Simulation Of Induction Heating Research Articles

Induction heating simulation for aircraft RTM toolings

Aircraft CFRP parts as sharklets are produced in resin transfer molding (RTM) tooling. The parts need to be heated up homogenously over the whole area with a constant temperature. The complex shape and accessibility of the tooling make it hard to introduce a common heating system. In addition, the heat must be transferred through the Invar metal tooling structure onto the CFRP. Infrared lamp, air fan and microwave heating are concepts in development. Electrical heating layer mats and cages are laborious in applying. Induction has the advantage of contact-less, efficient, and fast heating. Induction heating was tested for the structural bonding of CFRP frames and stringers showing high bonding strengths. To apply this technology for the RTM tooling, the placement and distance of the induction coils is important. Simulation can help to find the right adjustments and power needed for induction heating. With the program COMSOL the surface and the coils are modeled, and the numerically structured net is divided in small tetrahedron and quadratic sub elements. Since there is no magnetic streamline in the middle of the coil-section, a symmetric halving of the structure is applied as a boundary condition. The temperature-time development and the distance of the coils are simulated in 2D and 3D. Due to the material properties of the magnetic flux concentrator (MFC), higher flux concentration of the magnetic field occurred only in 2D. The results are validated by experiments and are in good agreement.

Commissioning of the inductive heater for hypervapotron testing

The paper describes commissioning of the inductive heater based on numerical simulation of inductive heating in the hypervapotron sample and test channel. The HEFEL loop is being developed to research a high heat flux cooling channels applicable in fusion devices. The Box Scraper hypervapotron channel geometry represents a primary focus of research. Conditions in the first wall of tokamak are simulated by induction heating of the tested hypervapotron channel. The exact heat flux of tested sample is difficult to measure, thus the numerical simulation of induction heating and thermohydraulic model of the cooling channel are an important part of HEFEL loop commissioning. ANSYS Maxwell 3D and ANSYS Fluent coupling is used for optimalization of the induction heating to achieve the highest heat fluxes using selected induction heating source.

Numerical simulation of inductive heating in thermoplastic unidirectional cross-ply laminates

Thermoplastic Composites can be re-melted allowing them to be joined via welding. This is an attractive alternative to conventional methods that are used to join thermoset composite parts such as mechanical fastening and adhesive bonding. In this work the inductive heating of uni-directional (UD) plies of thermoplastic carbon fiber reinforced polymer (CFRP) laminates is investigated. The focus is on developing a numerical electromagnetic and thermal simulation model that captures the main processes involved in eddy current generation and heat generation, in particular in the interface areas of the UD plies. A measurement technique has been developed to obtain the electric properties of the ply material. Furthermore, to support the modelling of both the induction heating equipment and work piece a field measurement of the magnetic field surrounding the coil and work piece has been developed. Inductive heating experiments were carried out on several thick composite laminate plates with different ply lay-ups to compare and validate the electro-magnetic-thermal simulation model. The measured surface temperatures were compared with the results from the simulation model. The results of this work can be used to support the design of UD-ply laminates to improve their ability to be welded via inductive heating. In addition, the results of this work can be used to assist in pre-determining induction welding equipment settings and heating times.

Numerical simulation of a magnetic induction coil for heat treatment of an AISI 4340 gear

In manufacturing industry, heat treatment is a fundamental requirement for improving the material quality of readily manufactured products. Induction heating technology is repeatable and easily controlled by the advantage of having an electronical control unit. Nowadays, numerical methods have gained so much importance that it become as a reference for the induction heating industry. Experimental methods are costly and time demanding procedures. However, making use of finite element method software, induction heating simulations of a steel gear can be performed relatively cost effective and in a short time. In this paper, induction heating simulation of an AISI 4340 steel gear using FEA software is performed. The effect of variation of inductor frequency and gear workpiece-inductor coil distance on the hardening depth of the gear surface is investigated. The temperature profile of the workpiece is obtained. From the temperature distribution on the steel gear workpiece, the regions of the gear at which the austenitizing temperature (Ac3) - responsible for martensite phase formation- are observed. From the numerical results, hardening profile and hardening depth of the gear is interpreted.

