Induction heating in estimation of thermal properties of conductive materials

Abstract

Purpose The purpose of the research was to develop a method for the determination of temperature characteristics of thermal diffusivity and specific heat on a single and the same stand, powered from an inverter for induction heating. Determination of the thermal diffusivity has been based on the idea of the pulse method. Searched solutions allowed to reduce inaccuracy of the pulse method when such an unusual source of pulse of energy is used. Design/methodology/approach Coupled electromagnetic and thermal calculations were carried out to verify proposed methods for estimating thermal properties of an induction heated charge. Presented methods were applied into a real laboratory stand and they were examined experimentally. Findings Achieved results of calculations allow to estimate thermal properties of the induction heated charge with 2 and 5 per cent of uncertainty, respectively, for heat capacity and thermal diffusivity. It gives possibility to use results as an input for further proceedings connected with estimation of electrical parameters in a more complex system. Practical implications Presented methods of estimating thermal properties of the induction heated charge were verified experimentally on a dedicated laboratory stand. It gives a practical possibility to implement previously established assumptions and examine them. This is a significant step toward the construction of an easy-to-use device for a comprehensive determination of material parameters of metals directly in the heat treatment plant. Originality/value This study presents a trial of implementation of induction heating as a source of energy in the impulse method for estimation of thermal properties of the material. Additionally, it presents a process of improving results achieved with the flash methods which were presented in previous papers. The method of estimation of specific heat which uses induction heating as the heat source was presented too.

An Inductive Method for Comprehensive Estimation of Temperature-Dependent Electrical and Thermal Properties of Conductive Ferromagnetic Materials

“…P ch = P IHS − P ind (10) where P IHS -power delivered to the inductor-charge system and P ind -power losses in the inductor.…”

“…On the other hand, growing technological requirements increasingly lead to the need for precise, reliable information about the properties of the processed material, which leads to the need to verify them in situ. The importance of the problem raised is confirmed by numerous publications [2][3][4][5][6][7][8][9][10][11], in which the issue of the possibly simplest and quickest way to determine material properties is considered, preferably several at once using one measurement station. The cited literature examples mainly concern attempts to determine thermal properties, that is, thermal diffusivity and volumetric heat capacity.…”

“…In the case of induction heating, we also have to determine not only thermal but Energies 2024, 17, 887 3 of 19 also electrical and magnetic properties, which further increases the risk of this error. In [10], an initial attempt was made to solve this problem by extending the scope of measurements performed. This extension involves performing measurement experiments on a test stand that will enable, with the highest possible accuracy, the estimation of the value of each of the sought material parameters separately.…”

Archives of Electrical Engineering

“…It is possible to consider non-linear materials e.g. [26,27], but this would increase the complexity of the forward problem and its cost, while in this paper the main scope is to provide a multi-physics problem solvable in shortest runtime on a standard hardware platform. The target of the multi-physics design is to evaluate the graphite disk temperature using a given inductor geometry.…”

A Different Approach to Estimate Temperature-Dependent Thermal Properties of Metallic Materials

“…Recently, many researchers have presented techniques to simultaneously estimate temperature-dependent thermal properties, such as Sadeghi et al [8] who determined thermal conductivity and diffusivity of SiC samples by applying the microwave heating process, Zamel et al [9] who presented an improved firework algorithm to solve inverse problems allowing simultaneous estimation of properties of molten salt, and Öztürk et al [10] who presented a method to estimate thermal conductivity and specific heat temperature-dependent of thermal protective fabric with good results. Other studies were performed [11,12,13,14,15,16], but none of them included the possibility of estimating thermal properties of metals depending on temperature simultaneously. Moreover, the experimental apparatus for most of these techniques is usually expensive.…”