International Journal of Applied Electromagnetics and Mechanics - Volume 49, issue 1

Authors: Farahi Shahri, Mohammad | Hossein Nezhad, Alireza

Article Type: Research Article

Abstract: In this paper, magnetohydrodynamic duct flow and heat transfer behind a square cylinder is studied numerically, using a quasi-two-dimensional (Q2D) model known as SM82. A variety of case studies are performed to signify the effects of the magnetic field intensity and the cylinder size on the total channel wall heat flux of a liquid metal (GaInSn) and the required pumping power. Comparing the results of the present study with the experimental data argued that the present Q2D model yields reliable results. Increasing the magnetic field intensity reduces the total channel wall heat flux. Current case studies show that in order …to maximize heat transfer rate from the heated channel wall, one can use a larger cylinder but at the expense of greater pumping powers. Show more

Keywords: Magnetohydrodynamic, square cylinder size, magnetic field intensity, heat transfer, pumping power

DOI: 10.3233/JAE-150019

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 1, pp. 123-132, 2015

Authors: Zheng, Wenpei | Zhang, Laibin | Su, Yinao | Fang, Taian

Article Type: Research Article

Abstract: Optimization design of alternating current field measurement inducer is done by means of experiments. Two kinds of magnetic inducers, twin coil inducer and U-shaped inducer are designed and a number of experiments are conducted to study influencing parameters of magnetic inducer to the perturbed magnetic field above the crack. Based on the experimental results, the optimization design of magnetic inducer is accomplished. Then quantitative detection performance and detection capacity of the optimized probe is determined by detection experiments on a serious of cracks of different dimentions. The results show that the optimized probe has the capacity of detecting cracks as …small as 3 mm in length. Show more

Keywords: Optimization design, ACFM, magnetic inducer

DOI: 10.3233/JAE-150024

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 1, pp. 133-143, 2015

Authors: Strauch, Ludvik | Pavlin, Mojca | Bregar, Vladimir Boštjan

Article Type: Research Article

Abstract: This paper presents a new design of ferrite core made of ferrite bars positioned in radial geometry. New core design is used in inductive wireless power transfer where the optimal design of ferrite bars was analyzed. Numerical simulations of seven ferrite bars geometries were performed in 3D models using Comsol Multiphysics in terms of the coupling coefficient. Two optimal designs of three and nine ferrite bars geometries were used for parameterization of geometric parameters. Both simulations of three and nine ferrite bars geometries were verified by measurements. Optimal design of nine ferrite bars geometry is proposed for use in wireless …power transfer because of low consumption of ferrite material. Ferrite bars geometry was also used as a magnetic shield to reduce magnetic fields which may interfere with the electronics nearby. Magnetic flux density in ferrite bars is low enough that prevents ferrite bars from the saturation. The angular alignment of optimal design of nine ferrite bars on the transmitter and receiver side was negligible as the difference in the coupling coefficient was 0.13%. Advantages of using optimal design of nine ferrite bars geometry are: high value of the coupling coefficient, low consumption of ferrite material, and reduced weight. Show more

Keywords: Ferrite cores, optimization, finite element method, wireless power transfer

DOI: 10.3233/JAE-150029

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 1, pp. 145-155, 2015

Authors: Bae, Jae-Sung | Hwang, Jai-Hyuk | Roh, Jin-Ho | Yi, Mi-Seon

Article Type: Research Article

Abstract: In the present study, an electromagnetic shock-absorber (EMSA) is proposed for a landing structure of a spaceship. The proposed EMSA consists of a copper and steel combined tube, a piston, permanent magnets, and a steel ring. A magnet fixed on the piston is designed to move through the tube when driven by an external shock. Shock energy is partially dissipated by an eddy current damping force and a friction force generated from the relative motion of the tube and the magnet. Some of the energy is stored in a magnetic spring consisting of two magnets in which their poles act …against each other. To investigate and predict the performance of the proposed EMSA these damping and magnetic forces are simulated and approximated by using an electromagnetic finite element program. Their approximations are verified by experimental results and the numerical model of the proposed EMSA is consequently developed. The proposed EMSA is fabricated and its performance is predicted and verified by the drop test. Show more

Keywords: Electromagnetic shock absorber (EMSA), eddy current damping (ECD), friction, attractive and propulsive magnetic force

DOI: 10.3233/JAE-150033

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 49, no. 1, pp. 157-167, 2015