自由液面渦中心に沿った3次元減圧量分布を考慮したガス巻込み評価手法の構築

抄録

In the design of sodium-cooled fast reactors (SFRs), cover gas entrainment phenomena induced by the vortex dimple at the free surface in upper plena is an important thermal-hydraulic issue. The authors have developed an evaluation method of gas entrainment with an evaluation tool named “StreamViewer”. In this study, the modification of the evaluation model to improve quantitatively the prediction accuracy of the gas core length was investigated. In this model, lines of the vortex center (vortex center lines) which elongated from the suction port where the entrance of the gas to the heat transport system, for instance, the IHX inlet in the pool type SFRs, to the free surface in the plenum were to be identified, and the distribution of pressure decrease along the vortex center line was calculated to judge the possibility of gas entrainment in comparisons with the hydraulic head. This evaluation model was applied to the results of the water experiment with a rectangular open channel, where unsteady vortices are generated. It was confirmed that this model can identify the occurrence of gas entrainment.