Abstract
Vapor explosion after the collapse of vapor film around a single drop and plural drops of hot LiNO3 submerged in tapped ethanol, whose degree of subcooling is widely changed, are studied by photographic observation and pressure measurement. At small degree of subcooling the vapor bubble region expands rather gradually and the pressure curve has only a small peak which is correspond to the vapor film collapse. At large degree of subcooling the curve has three typical peaks, and the third peak is generally the maximum. The propagation phenomenon is photographed by plural drops experiments. Since the pressure curve of plural drops is similar with that of a single drop, the coherence of the phenomenon during the whole process is confirmed. A model for vapor explosion mechanism is proposed and discussed. The maximum pressure peak is considered to be depend on the same mechanism with that of the cavitation which generates at the collapse and reexpansion of cavitation bubbles.
