Paolo Di Barba, Michele Forzan and Elisabetta Sieni
The purpose of this paper is to investigate a bi-objective optimization problem characterized by coupled field analysis. The optimal design of a pancake inductor for the…
Abstract
Purpose
The purpose of this paper is to investigate a bi-objective optimization problem characterized by coupled field analysis. The optimal design of a pancake inductor for the controlled heating of a graphite disk is considered as the benchmark problem. The case study is related to the design of industrial applications of the induction heating of graphite disk.
Design/methodology/approach
The expected goal of the optimization process is twofold: to improve temperature uniformity in the disk and also electrical efficiency of the inductor. The solution of the relevant bi-objective optimization problem is based on multiphysics field analysis. Specifically, the direct problem is solved as a magnetic and thermal coupled problem by means of finite elements; a mesh-inspired definition of thermal uniformity is proposed. In turn, the Pareto front trading off electrical efficiency and thermal uniformity is identified exploiting evolutionary computing.
Findings
By varying the problem targets, different Pareto fronts are identified trading off thermal uniformity and electrical efficiency of the induction-heating device.
Practical implications
These results suggest how to improve the design of this kind of device for the epitaxial growth of silicon wafer; the advantage of using a magnetic concentrator placed close to the inductor axis is pointed out.
Originality/value
The coupling of a multiphysics direct problem with a multiobjective inverse problem is presented as a benchmark problem and accordingly solved. The benchmark provides a simple analysis problem that allows testing various optimization algorithms in a comparative way.
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Andrey Morev and Alexander Aliferov
The purpose of this paper is to investigate the effect of the rotating magnetic field of permanent magnets on the aluminium melt bath.
Abstract
Purpose
The purpose of this paper is to investigate the effect of the rotating magnetic field of permanent magnets on the aluminium melt bath.
Design/methodology/approach
This model was developed in the ANSYS software package and is based on the application of the finite element method and finite volume.
Findings
The distribution of the velocity of the melt in a cylindrical vertical bath and the dependence of the maximum value of the melt displacement on the angular rotation velocity of the system of permanent magnets is obtained.
Originality/value
This work focusses on the interaction of the magnetic field of the moving magnets with the molten metal.
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Alexander Aliferov, Paolo Di Barba, Fabrizio Dughiero, Michele Forzan, Sergio Lupi, Maria Evelina Mognaschi and Elisabetta Sieni
An inductor for the uniform heating of the extremity of a ferromagnetic steel tube for stress relieving is considered. The main goal of the study is to investigate the possibility…
Abstract
Purpose
An inductor for the uniform heating of the extremity of a ferromagnetic steel tube for stress relieving is considered. The main goal of the study is to investigate the possibility to achieve a reasonable design of the inductor when dealing with many design variables.
Design/methodology/approach
Genetic optimization algorithms are used for this purpose, demonstrating the applicability of these techniques to the design of induction heating inductors. Genetic algorithms provide to the designer several optimal solutions belonging to Pareto Front, and this way they allow choosing the solution that better fits the technological requirements. In any case, the designer has to adapt the chosen solution to fit in with the real possibilities in industrial application.
Findings
The study demonstrates that automatic optimization methods may help the designer of the induction heating system to solve complex problems with very conflicting technological requirements.
Originality/value
In the paper, a problem with a high number of design variables is solved. Moreover, the goals of the optimization process are strongly conflicting, and the proposed problem is a challenging one.
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Martin Schulze, Alexander Nikanorov and Bernard Nacke
The transverse flux heating (TFH) concept offers very high electrical efficiency in combination with unique technological flexibility. Numerous advantages make this method beyond…
Abstract
Purpose
The transverse flux heating (TFH) concept offers very high electrical efficiency in combination with unique technological flexibility. Numerous advantages make this method beyond competition to be applied in e.g. processing lines. However, all potential advantages of TFH can be realized in practice only by optimal design of the inductor shape using numerical modelling and optimization techniques. This paper aims to describe a hierarchical approach to the optimal design of a one-sided induction coil, which will be used for one-sided TFH of continuous moving thin metal strip to achieve a homogeneous temperature distribution along the strip width.
Design/methodology/approach
Depending on the design step, 2D or 3D FEM simulations using ANSYS® Mechanical including the electromagnetics package are used. The harmonic electromagnetic solution is coupled to a transient thermal model which takes the strip movement into account. All models use the symmetries of the inductor workpiece arrangement to keep the calculation times as low as possible.
Findings
Due to the geometry of a TFH coil, the models can image a quarter or half of the arrangement. Preliminary investigations of different inductor head shapes can be carried out quickly and then further improved on more complex models in combination with the use of optimization algorithms.
Practical implications
Using hierarchical structure for designing a one-sided TFH coil, offers an efficient and quick way to create a coil which is adapted to the application.
