Investigation of Influence of Inlet Flow Conditions on Flow Structure in a Dual Elbow
A large number of troubles reported in nuclear power plants are related to pipe wall thinning. One of the causes for the thinning over a wide range and possibility of leading to large-scale pipe failures is Flow Accelerated Corrosion (FAC), a phenomenon that corrosion of pipes is promoted by fluid flow and is observed where complex flow occurs, like in bends, near orifices and so on. In this study, therefore a flow structure in an S-shaped dual elbow composed of two 90-degree elbows is analyzed by utilizing matched refractive-index PIV measurement so as to avoid refraction influence between the test fluid and pipe. Various inlet flow conditions of the dual elbow are tested in this study such as biased flows and swirling flow for the purpose of considering complex flow conditions assumed in an actual piping system. As a result of visualization for the all flow conditions, there exists high flow velocity area in the inside of the 2nd elbow where pipe wall thinning actually occurred in the actual piping. It is also found that the maximum flow velocity in the 2nd elbow becomes large as the inside velocity of the inlet of the 1st elbow becomes large. In addition, when the inlet flow condition is swirling flow, the maximum flow velocity in the 2nd elbow is suppressed to be lower than that observed in the others.
FAC PIV S-shaped dual elbow Biased flow Swirling flow
Hiroki YANAI Shinji EBARA Hidetoshi HASHIZUME Kazuhisa YUKI
Tohoku University 6-6, Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, JAPAN Tokyo University of Science Yamaguchi 1-1-1, Daigaku-dori, Sanyo-onoda, Yamaguchi 756-0884, JAPAN
国际会议
上海
英文
2059-2073
2010-10-10（万方平台首次上网日期，不代表论文的发表时间）