• Title/Summary/Keyword: Lorentz

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Numerical analysis of the attitude stability of a charged spacecraft in the Pitch-Roll-Yaw directions

  • Abdel-Aziz, Yehia A.;Shoaib, Muhammad
    • International Journal of Aeronautical and Space Sciences
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    • v.15 no.1
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    • pp.82-90
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    • 2014
  • In this paper, the effect of Lorentz force on the stability of attitude orientation of a charged spacecraft moving in an elliptic orbit in the geomagnetic field is considered. Euler equations are used to derive the equations of attitude motion of a charged spacecraft. The equilibrium positions and its stability are investigated separately in the pitch, roll and yaw directions. In each direction, we use the Lorentz force to identify an attitude stabilization parameter. The analytical methods confirm that we can use the Lorentz force as a stabilization method. The charge-to-mass ratio is the main key of control, in addition to the components of the radius vector of the charged center of the spacecraft, relative to the center of mass of the spacecraft. The numerical results determine stable and unstable equilibrium positions. Therefore, in order to generate optimum charge, which may stabilize the attitude motion of a spacecraft, the amount of charge on the surface of spacecraft will need to be monitored for passive control.

Analysis of The Liquid Metal Flow in the Rectangular Duct of an Electromagnetic Pump (전자기펌프의 사각덕트 내의 유동특성 해석)

  • Kwon, J.T.;Lim, H.J.;Kim, C.E.;Kim, S.H.;Kim, M.S.;Jeon, M.H.
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3110-3115
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    • 2007
  • The effect of Lorentz force(Electromagnetic force) on the liquid metal flow has been investigated. The flow velocity has been calculated by treating the Lorentz force as a source term in the Navier-Stokes equation. The liquid metal flow in the rectangular duct of an electromagnetic pump was analyzed with the Lorentz force varied.

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Development of Forming Equipment Using Electromagnetic Lorentz Force (전자기 로렌쯔력을 이용한 성형장비 개발)

  • Lee, H.M.;Ku, J.K.;Noh, H.G.;Song, W.J.;Ku, T.W.;Kang, B.S.;Kim, J.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.10a
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    • pp.313-317
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    • 2009
  • Electromagnetic forming(EMF) is a high-velocity forming process which uses electromagnetic Lorentz force. Advantages of this forming technique are improved formability, reduction in wrinkling, non-contact forming and applications of various forming process. But the application of electromagnetic forming technique is still limited in industry. Thus for continuous research and development of technique based on experiments, develop the forming equipment and carry out the forming experiments for validation of forming equipment.

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Development of Sheet Metal Forming Apparatus Using Electromagnetic Lorentz Force (전자기 로렌쯔력을 이용한 박판성형 장비 개발)

  • Lee, H.M.;Kang, B.S.;Kim, J.
    • Transactions of Materials Processing
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    • v.19 no.1
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    • pp.38-43
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    • 2010
  • Electromagnetic forming (EMF) method is one of high-velocity forming processes, which uses electromagnetic Lorentz force. Advantages of this forming technique are summarized as improvement of formability, reduction in wrinkling, non-contact forming and applications of various forming process. In this study, the EMF apparatus is developed. It is designed to be stored in 10 capacitors connected in parallel, each with a capacitance of $50{\mu}F$ and maximum working voltage of 5kV. The system has capacitance of $500{\mu}F$ and maximum stored energy of 6.25kJ. And EMF experiments are carried out to verify the feasibility of the EMF apparatus, which has enough forming force from the results of EMF experiment. In addition, peak current carrying a forming coil is predicted from theoretical background, and verified the predicted value compared with experimental value using the current measurement equipment. Consequently, EMF apparatus developed in this study can be applied to various EMF researches for commercialization.

Lorentz Force Type Self-Bearing Motor with 2-Pole Flux Distribution for Levitation and 4-Pole for Rotation (부상용 2극과 회전용 4극 자속 분포를 갖는 로렌쯔형 자기 부상 모터)

  • ;Yohji Okada
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11a
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    • pp.482-487
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    • 2001
  • This paper introduces a Lorentz force type four-pole self-bearing motor, where the new pole arrangement of a stator is intended to function both as a synchronous PM motor and as a magnetic bearing. The Lorentz force type has some good points such as linearity of control force, freedom from flux saturation, and high efficiency unlike conventional self-bearing motors. Mathematical expressions of torque and radial force are derived to show that they can be separately controlled regardless of rotational speed and time. To verify the proposed theory, a prototype is made, where a ring-shape outer is actively controlled in two radial directions while the other motions are passively stable supposing the radial stability. Through some experiments, it is shown that the proposed scheme can provide high capability and feasibility for a small high-speed self-bearing motor.