Numerical Simulation of Induction Heating of Well Casing

Numerical Simulation of Induction Heating of Well Casing

Simulation of induction heating of a ferromagnetic plate with a covering inductor

The paper presents the features of numerical simulation of induction heating of a ferromagnetic plate by a covering inductor when powered from a voltage source, a method for calculating a symmetric system containing an odd number of turns is described. The calculation results are compared with experimental data. The influence of the correction of the magnetization curve on the correspondence of the simulation and experimental results is investigated.

Industrial Steel Heat Treating: Numerical Simulation of Induction Heating and Aquaquenching Cooling with Mechanical Effects

This paper summarizes a mathematical model for the industrial heating and cooling processes of a steel workpiece corresponding to the steering rack of an automobile. The general purpose of the heat treatment process is to create the necessary hardness on critical parts of the workpiece. Hardening consists of heating the workpiece up to a threshold temperature followed by a rapid cooling such as aquaquenching. The high hardness is due to the steel phase transformation accompanying the rapid cooling resulting in non-equilibrium phases, one of which is the hard microconstituent of steel, namely martensite. The mathematical model describes both processes, heating and cooling. During the first one, heat is produced by Joule’s effect from a very high alternating current passing through the rack. This situation is governed by a set of coupled PDEs/ODEs involving the electric potential, the magnetic vector potential, the temperature, the austenite transformation, the stresses and the displacement field. Once the workpiece has reached the desired temperature, the current is switched off an the cooling stage starts by aquaquenching. In this case, the governing equations involve the temperature, the austenite and martensite phase fractions, the stresses and the displacement field. This mathematical model has been solved by the FEM and 2D numerical simulations are discussed along the paper.

Application of Selective Induction Heating for Improvement of Mechanical Properties of Elastic Hinges.

Injection molding is a polymer processing technology used for manufacturing parts with elastic hinges. Elastic hinges are widely used in FMCG (Fast Moving Consumer Goods) packaging (e.g., bottle closures of shampoos, sauces) and in the electrical engineering industry. Elastic hinge is a thin film that connect two regions of the injection molded part, where significant shear rates are present, which can lead to the degradation of polymers and the decrease in mechanical properties. Selective induction heating is the method that improves the flow of the polymer melt through thin regions by the local increase in mold temperature. In this study, selective induction heating was used to improve mechanical properties of elastic hinges by the reduction of material degradation due to high shear rates. To verify the change of shear rates, selective induction heating simulation and injection molding simulations were performed. The linear relation between mold temperature and maximum shear rate in the cross-section was identified and the mechanical tests showed significant differences in hinge stiffness, tensile strength and elongation at break.

Manifestation of the “striped heating” effect in numerical simulation of induction heating of ferromagnetic bodies near the Curie point

For the first time, the effect of “striped heating” in the induction heating of ferromagnetic materials is mentioned in the works of Soviet scientists Lozinski M.G. and Babat G.I. in the mid-20th century. They tried to give a physical explanation for the “striped heating” and expressed fears that the phenomenon might limit the use of induction hardening. However, in the practical use of induction heating in most cases, there was no significant influence of this effect on the process. In this regard, the “striped heating” was not actively discussed by the scientific community and was not sufficiently researched. The discussion on this issue was resumed by prof. Dzliev S. V. In the future, prof. Nemkov V.S. tried to gather all the available information about the “zebra effect” (as he called this phenomenon) and summarize it. This article continues the discussion about the effect of “striped heating”, and its manifestation in numerical modeling of induction heating of ferromagnetic bodies. A special case of the effect of “striped heating” in blackout induction heating with discrete overflow is given.

