Experimental study on boiling mechanism of superheated liquid containing ethanol impurity under different leakage conditions

The accidental rupture of a tank resulting in the unforeseen release of overheated liquid can result in overheat boiling. The presence of liquid impurities can increase the intensity of overheat boiling. This would significantly increase the risk of accidents. Therefore, this study designed a small-scale 17 L visualized tank to investigate the impact of rapid depressurization on overheating flash boiling in the presence of ethanol impurities at saturation concentration. The influence of leakage conditions such as the crack diameter and position was also investigated. A novel leakage mode called simultaneous discharge and overheating was proposed. This new leakage mode was demonstrated to increase the risk of abrupt tank rupture. The results revealed that after the container ruptured abruptly, the liquid containing ethanol impurities at a saturated concentration exhibited a variation in the rate of pressure increase at a diameter of 30 mm. The degree of flashing was the highest during gas-phase release, followed by gas–liquid phase release. The flashing phenomenon was not observed during liquid-phase release. This observation provides valuable insights into the safe handling and storage of overheated liquids containing ethanol impurities.