Numerical flow analysis in a large-diameter circular pipe with elbow

Yamano, Hidemasa   ; Muramatsu, Toshiharu; Fujii, Tadashi*

A conceptual design study of a large-scale sodium-cooled fast reactor adopts a two-loop primary cooling system with large-diameter piping in order to reduce plant construction cost. In this design, one of issues is a flow-induced vibration behavior of the piping under a high Reynolds number (10 order level) condition. To investigate its basic characteristic, a 1/3-scale flow-induced vibration test simulating a hot leg piping has been carried out with water. In this study, a numerical steady-state analysis has reproduced flow characteristics, such as velocity profile in a flow separation region, of the 1/3-scale test by specifying appropriate analytical models and conditions with STAR-CD. With the validated models, the effect of the coolant viscosity and scale has been investigated as well as flow characteristics under the reactor condition involving disturbance at the inlet boundary of hot leg piping.