• Title/Summary/Keyword: Lorentz Model

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CAE Analysis of $SF_6$ Arc Plasma for a Gas Circuit Breaker Design (가스차단기 최적설계를 위한 $SF_6$ 아크 플라즈마 CAE 해석)

  • Lee Jong C.;Ahn Heui-Sub;Kim Youn J.
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.365-368
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    • 2002
  • The design of industrial arc plasma systems is still largely based on trial and error although the situation is rapidly improving because of the available computational power at a cost which is still fast coming down. The desire to predict the behavior of arc plasma system, thus reducing the development cost, has been the motivation of arc research. To interrupt fault current, the most enormous duty of a circuit breaker, is achieved by separating two contacts in a interruption medium, $SF_{6}$ gas or air etc., and arc plasma is inevitably established between the contacts. The arc must be controlled and interrupted at an appropriate current zero. In order to analyze arc behavior in $SF_{6}$ gas circuit breakers, a numerical calculation method combined with flow field and electromagnetic field has been developed. The method has been applied to model arc generated in the Aachen nozzle and compared the results with the experimental results. Next, we have simulated the unsteady flow characteristics to be induced by arcing of AC cycle, and conformed that the method can predict arc behavior in account of thermal transport to $SF_{6}$ gas around the arc, such as increase of arc voltage near current zero and dependency of arc radius on arc current to maintain constant arc current density.

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Dynamic Characteristics of Composite Plates Subjected to Electromagnetic and Thermal Fields (자기장 및 열하중을 받는 복합재료 판의 동적 특성)

  • Kim, Sung-Kyun;Lee, Kune-Woo;Moon, Jei-Kwon;Choi, Jong-Woon;Kim, Young-Jun;Park, Sang-Yun;Song, Oh-Seop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.6
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    • pp.536-545
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    • 2011
  • Structural model of laminated composite plates based on the first order shear deformable plate theory and subjected to a combination of magnetic and thermal fields is developed. Coupled equations of motion are derived via Hamilton's principle on the basis of electromagnetic equations (Faraday, Ampere, Ohm, and Lorentz equations) and thermal ones which are involved in constitutive equations. In order to reveal the implications of a number of geometrical and physical features of the model, free vibration of a composite plate immersed in a transversal magnetic field and subjected to a temperature gradient is considered. Special coupling effects between the magnetic-thermal-elastic fields are revealed in this paper.

Calculation of Electrodynamic Repulsion Force in Molded Case Circuit Breakers Using the 3-D Finite Element Analysis (3차원 유한요소 해석을 이용한 배선용 차단기의 전자반발력 계산)

  • Kim, Yong-Gi;Park, Hong-Tae;Song, Jung-Chun;Seo, Jung-Min;Degui, Chen
    • Proceedings of the KIEE Conference
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    • 2003.10b
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    • pp.137-140
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    • 2003
  • To the optimization design of molded case circuit breakers(MCCBs), it is necessary and important to calculate the electro-dynamic repulsion force acting on the movable conductor. With 3-D finite element nonlinear analysis, according to the equations among current-magnetic field-repulsion force and taking into account the ferromagnet, contact bridge model is introduced to simulate the current constriction between contacts, so Lorentz and Holm force acting on the movable conductor and contact, respectively, can be integrated to calculate. Coupled with circuit equations, the opening time of movable contact also can be obtained using iteration with the restriction of contact force. Simulation and experiment for repulsion forte and opening time of five different configuration models have been investigated. The results indicate that the proposed method is effective and capable of evaluating new design of contact systems in MCCBs.

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Fundamental Aspects of the Unbalance Condition for the Forces involved in Rail Gun Recoil

  • Banerjee, Arindam;Radcliffe, P.J.
    • Journal of international Conference on Electrical Machines and Systems
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    • v.3 no.3
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    • pp.317-324
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    • 2014
  • The forces involved in the firing of the electromagnetic rail gun may be analyzed from Amperian, Maxwellian and Einsteinian approaches. This paper discusses these different paradigms with regard to rail gun performance modeling relating to the generation and balance of the forces caused by the currents and their induced magnetic fields. Recent experimental work on model rail guns, where the armature is held static, shows very little recoil upon the rails, thereby indicating a possible violation of Newton's Third Law of Motion. Dynamic testing to show this violation, as suggested by the authors in an earlier paper, has inherent technical difficulties. A purpose-built finite element C/C++ simulator that models that suspended rail gun firing action shows a net force acting upon the entire rail gun system. A new effect in physics, universal in scope, is thus indicated: a current circulating in an asymmetric and rigid circuit causes a net force to act upon the circuit for the duration of the current. This conclusion following from computer simulation based upon Maxwellian electrodynamics as opposed to the more modern relativistic quantum electrodynamics needs to be supported by unambiguous experimental validation.

Numerical Study on a Diffused-mode Arc within a Vacuum Interrupter (진공차단부에서 발생하는 확산형 아크 수치해석)

  • Cho, S.H.;Hwang, J.H.;Lee, J.C.;Choi, M.J.;Kwon, J.R.;Kim, Y.J.
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.479-482
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    • 2008
  • In order to more closely examine the vacuum arc phenomena, it is necessary to predict the magnetohydrodynamic (MHD) characteristics by the multidisciplinary numerical modeling, which is coupled with the electromagnetic and hydrodynamic fields, simultaneously. In this study, the thermal-fluid characteristics of high current vacuum arcs were calculated by a commercial multiphysics package, ANSYS, in order to obtain Joule heat, Lorentz force and the interactions with flow variables. We assumed the diffused-mode arc within an AMF vacuum interrupter. It was found with four different currents that the temperature distributions on the anode surface are diffused uniformly without concentration in 7kA for both types (cup and coil-type). But the arc plasma transition and an increase of thermal flux density for increasing the applied current have caused the change of temperature distributions on the anode surface. We should need further studies on the two-way coupling method and radiation model for arc plasmas in order to accomplish the advanced analysis method for multiphysics.

