NUMERICAL AND EXPERIMENTAL INVESTIGATION OF AIR-WATER SYSTEM TO SIMULATE BUBBLE DYNAMICS IN LIQUID SODIUM POOL

Abstract The dynamics of rising bubbles in a liquid sodium pool plays a significant role in the estimation of the radiological source term during anticipated transients and normal operation of a fast reactor. Sodium is chemically reactive with air and water. Therefore, carrying out experiments using sodium on a reactor scale level requires extra precautions. We report an in-house experimental technique to depict the bubble dynamics along with numerical support to establish similarity behavior between water and liquid sodium, to reduce the number of experiments in sodium systems for in-depth knowledge of bubble dynamics in the case of the fast breeder reactor. In the present work, 3-D bubble dynamics is studied in the OpenFOAM platform and the validated numerical model is used to study bubble dynamics in sodium to establish similitude between the water and sodium systems. The bubble aspect ratio of 0.9 cm diameter bubbles in the sodium system is found to be in close agreement with that of 0.5 cm bubbles in the water system. Experimental and numerical findings suggest similarity of the aspect ratio between water and scaled-up sodium systems. The similarity criteria established between water and sodium are found to be very useful in conducting water-based experiments to study bubble dynamics in sodium systems.