Analysis And Numerical Simulation Of The Billet Induction Heating Process With FEM And BEM

Induction heating is fast, efficient and well-proportioned, and it possesses many advantages such as high-grade production, no pollution, good controllability and easy to be automatized, so it developed very fast in the recent years. As the required techniques and precision for induction heating get higher and higher, the numerical simulation of it becomes more and more important. As the fast development of finite element method(FEM), many researchers begin to do the numerical simulation by it, and many achievements have been made, but it also has some disadvantages such as vast computation and introducing arbitrary boundaries; Boundary element method(BEM) is a new numerical simulation method developed from FEM, it has unique advantages in simulating electromagnetic field, reducing the dimension of the problem, dealing with the infinite boundary simply and so on, blazing a new way in the numerical simulation of induction heating. In this thesis, the 2-D axisymmetric FEM and BEM model is built based on the foundational principles of electromagnetic field and thermal field, the electromagnetic-thermal coupling field of induction heating is simulated with FEM by universal FEM software ANSYS and the electromagnetic field of the induction heating is simulated with BEM by MATLAB.Firstly, the FEM model is presented for solving the coupling fields of axisymmetric billet in induction heating process. The choice of the potential is emphasized in the electromagnetic field model, and the control equation of nonlinear transient thermal field is analyzed in the thermal field model. The principle and the computation flow of the coupling of electromagnetic and thermal fields are also presented.Secondly, the BEM model is presented for solving the electromagnetic field of axisymmetric billet in induction heating process, and with the use of a surface current approximation, the Green function of Helmholtz's equation is replaced by the Green function of Laplace's equation which has a weak singularity on the boundary, so the vast computation due to short elements on the boundary is avoided.In the end, the FEM analysis of the coupling of the electromagnetic and thermal fields is carried out using ANSYS, the thermal distribution of the billet at different heating time is obtained. The BEM analysis of the electromagnetic field is carried out using MATLAB, the electromagnetic distribution in the heating process is obtained. The simulation results are shown to be consistent with the test results and the practical measure results.