Fundamental validation of simulation method for thermal stratification in upper plenum of fast reactor

Ohno, Shuji; Oki, Hiroshi*; Sugahara, Akihiro*; Ohshima, Hiroyuki

Three-dimensional thermal-hydraulic analyses of thermal stratification phenomena have been carried out in order to validate simulating ability of single-phase thermal hydraulic code AQUA and commercial CFD codes STAR-CD and FLUENT. The analyses of thermal stratification water experiments demonstrated that the codes reproduced temperature gradient and upward movement of the stratification interface in the case of utilizing appropriate discretization method and computational mesh arrangement for gravitational direction. No remarkable difference was observed between the calculated results with three codes. It was also shown that three turbulence models of standard k-, RNG k- and RSM indicated little difference in the predicted results of basic stratification phenomena observed in the experiments.