Vapor explosions during the impact of molten tin droplets into a liquid pool

High-speed video imaging is used to study the impact of a molten tin droplet into a liquid pool. Three different regimes have been identified as nucleation boiling, film boiling or vapor explosion. The latter generally comprises two stages; during the first stage, vapor gets entrapped into the molten tin drop and then, at a second stage, the vapor is superheated by the tin material, creating a violent expansion (explosion). It was observed that the addition of surfactant to the fluid pool could promote the explosion and make it occur at a lower temperature. Furthermore, other parameters such as the pool liquid surface tension, boiling temperature, viscosity and molten tin temperature have been varied to examine the explosion dynamics.