대한기계학회논문집B (Transactions of the Korean Society of Mechanical Engineers B)

  • 제27권6호
  • /
  • Pages.714-725
  • /
  • 2003
  • /
  • 1226-4881(pISSN)
  • /
  • 2288-5324(eISSN)
대한기계학회 (The Korean Society of Mechanical Engineers)
권호 표지
DOI QR코드

DOI QR Code

2상류용 전류형식 전자기유량계 이론 및 환상류에서의 3차원 가상포텐셜 분포의 수치적 계산

Theory of a Current-Type Electromagnetic Flowmeter for Two-Phase Flow and Numerical Computation of the 3D Virtual Potential Distributions for Annular Flow

  • 오병도 (포항공과대학교 기계공학과) ;
  • 김무환 (포항공과대학교 기계공학과) ;
  • 안예찬 (포항공과대학교 기계공학과)
  • 발행 : 2003.06.01
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

The theory of the current-type electromagnetic flowmeter for a high temporal resolution was developed for two-phase flow measurements. To predict the output of the current-type flowmeter, the three-dimensional virtual potential distribution C and the newly introduced flow pattern coefficient f were derived and computed. The output of flowmeter depends on the liquid conductivity (sensitive to temperature) and flow configurations of the two-phase flow with the sinusoidal excitation over 100 Hz. The flow pattern coefficient was specially devised to separate the dependency on the flow configuration of the two-phase flow from that on the liquid conductivity which can be expressed with the calibration of single-phase flow. Using the finite difference method, the three-dimensional virtual potential distributions were computed for the electrode of finite size. By taking derivative of the virtual potential, the weight functions were evaluated and compared with existing analytic series solution for the point-electrode. There was a reasonable correspondence between the present and existing results. In addition, the flow pattern coefficients were evaluated for annular flows with various film thicknesses, and compared with the experimental results by the impedance spectroscopy. The numerical results agreed well with the experimental data.

키워드

참고문헌

  1. Shercliff, J.A., 1954, 'Relation Between the Velocity Profile and the Sensitivity of Electromagnetic Flowmeters,' J. Applied Physics 25, pp.817-818 https://doi.org/10.1063/1.1721749
  2. Bevir, M.K., 1970, 'The Theory of Induced Voltage Electromagnetic Flowmeters, J. Fluid Mechanics 43, part 3, pp.577-590 https://doi.org/10.1017/S0022112070002586
  3. O'Sullivan, Y.T. and Wyatt, D.G., 1983, 'Computation of Electromagnetic Flowmeter Characteristics from Magnetic Field Data: Ill. Rectilinear Weight Functions,' J. Phys. D: Appl. Phys. 16, pp.1461-1476 https://doi.org/10.1088/0022-3727/16/8/013
  4. Wyatt, D.G., 1986, 'Electromagnetic Flowmeter Sensitivity with Two-Phase Flow,' Int. J. Multiphase Flow 12, No. 6, pp.1009-1017 https://doi.org/10.1016/0301-9322(86)90040-6
  5. Zhang, X.Z., 1997, 'The Effect of the Phase Distribution on the Weight Function of an Electromagnetic Flow Meter in 2D and in the Annular Domain,' Meas. Sci. Tech. 8, pp.1285-1288 https://doi.org/10.1088/0957-0233/8/11/013
  6. Lim, K.W. and Chung, M.K., 1998, 'Relative Errors in Evaluating the Electromagnetic Flowmeter Signal using the Weight Function Method and the Finite Volume Method,' Flow Meas. Inst. 9, pp.229-235 https://doi.org/10.1016/S0955-5986(98)00029-6
  7. Mi, Y., Ishii, M. and Tsoukalas, L.H., 2001, 'Investigation of Vertical Slug Flow with Advanced two-Phase Flow Instrumentation,' Nuclear Eng. Des., 204, pp.69-85 https://doi.org/10.1016/S0029-5493(00)00326-5
  8. Hemp, J., 1991, 'Theory of Eddy Currents in Electromagnetic Flowmeters,' J. Phys. D: Appl. Phys. 24, pp.244-251 https://doi.org/10.1088/0022-3727/24/3/004
  9. Tsiknakis, E., 1988, 'Novel Excitation Waveforms and Signal Processing for Electromagnetic Flowmetering,' Ph.D. Thesis, Univ. of Bradford, UK
  10. Watanabe, M., 1977, 'Noise Compensation in Electromagnetic Flowmeter,' US Patent 4,019,385
  11. Ahn, Y.C., Cha, J.E. and Kim, M.H., 2002, 'A real-Time Measurement of Slug Flow using Electromagnetic Flowmeter with High Frequency Triangular Excitation,' Transactions of the KSME, 26, pp.1570-1577 https://doi.org/10.3795/KSME-B.2002.26.11.1570
  12. Krafft, R., 1993, 'Electromagnetic Flowmeters in Multiphase Flow,' Ph.D. Thesis, Cranfield Univ., UK
  13. Yu, P.L., Zhang, C.Y. and Zmood, R.B., 1997, 'Wide-Band Low-Input-Impedance Trans-Impedance Amplifiers for Instrumentation Application,' Meas. Sci. Tech. 8, pp.1351-1355 https://doi.org/10.1088/0957-0233/8/11/022
  14. Glasstone, S., 1942, 'An Introduction to Electrochemistry,' Van Nostrand, New York
  15. Macdonald, J.S., 1987, Impedance Spectroscopy: Emphasizing Solid Materials and Systems, John Wiley & Sons, New York
  16. Shercliff, J.A. 1962 The Theory of Electromagnetic Flow-Measurement, Cambridge Univ. Press
  17. Thompson, J.F. et al. 1985, 'Numerical Grid Generation: Foundations and Applications,' North-Holland, New York
  18. Lighthill, M.J., 1980, 'Introduction to Fourier Analysis and Generalised Functions,' Cambridge Univ. Press, London