Measurement and modeling of thermal evolution during induction heating and thixoforming of low carbon steel

A comparative study of thixoforming and forging of double-cup parts in low carbon steel was performed using a combination of process in-situ experimental analysis and modeling. First, the thermal profile resulting from induction heating of the slug prior thixoforming was experimentally determined using thermocouples and compared to the results of 3D numerical simulation of induction heating. The thermal profile was found to be heterogeneous with temperature ranging from 1150 °C to 1425 °C. Numerical modeling of the thermocoupled slug demonstrated that the geometry alteration induced by thermocouples disturbs the magnetic field and thermal diffusion during induction heating resulting in a significant modification of the temperature distribution within the slug. Thermal evolution during transfer from the heating cell to the press was also monitored and the data were used to determine the heat transfer coefficient which was found to be approximately 150 W.m−2.K−1 on a temperature range of 1300 °C–1400 °C. Numerical simulation of thixoforming and forging processes was performed using a micro-macro model and the calculated forming load evolution was compared with the in-situ experimental data collected in-situ using a force sensor located on the upper punch. The comparative study demonstrates the essential influence of the input thermal profile to carry out reliable numerical simulation. The load applied to thixoform the double-cup part was found to be 40 % lower than in forging condition whereas the extruded length resulting from thixofming is approximately 12 % higher than for the forged specimen. Post-process analysis shows that thixofomring does not affect the microstructure and tnsile propeties of the specimen in comparison with forging, except for a sligh grain coarsening of the non-extruded part of the specimen.

Modeling of induction heating of thermoplastic composites

In this article, a hybrid finite element model is presented for the simulation of induction heating of layered composite plates. Modeling includes the alternating electromagnetic field generated by an alternating current running through a coil, the current densities in the composite plate resulting from the electromagnetic field, the heat generation resulting from the current density distribution, and the heat transfer resulting from the nonuniform heat generation in the plate and the temperature distribution in the plate. The different elements of the model are shown to capture the time-dependent temperature distribution resulting from a coil moving over the surface of a composite laminate.

Numerical investigation and thermal predictions of asphalt pavement containing inductive materials under alternating magnetic field

Inductive heating asphalt pavement (IHAP) has been widely investigated as the functional pavement, and IHAP is heated by induction heating of randomly dispersed inductive material under alternating magnetic field. Due to the randomly dispersed heat sources in IHAP, it is easy to cause uneven temperature distribution, which is difficult to be described by the existing thermal calculation methods. To reflect the dispersed states of the heat sources and air voids in IHAP and regulate the pavement temperature field, a novel heat source simulation method was proposed through the modified random aggregate algorithm, and an induction heating simulation of IHAP was established. The maximal temperature (Tmax) and average temperature (Tave) of the pavement surface were used as the prediction targets, and the influences of the operational parameters, material composition and the environmental factors on the above targets were discussed. To increase Tmax and Tave, operational parameters and waste steel shavings content should be increased, while the increment of ambient temperature and the decrement of heat transfer coefficient are beneficial to the increase of Tmax and Tave. Moreover, the prediction models between the above influencing factors and the targets were established by response surface methodology. The prediction models and suggestions for acquiring reasonable targets could provide scientific guidance for applications of the IHAP to achieve various pavement functions.

Simulation of induction heating of a titanium sample in a container with a carbon-containing medium and determination of the amount of heat losses during chemical heat treatment

In this work, the process of induction heating of a container with a titanium sample in a carbon-containing medium was simulated using the finite element method. The dependence of the inductor current I and the duration of treatment on the heating kinetics T(I,t) of the “inductor – container – sample” system taking into account the heat losses QL(I, T) on the process of chemical-thermal treatment of titanium was established.

Induction heating simulation of the waveguide assembly elements

The waveguide path systems consisting mainly of aluminum alloys with improved weight, size, and electrical parameters are used to ensure the functioning of the spacecraft and its onboard equipment in accordance with a given program. When assembling the elements of the waveguide paths, in particular a thin-walled pipe of rectangular cross section, coupling and flange, induction brazing is used. Element-by-element assembly of lightweight waveguide paths using the method of induction soldering is connected with a number of technological difficulties such as the uneven distribution of temperature fields, the thickness variation of the soldered products and the design features of the inductors. This paper presents a model describing the process of heating a pipe-inductor system during induction brazing. The presented model describes the process of induction heating of the pipe as a separate structural element of the waveguide path. In the process of simulation in the Comsol software, on the basis of numerical simulation methods with the connection of the necessary media involved in induction heating, the pipe heating graphs are obtained.

