Jacques Nuns

Eddy currents in thin plates modelled as surface regions

This paper analyses the conditions for which the results of eddy currents computation in thin regions modelled by surface regions are concordant with those obtained using volume finite elements. The concepts of geometrically thin or thick region, electromagnetically thin or thick region, 2D or 3D problem, transverse or longitudinal flux problem are used to characterise the limits of the surface model. The computation of eddy currents in sheets heated in transverse flux inductors and of the eddy current losses in metallic casing of an induction furnace highlights the surface finite element applicability.

Medium frequency induction‐heated chemical reactor with cooling metallic envelope of the tank

Purpose – Analysis and development of a high efficiency, induction heated chemical reactor, medium frequency supplied (1,000‐2,000 Hz), able to be equipped with efficient cooling circuits.Design/methodology/approach – The numerical investigations of the technical solutions proposed in this paper are based on 3D finite element models that are experimentally validated.Findings – Solutions to increase the transparency of the cooling envelope of the reactor tank with respect to magnetic field. The positions of envelope regions characterized by high values of power losses are experimentally confirmed by infrared temperature measurements.Practical implications – The numerical analysis and the experimental investigations, show the possibility to implement efficient cooling circuits in chemical reactors without affecting the performances of the induction heating process. By designing properly the metallic envelope of the tank the global efficiencies of the chemical reactors increase at around 90 percent with redu...