• Title, Summary, Keyword: Lorentz force

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Development of Rotary Actuator Including Function of Axial Bearing (축방향 베어링 통합 회전 구동기의 개발)

  • 허진혁;정광석;백윤수
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1083-1086
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    • 2003
  • Recently, the study on bearingless motors which integrate both motor and magnetic bearing function in one stator is very active, as many machines have high rotational speed, high precision, smaller size and lighter weight. In this paper, we propose a novel rotary actuator including function of axial bearing using Lorentz force as a preceding research for development of a bearingless motor. As using Lorentz force, this type has some merits such as the linearity of control force, freedom from flux saturation and high efficiency unlike conventional rotary actuators using a reluctance force. This type is cotrolled independently in levitation and rotational directions respectively. It shows by mathematical expression of levitation force and torque in the proposed rotary actuator. And also, the levitation force is generated by magnetic interaction between the magnetic materials and the rotational torque is generated by Lorentz force. Finally. for verification of this proposed system, a prototype is made and some experiments will be performed in the near future.

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Numerical Investigation of Cross- Flow of a Circular Cylinder Under an Electromagnetic Force (전자기력을 이용한 유동제어에 관한 수치해석적 연구)

  • Kim, Seong-Jae;Lee, Choung-Mook
    • Proceedings of the KSME Conference
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    • pp.148-153
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    • 2001
  • A computational investigation of the effect of the electromagnetic force(or Lorentz force) on the flow behavior around a circular cylinder, a typical model of bluff bodies, is conducted. Two-dimensional unsteady flow computation for $Re=10^2$ is carried out using a numerical method of finite difference approximation in a curvilinear body-fitted coordinate system by solving the momentum equations including the Lorentz force as a body force. The effect of the spatial variations of the Lorentz forcing region and forcing direction along the cylinder circumference is investigated. The numerical results show that the Lorentz force can effectively suppress the flow separation and oscillation of the lift force of the circular cylinder cross-flow, leading to the reduction of the drag.

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Numerical Investigation of Cross-Flow Around a Circular Cylinder at a Low-Reynolds Number Flow Under an Electromagnetic Force

  • Kim, Seong-Jae;Lee, Choung-Mook
    • Journal of Mechanical Science and Technology
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    • v.16 no.3
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    • pp.363-375
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    • 2002
  • The effect of the electromagnetic force (or Lorentz force) on the flow behavior around a circular cylinder is investigated by computation. Two-dimensional unsteady flow computation for Re=10$^2$is carried out using a numerical method of finite difference approximation in a curvilinear body-fitted coordinate system by solving the momentum equations including the Lorentz force as a body force. The effect of spatial variations of the Lorentz forcing region and forcing direction along the cylinder circumference is investigated. The numerical results show that the Lorentz force can effectively suppress the flow separation and oscillation of the lift force of circular cylinder cross-flow, leading to reduction of drag.

MHD (Magnetohydrodynamic) Micropump Using Lorentz Force (로렌츠 힘을 이용한 MHD(Magnetohydrodynamic) 마이크로펌프)

  • 장재성;이승섭
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.11
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    • pp.93-99
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    • 1998
  • We present a novel micropump of which pumping mechanism is based upon MHD (Magnetohydrodynamic) principle. The MHD micropump uses Lorentz force as pumping source. In the MHD micropump, Lorentz force is applied into initially stagnant conducting fluid to drive it in magnetic and electric field to flow in both directions. The performance of the MHD micropump is obtained by measuring the pressure head difference and flow rate as applied voltage changes from 10 to 60 V DC at 0.19 and 0.44 Tesla. The pressure head difference is 18 mm at 38 mA and the flow rate is 63 ${\mu}{\ell}$ /min at 1.8 mA when the inside diameter of inlet/outlet tube is 2 mm and the magnetic flux density is 0.44 Tesla.

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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.

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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    • 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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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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    • 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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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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    • 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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