Originality/value
The one-sided inductor design is considered, and the results are generally valid.
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S. Lupi and A. Aliferov
Distribution of alternating current density and internal power sources in the cross‐section of curvilinear hollow work pieces under resistance heating are presented in this paper…
Abstract
Distribution of alternating current density and internal power sources in the cross‐section of curvilinear hollow work pieces under resistance heating are presented in this paper. The calculation is based on an analytical model. The results of analytical calculations are compared with experimental data. The received expression was investigated in a wide range of geometrical parameters.
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A. Aliferov and S. Lupi
The paper deals with the current density distributions in toroidal conductors of circular cross‐section.
Abstract
Purpose
The paper deals with the current density distributions in toroidal conductors of circular cross‐section.
Design/methodology/approach
A review of the analytical solutions existing in the literature only for the case of very thin skin depth is presented.
Findings
Results are given for different aspect ratios of torus. The accuracy of these analytical solutions is verified by comparison with numerical results. Finally, a set of numerical results are given for the same aspect ratios but different penetration depths of the electromagnetic wave in the conducting material.
Originality/value
The paper provides results for different penetration depths of electromagnetic wave in conducting material and different torus aspect ratios.
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Roberta Bertani, Flavio Ceretta, Paolo Di Barba, Fabrizio Dughiero, Michele Forzan, Rino Antonio Michelin, Paolo Sgarbossa, Elisabetta Sieni and Federico Spizzo
Magnetic fluid hyperthermia experiment requires a uniform magnetic field in order to control the heating rate of a magnetic nanoparticle fluid for laboratory tests. The automated…
Abstract
Purpose
Magnetic fluid hyperthermia experiment requires a uniform magnetic field in order to control the heating rate of a magnetic nanoparticle fluid for laboratory tests. The automated optimal design of a real-life device able to generate a uniform magnetic field suitable to heat cells in a Petri dish is presented. The paper aims to discuss these issues.
Design/methodology/approach
The inductor for tests has been designed using finite element analysis and evolutionary computing coupled to design of experiments technique in order to take into account sensitivity of solutions.
Findings
The geometry of the inductor has been designed and a laboratory prototype has been built. Results of preliminary tests, using a previously synthesized and characterized magneto fluid, are presented.
Originality/value
Design of experiment approach combined with evolutionary computing has been used to compute the solution sensitivity and approximate a 3D Pareto front. The designed inductor has been tested in an experimental set-up.
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Michele Forzan, Fabrizio Dughiero, Mattia Guglielmi and Antonio Marconi
This paper aims to study the possibility of controlling the electromagnetic stirrer (EMS) is fundamental in a continuous casting line to achieve the desired properties of…
Abstract
Purpose
This paper aims to study the possibility of controlling the electromagnetic stirrer (EMS) is fundamental in a continuous casting line to achieve the desired properties of homogeneity and mechanical strength in the solidified cast.
Design/methodology/approach
Coupled electromagnetic (EM) and fluid dynamic (FD) simulations allow to predict the mixing effect on molten metal, in terms of velocity amplitude and shape of the flow. This paper describes the numerical results of EMS effect within a cylindrical crucible, surrounded by a solenoidal inductor, filled with a low melting temperature alloy, i.e. GalInStan.
Findings
Induced forces and resulting velocity distribution of the flow of the liquid metal have been calculated depending on varying amplitude and frequency of the supplied current. As expected, at a given amplitude of the current supply, the velocity distribution shows a maximum at a certain frequency while the intensity of electrodynamic forces monotonically increase as the frequency increases
Originality/value
The paper deals with simply models and experiments applied to coupled EM and FD problem, to assess the applied methodology.
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Michele Forzan, Fabrizio Dughiero, Sergio Lupi and Marcello Zerbetto
The purpose of this paper is to present the main experimental results obtained on the first prototype of an innovative induction heating system. MAGNHEAT was a LIFE project…
Abstract
Purpose
The purpose of this paper is to present the main experimental results obtained on the first prototype of an innovative induction heating system. MAGNHEAT was a LIFE project, funded by EU Commission, proposed to demonstrate the possibility of industrial application of a new technology for the induction heating of aluminum billets before extrusion. This technology uses permanent magnet heaters (PMHs), which constitute a high efficiency solution for the heating of high conductive metals.
Design/methodology/approach
The paper briefly describes the main steps of the project: the design of the PMH, the realization and installation of the demonstrator on an extrusion production line of Pandolfo Alluminio SpA and, mostly, the performance of the system.
Findings
The main results achieved during the preliminary tests on an industrial line have been summarized by evaluating some key performance indicators, as reported in the paper.
Originality/value
The new technology allows a significant reduction of the energy consumption and guarantees the same performance of a classical induction heater.