Research On Electromagnetic Field Of Coaxial Structure ESR System And Analysis Of Eddy Current Loss In Mould

The coaxial structure ESR system compared to the traditional ESR system has excellent performance on diamagnetic interference,energy saving property and the loop reactance etc.A 3D finite element model including electrode,slag pool,ingot,mold lining,outer wall,bottom tank and coaxial structure has been developed for the rarely studied complete ESR system with coaxial structure based on electromagnetic field theory.The theoretical basis for the development of coaxial ESR system is provided,and the feasible direction of reducing the energy consumption of ESR technology is also explored.The main contents of this subject are as follows:1.The mathematical model of the electromagnetic field of the coaxial ESR system is established,the magnetic vector potential(A)and the electric scalar position(?)are used as unknown functions in the eddy current region,and the magnetic vector potential(A)is used as an unknown function in the non-eddy current zone.A finite element model is established including electrode,slag,steel ingot,mould lining,mould wall,water tank,coaxial structure etc.for the complete ESR system with coaxial structure,and the spatial distribution of magnetic flux density,current density and the law of joule heat distribution in the ESR system are investigated.2.Based on the finite element model of the complete ESR system with coaxial structure,The spatial electromagnetic effect laws of ESR system with four coaxial structures at different frequencies is compared and analyzed,The relevant laws of the four coaxial,six coaxial and thin-walled ESR system with coaxial structure are compared and studied,The advantages and disadvantages between cylindrical coaxial and tubular coaxial are analyzed On the basis of further comparative,and the electromagnetic interaction laws about tubular coaxial ESR system with different axis distance is explored combined with furnace design requirements of industrial production.3.Based on the finite element model of the complete ESR system with coaxial structure,the eddy current loss is analyzed under the condition that the mould wall is made respectively by different materials.The main conclusions of this subject are as follows:1.The simulation results indicate that current density distribution inside the electrode of the ESR system with coaxial structure affected by the comprehensive effect among skin effect,proximity effect and the magnetic field around the coaxial leads.The area of electrode with the smallest current density is not the center of electrode but the position at a certain depth below the surface of the electrode,and contrary to current flow on both sides of this area,the current will be redistributed where the current from the electrode into the slag pool with higher resistance,a certain proportion of the current will flow into the mould;In addition,the use of lower frequency alternating current is beneficial to reduce the extra energy loss and maintain the uniform melting speed.2.coaxial structure has restraining effect on electromagnetic field in ESR system,forming a magnetic shielding layer around the electroslag furnace.The magnetic shielding layer not only effectively control the magnetic field of ESR system,to reduce the adverse effects on the surrounding metal structure,but also shield the stray magnetic field around the system space,to avoid the abnormal fluctuation of molten pool interface.Besides,the ESR furnace with multi-coaxial structure has great performance.There are two reverse magnetic fields between the electrode and the coaxial leads,and the presence of the induction field near the electrode leads to the area between electrode and coaxial leads where the magnetic induction intensity decreases In addition,the magnetic induction intensity in the space area within the height range of the mould is greater than space area above the mould where the magnetic is more susceptible to constraints,the necessary ferromagnetic structure arranged around ESR furnace should be avoided in the area space of mould height range,which is usually one of the ESR furnace crystallizer the reason is part of the installation under the ground.3.Comparison of mold materials between stainless steel and 45 stainless steel indicate that the magnetic induction intensity around the mould maded by stainless steel is lower,not only the mould itself has less eddy current loss,but also has little influence on the surrounding ferromagnetic structure.Based on long-term interest considerations,stainless steel mould is recommended to save energy and reduce enterprise costs.