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1 – 10 of 39This paper aims to elaborate the method and algorithm for the analysis of the influence of high temperature on electric and thermal properties of the materials, as well as thermal…
Abstract
Purpose
This paper aims to elaborate the method and algorithm for the analysis of the influence of high temperature on electric and thermal properties of the materials, as well as thermal phenomena process.
Design/methodology/approach
The paper presents specially author’s software for the transient finite element analysis of coupled electromagnetic-thermal problems in a squirrel cage induction motor. The numerical implementation is based on finite element method and step-by-step algorithm. The nonlinearity of a magnetic circuit, the dependence of electric and thermal parameters on temperature, the movement of a rotor and skewed rotor bars have been taken into account. To verify the developed algorithm and software, the influence of high ambient temperature on selected electromagnetic and thermal parameters of the induction motor was examined.
Findings
The results of simulations compared with measurements confirm the adequacy of this approach to the analysis of coupled electromagnetic-thermal problems.
Research limitations/implications
3D effects have only been taken into account when using quasi-3D techniques (e.g. the multi-slice for skewed rotor slots).
Practical implications
The author’s software developed can be useful in the analysis and design of squirrel cage motors, especially motors working in high ambient temperature.
Originality/value
The paper offers appropriate author’s software for the transient and steady-state analysis of coupled electromagnetic and thermal problems in squirrel cage motors with skewed slots.
Details
Keywords
Mariusz Baranski, Wojciech Szelag and Wieslaw Lyskawinski
This paper aims to elaborate the method and algorithm for the analysis of the influence of temperature on back electromotive force (BEMF) waveforms in a line start permanent…
Abstract
Purpose
This paper aims to elaborate the method and algorithm for the analysis of the influence of temperature on back electromotive force (BEMF) waveforms in a line start permanent magnet synchronous motor (LSPMSM).
Design/methodology/approach
The paper presents a finite element analysis of temperature influence on BEMF and back electromotive coefficient in a LSPMSM. In this paper, a two-dimensional field model of coupled electromagnetic and thermal phenomena in the LSPMSM was presented. The influence of temperature on magnetic properties of the permanent magnets as well as on electric and thermal properties of the materials has been taken into account. Simulation results have been compared to measurements. The selected results have been presented and discussed.
Findings
The simulations results are compared with measurements to confirm the adequacy of this approach to the analysis of coupled electromagnetic-thermal problems.
Originality/value
The paper offers appropriate author’s software for the transient and steady-state analysis of coupled electromagnetic and thermal problems in LSPMS motor.
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Keywords
J.M. Allegre, C. Marchand and A. Razek
In analysing coupled electromagnetic thermal behaviours in electrical devices one of the main difficulties is related to the uncertainties of thermal parameters. The authors…
Abstract
In analysing coupled electromagnetic thermal behaviours in electrical devices one of the main difficulties is related to the uncertainties of thermal parameters. The authors present, in this work, a technique using the method of experimental designs for the identification of thermal parameters necessary for a coupled finite element model analysing the magneto‐thermal behaviour of an electromagnetic device.
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Morteza Ghaseminezhad, Aref Doroudi, Seyed Hossein Hosseinian and Alireza Jalilian
Voltage fluctuation (flicker) is a power quality disturbance that can produce several undesirable effects on industrial equipment. This paper aims to present the methodology and…
Abstract
Purpose
Voltage fluctuation (flicker) is a power quality disturbance that can produce several undesirable effects on industrial equipment. This paper aims to present the methodology and results of investigations undertaken to examine the speed and torque of an induction motor (IM) under voltage fluctuation conditions.
Design/methodology/approach
The IM response to different characteristics of voltage fluctuations is presented. It will be shown that under a special condition the IM torque can even reach two times the rated torque. To show how this occurs, a qualitative discussion is given on the motor response by linearized equations.
Findings
The small-signal analysis was used to determine the frequency which leads to maximum speed fluctuations. It was shown that, if the motor is excited with a modulation frequency (resonant frequency) which is one of its natural frequencies (modes), the mode will act as a fluctuating amplifier and greatly increase the amplitude of torque and speed fluctuations. Sensitivity analysis is also carried out to evaluate the influence of motor parameters on the resonance frequency. The results show that the resonance frequency is not affected at all by the changes in magnetizing reactance. This has been shown that magnetic saturation does not have any impact on the resonance frequency. The most effective parameters are rotor and stator resistances.
Originality/value
With the increasing popularity and use of arc furnace loads in the metallurgy industry and due to the wide application of large IMs in the industry, it is possible that the frequency of torque pulsation locates near a natural frequency and then will create an oscillation with a large magnitude, potentially leading to accelerated fatigue or severe damage of shaft. However, if this phenomenon occurs in industries, the resonance frequency must be filtered from the input voltage. Experimental results on a 1.1 kW, 380 V, 50 Hz, 2 pole IM are used to validate the accuracy of simulation results.
