Induction Heating Device Research Articles

A combined method of simulation of an electric circuit and field problems in the theory of induction heating

A combined method for numerical computation of the electromagnetic field in induction-heating systems is proposed and used. The method consists in a combination of methods of integral equations for the computation of the electromagnetic field in the area outside the load and methods of finite elements or finite differences for the computation of the electromagnetic field inside the load. A method of simulation of electrotechnical systems with simultaneous solving of circuit and field problems is proposed based on this method. Using the example of induction-heating devices, an external problem associated with the computation of circuit inductors, power supplies, and balancing capacitors and an internal problem related to the computation of the electromagnetic field and internal heat sources inside the load are formulated. The simulation of induction heaters is considered taking into account features of thyristor frequency converters with a parallel inverter.

A Special Case of Electronic Power Control of Induction Heating Equipment

Although electronic power control of induction equipment, as the title refers to a specific device, in the present paper, we will show that the method is commonly used for every band-pass characteristics loads at alternating current. Being aware of the benefits of the proposed solution with respect to the conventional power control electronics procedures we can also find a specific solution that is carried out using an embedded microcontroller in the varying conditions of a certain value power control. The proposed control has been applied to an induction heating device, which yields strong results.

Non-Linear Multi-Physics Analysis and Multi-Objective Optimization in Electroheating Applications

The design optimization of an induction heating device is considered. The non-linear multi-physics analysis is carried out by means of finite-element method, while the optimal design problem is solved by NSGA-II genetic algorithm. A comparison with the results obtained by a simplified linear analysis is shown. The original contribution of this paper is the Pareto front identification for a design problem in which the field analysis is multi-physics, dynamic, and non-linear.

Mathematical Modeling of Eddy-Current Loss for a New Induction Heating Device

A new induction heating device is presented in this paper. This device can convert mechanical energy into heat energy by utilizing eddy currents, which are induced by rotating permanent magnets. A mathematical model is established for estimating eddy-current loss of the device. The distribution of induced currents and the resultant magnetic field intensity are considered in the process of modeling the eddy-current loss and so is the mutual influence of the electric field between neighborhood pole projection areas. Particularly, the skin effect is considered by correcting the numerical integral domain of eddy current density, which has great effect on the calculating results. Based on specific examples, the effectiveness and correctness of proposed model are proved by finite element analysis. The results show that the mathematical model can provide important reference for design and structure optimization of the device.

Thermo mechanical fatigue behaviour of a duplex stainless steel in the range of 350–600 °C

The thermo mechanical fatigue behaviour of a ferritic–austenitic duplex stainless steel has been investigated in a temperature range of 350–600°C. The Curie temperature (TCURIE) was determined by an abrupt increase of the power of the inductive heating device and a small control deviation of the temperature. Thus, according to Tavares et al. [1] the evolution of the spinodal decomposition in the DSS was characterised by the shift of the Curie temperature for each test. The results are compared with ageing and annealing experiments in combination with tensile tests at room temperature. In addition, microstructure observations were performed in a field-emission scanning electron microscope.

Multiphysics field analysis and multiobjective design optimization: a benchmark problem

A magneto-thermal inverse problem, dealing with the optimal design of an induction heating device, is proposed as a benchmark. The coupled-field problem is analysed by means of a higher order finite element method. Then the optimal design problem is solved in terms of the Pareto front trading off two conflicting objective functions.

Induction healing of dense asphalt concrete

Induction heating can be used for repairing cracks in asphalt concrete. With this purpose, electrically conductive particles have to be added to the asphalt mixture, which is then heated with an induction heating device. Since the factors affecting the induction healing of dense asphalt concrete are not well-known, in this article, different mixtures, with different lengths, quantities and diameters of steel wool fibres have been considered. It was found that there is a minimum temperature for healing asphalt concrete. Additionally a semi-empirical model, explaining asphalt healing through the capillary theory has been developed and fitted to the results.

