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Article
Publication date: 5 January 2015

Shuye Ding and Mengqi Wang

The purpose of this paper is to explore the relationship of fluid flow and heat transfer inside the generator, a large hydro-generator is taken for an example and the temperature

Abstract

Purpose

The purpose of this paper is to explore the relationship of fluid flow and heat transfer inside the generator, a large hydro-generator is taken for an example and the temperature field in the generator is calculated according to computation of fluid field by using of corresponding mathematics methods based on fluid mechanical theory and heat transfer theory.

Design/methodology/approach

To calculate the temperature field of the generator more accurately, a large-scale hydro-generator is taken as an example and the mathematical model and physical model of 3D stator temperature field and fluid field are established. And the calculation results of the fluid field are applied into the physics field of generator, coupled relationship between fluid field and temperature field was calculated by using of finite volume method and finite element method, respectively. The temperature fields based on fluid fields and the effect of different fluid flow state on generator temperature were analyzed and compared.

Findings

The calculated results shows show good agreement with the measured results, meanwhile the effect of different fluid field state on the temperature field is analyzed and the relationship between temperature fields and fluid fields is achieved, which will provide a theoretical basis for ventilation structure design and calculation of synthesis physical fields.

Originality/value

The relationship between temperature fields and fluid fields is obtained, providing a theoretical basis for ventilation structure design and calculation of synthesis physical fields.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 7 March 2016

Yilun Li and Shiyou Yang

The temperature drop, especially in the edge of rolled steel in the hot rolling cooling has a catastrophic effect on the steel quality. The purpose of this paper is to study the…

Abstract

Purpose

The temperature drop, especially in the edge of rolled steel in the hot rolling cooling has a catastrophic effect on the steel quality. The purpose of this paper is to study the coupled eddy current-temperature field of a C-type edge induction heater to provide references for engineering applications and designs.

Design/methodology/approach

Three-dimensional finite element analysis (FEA) model of a C-type edge induction heater is developed. Especially, a numerical methodology to couple the eddy current and temperature fields is proposed for coupled eddy current and temperature problems involving movement components. FEA software ANSYS is used to solve the coupled eddy current and temperature fields. The heat loss from the eddy current fields is abstracted and processed, and taken as internal heat source in the analysis of the temperature field. The temperature distribution of the rolling steel is obtained.

Findings

The numerical results can predict exactly the temperature rise of the rolled steel by means of the edge induction heating system.

Practical implications

The proposed numerical methodology for coupling eddy current and temperature fields can be applied to engineering coupled eddy current and temperature problems involving movement components. Also, the developed model and method can be used in the analysis and design of the edge induction heating system.

Originality/value

A numerical methodology to couple eddy current and temperature field for solving multi-physics field problems involving movement components is proposed and implemented in available commercial software. A three-dimensional model of the C-type edge induction heat heater is developed. Finite element method is employed to study the coupled eddy current-thermal problem. A method to deal with the movement of the strip steel is proposed. The proposed methodology can be applied to other coupled eddy current-temperature field problem with moving components.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 35 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 12 May 2022

Cheng Zhang, Jianfeng Zhou and Xiannian Meng

In the magnetorheological fluid (MRF) sealing, a large amount of friction heat is generated in the fluid film with micron thickness due to the viscosity dissipation, which leads…

Abstract

Purpose

In the magnetorheological fluid (MRF) sealing, a large amount of friction heat is generated in the fluid film with micron thickness due to the viscosity dissipation, which leads to seal failure and MRF deterioration. The purpose of this study is to investigate the mechanism of temperature rise of MRF film under the action of the three-field coupling of the flow field, temperature field and magnetic field.

Design/methodology/approach

The fluid film was simplified as a Couette flow in this work to simulate the temperature change in the sealing fluid film under different working conditions. The corresponding experiment for test the temperature rise was also carried out, and the temperature of the characteristic point of the stationary ring was measured to validate the model.

