. . . .     Nowadays induction heating systems are widely used in the industry. Induction heating plays an important role in industrial heating. It can heat very accurately depths and surface areas in clean operating conditions with high power densities and short heat times. That is why they are of permanent interest to researchers in recent years.
    Flat inductor with constant step of winding has been developed as a prototype for heating up to temperature of 800-900^oC for stainless steel discs for agricultural tools, having outer diameter of 600-700 mm and thickness 6 mm before the hardening. Having in mind the lack of theoretical analysis of the distribution of the electromagnetic and thermal field the requirement for the specific distribution of the temperatures has not been fulfilled. This is the motivation for the numerical and experimental modelling, for which a laboratory prototype has been created. . . . .

. . . .   The results are obtained for time period of 600 seconds. The following procedure was employed. The quasistationary electromagnetic problem was solved at every 10sec. taking into account the temperature dependence of the magnetic permeability and electric conductivity. As a result from the electromagnetic field analysis, the generated heat in the heated detail is obtained and used as heat source during the next 10 sec. The thermal problem was solved as nonlinear and temperature dependence of the thermal conductivity was taken into account . . . .

Introduction: This paper presents an analysis of the temperature distribution in a load while heating it by a cylindrical inductor. The practical approach considered here enables its determination through modeling of the inductor-load system and fulfilling a computational procedure. The main relationships used in solving the electromagnetic and the thermal problem are described. The basic geometric parameters to be determined are the pitch of winding of the inductor and the distance between the inductor and the load, while analyzing the relationship between them and the temperature distribution. The results thus obtained have been confirmed experimentally.

Introduction:The results obtained when studying induction heating by analytical relationships do not take into consideration any alteration of parameters. A similar case is studying the details of a complex shape by modifying them into relatively simpler ones. Imprecise computations affect the distribution of electromagnetic and thermal fields, which in turn affects the quality of thermal treatment. Modeling through application of numerical methods enables studying a particular process in a particular detail without generalizing on all similar cases. Regardless of the approach, the obtained results differ from the real process because they do not account for incidental interfering factors.
This paper offers a comparative analysis between analytical computation, model and experiment of a system of a cylindrical inductor and a load. The purpose is to determine the factors affecting the error in modeling of induction devices.

    One of the main activities of the Physical Process Modeling team is analysis, modeling and design of thermal devices.
    This is a team specialized in design of resistance, chamber and blast furnaces. The materials published here discuss computational procedures which simulate the transitional processes of heating. While not claiming a unique approach, we suggest that the operative sequence developed by us for designer's practices affords a number of advantages, such as:

• Fewer hours of work. The use of software developed for specific business needs exempts the designer from computational work. The time to find a required construction is shorter with a data base of modern electric-resistance furnaces (ERF) already designed.
• Enhanced preciseness of work. There is no longer any need to deal with graphs or to account for criterial correlations when applying the suggested approach: using a model comprising a system of Differential Equation (DE), Finite Element Method (FEM) and realization by numerical methods.
• Integral methodology of work. Suffice it to use one model and computational procedure to determine the parameters of the ERF being designed: distribution of temperature in the chamber and in the insulation, temporal parameters of the transitional process, analysis of the parameters of the regulator, energy analysis, and optimization of the construction.
• Widely applicable design. The design thus realized could be used in the exploitation of the thermal assembly; the models developed could be incorporated into the passport of the furnace and serve for evaluation of the technological processes; they could also be used by non-specialists in designer's practice.

    The Physical Process Modeling team hopes that the materials presented by us will be useful for designers dealing with matters of this kind.

Transient processes in high temperature vacuum electrical resistance furnace with MoSi₂ heaters

    In this publication is analyzed the work of high temperature vacuum ERF with MoSi₂ heaters, loaded with details with different thermal parameters and to implement of processes with given requirements by controlling different parameters of the power system.
    For analysis of transient heat processes in high temperature vacuum ERF with water cooled walls, a system of differential equations is composed corresponding to the thermal schematic and is visually modeled in MATLAB/SIMULINK.