Electrical, Thermal and Induction Heating Properties of Dense Asphalt Concrete

Induction heating consists in adding electrically conductive fibers to the asphalt mixture and heating them with an induction heating device. But still, the factors that affect the increase of temperature are not well-known. With this purpose, 25 different mixtures, with the same aggregates distribution and amount of bitumen, but with 2 different lengths, 4 different quantities, and 4 different diameters of steel wool fibers have been considered. The influence of fibers on the air void content, electrical and thermal conductivity and on the induction heating of dense asphalt concrete has been studied. It was found that steel wool fibers increase slightly the electrical and thermal conductivities of dense asphalt concrete. Finally, it has been observed that the temperature reached due to the induction heating, increases with the number of fibers in the mixture and with their diameter.

Experimental evaluation of dense asphalt concrete properties for induction heating purposes

Induction heating of asphalt concrete is a technique that has been recently developed to increase the self-healing rates of asphalt concrete. It consists in adding electrically conductive fibers to the asphalt mixture and heating them with an induction heating device. In this way, the temperature of asphalt concrete can be indirectly increased. But still, the factors that affect the increase of temperature are not well-known. With the purpose of finding them, 25 different mixtures, with the same aggregates distribution and amount of bitumen, but with two different lengths, four different quantities, and four different diameters of steel wool fibers have been considered. The influence of fibers on the air void content, electrical and thermal conductivity of dense asphalt concrete has been studied. Furthermore, the effect of these properties on the maximum temperature reached after a fixed time induction heating is analysed. It was found that steel wool fibers increase slightly the electrical and thermal conductivities of dense asphalt concrete. Additionally, in the case of the thermal conductivity, an increase on the volume of steel wool fibers serves to compensate the loss in the thermal conductivity that happens when the air void content is increased. Finally, it has been observed that the temperature reached due to the induction heating increases with the number of fibers in the mixture and with their diameter. As a recommendation, it is indicated that, for induction heating purposes, short fibers, with big diameters should be used.

Study on Cancer Treatment using Magnetic Fluid for Medicine and Induction Heating Device

Two electromagnetic heating methods have been studied in the hyperthermic treatment of cancer: dielectric heating, and induction heating using magnetic substances. Dielectric heating devices heat even normal tissues around cancer. On the other hand, induction heating has an advantage that it can heat cancer selectively. However, so far effective induction heating has been difficult: enough heat was not generated in the body because of (1) the magnetic field generated by portable induction heating devices was not strong enough, and (2) non-existence of excellent magnetic substances, and (3) strongly invasive temperature measurement in the body. In this paper, we try to solve those problems.Firstly, we develop an effective high-power induction heating device. Secondly, we obtain an excellent superparamagnetic substance known as magnetic fluid (MF) with large magnetic particles. Thirdly, we propose a detection technique of magnetic particle distribution in the body, using X-ray CT, from which the internal body temperature can be estimated. We confirm the validity of the proposed method in vitro. Finally, we do an experiment to heat the excellent MF injected into VX-2 bearing rabbits. A significant anti-cancer effect was observed. Such results suggest that our study would be quite useful for the development of induction heating hyperthermia.

Computer simulation and optimal designing of energy-saving technologies of the induction heating of metals

Advanced energy-saving technologies of induction heating of metals are discussed. The importance of the joint simulation of electromagnetic and temperature fields on induction heating is demonstrated. The package of specialized programs for simulating not only induction heating devices, but also technologies that employ industrial heating has been developed. An intimate connection between optimal design and control of induction heaters is shown.

