Development of design technology on thermal-hydraulic performance in tight-lattice rod bundle, 4; Large paralleled simulation by the advanced two-fluid model code

稠密格子炉心熱流動特性技術開発,4; 二流体モデル解析コードによる大規模並列シミュレーション

三澤 丈治; 吉田 啓之  ; 秋本 肇

Misawa, Takeharu; Yoshida, Hiroyuki; Akimoto, Hajime

Japan Atomic Energy Agency (JAEA) has been developing three-dimensional two-fluid model analysis code ACE-3D, which adopts boundary fitted coordinate system to simulate complex shape channel flow such as a tight lattice rod bundle. In this paper, as a part of development of ACE-3D to apply to rod bundle analysis, introduction of parallelization to ACE-3D and assessments of ACE-3D are shown. In analysis of large-scale domain such as a rod bundle, even if a two-fluid model is used, a large number of computer resources are required; calculation memory, time, performance, etc. Then, this research was performed to enhance the calculation efficiency of the ACE-3D code and to achieve large-scale simulations by it. The parallelization algorithm was introduced into the code and the analytical method was improved. In order to evaluate validity of the improved ACE-3D code, the large-scale two-phase flow simulations were carried out under 37-rod bundle geometry and the simulated results were compared with the experimental results. Consequently, it was confirmed that the present ACE-3D code can be done large-scale simulations with high efficiency, and then, it is the same prediction accuracy as a conventional ACE-3D code.