The Dynamics of Vapor Void under Conditions of Thermal Interaction of a Hot Spherical Particle with Ambient Water

The problem on the thermal interaction of a hot spherical particle with ambient water heated to the boiling point is solved. The level of physical parameters is treated that corresponds to the interaction between molten core droplets and cooling water in the case of severe accident in a nuclear reactor. In calculating the heat transfer via the vapor shell, the thermal radiation of the particle is included. An analytical solution in isobaric approximation is derived for the initial stage of interaction. As demonstrated by the results of comparison with a complete numerical solution, the oscillations of vapor pressure and vapor shell thickness do not affect the mean parameters of heat transfer from particle to water. Results are obtained that illustrate the damping effect of thermal radiation of the particle on the oscillation of the particle vapor shell. The possible destruction of a melt droplet under the effect of oscillation of pressure in the vapor shell is estimated, and the value of the droplet size is obtained at which its further destruction is unlikely.