Abstract
To measure small size bubbles in gas-liquid two-phase flows, we have already developed a Single-Tip Optical fiber Probe (S-TOP). Our purpose of this study is to reduce the errors in a bubble measurement by the S-TOP, which is caused by random positions pierced by the S-TOP. To realize it, we pay notice to a pre-signal. This signal appears sharply, just before the S-TOP tip touches the bubble center region. Using this, we can easily detect the pierced position. The difference of chord lengths measured by the visualization and by the S-TOP was improved within 5 %. In this study, we conducted the experiment in which the S-TOP pierces bubbles under various conditions of the bubble orientation. We confirm that one can extract the signals that the S-TOP vertically pierces the bubble center region.