Pages 257-258
The triggering process of vapor explosion was visualized by high-speed digital video cameras at an interface between a water droplet and a molten tin pool. A cluster of bubble generated by spontaneous bubble-nucleation covered the whole contact area at 0.10ms after the impingement. Prominent fine mixing between two liquids were found to start at 0.55ms that resulting in vapor explosion. A water micro jet toward the molten tin surface might induce the fine mixing after the bubbles had expanded excessively and had contacted the subcooled water.