CUPID코드를 활용한 2×2 봉다발 부수로 내부 단상 및 2상 난류유동 해석

It is important to understand the flow characteristic in a subchannel of nuclear rod bundle in the design process of a nuclear reactor considering the safety margin. In this study, the CUPID code was used to simulate the flow phenomena in the 2x2 rod bundle. The simulation of 2x2 rod bundle test under single- and two-phase flow conditions were conducted to validate the turbulence model. The liquid velocities at 0.45 m along the flow path with 0 and 45 degree of azimuthal angle were compared with experimental data. The CUPID　results were a good agreement with experimental data, though the ones for 0 degree case has a little discrepancy. For the future work, the turbulent flow will be investigated by applying different turbulence models to improve the prediction of velocity near wall.