Study on turbulent modeling in gas entrainment evaluation method

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

In the design study on a large-scale sodium-cooled fast reactor in Japan (JSFR), the suppression of gas entrainment (GE) phenomena caused by free surface vortices are very important. However, due to the non-linearity and/or locality of the GE phenomena, it is not easy to evaluate the occurrences of the GE phenomena accurately. 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.