Simulation Of High Temperature Superconductor Direct Current Inducting Heating Aluminum Billet

Electromagnetic induction heating is widely used in the processing of non-ferrous metal materials,the energy utilization efficiency of traditional AC induction heating is below 50% generally.By adopting a new superconducting DC induction heating method,energy efficiency of induction heating can be greatly improved.In DC induction heating,there is basically no excess loss except that mechanical energy is converted into heat energy and the heated material itself exchanges energy with the external enviroment.Therefore,the energy utilization rate of the DC induction heating method is higher than the traditional AC induction heating.However,the current high temperature superconducting(HTS)DC induction heating equipment still has many shortcomings.It is necessary to optimize the heating effect of induction heating equipment and operation stability,etc.In this paper,a three-dimensional complete model and a symmetrical model are established according to the real size of the HTS DC induction heating equipment,and the numerical results of the two models are compared to verify the validity of the symmetrical model.The influence of material parameters of aluminum billet on numerical simulation results in DC induction heating is studied.The main research contents of this paper are as follows.Firstly,the theoretical model of direct current induction heating of aluminum billet is established in this paper,and the governing equations of electromagnetism and heat transfer are derived.Based on the finite element method,a two-dimensional model of the DC induction heating aluminum billet is established.The two-dimensional aluminum billet rotation model is verified by the numerical results.Then,the changes of the induced current and the magnetic field in the cross section of the aluminum billet with the rotation speed under the uniform rotating magnetic field are discussed.Subsequently,the influence of the number of grid divisions on the calculation accuracy and calculation speed of the numerical model is discussed,and the influence of the parameter change on the magnetic field distribution of the air gap in the three-dimensional model is studied.The numerical simulation results of the magnetic field distribution between the air gaps are compared with the experimental results.Finally,based on the numerical model,the effects of coil current,air gap width,magnetization curve,aluminum billet conductivity and aluminum billet thermal parameters on the heating results of aluminum billets are studied,and the changes of the above parameters on the heating time of aluminum billets are also analyzed.The influence of the iron core distribution on the heating result of the aluminum billet is studied in the adjustable iron core structure model.The three-dimensional models using non-uniform iron core structure are established,and the numerical simulation results of the non-uniform iron core model are discussed.Then the influence of the gradient iron core structure on the numerical simulation results is analyzed,and the influence of the aluminum billet size with the gradient iron core structure on the heating result is studied.