Measurement of void distribution in transient flows

By means of X-ray Beam Scanning Method, void distributions in horizontal pipes during blowdown were measured for various conditions. Two types of X-ray void fraction meters were used ; One was scanning upward and downward across the pipes, and the other was highspeed scanning type by a rotating disc. Highspeed scanning type had a void distribution color display system that made easy to recognize even a slug flow. The data were plotted on the flow regime map and compared with available data. For high mass flux, flow, pattern became annular flow and was weak dependent on pressure. While for low mass flux, flow pattern became stratified flow due to gravity. (author)