| During the continuous casting process,the distribution molten steel flow,temperature and inclusions in the tundish have an important influence on the operation of the continuous casting process and the quality of the billet.The technology of tundish electromagnetic induction heating can effectively compensate for the heat loss of molten steel,precisely control the temperature of molten steel and improve the removal of inclusions,so that it is more and more widely used in factory.In this paper,we study the law of the magnetic field,the flow field and the temperature field in the tundish and the channel under the different electromagnetic parameters and process parameters by using the numerical simulation method for the single-flow double channel electromagnetic induction tundish in order to provide a theoretical basis to optimize the design.The numerical simulation results of magnetic tundish magnetic field show that:the induction current,magnetic induction,electromagnetic force and Joule heat in the electromagnetic tundish are mainly concentrated in the channel.Induction current form a current loop through the two channels and was evenly distributed within the channel.The magnetic induction density is in a parabolic shape on the centerline of the channel with the opening downward and the maximum magnetic induction density is in the side of induction coils.The magnetic induction density in the radial direction of the channel shows a logarithmic distribution and the maximum magnetic induction density is close to the induction coils.The electromagnetic force in the channel is point to the inside of channel and was off-center,which produce the pinch effect and rotational motion to the molten steel produce.The Joule heat is evenly distributed on the centerline of the channel and the largest Joule heat in the radial direction is near the induction coil and gradually decreases toward the other side.The numerical simulation results of flow field on electromagnetic tundish show that:When the electromagnetic induction heating is applied,the molten steel is affected by the electromagnetic force and Joule heat in the channel,and the heated molten steel move to the casting cavity in a spiral way;The heated molten steel flow rise to the upper part of the casting chamber because of the role of buoyancy.The induction heating technology prolongs the movement time of molten steel in the tundish.The application of electromagnetic induction heating intensifies the heat transfer of molten steel in tudish.The numerical simulation results of temperature field on electromagnetic tundish shows that:The higher the induction heating power,the higher the velocity of molten steel is in the channel,the stronger the stirring effect of molten steel and the temperature of continuous casting chamber are,and the smaller the low temperature zone in casting chamber is,so that the better the temperature uniformity of molten steel is.When the induction heating power increases to 1000kW,the outlet temperature of tundish casting chamber increased by 28K.For each additional 200kW of induction heating power,the outlet temperature of casting chamber increased by about 6K,which can be used to control the outlet temperature of molten steel in tundish casting chambe.When the induction heating power is 1000kW,and the channel diameter is increased from 90mm to 100mm and 120mm,the temperature of the tundish channel is increased by only 2K,and the outlet temperature in continuous casting chamber is increased by about 1K,so the temperature rise in the tundish is not obvious,so that the channel diameter of 120mm is the optimal.When the induction heating power is 1000kW,and the channel inclination angle is 2 °,3 °and 4 °,the variation of the temperature in the channel and continuous casting cavity of tundish is only about 1K,so that the channel inclination of 3 ° is the best.The comparison of RTD curve in tundish with induction heating of 1000kW and OkW show that the response time of the molten steel outlet,the peak time of tracer concentration and the average residence time in tundish was extended by 3.27s,415.1s and 177s,respectively,and the dead volume in tundish was decreased by 14.8%.When the channel diameter is 120mm,channel inclination angle is 3 °,and the induction heating power is 1000kW,,the minimum response time,the average residence time and the dead volume in tundish is 7.75s,1001s and 16.58%,respectively.Compared with other schemes,its minimum response time and average residence time is the longest,and its dead volume is the smallest,so that the effective utilization rate of the tundish is the highest. |
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