Two-phase flow simulation of gas entrainment phenomena in large-scale fast reactor

大型高速炉におけるガス巻込み現象の二相流解析

伊藤 啓; 功刀 資彰*; 大島 宏之; 河村 拓己*

Ito, Kei; Kunugi, Tomoaki*; Ohshima, Hiroyuki; Kawamura, Takumi*

ナトリウム冷却大型高速炉(JSFR)におけるガス巻込み現象を解析するため、高精度気液二相流数値解析手法の開発を進めている。本研究では、開発した手法によって大規模実機形状模擬水試験の解析を行った結果を示す。解析には約100万セルの非構造格子を用い、後流渦とそれに伴うガス巻込み現象を発生させる配管近傍には詳細な格子を配置した。非定常解析の結果、ガスコア(界面くぼみ)の発生と発達を捕らえることに成功し、開発した手法がJSFRガス巻込み現象の評価に適用できることを確認した。

The authors have been developed a high-precision numerical simulation algorithm for gas-liquid two-phase flows to simulate the gas entrainment (GE) phenomena in a large-sized sodium-cooled fast reactor in Japan (JSFR). In this paper, the developed simulation algorithm is applied to the GE phenomena in a large-scale water experiment which models the complicated geometrical configurations of the system components in JSFR. For the numerical simulation, an unstructured mesh with about one million cells are generated and optimized to simulate the interfacial deformations near inlet and outlet pipes which cause vortical flows behind them to induce the GE phenomena. As a result of the unsteady simulation, a typical interfacial dynamic behavior, i.e. the development of a gas core (interfacial dent), is well simulated. Therefore, it is confirmed that the developed simulation algorithm is suitable to evaluate numerically the GE phenomena in JSFR.