Modeling the Induction Hardening of High-Carbon Saw Blades

Abstract Saws for food processing are designed to exhibit good resistance to corrosion and wear during service; the saws are made from high-carbon steel and are subjected to induction hardening to achieve the required properties. Such process offers good industrial advantages because heating is done at specific regions during very short times without heating all the material. The localized heating allows for the rapid cooling of the heated-up regions that result in transformation to austenite. This work presents the results of the simulation of induction heating using the finite and the boundary element methods to solve the heat transfer and electromagnetic phenomena. The model was coupled to a commercial package that considers the phase transformations occurring during the heating and quenching stages. The results of the simulation were validated with trials carried on site.

Induction brazing of thin-walled pipes from AISI 304 steel using copper-based solder

Pipes made of austenitic stainless steels are widely used in automotive industry. They are connected together or to other components by different joining technologies. The quality of produced joints is often critically important for passenger safety assurance. The joint lifetime is significantly influenced by their corrosion behaviour. The paper deals with induction brazing of thin-walled pipes from austenitic stainless steel using high corrosion-resistant Cu-Ni solder. To design appropriate parameters of induction heating, the effective method of numerical simulation of induction heating using the software ANSYS was applied. Simulation model for evaluation of electro-magnetic and temperature fields in the process of induction brazing of exhaust pipes from AISI 304 steel using copper-based solder was developed and verified by experimental temperature measurement during pipe induction heating. Based on performed numerical experiments and results of numerical simulations, appropriate parameters and operating diagram for the induction brazing of thin-walled pipes of the AISI 304 steel using copper-based solder were suggested.

Numerical simulation of induction heating of a carburizing container with a titanium sample

Induction heating of a carburizing container using induction heating was studied. The dependency of heating up to the temperature of 1660 °C was determined depending on the current values I from 0.5 to 2 kA on the inductor at the frequency of 112.5±2.5 kHz. Experimental results were compared to the data of numerical simulation of heat transfer in the carburizing container.

Numerical simulation of induction heating thick-walled tubes

In the paper is shown the connection of two toolboxes in an Ansys Workbench solution for induction heating. In Ansys Workbench, Maxwell electromagnetism programs and Fluent have been linked. In Maxwell, a simulation of electromagnetic induction was performed, where data on the magnetic field distribution in the heated material was obtained and then transformed into the Fluent program in which the induction heating simulation was performed.

Numerical simulation of induction heating considering the surface oxidation of cp-Ti samples

Induction heating and oxidation of cp-Ti samples surface using high frequency currents are studied. The dependency of heating up to the temperature from 800 to 1500 °C is determined depending on the current values from 1.5 to 3 kA on the inductor at 90 kHz. Experimental results are compared to the data of numerical simulation of heat transfer in titanium samples.

An axisymmetrical non-linear finite element model for induction heating in injection molding tools

To analyze the heating and cooling phase of an induction heated injection molding tool accurately, the temperature dependent magnetic properties, namely the non-linear B-H curves, need to be accounted for in an induction heating simulation. Hence, a finite element model has been developed, including the non-linear temperature dependent magnetic data described by a three-parameter modified Fröhlich equation fitted to the magnetic saturation curve, and solved with an iterative procedure. The numerical calculations are compared with experiments conducted with two types of induction coils, built in to the injection molding tool. The model shows very good agreement with the experimental temperature measurements. It is also shown that the non-linearity can be used without the temperature dependency in some cases, and a proposed method is presented of how to estimate an effective linear permeability to use with simulation codes not able to utilize a non-linear solver.