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吉田 啓之; 上澤 伸一郎
Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 7 Pages, 2020/08
The radioactive aerosol removal equipment is used as one of the safety systems of nuclear reactors. In this equipment, microparticles of aerosol are removed through gas-liquid interfaces of two-phase flow. The mechanism related to the removal of microparticles through the gas-liquid interface is not precise; a numerical evaluation method of performance of aerosol removal equipment is not realized. Then, we have started to construct a numerical simulation method to simulate the removal of microparticles through gas-liquid interfaces. In this simulation method, a detailed two-phase flow simulation code TPFIT is used as the basis of this method. TPFIT adopts an advanced interface tracking method and can simulate interface movement and deformation directly. Also, to simulate the movement of particles, the Lagrangian particle tracking method is incorporated. By combining the interface tracking method, and the Lagrangian particle tracking method, the interaction between interfaces and microparticles can be simulated in detail. To solve the Lagrangian equations of particles, fluid properties and fluid velocity surrounding aerosol particles are evaluated by considering the relative position of particles and gas-liquid interface, to simulate particle movement near the interface. In this paper, we show an outline and preliminary results of this simulation method.
吉田 啓之; 上澤 伸一郎; 堀口 直樹; 宮原 直哉; 小瀬 裕男*
Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 6 Pages, 2018/11
The radioactive aerosol removal equipment is used as one of the safety systems of nuclear reactors. In this equipment, micro particles of aerosol remove through gas-liquid interfaces of two-phase flow. The mechanism related to the removal of micro particles through the gas-liquid interface is not clear, a numerical evaluation method of performance of aerosol removal equipment is not realized. Then, we have started to construct a numerical simulation method to simulate removal of micro particles through gas-liquid interfaces. In this simulation method, detailed two-phase flow simulation code TPFIT is used as the basis of this method. TPFIT adopts an advanced interface tracking method and can simulate interface movement and deformation directly. In addition, to simulate the movement of particles, the Lagrangian particle tracking method is incorporated. By combining the interface tracking method and the Lagrangian particle tracking method, the interaction between interfaces and micro particles can be simulated in detail. To solve the Lagrangian equations of particles, fluid properties and fluid velocity surrounding aerosol particles are evaluated by considering the relative position of particles and gas-liquid interface, to simulate particle movement near the interface. In this paper, outline and preliminary results of this simulation method are shown.
茂木 孝介; 久木田 豊; 柴本 泰照
no journal, ,
プールスクラビングによるエアロゾル除去は、原子炉シビアアクシデント時に放射性物質の環境放出を抑制させる有力な手段のひとつとして、事故対策に適用されている。既存のスクラビングコードに採用されたモデルには、気泡内の粒子濃度分布を均一として扱うことで気泡内部の非定常な粒子運動の解析を省略し、粒子除去率を定常解として求めるという過度な単純化の課題がある。本項では気泡内気体流動場にHillの球形渦を用い、気体中を移行するエアロゾルをLagrangian粒子追跡することで、粒子数濃度分布を非定常で解析し除去率を求めた。その結果、気泡内を運動する低Stokes数の慣性粒子軌道に対してスケーリング則が成立することを明らかにした。これを用いて、単一粒子の軌道から気泡内の粒子不均一性を考慮した除染係数の計算方法を提案し、既存モデルと比較する。この様にして得られ除染係数にも同様なスケーリング則が成立することを示す。