Modeling and Optimization of a Goemetrique Induction Cooking for Improving the Temperature

This paper presents an optimal geometric design of a method for induction heating system. The objective of this design is to obtain a desired optimal distribution temperature in the load. The dimensions of the inductors are taken as design parameters and are replaced at each iterative step, using the bisection method to minimize the error of the calculated tem- perature and the desired one in each node. The study of such a device requires the use of models or modeling, physical, mathematical and numerical. Representation this modeling is the basis of the understanding, design and optimization of these systems. The optimization technique is to find values of variables that maximize or minimize the objective function. Through the researches achieved in the last twenty years, many industrial processes requiring heating operations make use of induction heating devices. Many industrial applica- tions have been developed, surface heat treatment, forging, bonding by polymerization, domestic and household appli- cations. Read phonetically However, the development of heating equipment induc- tion is not easy. The inductors are still often dimensioned empirically, based on the experience gained by the manu- facturer, and the power profile to be injected into the part (pan), obtained by trial and error. However, the tests are long and costly. Also computer-aided design, based on numerical simulation of magnetic and thermal phenomena involved, has certain advantages in terms of cost, time and optimization for the development of induction heating processes. The prediction of magneto-thermal behavior of the whole work space - inductor allows the optimization of both electrical and mechanical design of the inductor, and also the necessary power required to treat the work space. The temperature distribution is itself a key factor for predicting the effectiveness of heat treatment; physical properties of materials are strongly temperature dependent. For nonlinear problems with complex geometry, the finite volume method developed in recent years, considered as an

Development of a Binary Zn-Based Solder Alloy for Joining Wrought Magnesium Alloy AZ31B

In the present article, the wrought magnesium alloy AZ31B sheets were soldered by means of high-frequency induction heating device using a novel binary Zn-based solder alloy in argon gas shield condition. The interfacial microstructure, phase constitution, and fracture morphology of the soldered joint were studied. The microhardness and shear strength of the soldered joint were tested. The experimental results exhibit that α-Mg solid solution and γ-MgZn phase were formed in soldering region. Moreover, the β-Mg7Zn3 phase in the original Zn-based solder alloy disappeared completely after the soldering process due to the fierce alloying between the molten binary Zn-based solder alloy and the base metal AZ31B during soldering. Test results show that the shear strength of the soldered joint is 28 MPa. The fracture morphology of the soldered joint displays an intergranular fracture mode, and the crack originates from α-Mg + γ-MgZn eutectoid structure. The interaction between the molten Zn-based solder alloy and the base metal AZ31B leads the Zn-based solder alloy to be transformed into Mg-based soldering metal during soldering.

Interface characteristics and mechanical properties of the induction brazed joint of magnesium alloy AZ31B with an Al-based filler metal

In this paper, wrought magnesium alloy AZ31B sheets were brazed by means of high-frequency induction heating device using a novel Al-based filler metal in argon gas shield condition. The interfacial microstructure, phase constitution and fracture morphology of the brazed joint were studied. The experimental results show that α-Mg solid solution and β-Mg17Al12 phase were formed in brazing region. Moreover, the homogeneous Mg32(Al, Zn)49 phase in the original Al-based filler metal disappeared entirely after the brazing process due to the fierce alloying between the molten filler metal and the base metal during brazing. Test results show that the shear strength of the brazed joint is 45MPa. The fracture morphology of the brazed joint exhibits intergranular fracture mode and the crack originates from the hard β-Mg17Al12 phase.

Eigenvector placement in state space control of induction heating device

Metal industries still use furnace that have low efficiency and are based on thermal heating produced by combustion process. To have better cost production and low gas emission, induction heating is a way to be explored. This paper presents an industrial multiphase induction heating process focusing on the inductor's current control. A model of the electrical power part is described linking the power sources, the inverter currents and the power density produced to heat the metal piece. Due to the structure of the global power system, couplings between currents should be well managed to control the temperature. A state space representation is used not only to control in closed loop the dynamics of both currents but also a specified eigenvector placement is forced to get uncoupling and robust behavior of the global system. The results obtained in simulation show good performances and fulfill the industrial constraints.

Particle Swarm Optimization of a Multi-Coil Transverse Flux Induction Heating System

In this paper the optimization of a transverse flux induction heating device by means of a parameter-free, self-adaptive particle swarm optimizer is presented. The novelty of this work is represented by the fact that concentric multi-coil induction heaters have never been optimized before in their full three-dimensional complexity. The main technical challenge of the problem consists in designing a single configuration capable of heating strips of different widths while satisfying geometrical, electrical and heating process constraints. It will be shown that a system consisting of three coils can successfully heat strips of widths between 600 mm and 800 mm with the required uniformity.