Findings

The results show that the temperature rise is mainly affected by the rotational speed, magnetic field strength and fluid film thickness. The magnetic field enhances the convective heat transfer in the MRF film. The thinner the fluid film, the more frictional heat generated. The MRF film reaches its maximum temperature at the contact with the end face of rotating ring due to frictional heat.

Originality/value

A method for temperature rise analysis of MRF fluid sealing films based on Couette flow is established. It is helpful for the study of liquid film frictional heat in MRF seals.

Details

Industrial Lubrication and Tribology, vol. 74 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 17 May 2023

Lulu Huang, Xiang Huang and Shuanggao Li

Large size of aircraft assembly tooling structure and complex measurement environment exist. The laid enhanced reference points (ERS) are subject to a combination of nonuniform…

Abstract

Purpose

Large size of aircraft assembly tooling structure and complex measurement environment exist. The laid enhanced reference points (ERS) are subject to a combination of nonuniform temperature fields and measurement errors, resulting in increased measurement registration errors. In view of the nonuniform temperature field and measurement errors affecting the ERS point registration problem, the purpose of this paper is to propose a neural network-based ERS point registration compensation method for large-size measurement fields under a nonuniform temperature field.

Design/methodology/approach

The approach is to collect ERS point information and temperature data, normalize the collected data to complete the data structure design and complete the construction of the neural network prediction model by data training. The data learning is performed to complete the prediction model construction, and the prediction model is used to complete the compensation analysis of ERS points. Finally, the algorithm is verified through experiments and engineering practice.

Findings

Experimental results show that the proposed neural network-based ERS point prediction and compensation method for nonuniform temperature fields effectively predicts ERS point deformation under nonuniform temperature fields compared with the conventional method. After the compensation analysis, the registration error is effectively reduced to improve registration accuracy. Reducing the combined effect of environmental nonuniform temperature field and measurement error has apparent advantages.

Originality/value

The method reduces the registration error caused by combining a nonuniform temperature field and measurement error. It can be used for aircraft assembly site prediction and registration error compensation analysis, which is essential to improve measurement accuracy further.

Details

Robotic Intelligence and Automation, vol. 43 no. 2
Type: Research Article
ISSN: 2754-6969

Keywords

Article
Publication date: 14 July 2020

Subhasree Dutta, Somnath Bhattacharyya and Ioan Pop

This study aims to numerically analyse the impact of an inclined magnetic field and Joule heating on the conjugate heat transfer because of the mixed convection of an Al2O3–water…

Abstract

Purpose

This study aims to numerically analyse the impact of an inclined magnetic field and Joule heating on the conjugate heat transfer because of the mixed convection of an Al2O3–water nanofluid in a thick wall enclosure.

Design/methodology/approach

A horizontal temperature gradient together with the shear-driven Flow creates the mixed convection inside the enclosure. The nonhomogeneous model, in which the nanoparticles have a slip velocity because of thermophoresis and Brownian diffusion, is adopted in the present study. The thermal performance is evaluated by determining the entropy generation, which includes the contribution because of magnetic field. A control volume method over a staggered grid arrangement is adopted to compute the governing equations.

Findings

The Lorentz force created by the applied magnetic field has an adverse effect on the flow and thermal field, and consequently, the heat transfer and entropy generation attenuate because of the presence of magnetic force. The Joule heating enhances the fluid temperature but attenuates the heat transfer. The impact of the magnetic field diminishes as the angle of inclination of the magnetic field is increased, and it manifests as the volume fraction of nanoparticles is increased. Addition of nanoparticles enhances both the heat transfer and entropy generation compared to the clear fluid with enhancement in entropy generation higher than the rate by which the heat transfer augments. The average Bejan number and mixing-cup temperature are evaluated to analyse the thermodynamic characteristics of the nanofluid.

