• 제목/요약/키워드: biot-savart law

검색결과 37건 처리시간 0.02초

Development of a magnetic field calculation program for air-core solenoids which can control the precision of a magnetic field

  • Huang, Li;Lee, Sangjin
    • 한국초전도ㆍ저온공학회논문지
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    • 제16권4호
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    • pp.53-56
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    • 2014
  • A numerical method of magnetic field calculation for the air-core solenoid is presented in this paper. In application of the Biot-Savart law, the magnetic field induced from the source current can be obtained by a double integration ormula. The numerical method named composite Simpson's rule for the integration is applied to the program and the adaptive quadrature method is used to adjust the step size in the calculation according to the precision we need. When the target point is in the solenoid and the intergrand's denominator may be zeroin the process of calculation, the method sill can provide an appropriate result. We have developed a program which calculates the magnetic field with at least 1ppm precision and named it as rzBI() to implement this method. The method has been used in the design of an MRI magnet, and the result show it is very flexible and convenient.

Data processing technique for data measured in MO image measurement system

  • Lee, Wongi;Lee, Hyoyeon;Yoo, Jaeun;Youm, Dojun
    • 한국초전도ㆍ저온공학회논문지
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    • 제15권1호
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    • pp.25-28
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    • 2013
  • We report processing technique in the MO image measurement system. Calibration procedure is not only considered to perpendicular field but also in-plane field. Current density and field profiles are obtained by Biot-savart law and inversion method. We show example of $(Gd,Y)_1Ba_2Cu_3O_{7-{\delta}}-BaZrO_3$ film that have tilted nano rod pinning centers about $13^{\circ}$ from the c-axis.

입자와법에 의한 급 출발하는 타원형 실린더 주위 유동해석 (Numerical study of Flow around Impulsively Started Elliptic Cylinder using Vortex Particle Method)

  • 주남수;이상환
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.1601-1606
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    • 2004
  • In this paper, the unsteady behavior of the viscous flow field past an impulsively started elliptic cylinder is studied numerically. In order to analyze flow field, we introduce vortex particle method. The vorticity transport equation is solved by fractional step algorithm which splits into convection term and diffusion term. The convection term is calculated with Biot-Savart law, the no-through boundary condition is employed on solid boundaries. The diffusion term is modified based on the scheme of particle strength exchange. The particle redistributed scheme for general geometry is adapted. The flows around an elliptic cylinder are investigated for various attack angles at Reynolds number 200. The comparison between numerical results of present study and experimental data shows good agreements.

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Flow Past Airfoil Moving Reciprocally in a Channel by Vortex Method

  • Ro Ki-Deok
    • Journal of Mechanical Science and Technology
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    • 제20권8호
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    • pp.1248-1255
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    • 2006
  • The velocity and pressure fields of a ship's propulsion mechanism of the Weis-Fogh type, in which a airfoil moves reciprocally in a channel, are studied in this paper using the advanced vortex method. The airfoil and the channel are approximated by a finite number of source and vortex panels, and the free vortices are introduced from the body surfaces. The viscous diffusion of fluid is represented using the core-spreading model to the discrete vortices. The velocity is calculated on the basis of the generalized Biot-Savart law and the pressure field is calculated from integrating the equation given by the instantaneous velocity and vorticity fields. Two-dimensional unsteady viscose flows of this propulsion mechanism are numerically clarified, and the calculated results agree well with the experimental ones.

입자와법에 의한 급 출발하는 타원형 실린더 주위 유동해석 (Numerical Study of Flow Around Impulsively Started Elliptic Cylinder Using Vortex Particle Method)

  • 이상환;주남수
    • 대한기계학회논문집B
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    • 제28권7호
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    • pp.809-817
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    • 2004
  • In this paper, the unsteady behavior of the viscous flow field past an impulsively started elliptic cylinder is studied numerically. In order to analyze flow field, we introduce vortex particle method. The vorticity transport equation is solved by fractional step algorithm which splits into convection term and diffusion term. The convection term is calculated with Biot-Savart law, the no-through boundary condition is employed on solid boundaries. The diffusion term is modified based on the scheme of particle strength exchange. The particle redistributed scheme for general geometry is adapted. The flows around an elliptic cylinder are investigated for various attack angles at Reynolds number 200. The comparison between numerical results of present study and experimental data shows good agreements.

실험을 통한 풍력발전기의 후류구조 분석 (Wake Analysis of the HAWT by Windtunnel Test)

  • 박지웅;김호건;신형기;이수갑
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 춘계학술대회
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    • pp.273-276
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    • 2006
  • To generate electricity from wind energy, wind turbine generally has a rotor blade. Since this rotor blade is a kind of the rotating machinery, the wake from the rotor is very Important role in the side of the aerodynamic performances. Thus the study about wake is essential to analyze wind turbine aerodynamics. In this study wake characteristics are analyzed by hot-wire probe in the K.A.F.A(Korea Air Force Academy) wind tunnel. It is possible to analyze the wake characteristics by hot-wire probe from acquiring the velocity fluctuations at given positions in the flow. This velocity data are arranged by trigger signal at same azimuth of the blade in periodic manner of the rotor blade. From this various wake characteristics are found : radial and axial position of the tip vortex, vortex core characteristics in the flow etc.

