Experimental investigation of the puncture position and film rolling speed of bubbles bursting under different liquid pool conditions

Abstract

During severe accidents, pools containing radioactive aerosols will boil and generate bubbles as a result of the increasing heat or decreasing pressure. The generated bubbles will then burst at the pool surface. In the process of bursting, a large number of droplets containing aerosols will be released, leading to the risk of radioactive hazards. Thus, a visualization experiment platform was built in a laboratory to investigate the bursting characteristics of bubbles in liquid pools with different aerosols and temperatures. Radioactive aerosols were replaced with materials having similar physical properties. The parameters during the bubble breaking process, such as the puncture position and film rolling speed, are very important for the breaking bubble to form droplets. Images of bubbles bursting were processed using an image processing program, and the experimental results show that the bubbles, which have a cap diameter in the range of 9–16 mm, are mainly punctured at the bottom of the bubble cap. Moreover, in distilled water, as the temperature increases, more bubbles are punctured at the bottom of the cap. This probability also continues to increase with an increasing mass concentration of aerosols. The film rolling speed in the presence of aerosols was also obtained. With a suspension of 0.1 g/L TiO2, the speed decreases with increasing temperature; however, when the concentration of TiO2 increases to 0.2 g/L, the speed does not decrease notably with increasing temperature. Furthermore, the phenomenon of aerosol aggregation at the liquid surface was observed at high temperatures.