A Novel Crossed Traveling Wave Induction Heating System and Finite Element Analysis of Eddy Current and Temperature Distributions

A novel crossed traveling wave induction heating (C-TWIH) system for heating thin industrial strips is proposed and its finite element method (FEM) simulations are reported. Compared with a typical traveling wave induction heating (TWIH) device, C-TWIH has more uniform and concentrated eddy current density distributions. This is because the C-TWIH system exploits a three-phase induction heater with crossed yoke arrangement, and the magnetic fluxes generated by each phase are interacting and complementing each other to compensate for the weak magnetic areas of each phase. Temperature distribution and variation of the C-TWIH system is also characterized. The fabricated novel model has a temperature range from 251degC to 270degC and its undesired temperature non-uniformity is reduced by 43% compared with those in typical TWIH devices.

Coupled Electromagnetic-Thermal Field Investigation in Induction Heating Device

The aim of the work is precise coupled –electromagnetic and temperature field analysis of an induction heating system by finite element method. Presented example is referred to real induction heating system. The problem was solved as nonlinear, transient and axisymmetrical. The numerical model of the coupled fields is based on the finite element method and electromagnetic and temperature distributions have been obtained using COMSOL 3.3 software package.

Analysis of perforated magnetic shields for electric power applications

The shielding performance of perforated magnetic shields for electric power applications is described. The shielding of an axisymmetric induction heating device is studied as a function of frequency, number of perforations and dimensions of the perforations. From the numerical point of view, the perforations cause the numerical model to be 3D. A numerical optimisation is carried out to find the optimal geometry with respect to the shielding factor and the volume of the shield. For the optimisation, two approaches are presented. The first approach is fast and easy-to-implement, but has limited accuracy. It uses a classical 2D axisymmetric model where the perforations are approximated by ‘axisymmetric air gaps’ resulting in a segmented shield. It is shown how to modify the 2D model to obtain results that are similar to the ones of a 3D model. The second approach is more accurate although quite fast, but more difficult to implement. It combines a 3D thin-shell finite element model with the unmodified 2D model in a space mapping optimisation algorithm. The validation of both models is based on experimental work for an unperforated shield and for the optimised perforated shield.

Uniaxial and biaxial compressive response of a bulk metallic glass composite over a range of strain rates and temperatures

The uniaxial and biaxial compressive responses of Zr57Nb5Al10Cu15.4Ni12.6–W composite were investigated over a range of strain rates (∼10−3 to 103 s−1) using an Instron universal testing machine (∼10−3 to 10° s−1), drop-weight tower (∼200 s−1), and split Hopkinson pressure bar (103 s−1). The temperature dependence of the mechanical behavior was investigated at temperatures ranging from room temperature to 600 °C using the instrumented drop-weight testing apparatus, mounted with an inductive heating device. The deformed and fractured specimens were examined using optical and scanning electron microscopy. Stopped experiments were used to investigate deformation and failure mechanisms at specified strain intervals in both the drop weight and split Hopkinson bar tests. These stopped specimens were also subsequently examined using optical and scanning electron microscopy to observe shear band and crack formation and development after increasingly more strain. The overall results showed an increase in yield strength with strain rate and a decrease in failure strength, plasticity, and hardening with strain rate. Comparison of uniaxial and biaxial loading showed strong susceptibility to shear failure since the additional 10% shear stress caused failure at much lower strains in all cases. Results also showed a decrease in flow stress and plasticity with increased temperature. Also notable was the anomalous behavior at 450 °C, which lies between the Tg and Tx and is in a temperature regime where homogeneous flow, as opposed to heterogeneous deformation by shear banding, is the dominant mechanism in the bulk metallic glass.