| Due to the advantages of large production capacity,superior refining effect and short processing cycle,RH vacuum refining is widely used during the steelmaking production.The rotating magnetic field can change the flow direction and velocity of fluid,enhance the solute transport and promote the chemical reactions in liquid steel.There are large amount of CO bubbles produced by carbon-oxygen reaction in liquid steel of RH.However,the effect of CO bubbles on gas-liquid flow and decarburization is neglected in traditional mathematical model.Thus,the flow field and decarburization model of RH are two-way coupled in this mathematical model.In the meantime,the stirring effect of CO bubbles in fluid is analyzed,and the concentration variation of dissolved carbon in liquid steel are predicted and verified during decarburization.Besides,the geometric model of RH furnace with rotating magnetic field is established,and this paper discusses the influence of rotating magnetic field on liquid steel flow and decarburization.The conclusion’s can be summed up as follows:(1)For the entire decarburization process in RH,the CO mole number is 0.68 time of argon blown into the up snorkel.Compared with the one-way coupling mathematical model,the dissolved carbon concentration predicted by two-way coupling mathematical model is closer to the experimental data in liquid steel,and the prediction result is more reasonable.(2)With the effect of rotating magnetic field,the flow velocity of liquid steel is increased and the circulating feature is improved.The average flow velocity of liquid steel in crosssection of up snorkel increases by about 10%when the current intensity is 500A and the current frequency is 10Hz.Besides,the circulation flow rate increases by about 3%when current increases 200A.(3)With the influence of rotating magnetic field,the liquid steel flows in anticlockwise direction around the center of up snorkel.In addition,the liquid steel maintains rotational flow state in the vacuum chamber and the down snorkel,and the decarburization rate is larger than there is no rotating magnetic field in RH.At the second minute,the carbon concentration in liquid steel is lower about 6.25%than there is no rotating magnetic field.(4)The decarburization rate of RH remains basically unchanged when the current intensity is 500,700,900A or the current frequency is 10,25,40Hz. |
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