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Multiphase Science and Technology
SJR: 0.124 SNIP: 0.222 CiteScore™: 0.26

ISSN Imprimer: 0276-1459
ISSN En ligne: 1943-6181

Multiphase Science and Technology

DOI: 10.1615/MultScienTechn.v21.i1-2.10
pages 1-12

EXTRACTING INFORMATION FROM TIME SERIES DATA IN VERTICAL UPFLOW

Ryuhei Kaji
Process and Environmental Engineering Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
John H. Hills
Process and Environmental Engineering Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
Barry J. Azzopardi
Department of Chemical, Environmental and Mining Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, England

RÉSUMÉ

Data was obtained from eight ring-pair probes mounted along the length of a vertical 19-mm-diameter, 7-m-long pipe. This was provided with air and water at its base and the flow was allowed to develop. The ring-pair probes consisted of two stainless steel rings mounted flush with the pipe wall and a short distance apart. The conductivity between them was measured continuously. Careful calibration allowed the void fraction or film thickness to be obtained from this data. This presentation shows the type of information that can be extracted from the void fraction time series. For time series taken at conditions corresponding to slug flow, two thresholds were employed to separate Taylor bubble and liquid slug regions. The crests and troughs were detected through a change in the sign of the void fraction/time curve. Then the velocities of individual Taylor bubble were obtained by cross-correlating signals from two successive probes with selective fragments. The distribution of lengths of Taylor bubbles and liquid slugs is presented. In addition, careful examination of portions of the time series enabled the waves on the film surrounding the Taylor bubbles to be identified and quantified. These results show that there is a distribution of velocities of these small waves, with some travelling upward and some downward.

RÉFÉRENCES

  1. Chu, K. J. and Dukler, A. E., Statistical characteristics of thin, wavy films: Part II. Studies of the substrate and its wave structure.

  2. Broz, W., Uber die Vorausberechnung der Absorptionsgeschwindigkeit von Gasen in stromenden Flussigkeitsschichten. DOI: 10.1002/cite.330260809

  3. Fossa, M., Design and performance of a conductance probe for measuring the liquid fraction in two-phase gas-liquid flow. DOI: 10.1016/S0955-5986(98)00011-9

  4. Fulford, G. D., The flow of liquids in thin films.

  5. Karimi, G. and Kawaji, M., Flooding in vertical counter-current annular flow. DOI: 10.1016/S0029-5493(99)00331-3

  6. Nusselt, W., Die oberflachenkondensation des wasserdampfes.

  7. Prasser, H.-M., Bottger, A., and Zschau, J., A new electrode-mesh tomograph for gas-liquid flows. DOI: 10.1016/S0955-5986(98)00015-6

  8. Sekoguchi, K. and Mori, K., New development of experimental study on interfacial structure in gas-liquid two-phase flow.

  9. Tsochatzdis, N. A., Karapantsios, T. D., Vostoglou, M. V., and Karabelas, A. J., A conductance probe for measuring liquid fraction in pipes and packed beds. DOI: 10.1016/0301-9322(92)90037-H

  10. Webb, D. R. and Hewitt, G. F., Downwards co-current annular flow. DOI: 10.1016/0301-9322(75)90027-0