%0 Journal Article %A Kaji, Ryuhei %A Hills, John H. %A Azzopardi, Barry J. %D 2009 %I Begell House %N 1-2 %P 1-12 %R 10.1615/MultScienTechn.v21.i1-2.10 %T EXTRACTING INFORMATION FROM TIME SERIES DATA IN VERTICAL UPFLOW %U https://www.dl.begellhouse.com/journals/5af8c23d50e0a883,3003408060e425f0,3fc83d4e106e481e.html %V 21 %X 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. %8 2009-05-29