Study on turbulent modeling in gas entrainment evaluation method

ガス巻込み評価手法における乱流渦粘性モデル

伊藤 啓; 大島 宏之; 中峯 由彰*; 今井 康友*

Ito, Kei; Ohshima, Hiroyuki; Nakamine, Yoshiaki*; Imai, Yasutomo*

ナトリウム冷却高速炉におけるガス巻込み現象を評価するため、CFDに基づく評価手法の整備を進めている。本研究では、ガス巻込み現象の評価精度向上のため、乱流渦粘性モデルの構築と検証を行う。乱流渦粘性モデルを導入した評価手法によって、従来の手法よりも短いガスコア長さが得られ、試験結果との整合性が向上することを示す。

Suppression of gas entrainment (GE) phenomena caused by free surface vortices are very important to establish an economically superior design of the sodium-cooled fast reactor in Japan (JSFR). Therefore, the authors are developing a CFD-based evaluation method in which the non-linearity and locality of the GE phenomena can be considered. In this study, the authors develop a turbulent vortex model to evaluate the GE phenomena more accurately. Then, the improved GE evaluation method with the turbulent viscosity model is validated by analyzing the GC lengths observed in a simple experiment. The evaluation results show that the GC lengths analyzed by the improved method are shorter in comparison to the original method, and give better agreement with the experimental data.