The effect of a time-periodic electromagnetic field on the temperature fields and stresses in an electrically conducting layer

1974 ◽  
Vol 10 (7) ◽  
pp. 720-725
Author(s):  
Ya. I. Burak ◽  
A. R. Gachkevich
Keyword(s):  
Electromagnetic Field ◽  
Temperature Fields ◽  
Conducting Layer ◽  
Electrically Conducting ◽  
Time Periodic

scholarly journals Span-Wise Fluctuating MHD Convective Flow of a Viscoelastic Fluid through a Porous Medium in a Hot Vertical Channel with Thermal Radiation

2016 ◽  
Vol 21 (3) ◽  
pp. 667-681 ◽  
Author(s):  
K.D. Singh
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Vertical Channel ◽  
Magnetic Reynolds Number ◽  
Conducting Fluid ◽  
Temperature Fields ◽  
Convection Flow ◽  
Electrically Conducting ◽  
Unsteady Mixed Convection ◽  
Phase Angles

Abstract An unsteady mixed convection flow of a visco-elastic, incompressible and electrically conducting fluid in a hot vertical channel is analyzed. The vertical channel is filled with a porous medium. The temperature of one of the channel plates is considered to be fluctuating span-wise cosinusoidally, i.e., $T^* \left( {y^* ,z^* ,t^* } \right) = T_1 + \left( {T_2} - {T_ 1} \right)\cos \left( {{{\pi z^* } \over d} - \omega ^* t^* } \right)$ . A magnetic field of uniform strength is applied perpendicular to the planes of the plates. The magnetic Reynolds number is assumed very small so that the induced magnetic field is neglected. It is also assumed that the conducting fluid is gray, absorbing/emitting radiation and non-scattering. Governing equations are solved exactly for the velocity and the temperature fields. The effects of various flow parameters on the velocity, temperature and the skin friction and the Nusselt number in terms of their amplitudes and phase angles are discussed with the help of figures.

scholarly journals Influence of Rectifiers on Permanent Magnet Wind Generator Electromagnetic and Temperature Fields

2016 ◽  
Vol 10 (1) ◽  
pp. 205-219
Author(s):  
Qiu Hongbo ◽  
Dong Yu ◽  
Yang Cunxiang
Keyword(s):  
Electromagnetic Field ◽  
Temperature Field ◽  
Permanent Magnet ◽  
Core Loss ◽  
Harmonic Distortion ◽  
Temperature Fields ◽  
Stator Core ◽  
Current Harmonics ◽  
Copper Loss ◽  
Wind Generator

Power rectifiers are very necessary in the wind power generation systems since they are the necessary channels that link the generator and power gird together. However, they have some effects on the permanent magnet wind generator due to their work on fast on-off transitions. Taking an 8kW 2000r/min wind-driven permanent magnet generator as an example, the system model and external circuit were established. Firstly, based on the field-circuit coupling calculation method, the voltage and current harmonics have been studied respectively when the generator was connected to rectifier loads and pure resistance loads, so did the total harmonic distortion. The mechanism of harmonic impacted by rectifiers was revealed. Secondly, combined the harmonic electromagnetic field theory, the stator core loss, armature winding copper loss and rotor eddy loss were analyzed when the generator connected different loads. Furthermore, according to the definition of nonlinear circuits PF, the numerical analysis method was adopted to calculate the power factor when the generator connected two loads respectively. The change mechanism of PF impacted by rectifiers has been revealed. In addition, the temperature field model has been established and the generator temperature was also analyzed. The temperature distributions were obtained when the wind generator was connected to different loads. Then, the relationship between losses and temperature was combined, the change rules of permanent magnet temperature by the eddy current loss were studied under different load. At last, it can prove that the rectifiers have influences on both electromagnetic field and temperature field through comparing the simulation results with experimental test data.

scholarly journals Effect of A Superstrate on On-Head Matched Antennas for Biomedical Applications

Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1099
Author(s):  
Md Rokunuzzaman Robel ◽  
Asif Ahmed ◽  
Akram Alomainy ◽  
Wayne S. T. Rowe
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Performance Improvement ◽  
Direct Contact ◽  
Biomedical Applications ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Conducting Layer ◽  
Electric And Magnetic Field ◽  
Biomedical Diagnosis

The effect of using a superstrate dielectric layer on an on-head matched antenna for biomedical diagnosis applications is investigated. Two on-head matched antennas are considered with different length meandered lines ensuring operation around 0.9 GHz frequency. The first antenna’s conductive radiating structure is in direct contact with the head phantom, whereas the second one utilises a 0.5 mm thick superstrate layer on top of the conducting layer as a buffer. The lateral dimensions of both antennas are held constant at 30 × 30 mm2. The electric and magnetic field distribution is analysed and the power penetration, 50 mm inside the head phantom, is derived from the electromagnetic field surrounding the antennas. Both homogeneous and inhomogeneous head phantoms are considered while evaluating the antennas in terms of their reflection coefficient, current distribution, electric field, magnetic field, specific absorption rate (SAR) and power penetration inside the head. The antennas are fabricated and measured utilizing an inhomogeneous phantom to validate the proposed performance improvement using a superstrate. It is shown that the superstrate antenna achieves a ~8 dB increase in power penetration inside the head phantom along with a 0.0731 W/kg decrease in SAR compared to the antenna without a superstrate.

