Abstract
Measurements of void fraction distribution around tubes across horizontal tube bundle in liquid-gas two-phase flow were carried out using X-ray radiography system. Under bubbly flow condition, it was observed that bubbles mainly passed through the vertical tube gaps and accumulated on the upstream side of the tubes. Also it was observed that void fraction was lower around the wall side tubes than that the center tubes. Measurements results of the void fraction were underestimated comparing to the previous studies. Because void fraction near the wall is lower than that in the center-region. Thus, cross-sectional averaged void fraction decreased comparing to the void fraction which was averaged except for the near-wall region.