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Keywords
Mariusz Baranski, Andrzej Demenko, Wieslaw Lyskawinski and Wojciech Szelag
The purpose of this paper is to elaborate the method and algorithm for the analysis of electromagnetic and thermal transients in a squirrel cage induction motor.
Abstract
Purpose
The purpose of this paper is to elaborate the method and algorithm for the analysis of electromagnetic and thermal transients in a squirrel cage induction motor.
Design/methodology/approach
The paper presents the special software for transient finite element (FE) analysis of coupled electromagnetic‐thermal problems in a squirrel cage induction motor. The software has been prepared and is successfully applied in the design of special squirrel cage motors, e.g. the motors working in cryogenic conditions. A time‐stepping FE method and transients analysis of an induction motor has been applied. The nonlinearity of the magnetic circuit, the movement of the rotor and the skewed slots have been taken into account. The results of computations have been compared with measurements.
Findings
The method presented and the elaborated specialised software for FE analysis of electromagnetic and thermal transients are used to determine the dynamic performance of the squirrel‐cage induction motor. The results of simulations compared with measurements confirm the adequacy of this approach to the analysis of coupled electromagnetic‐thermal problems.
Research limitations/implications
3D effects have only been taken into account by quasi‐3D techniques (e.g. the multi‐slice for the skewed rotor slots).
Practical implications
The software developed can be useful in the analysis and design of squirrel cage motor, especially motors working in cryogenic conditions.
Originality/value
The paper offers appropriate software for transient analysis of coupled electromagnetic and thermal problems in squirrel cage motors with skewed slots.
Details
Keywords
Z. Makni, M. Besbes and C. Marchand
This paper aims to describe a CAD tool of permanent magnet electric machines. The software tool is operational from the first design phases and allows to study coupled phenomena.
Abstract
Purpose
This paper aims to describe a CAD tool of permanent magnet electric machines. The software tool is operational from the first design phases and allows to study coupled phenomena.
Design/methodology/approach
The described design methodology is based on the association of analytical and numerical approaches. A coupled electromagnetic‐thermal model is used for the analytical study. The numerical one uses the finite element method.
Findings
The sequential implementation of the two approaches highlights their complementarities and improves the time consuming and the reliability of the design process. The thermal coupling allows to anticipate the overheating of the machine and to take it into account in the design process.
Research limitations/implications
The simplifying assumptions made in the analytical model degrade the accuracy of temperature calculation.
Practical implications
This is a useful tool for electric machines manufacturer planning to obtain a fast and reliable solution in response to datasheet specifications.
Originality/value
This paper describes a multidisciplinary design methodology which is performed by coupling methods and software tools at the aim to take advantage of each one.
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Muhammad Umair, Faisal Khan and Wasiq Ullah
Field excited flux switching machines (FEFSM) are preferred over induction and synchronous machines due to the confinement of all excitation sources on the stator leaving a robust…
Abstract
Purpose
Field excited flux switching machines (FEFSM) are preferred over induction and synchronous machines due to the confinement of all excitation sources on the stator leaving a robust rotor. This paper aims to perform coupled electromagnetic thermal analysis and stress analysis for single phase FEFSM as, prolonged high-speed operational time with core and copper losses makes it prone to stress and thermal constraints as temperature rise in machine lead to degraded electromagnetic performance whereas the violation of the principle stress limit may result in mechanical deformation of the rotor.
Design/methodology/approach
This paper presents the implementation of coupled electromagnetic-thermal and rotor stress analysis on single-phase FEFSM with non-overlap winding configurations using finite element analysis (FEA) methodology in JMAG V. 18.1. three-dimensional (3D) magnetic loss analysis is performed and extended to 3D thermal analysis to predict temperature distribution on various parts of the machine whereas Stress analysis predicts mechanical stress acting upon edges and faces of the rotor.
Findings
Analysis reveals that temperature distribution and rotor stress on the machine is within acceptable limits. A maximum temperature rise of 37.7°C was noticed at armature and field windings, temperature distribution in stator near pole proximity was 35°C whereas no significant change in rotor temperature was noticed. Furthermore, principal stress at the speed of 3,000 rpm and 30,000 rpm was found out to be 0.0305 MPa 3.045 MPa, respectively.
Research limitations/implications
The designed machine will be optimized for improvement of electromagnetic performance followed by hardware implementation and experimental testing in the future.
Practical implications
The model is developed for axial fan applications.
Originality/value
Thermal analysis is not being implemented on FEFSM for axial fan applications which is an important analysis to ensure the electromagnetic performance of the machine.