Originality/value

This literature survey suggests that the impact of an inclined magnetic field and Joule heating on conjugate heat transfer based on a two-phase model has not been addressed before. The impact of the relative slip velocity of nanoparticles diminishes as the magnetic field becomes stronger.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 3 November 2022

Sandeep Singh Sheoran, Shilpa Chaudhary and Kapil Kumar Kalkal

The purpose of this paper is to study the transient thermoelastic interactions in a nonlocal rotating magneto-thermoelastic medium with temperature-dependent properties…

Abstract

Purpose

The purpose of this paper is to study the transient thermoelastic interactions in a nonlocal rotating magneto-thermoelastic medium with temperature-dependent properties. Three-phase-lag (TPL) model of generalized thermoelasticity is employed to study the problem. An initial magnetic field with constant intensity acts parallel to the bounding plane. Therefore, Maxwell's theory of electrodynamics has been effectively introduced and the expression for Lorentz's force is obtained with the help of modified Ohm's law.

Design/methodology/approach

The normal mode technique has been adopted to solve the resulting non-dimensional coupled field equations to obtain the expressions of physical field variables.

Findings

For uniformly distributed thermal load, normal displacement, temperature distribution and stress components are calculated numerically with the help of MATLAB software for a copper material and the results are illustrated graphically. Some particular cases of interest are also deduced from the present study.

Originality/value

Influences of nonlocal parameter, rotation, temperature-dependent properties, magnetic field and time are carefully analyzed for mechanically stress free boundary and uniformly distributed thermal load. The present work is useful and valuable for analysis of problem involving thermal shock, nonlocal parameter, temperature-dependent elastic and thermal moduli.

Details

Multidiscipline Modeling in Materials and Structures, vol. 18 no. 6
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 7 November 2016

Hongbo Qiu, Wenfei Yu, Bingxia Tang, Weili Li, Cunxiang Yang and Yanfeng Wang

Taking a 2,000 r/min 10 kW permanent magnet motor as an example, the purpose of this paper is to study the influence of driving modes on the performance of permanent magnet motor…

Abstract

Purpose

Taking a 2,000 r/min 10 kW permanent magnet motor as an example, the purpose of this paper is to study the influence of driving modes on the performance of permanent magnet motor at limit conditions, and researched the variation mechanism of motor performance influenced by different driving modes.

Design/methodology/approach

A two-dimensional electromagnetic field model of the permanent magnet motor was established, and a rectangular-wave driving circuit was built. By using the finite element method, the electromagnetic field, current, harmonic content and eddy current loss were calculated when the motor operated at rated load and limit load. On the basis of the motor loss calculation, the temperature field of the motor operating at rated condition and limit condition was researched, and the factors that influence motor limit overload capacity were analyzed. By analyzing the motor loss variation at different load conditions, the change mechanism of the motor temperature field was determined further. Combined with the related experiments, the correctness of the above analysis was verified.

Findings

Permanent magnet synchronous motor (PMSM) driven by sine wave is better compared with brushless direct current motor (BLDCM) driven by rectangular wave in reducing the magnetic field harmonics, motor losses and optimizing the temperature distribution in the motor. The method driven by sine wave could improve the motor output performance including the motor efficiency and the motor overload capacity. The winding temperature is the most important factor that limits the output capability of PMSM operating for a long time. However, because of the large rotor eddy current losses, the permanent magnet temperature is the most important factor that limits the output capability of BLDCM operating for a long time.

Practical implications

The influence of driving modes on the motor magnetic field, losses and temperature distribution, efficiency and overload capacity was determined, and the influence mechanism was also analyzed. Combined with the analysis of the electromagnetic and temperature fields, the advantages of different driving modes were presented. This study could provide an important basis for the design of permanent magnet motors with different driving modes, and it also provides reference for the application of permanent magnet motor.

Originality/value

This paper presents the influence of driving modes on permanent magnet motors. The limit output capacity of the motor with different driving modes was studied, and the key factors limiting the motor output capability were obtained.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 35 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 16 March 2020

Zhenyang Zhu, Yi Liu, Zhe Fan, Sheng Qiang, Zhiqiang Xie, Weimin Chen and Congcong Wu

The buried pipe element method can be used to calculate the temperature of mass concrete through highly efficient computing. However, in this method, temperatures along cooling…

Abstract

Purpose

The buried pipe element method can be used to calculate the temperature of mass concrete through highly efficient computing. However, in this method, temperatures along cooling pipes and the convection coefficient of the cooling pipe boundary should be improved to achieve higher accuracy. Thus, there is a need to propose a method for improvement.

