Papers by Keyword: Electromagnetic Field (EMF)

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Authors: Xiang Jie Wang, Jian Zhong Cui, Hai Tao Zhang
Abstract: The rules of the distribution of magnetic field were carried out by numerical simulation. The distribution of magnetic field was got, and the effects of current intensity and frequency on the distribution of magnetic field were analyzed by constructing three-dimensional finite element model and using ANSYS software which is a kind of commercial FEM analysis software. The results show that the intensity of magnetic field is proportional to current intensity, magnetic field is mainly localized in the surface region of liquid melt and there is a notable edge effect in the corner.
Authors: Xiang Jie Wang, Gang Sun, Li Juan Wang, Peng Wei Li, Jian Zhong Cui
Abstract: Aluminum is the richest metallic element in the earth, the ingots cast by DC casting process are usually extruded into aluminum bars. When the final products do not require high strength, this process appears to be low efficiency and high cost. We try to design a new technology to cast aluminum bar by horizontal direct chill (HDC) casting process directly. An electromagnetic field is applied during the horizontal continuous casting of 6061 aluminium bar with a diameter of 30mm. The experimental results show the asymmetry of the sump can be overcome by electromagnetic field. Ingot with good upper and lower surface quality is obtained. The structure of ingot is refined and the angle between growth direction and horizontal direction becomes small with increasing casting speed.
Authors: Xiang Jie Wang, Jian Zhong Cui, Hai Tao Zhang
Abstract: On the basis of conventional hot-top casting and Casting, Refining and Electromagnetic process, a lower frequency electromagnetic field was applied during the hot-top casting process. A comprehensive two-dimensional (2-D) mathematical model based upon the ANSYS and FLUENT has been developed for the computation of the electromagnetic field, solidification, fluid flow and heat transport during conventional and low frequency electromagnetic hot-top casting processes. The results show that there is a good agreement between the experimental results and calculated results.
Authors: Yu Ping Sun, Kai Kang
Abstract: This paper has designed and produced an ac/dc permanent magnet synchronous generator which used in ac/dc power system independent. The design of the motor and the basic properties of the motor is discussed in this paper. In order to reduce the voltage regulation of the permanent magnet generator, installation of a soft magnetic material in the generator permanent magnetic pole tail, by increasing the motor load quadrature axis reactance drop improves motor voltage regulation. A prototype is made and test analysis, the generator voltage regulation rate of small, high efficiency, and the simulation result is consistent with the basic design to achieve the requirements.
Authors: Jiang Hua Deng, Yi Ming Zheng, Chao Tang, Yan Ran Zhan
Abstract: The analysis of charge circuit and discharge circuit is a key part in the theoretical study of electromagnetic riveting electromagnetic field. Numerical simulation was used to establish the charge circuit model and the discharge circuit model which was an electric circuit-magnetic circuit coupling process by ANSYS. The simulation of charge circuit shows that the development of the charge current over time is an exponential descending change and that of the charge voltage over time is an exponential ascending change. And, the simulation of discharge circuit indicates that the driver is mainly subjected to axial magnetic force, whose distribution is non-uniform along the radial direction of driver, and the maximum value of axial magnetic force locates in about half of the driver radius.
Authors: Keita Hada, Masanori Kunieda
Abstract: In wire electrical discharge machining (WEDM), discharge current is one of the important factors which determine the machining properties, such as machining speed or machining accuracy. Previously developed machining simulators of WEDM, however, neglected the influence of workpiece conditions on the discharge current. Hence, this study developed a simulation tool for analyzing the discharge current in WEDM, where the electromagnetic field analysis around the wire electrode was coupled with the analysis of the equivalent circuit of the entire pulse generator circuit. The simulation results showed that, under the same pulse voltage and duration, the discharge current may change depending on the electromotive force which is determined by material properties, geometry and size of workpiece and wire electrode. In this study, the discharge current was calculated with different workpiece thicknesses. In addition, the discharge current was measured and compared with the calculation results in order to show the validity of the simulation tool.
Authors: Lin Suo Zeng, Li Zhu Sun
Abstract: Low speed high torque direct drive motor has been widely applied in various industries. However, operation faults occur frequently due to the complex working conditions of the motor, especially the locked-rotor fault. Therefore, it is necessary to do deeply research in this case of the electromagnetic field and the temperature field distribution of the motor. Taking a 5kW, 10-pole tangential type Low speed high torque permanent magnet (PM) motor for example, based on field-circuit coupled finite element method, 2-D motor field, circuit and motion coupling is achieved. On this basis, the temperature field of the motor is analyzed. Finally the results which are consistent with the actual project are obtained.
Authors: Zhi Ding Ying, Yu Long Fang, Xin Fu Xu, Wei Sun, Yang Chu
Abstract: To analyze the variation of electromagnetic field distribution, a mathematical model of the eddy current brake (ECB) is established and the two-dimensional simulation and three-dimensional simulation are comparatively analyzed. Then the curves of the braking torque of the ECB at different speeds are obtained by the simulations. The characteristics of two-dimensional and three-dimensional simulation of the electromagnetic field of the ECB are summarized by contrasted comparative curves between simulation date and test date. The analysis is helpful to optimizing the application of electromagnetism by using software.
Authors: Pi Cui Zhang, Wei He, Liu Ling Wang, Li Feng Ma
Abstract: t is generally needed to know precisely spatial distribution of lightning electromagnetic fields in the lightning protection measurements. Therefore, the research on the lightning electromagnetic field is of practical significance. In this paper, the Maxwell equations were used to calculate and analyze the spatial distribution of lightning electromagnetic fields surrounding lightning current. And the expressions of lightning current electromagnetic fields were deduced under the assumption that the earth was under the condition of perfect conductor. The spatial distributions of the components of lightning electromagnetic fields have been plotted by Matlab. The results would provide fundamental theory for the research of lightning electromagnetic field and lightning protection measurements.
Authors: Ji Shan Li, Ri Dong Liao
Abstract: The electromagnetic field and the heat generation rate distribution in the semi-infinite body which is heated by the induction coil, are obtained by solving the Maxwell equations through the analytical method. The impacts of the air gap width, induction coil width, current density and current frequency on the heat generation rate distribution in the workpiece are studied. The results show that the heat generation rate in the workpiece is in direct proportion to the square of the eddy current density and the square of the induction coil width. The heat generation rate follows the exponential attenuation law with the increase of the air gap width. The current density has effects on both the maximum heat generation and the heat generation distribution. When the effect of the air gap is neglected, the higher the current frequency, the larger the maximum heat generation rate. However, when the effect of the air gap is considered, the maximum heat generation rate will increase with the augment of the frequency when the frequency is less than the critical frequency and decrease with the augment of the frequency when the frequency is larger than the critical frequency, which is firstly reported in the paper. Moreover, the higher the current frequency, the heavier the heat generation rate attenuation in the workpiece.
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