Analytical and Experimental Validation of Electromagnetic Simulations Using COMSOL®, re Inductance, Induction Heating and Magnetic Fields

Abstract: COMSOL ® is a powerful numerical modelling tool for electromagnetic calculations. The present paper examines the numerical agreement between COMSOL ® 2D axial symmetric models, classical analytical solutions and experimental data. Comparison is made between the analytical solution for the inductance of an empty ‘current sheet’ inductor and the numerical results of COMSOL ® Version 4.2, as a benchmark of the fundamental accuracy of the software. The effect of the size of the computational space or ‘magnetic domain ’ on the calculated total inductance is also examined. COMSOL®’s single and multi-turn domains are used to model an induction coil, and the simulations of induction heating are made at a range of frequencies from 50 Hz to 500 kHz. Results are compared with the predictions of a 1D analytical model at each frequency and a representative experimental value at 50 Hz. The obtained COMSOL® predictions of the magnetic flux density are compared with experimental values measured using Hall probes at 50 Hz, for both an empty coil and for a coil containing a work piece. The numerical magnetic field results obtained in the present study are in excellent agreement with the analytical solution for the ‘air core’ coil. Based on the present results analytical criteria are presented as guidelines for when to use COMSOL®’s single or multi-turn domains, and for the minimum mesh size to be used to achieve accurate high frequency simulations of induction processes