수평관 기포유동 실험 데이터를 이용한 3차원 2상유동 해석코드 CUPID 평가

다국어 초록 (Multilingual Abstract)

Bubbly flows may occur in horizontal pipes during an accident in a nuclear power plant. Horizontal bubbly flows are characterized by asymmetric distribution of main parameters, such as void fraction and velocity, and slip ratio less than 1. Thus, three-dimensional simulation capability is needed for horizontal bubbly flows. In this study, horizontal bubbly flows were simulated using the CUPID code. The model evaluation results showed that the particle based 2-fluid momentum equation simulated more physically reasonable slip ratio than standard 2-fluid momentum equation and the turbulent dispersion force was the most important factor in the prediction of void fraction. In the quantitative assessments, it was shown that the CUPID code predicted well the axial pressure drop within the error range of 10%. Also, the code estimated well axial development process of void fraction. However, it was found that the code can not simulate asymmetric distribution of flow parameters and phenomena which gas phase moves slower than liquid phase. To improve the prediction ability, the modification of turbulence model such as turbulent shear stress, bubble induced turbulence, and so on, or the additional term in momentum equation are needed.

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