NUMERICAL-SIMULATION OF INDUCTION-HEATING - A FINITE-ELEMENT APPROXIMATION

A precise knowledge about the electromagnetic field, the eddy currents and the temperature distribution is necessary to optimize induction heating devices which are used to heat up thin, moving metal strips in a continuous process. As this information cannot be gained from conventional, analytical methods, a new numerical simulation method, based on a finite-element approximation, has been developed. The coupled electrical-thermal process is modelled by a set of partial differential equations which are discretized using the Method of Weighted Residuals (Galerkin-Method). The temperature dependency of the electrical and thermal conductivity as well as convection and radiation at the surface of the strip are included in the mathematical model. The validity of this numerical approximation is proved by the comparison of calculated and measured temperature distributions in two test cases. Finally, a simple example shows how the new method can be used in the analysis and optimization of the induction heating system.