Numerical simulation of bubble hydrodynamics for pool scrubbing

プールスクラビングのための気泡流体力学数値シミュレーション

岡垣 百合亜  ; 柴本 泰照 ; 和田 裕貴   ; 安部 諭  ; 日引 俊詞*

Okagaki, Yuria; Shibamoto, Yasuteru; Wada, Yuki; Abe, Satoshi; Hibiki, Takashi*

Pool scrubbing is an important filtering process that prevents radioactive aerosols from entering the environment in the event of severe accidents in a nuclear reactor. In this process of transporting aerosol particles using bubbles, bubble hydrodynamics plays a crucial role in modeling pool scrubbing and significantly affects particle removal in a bubble. The pool scrubbing code based on Lumped Parameter (LP) approach includes the particle removal model, and its hydrodynamic parameters are determined based on simple assumptions. We aim to apply the three-dimensional Computer Fluid Dynamics (CFD) approach to understand the detailed bubble interaction. This study validated the applicability of the CFD simulation to bubble hydrodynamics at the flow transition from a globule to a swarm region, which is critical in the stand-alone pool scrubbing code-SPARC-90. Two types of solvers based on the Volume Of Fluid (VOF) and the Simple Coupled Volume Of Fluid with Level Set (S-CLSVOF) methods were used to capture the gas-liquid interface in the CFD simulation. We used the experimental data for validation. As a result, the VOF and S-CLSVOF methods accurately predicted the bubble size and void fraction distributions. In addition, we confirmed that the bubble rise velocity of the S-CLSVOF method almost agreed with the experimental results.