Convergence Acceleration of Time-Periodic Electromagnetic Field Analysis by the Singularity Decomposition-Explicit Error Correction Method

2010 ◽  
Vol 46 (8) ◽  
pp. 2947-2950 ◽  
Author(s):  
Yasuhito Takahashi ◽  
Tadashi Tokumasu ◽  
Akihisa Kameari ◽  
Hiroyuki Kaimori ◽  
Masafumi Fujita ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Error Correction ◽  
Convergence Acceleration ◽  
Correction Method ◽  
Field Analysis ◽  
Error Correction Method ◽  
Time Periodic

scholarly journals Natural Convection Flow Of An Electrically Conducting Fluid In A Rectangular Cavity Having Internal Energy Sources With Linearly Heated Bottom Wall

2013 ◽  
Vol 32 ◽  
pp. 61-73
Author(s):  
M Obayedullah ◽  
M M K Chowdhury
Keyword(s):  
Natural Convection ◽  
Rectangular Cavity ◽  
Conducting Fluid ◽  
Bottom Wall ◽  
Temperature Fields ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
Rayleigh Numbers

Natural convection flow in a rectangular cavity containing internally heated and electrically conducting fluid has been investigated numerically. The bottom wall of the cavity is linearly heated whereas the top wall is well insulated. The left and right vertical walls are maintained at constant hot and cold temperature respectively.Results have been obtained with respect to Rayleigh numbers and Hartmann numbers. Flow and temperature fields for these cases have been studied. Average Nusselt numbers at hot, cold and linearly heated bottom wall have been calculated. It is found that the temperature, fluid flow and heat transfer strongly depend on internal and external Rayleigh numbers and Hartmann numbers. DOI: http://dx.doi.org/10.3329/ganit.v32i0.13648 GANIT J. Bangladesh Math. Soc. (ISSN 1606-3694) 32 (2012) 61-73    

scholarly journals Influence of electrical-conductivity of walls on magnetohydrodynamic flow and heat transfer of micropolar fluid

2018 ◽  
Vol 22 (Suppl. 5) ◽  
pp. 1591-1600 ◽  
Author(s):  
Milos Kocic ◽  
M. Zivojin-Stamenkovic ◽  
Jelena Petrovic ◽  
Milica Nikodijevic
Keyword(s):  
Heat Transfer ◽  
Electrical Conductivity ◽  
Micropolar Fluid ◽  
Coupling Parameter ◽  
Temperature Fields ◽  
Closed Form Solutions ◽  
Electrically Conducting ◽  
Viscosity Parameter ◽  
Flow And Heat Transfer ◽  
Different Temperatures

In this paper, flow and heat transfer in a horizontal channel with isothermal walls has been investigated. The upper and lower plate have been kept at the two constant different temperatures, micropolar fluid is electrically conducting, while the channel plates have arbitrary electrical-conductivity. Applied magnetic field is perpendicular to the flow and the full MHD model is investigated. The general equations that describe the discussed problem under the adopted assumptions are reduced to ODE and closed-form solutions are obtained. The profiles of velocity, microrotation, induced magnetic and temperature fields in function of electrical-conductivity and the coupling parameter and the spin-gradient viscosity parameter together with electrical-conductivity, are graphically shown and discussed.

Nonlinear Stretching Flow with Thermal Radiation

2010 ◽  
Vol 65 (10) ◽  
pp. 761-770
Author(s):  
Tasawar Hayat ◽  
Rabia Noureen ◽  
Tariq Javed
Keyword(s):  
Radiation Effects ◽  
Temperature Fields ◽  
Porous Space ◽  
Analysis Method ◽  
Electrically Conducting ◽  
Homotopy Analysis ◽  
Layer Flow ◽  
Rotating Boundary ◽  
Nonlinear Stretching ◽  
Stretching Flow

This work concerns with the radiation effects on rotating boundary layer flow of an electrically conducting incompressible fluid over a nonlinear stretching surface. The viscous fluid fills the porous space. The flow is permeated by a constant magnetic field applied in the transverse direction. Two types of temperatures are prescribed to the surface. The resulting problems of velocity and temperature are obtained using the homotopy analysis method (HAM). Convergence of the developed series solutions is carefully checked. Graphical results of the velocity and temperature fields for various values of the parameters of the problems are presented and discussed.

Sign in / Sign up

Export Citation Format

Share Document