Experimental study of interfacial area of bubble plume based on bubble tracking by wire-mesh sensor

Abstract

The fundamental information of bubble plume such as interfacial area, three-dimensional velocity, and bubble diameter are necessary to develop a kinematic pool scrubbing model for uncertainty reduction of severe accident analysis. In this study, an algorithm was introduced to polygonize the cross-sectional void fraction of the wire-mesh sensor and reconstruct it in 3D to track the individual bubbles detected. Based on the result, the interfacial area and three-dimensional velocity of individual bubbles in a bubble plume were obtained. The results show that the interfacial area from MELCOR model tends to overestimate the analyzed results due to remaining of large bubbles in the downstream. In addition, the effect of subcooling temperature and steam fraction on bubble formation was evaluated by applying the developed method into condensable gas experiments. The interfacial area increased significantly under high subcooling temperature and steam fraction due to atomization of bubbles caused by steam condensation.