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Keywords
Laetitia Jacoutot, Emilien Sauvage, Annie Gagnoud, Yves Fautrelle, Patrice Brun and Jacques Lacombe
This paper aims to report on a vitrification process based on direct induction that has been developed by the French Atomic Energy Commission (CEA, France). This process is…
Abstract
Purpose
This paper aims to report on a vitrification process based on direct induction that has been developed by the French Atomic Energy Commission (CEA, France). This process is characterized by currents directly induced inside the molten glass and by the cooling of all the crucible walls. In addition, a mechanical stirring device is used to homogenize the molten glass. This paper presents a global modelling of coupled phenomena that take place within the glass bath.
Design/methodology/approach
Electromagnetic, thermal and hydrodynamic phenomena are modelled. The aim of this study is to develop strategy of coupled modelling between these aspects. The thermohydrodynamic calculations are achieved with the Fluent software (distributed by Fluent France) and the electromagnetic aspects are solved by the OPHELIE program based on integral methods (developed in EPM laboratory).
Findings
Two configurations are considered: the first deals with thermal convection in an unstirred bath and the second takes into account the mechanical stirring.
Research limitations/implications
The main limitation is that repartition of the Joule power density within the molten glass is supposed to be not perturbed by the intrusive elements like the thermocouples or the stirrer. This assumption allows us to perform only axisymmetric calculations of induction effect.
Originality/value
This paper present different strategy of coupling the thermohydrodynamic and direct induction phenomena taken place in the molten glass.
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A general framework for the application of the Newton methods in non‐linear coupled electromagnetic‐thermal problems solved with the FEM on independent subproblem meshes is…
Abstract
A general framework for the application of the Newton methods in non‐linear coupled electromagnetic‐thermal problems solved with the FEM on independent subproblem meshes is presented. The explicit derivation of the Jacobian matrix is outlined and discussed. A matrix‐free quasi‐Newton method, to be used along with linear system solvers built around Jacobian‐vector products is presented. This method does not require explicit derivatives and can be parallelised. The numerical aspects of these methods are discussed. The different Newton methods are demonstrated using a steady‐state conductive heating example problem.
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Keywords
Petra Kumi, Stephanie A. Martin, Vadim V. Yakovlev, Martin S. Hilario, Brad W. Hoff and Ian M. Rittersdorf
The paper introduces and illustrates the use of numerical models for the simulation of electromagnetic and thermal processes in an absorbing ceramic layer (susceptor) of a new…
Abstract
Purpose
The paper introduces and illustrates the use of numerical models for the simulation of electromagnetic and thermal processes in an absorbing ceramic layer (susceptor) of a new millimeter-wave (MMW) heat exchanger. The purpose of this study is to better understand interaction between the MMW field and the susceptor, choose the composition of the ceramic material and help design the physical prototype of the device.
Design/methodology/approach
A simplified version of the heat exchanger comprises a rectangular block of an aluminum nitride (AlN) doped with molybdenum (Mo) that is backed by a thin metal plate and irradiated by a plane MMW. The coupled electromagnetic-thermal problem is solved by the finite-difference time-domain (FDTD) technique implemented in QuickWave. The FDTD model is verified by solving the related electromagnetic problem by the finite element simulator COMSOL Multiphysics. The computation of dissipated power and temperature is based on experimental data on temperature-dependent dielectric constant, loss factor, specific heat and thermal conductivity of the AlN:Mo composite. The non-uniformity of patterns of dissipated power and temperature is quantified via standard-deviation-based metrics.
Findings
It is shown that with the power density of the plane wave on the block’s front face of 1.0 W/mm2, at 95 GHz, 10 × 10 × 10-mm blocks with Mo = 0.25 – 4% can be heated up to 1,000 °C for 60-100 s depending on Mo content. The uniformity of the temperature field is exceptionally high – in the course of the heating, temperature is evenly distributed through the entire volume and, in particular, on the back surface of the block. The composite producing the highest level of total dissipated power is found to have Mo concentration of approximately 3%.
Research limitations/implications
In the electromagnetic model, the heating of the AlN:Mo samples is characterized by the volumetric patterns of density of dissipated power for the dielectric constant and the loss factor corresponding to different temperatures of the process. The coupled model is run as an iterative procedure in which electromagnetic and thermal material parameters are upgraded in every cell after each heating time step; the process is then represented by a series of thermal patterns showing time evolution of the temperature field.
Practical implications
Determination of practical dimensions of the MMW heat exchanger and identification of material composition of the susceptor that make operations of the device energy efficient in the required temperature regime require and expensive experimentation. Measurement of heat distribution on the ceramic-metal interface is a practically challenging task. The reported model is meant to be a tool assisting in development of the concept and supporting system design of the new MMW heat exchanger.
Originality/value
While exploitation of a finite element model (e.g. in COMSOL Multiphysics environment) of the scenario in question would require excessive computational resources, the reported FDTD model shows operational capabilities of solving the coupled problem in the temperature range from 20°C to 1,000°C within a few hours on a Windows 10 workstation. The model is open for further development to serve in the ongoing support of the system design aiming to ease the related experimental studies.
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