Известия Томского политехнического университета: Инжиниринг георесурсов (May 2019)
Features of heating non-magnetic items of rectangular section in rotating field of permanent magnets
Abstract
Relevance of the work is caused by the fact that at the present time in the field of new energy-saving electrotechnologies for heating non-ferrous metals products the focus is on induction heating in a transverse magnetic field. A large range of products with rectangular cross-section made of non-ferrous metals turned out not to be covered by the heating method in a transverse magnetic field. Currently such products are heated in the induction heating installations in alternating longitudinal magnetic field while electrical efficiency is not greater than 0,5. The attractiveness of such products heating in the transverse rotating magnetic field of permanent magnets is its potential to achieve electrical efficiency equal to 0,75-0,85. The paper considers the carried out studies of heating aluminum products with rectangular cross-section to a temperature of 550 °C. The main aim of the study is to develop a numerical model on the basis of the program package ANSYS for calculating electromagnetic parameters of system "inductor-product" and the temperature field in the heated product; to calculate distributions of electromagnetic and temperature fields parameters in the heated product. The methods used in the study: The main instrument of the study is the software package ANSYS, which allows modeling different spatial physical systems which behavior can be described by the differential equations. The finite element method was taken as the basic one. It allows dividing a continuous problem domain having an infinite number of freedom degrees into a finite, but sufficiently large, number of areas where parameters are constant. Physical properties and external influences are concentrated in the nodes of the system. The results: The developed model allows calculating the coupled electromagnetic and thermal problems of heating non-magnetic product with rectangular cross-section in rotating magnetic field of permanent magnets. The paper introduces the dependencies of the maximum temperature differences obtained in the cross-sections of rectangular products made of aluminum. The dependencies are given as functions of rotational speed of permanent magnets, producing a transverse magnetic field, the number of pole pairs of the magnets and the gap between the heated product and magnets.