Design/methodology/approach

According to the principle of heat balance and the temperature gradient characteristics of concrete around cooling pipes, a method to calculate the water temperature along cooling pipes using the buried pipe element method is proposed in this study. By comparing the results of a discrete algorithm and the buried pipe element method, it was discovered that the convection coefficient of the cooling pipe boundary for the buried pipe element method is only related to the thermal conductivity of concrete; therefore, it can be calculated by inverse analysis.

Findings

The results show that the buried pipe element method can achieve the same accuracy as the discrete method and simulate the temperature field of mass concrete with cooling pipes efficiently and accurately.

Originality/value

This new method can improve the calculation accuracy of the embedded element method and make the calculation results more reasonable and reliable.

Details

Engineering Computations, vol. 37 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 23 August 2021

Xiao Fang, Yajie Zeng, Feng Xiong, Jiang Chen and Fei Cheng

Seepage of the dam is an important safety problem, which may cause internal erosion of the structure. In the field of seepage monitoring in civil engineering, the distributed…

Abstract

Purpose

Seepage of the dam is an important safety problem, which may cause internal erosion of the structure. In the field of seepage monitoring in civil engineering, the distributed optical fiber sensing technology based on the temperature tracing method has been paid more attention due to its unique advantages of high sensitivity, good stability and high resolution. The purpose of this paper is to make a review of the existing related research, so as to facilitate the later scholars to understand and further study more systematically.

Design/methodology/approach

In this paper, three kinds of commonly used distributed fiber temperature measurement technologies are introduced. Based on the working principle, monitoring system, theoretical analysis, experimental research and engineering application of the fiber seepage monitoring technology, the present situation of dam seepage monitoring based on distributed fiber is reviewed in detail and their advantages and disadvantages are compared.

Findings

The thermal monitoring technology of seepage measurement depends on the accuracy of optical fiber temperature measurement (including the accuracy of the system and the rationality of the discrimination method), the correct installation of optical fiber and the quantitative analysis of temperature data. The accuracy of the current monitoring system can basically meet the existing measurement requirements, but the correct installation of optical fiber and the calibration of temperature data need to be further studied for different discrimination methods, and this field has great research value.

Originality/value

At present, there are many applications and research studies of optical fiber sensing in the field of structural health monitoring, and there are also reviews of related aspects. However, there is little or no review only in the field of seepage monitoring. This paper summarizes the research and application of optical fiber sensing in the field of seepage monitoring. The possibility of the gradient method to find its new prospect with the development of monitoring systems and the improvement of temperature resolution is discussed. The idea of extending the seepage monitoring method based on distributed optical fiber thermal monitoring technology to other monitoring fields is also given in the paper.

Article
Publication date: 1 March 2003

Alfred Mühlbauer, Andris Muiznieks, Gundars Ratnieks, Armands Krauze, Georg Raming and Thomas Wetzel

The paper describes numerical simulation tools for electromagnetic (EM), hydrodynamic, temperature and concentration fields in industrial Czochralski (CZ) and floating zone (FZ…

Abstract

The paper describes numerical simulation tools for electromagnetic (EM), hydrodynamic, temperature and concentration fields in industrial Czochralski (CZ) and floating zone (FZ) single silicon crystal growth facilities under the influence of several alternating current (AC) and static DC magnetic fields. Such fields are expected to provide additional means to influence the melt behaviour, especially in the industrial growth of large diameter (200–300 mm) silicon crystals. The simulation tools are based on axisymmetric 2D models for (1) AC and DC magnetic fields in the whole crystal growth facility and (2) hydrodynamics, temperature and mass transport in the melt under the influence of the EM fields. The simulation tools are verified by comparison to temperature and velocity measurements in a laboratory CZ set‐up with eutectics InGaSn model melt and to resistivity measurements in grown silicon crystals.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 22 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

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