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Angular Self-Sensing Algorithm of Lorentz Force Type Integrated Motor-Bearing System (로렌츠형 자기베어링 내장 전동기의 회전각 추정기)

  • Jeon, Han-Wook;Park, Sung-Ho;Park, Young-Jin;Lee, Chong-Won
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.852-857
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    • 2004
  • In this paper, an angular self-sensing algorithm is proposed and implemented to a Lorentz force type integrated motor-bearing system. It is based on the principle that the flux linkages of stator windings, calculated from the voltage and torque control current, are the functions of the rotor angle. The tracking angular position error is proven to vanish using the Lyapunov stability method, and the experimental results show that the initial error decays within about 5 seconds. It is found that the resolution of the algorithm remains about 1º over the speed range of 100 to 1000 rpm.

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Liquid Metal Flow Analysis for Electromagnetic Pump Design (액체금속 이송용 전자기 펌프 설계를 위한 유동해석)

  • Kwon, Jeong-Tae;Lim, Hyo-Jae;Kim, Seo-Hyun;Nam, Taek-Hun;Kim, Chang-Eob
    • Proceedings of the SAREK Conference
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    • 2008.11a
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    • pp.137-144
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    • 2008
  • The effect of Lorentz force(Electromagnetic force) on the liquid metal flow has been investigated. The flow velocity has been calculated by treating the Lorentz force as a source term in the Navier-Stokes equation. The liquid metal flow in the annular duct of an electromagnetic pump was analyzed with the Lorentz force varied.

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The Analysis of Liquid Metal Flow Characteristics in the Annular Passage of an Electromagnetic Pump

  • Kim, Chang-Eob;Jeon, Mun-Ho;Kwon, Jeong-Tae;Lim, Hyo-Jae;Lee, Suk-Won
    • Journal of Electrical Engineering and Technology
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    • v.5 no.2
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    • pp.270-275
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    • 2010
  • An electromagnetic pump using a tubular induction motor (TLIM) has been proposed to pump liquid metal fluids. TLIM has been designed for liquid metal flow systems with a motor with a thrust force of 40~77[N]. The flow characteristics have been investigated by solving the Navier-Stokes equation, where the Lorentz force was included simply by considering it as a constant in the Navier-Stokes equation. A wood metal was chosen to simulate the liquid metal. The effect of Lorentz force on the flow rate was investigated. An experiment was conducted and its results were compared with those of the simulation. The simulation result showed an overestimation of about 17% compared with the experimental one.

A Study on the Novel Micro Mixer for the Application of LOC (LOC적용을 위한 새로운 마이크로믹서의 연구)

  • Choi, Bum-Kyoo;Lee, Seung-Hyeon;Kang, Ho-Jin
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.6
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    • pp.143-149
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    • 2008
  • This paper presents the results of the study on the novel micro mixer. Existing micro mixer is classified as active mixing and passive mixing by the mixing principles. Both mixing principles have problems. For solving these problems, this research has developed the novel micro mixers based on a totally different principle compared with former mixers. They not only have a simpler structure than former ones but also are able to achieve high mixing efficiency in spite of low power consumption due to using Lorentz Force. In addition, they are designed to increase the efficiency of mixing by changing the rotating direction of fluid with a polar switching circuit. Driving forces of the mixer are Lorentz force and a moving force of fluid due to electrophoresis. Because the efficiency of mixer is affected by electrode shape, several models have been made. The computer simulation has been made to estimate the efficiency of each mixer.

Study of micro-plastics separation from sea water with electro-magnetic force

  • Nomura, Naoki;Mishima, Fumihito;Nishijima, Shigehiro
    • Progress in Superconductivity and Cryogenics
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    • v.23 no.3
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    • pp.10-13
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    • 2021
  • The method of removing micro-plastics from sea water has been developed using electro-magnetic force. Plastics are difficult to decompose and put a great load on the marine environment. Especially a plastic with a size of 5 mm or less is defined as micro-plastic and are carried by ocean currents over long distances, causing global pollution. These are not easily decomposed in the natural environment. The Lorentz force was generated in simulated sea water and its reaction force was applied to the micro-plastic to control their motion. Lorentz force was generated downward and the reaction force to the plastics was upward. The plastic used in the experiment was polystyrene with a diameter of 6 mm, and the density was 1.07 g/cm3. The polystyrene sphere levitated at the current density of 0.83 A/cm2 and the external field of 0.87T. The particle trajectory calculation was also made to design separation system using superconducting magnet.