MODEL OF ELECTROTHERMAL PROCESSES IN AN INDUCTION PLANT FOR ZONE HEATING OF A MOVING FERROMAGNETIC BILLET

Abstract

The article considers a model of an induction plant with four inductors for zone heating of a cylindrical billet. The finite element model of the plant is implemented in Comsol. The model takes into ac- count the motion of the billet and the nonlinear dependences of the electrical conductivity and the relative magnetic permeability of the material of the ferromagnetic billet on the temperature. The model uses circuits with PI-regulators which allow simulating the power of inductors with a constant voltage or power. Thermal processes are studied in the model when the inductors are supplied with unchanging currents, voltages or work with constant powers. The temperature profiles of the billet are obtained for different inductor power options and the temperature variation transients for the moving section. Transient for currents, electromo- tive forces, powers and Q-factors of inductors are obtained for different power supply variants. The transient process of changing the surface temperature of a moving section has an extremum in the inductor region in which the temperature reaches the Curie point. When supply inductors from a source with a constant power voltage in a steady state, they decrease in inductors with a higher temperature. The model can be used to determine and verify the zone heating program with the specified requirements.