optimized the design of the flow control device of the induction heating tundish transformed from T-shaped tundish technology to eight-channel type,and sought to obtain the channel structure with universal significance for it to guide production practice.The results show: The heating of the channel in the tundish significantly affected the distribution of the flow field.On the one hand,the range and intensity of the turbulent flow distribution in the tundish was strengthened.On the other hand,the flow state of the flow field in the tundish was obviously improved,and its metallurgical effect was significantly improved compared with the original tundish.Compared with the PIV velocity measurement results in the physical simulation,it was found that the average flow velocity of the liquid surface of different research objects increased by 47% and 50% respectively than in the isothermal conditions under the non-isothermal state.Therefore,the existence of nonisothermal state in the tundish changed the force of fluid micelles and the flow state of the whole flow field.For the RTD curve of the tundish,after the channel supplementary heat was turned on,the residence time was prolonged and the peak value was reduced,indicating that the application of the channel supplementary heat method can indeed improve the flow field state.After comparing the flow control scheme,the best channel design was when the channel was set at the bottom of the tundish,the angle with the bottom surface was set to 3°;the outlet was set at a fork of 90° angle to the channel and the junction was at an elevation angle of 30° to the main channel surface.