Numerical simulation of 3D electromagnetic-thermal phenomena in an induction heated slab

A mathematical model was developed to get an insight into 3D electromagnetic-thermal phenomena in an induction heated steel slab with a large width/thickness ratio by solving a fully coupled Maxwell equations and energy conservation equation. The spatial heat radiation between the slab surface and the refractory wall in an induction furnace was considered. The electromagnetic induction and temperature distribution features inside the slab with time evolution were described. The effects of electromagnetic induction parameters, thermal conductivity of the material and process parameters on the induction heating process were theoretically examined. Numerical results show that the spatial distribution of induction heat generation inside the slab is non-uniform. The high work frequency and the low heat conductivity of slab increase the non-uniformity of slab induction heating process. The radiative heat loss and heat transfer between the slab and the metal parts used for holding the slab have an important effect on the slab surface temperature. It is necessary to separately control the current input in the multi-layer coil windings along the height direction of furnace and adopt the multi-step heating strategies with time evolution to improve the homogenization of the slab temperature.