ИСТИНА

The dynamics of a bubble of hot non-condensable gas formed at the interface between the high temperature melt and subcooled water is analyzed numerically in a one-dimensional spherically symmetric approximation. It is shown that for significant initial superheat of the bubble relative to the water, a rapid drop in pressure in the bubble occurs due to strong heat removal into the water. This leads to the collapse of the bubble and the appearance of an accompanying water flow. The results obtained made it possible to approximately describe the stage of collapse of the bubble as the polytropic process and to determine its power. The axisymmetric problem of the impact of the water jet on the surface of a melt during collapse of a gas bubble near the interface between the melt and water is numerically investigated. In this case, the obtained polytropic process equation is used to determine the pressure in the bubble. It is found that the resulting hydrodynamic impact on the melt is capable to produce melt splashing into the water to a height of several centimetres. If the frequency of formation of such bubbles is high enough, then, as a result of their collapses, the melt-water interface will be transformed into a premixed layer, which is capable to produce steam explosions.