Issue
Korean Journal of Chemical Engineering,
Vol.20, No.4, 601-608, 2003
Two Phase Visualization by Electrical Impedance Tomography with Prior Information
Numerical and experimental work was conducted to develop a visualization technique for the phase distribution in a two-phase flow field with known internal structures by electrical impedance tomography technique, which reconstructs the resistivity distribution with the electrical responses that are determined by corresponding excitations. The finite element method is employed to solve the electrical field induced by the currents through electrodes placed along the boundary and a modified Newton-Raphson iterative method is used to determine the search step minimizing the error between the calculated and the measured voltages at the electrodes. The locations and resisitivities of the known structures are considered as prior information. To mitigate the ill-posedness of inverse problem and to incorporate prior information, the modified Tikhonov regularization technique is employed. Also, with an apparatus developed for impedance imaging this study attempts to reconstruct the images of the simulated bubble distributions and the reconstructed images imply the potential possibility of the electrical impedance tomography for the two-phase flow visualization.
[References]
  1. Cheney M, Isaacson D, Nowell JC, Simske S, Globe J, Int. J. Imaging Systems Tech., 2, 66, 1991
  2. Cho KH, Kim S, Lee YJ, Int. Commun. Heat Mass Transf., 26, 637, 1999
  3. Cho KH, Kim S, Lee YJ, Nucl. Eng. Des., 204, 57, 2001
  4. Heikkinen LM, Vauhkonen M, Savolainen T, Leinonen K, Kaipio JP, Inverse Problems Eng., in press, 2001
  5. Heikkinen LM, Vauhkonen M, Savolainen T, Kaipio JP, Measurement Sci. Technol., in press, 12, 2001
  6. Hua P, Webster JG, Tompkins WJ, Clin. Phys. Physiol. Meas., 9(SA), 137, 1988
  7. Jones OC, Lin JT, Ovacik L, Shu H, Nucl. Eng. Des., 141, 159, 1993
  8. Kim MC, Kim S, Kim KY, Lee YJ, Int. Commun. Heat Mass Transf., 28, 773, 2001
  9. Lyon GM, Oakley JP, "A Simulation Study of Sensitivity in Stirred Vessel Electrical Impedance Tomography," Tomography Techniques for Process Design and Operation, Computational Mechanics Publications, Southampton, UK, pp. 137-146, 1993
  10. Ovacik L, Jones OC, "Development of an Electrical Impedance Computed Tomographic Two-phase Flows Analyzer," USDOE Report, DE-FG07-90ER 13032, 1998
  11. Vauhkonen M, "Electrical Impedance Tomography and Prior Information," Ph.D. Thesis, University Kuopio, Finland, 1997
  12. Webster JG, "Electrical Impedance Tomography," Adam Hilger, 1990
  13. Williams RA, Jia X, Mckee SL, Powder Technol., 87(1), 21, 1996
  14. Yorkey TJ, Webster JG, IEEE Trans. Biomed. Eng., 34, 843, 1987