Abstract
In FCIs, the fragmentation process is a key factor to determine the ratio of heat transferred to power. So, in this paper, the fragmentation process of melt droplets triggered by boiling effect is investigated. The dynamic boiling process is modeled by writing a momentum equation for vapor film dynamics, an energy equation for each region of the droplet, coolant vapor and liquid and linking each region by the appropriate boundary conditions. The integral approach is used in each region for the energy equations where the differential equation is integrated over the region and a temperature profile is assumed. By using these developed models, the fragmented mass of the droplet triggered by boiling effect can be calculated. The result shows that the fragmentation rate is large than that given by hydrodynamic model. The parameter, which is related to the droplet condition and the acceleration exerted on the droplet surface, is a function of pressure in the vapor film.