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Field gradient calculation of HTS double-pancake coils considering the slanted turns and the splice

  • Baek, Geonwoo;Kim, Jinsub;Lee, Woo Seung;Song, Seunghyun;Lee, Onyou;Kang, Hyoungku;Ko, Tae Kuk
    • 한국초전도ㆍ저온공학회논문지
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    • 제19권1호
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    • pp.51-55
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    • 2017
  • To obtain Nuclear Magnetic Resonance (NMR) measurement of membrane protein, an NMR magnet is required to generate high intensity, homogeneity, and stability of field. A High-Temperature Superconducting (HTS) magnet is a promising alternative to a conventional Low-Temperature Superconducting (LTS) NMR magnet for high field, current density, and stability margin. Conventionally, an HTS coil has been wound by several winding techniques such as Single-Pancake (SP), Double-Pancake (DP), and layer-wound. The DP winding technique has been frequently used for a large magnet because long HTS wire is generally difficult to manufacture, and maintenance of magnet is convenient. However, magnetic field generated by the slanted turns and the splice leads to field inhomogeneity in Diameter of Spherical Volume (DSV). The field inhomogeneity degrades performance of NMR spectrometer and thus effect of the slanted turns and the splice should be analyzed. In this paper, field gradient of HTS double-pancake coils considering the slanted turns and the splice was calculated using Biot-Savart law and numerical integration. The calculation results showed that magnetic field produced by the slanted turns and the splice caused significant inhomogeneity of field.

Magnetic Field Gradient Optimization for Electronic Anti-Fouling Effect in Heat Exchanger

  • Han, Yong;Wang, Shu-Tao
    • Journal of Electrical Engineering and Technology
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    • 제9권6호
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    • pp.1921-1927
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    • 2014
  • A new method for optimizing the magnetic field gradient in the exciting coil of electronic anti-fouling (EAF) system is presented based on changing exciting coil size. In the proposed method, two optimization expressions are deduced based on biot-savart law. The optimization expressions, which can describe the distribution of the magnetic field gradient in the coil, are the function of coil radius and coil length. These optimization expressions can be used to obtain an accurate coil size if the magnetic field gradient on a certain point on the coil's axis of symmetry is needed to be the maximum value. Comparing with the experimental results and the computation results using Finite Element Method simulation to the magnetic field gradient on the coil's axis of symmetry, the computation results obtained by the optimization expression in this article can fit the experimental results and the Finite Element Method results very well. This new method can optimize the EAF system's anti-fouling performance based on improving the magnetic field gradient distribution in the exciting coil.

Study on the shape design of field coil in HTS generator considering stress condition

  • Jo, Young-Sik;Lee, Ju-Min;Hong, Jung-Pyo;Lee, Ju;Sohn, Myung-Hwan;Kwon, Young-Kil;Ryu, Kang-Sik
    • 한국초전도학회:학술대회논문집
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    • 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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    • pp.257-261
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    • 2000
  • The value of I$_c$(critical current) in HTS (High Temperature Superconductor) tape has a great influence on B${\bot}$(vertical field). Therefore, in shape design of field coil for the HTSG(High Temperature Superconducting Generator), a method to reduce the B${\bot}$ should be considered in order to maintain the stability and substantial improvement on the performance. On the basis of the magnetic field analysis, this paper deals with various field coil shape according to the iron plate to obtain small B${\bot}$ by using Biot-Savart's law, image method and 2D FEA(2 Dimensional Finite Element Analysis) considering the stress condition of HTS. Moreover, the analysis is verified by comparison with experimental results. And also this paper presents the advanced model by using 3D FEA, in which flux density at armature is calculated in 5kVA class HTSG.

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SQUID 2차미분기 성능 평가용 균일자기장 및 2차 미분 자기장 발생원 (Sources of uniform and 2nd-order gradient fields for testing SQUID performance)

  • 이순걸
    • Progress in Superconductivity
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    • 제8권2호
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    • pp.152-157
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    • 2007
  • Uniaxial square Helmholtz coils for testing SQUID sensors were designed and their field distributions were calculated. Optimum parameters for maximizing the uniform region in the Helmholtz mode were obtained for different uniformity tolerances. The coil system consists of 2 pairs of identical square loops, a Helmholtz pair for generating uniform fields and the other for the 2nd-order gradient fields in combination with the Helmholtz pair. Full expressions of the axial component of the field were calculated by using Biot-Savart's law. To understand the behavior of the field near the coil center, analytical expressions were obtained up to the 4th-order in the midplane and along the coil axis. The Helmholtz condition for generating uniform fields was calculated to be $d/{\alpha}=0.544505643$, where 2d is the inter-coil distance and $2{\alpha}$ is the side length of the coil square. Maximized uniform range can be obtained for a given nonuniformity tolerance by choosing $d/{\alpha}$ slightly lower than the Helmholtz condition. The pure second-order gradient field can be generated by subtracting the Helmholtz field from the field of the 2nd pair with equal magnitudes of the center fields of the two pairs. The coil system is useful for testing balance and sensitivity of SQUID gradiometers.

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