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A Numerical Study on the Internal Flow Characteristics and Pumping Performance of a Piezoelectric-based Micropump with Electromagnetic Resistance (전자기 저항을 이용한 압전 구동방식 마이크로 펌프의 내부유동 특성과 펌핑성능에 대한 수치해석적 연구)

  • An, Yong-Jun;Oh, Se-Hong;Kim, Chang-Nyung
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.10
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    • pp.84-92
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    • 2010
  • In this study a numerical analysis has been conducted for the flow characteristics and pumping performance of a piezoelectric-based micropump with electromagnetic resistance exerted on electrically conducting fluid. Here, electromagnetic resistance is alternately applied at the inlet and outlet with alternately applied magnetic fields in association with the reciprocal membrane motion of the piezoelectric-based micropump. A model of Prescribed Deformation is used for the description of the membrane motion. The internal flow characteristics and pumping performance are investigated with the variation of magnetic flux density, tube size, displacement of membrane and the frequency of the membrane. It turns out that the current micropump has a wide range of pumping flow rate compared with diffuser-nozzle based micropumps.

Study on Design Parameters that Affect the Forming Force of the Magnetic Pulse Forming Device (자기 펄스 성형장치의 성형력에 영향을 미치는 설계 파라미터에 관한 연구)

  • Lee, Man Gi;Yi, Hwa Cho;Kim, Jin Ho
    • Journal of the Korean Magnetics Society
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    • v.25 no.3
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    • pp.79-82
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    • 2015
  • The design parameter study about the magnetic pulse forming is performed using finite element analysis with MAXWELL. The first case of design parameters is about the initial charging voltage and the capacitance and the second case of design parameters are about the winding turns and the spacing of electromagnetic coil. The 3D finite element model of electromagnetic forming system is created and the magnetic force is calculated. The effects of design parameters on the magnetic forming force are investigated.

The Braking Torque Analysis of Eddy Current Brake with the Use of Coulomb′s law and the Method of Image (쿨롬 법칙과 영상법을 이용한 와전류 브레이크의 제동토크 해석)

  • Lee, Gap-Jin;Park, Gi-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.50 no.9
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    • pp.431-437
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    • 2001
  • Since the eddy current problem usually depends on the geometry of the moving conductive sheet and the shape of the pole projection area, there is no general method to find out its analytical solution. The analysis of the eddy current in a rotating disk is performed in the case of time-invariant field to find its analytical solution. As a method to solve the eddy current problem, the concept of the Coulomb charge and image method are proposed with the consideration of the boundary condition. Firstly, the line charge is obtained from the volume charge generated in the rotating disk and Coulomb's law is applied. Secondly, the finite disk radius is considered by introducing an imaginary eddy current to satisfy the boundary condition that the radial component of the eddy current is zero at the edge of the relating disk. Thirdly, the braking torque is calculated by applying Lorentz force law. Finally, the computed braking torque is compared with the measured one As a result, it can be said that the proposed model presents fairly accurate results in a low angular velocity range although a large error is observed as the angular velocity of the disk increases.

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Analysis of 3-Dimensional Magnetic Field Distribution in CPM Considering Magnetization Vector Distribution and Design of CPM (자화 벡터 분포를 고려한 CPM의 3차원 자계 분포 해석 및 설계)

  • Lee, Cheol-Gyu;Gwon, Byeong-Il;Park, Seung-Chan;U, Gyeong-Il
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.10
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    • pp.545-553
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    • 2002
  • This paper is about the analysis of 3-dimensional magnetic field distribution in CPM(Convergence Purity Magnet) considering magnetization vector and the optimum design of CPM. The magnetization vector of CPM is obtained using 2-dimensional magnetization FEA(Finite Element Analysis) coupled with Priesach model. Using this magnetization vector of CPM, we analysed the 2-dimensional and 3-dimensional magnetostatic field of CPM and know that these analysis results are not equal. From experimental result, we know that the 3-dimensional analysis is accurate because the magnetic field distribution in CPM cannot be considered correctly by 2-dimensional analysis because of the shape of CPM. Finally, the optimum designing of CPM which control accurately the electron beam deflection in CRT(Cathode Ray Tube) was possible using 3-dimensional magnetic field analysis result.

Dynamic vibration response of functionally graded porous nanoplates in thermal and magnetic fields under moving load

  • Ismail Esen;Mashhour A. Alazwari;Khalid H. Almitani;Mohamed A Eltaher;A. Abdelrahman
    • Advances in nano research
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    • v.14 no.5
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    • pp.475-493
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    • 2023
  • In the context of nonclassical nonlocal strain gradient elasticity, this article studies the free and forced responses of functionally graded material (FGM) porous nanoplates exposed to thermal and magnetic fields under a moving load. The developed mathematical model includes shear deformation, size-scale, miscorstructure influences in the framework of higher order shear deformation theory (HSDT) and nonlocal strain gradient theory (NSGT), respectively. To explore the porosity effect, the study considers four different porosity models across the thickness: uniform, symmetrical, asymmetric bottom, and asymmetric top distributions. The system of quations of motion of the FGM porous nanoplate, including the effects of thermal load, Lorentz force, due to the magnetic field and moving load, are derived using the Hamilton's principle, and then solved analytically by employing the Navier method. For the free and forced responses of the nanoplate, the effects of nonlocal elasticity, strain gradient elasticity, temperature rise, magnetic field intensity, porosity volume fraction, and porosity distribution are analyzed. It is found that the forced vibrations of FGM porous nanoplates under thermal and live loads can be damped by applying a directed magnetic field.