Experimental study of the thermal interaction for molten tin dropped into water

Multiflash photography with extremely short exposure duration times has been used to observe the interaction of molten tin dropped into a water bath. Detailed photographic evidence is presented which demonstrates that transition, or nucleate boiling, is a possible triggering mechanism for vapor explosions and fragmentation. It was also found that the thermal constraints required to produce vapor explosions could be relaxed by introducing a stable thermal stratification within the coolant. It is shown that the constraints can be relaxed sufficiently to cause vapor explosions for test conditions for which the calculated interface contact temperatures are lower than the homogeneous nucleation temperature of water. This latter finding shows that achievement of limiting coolant superheats associated with spontaneous nucleation is not the only mechanism by which vapor explosions in liquid-liquid systems are possible