Effects of Surface Evaporation and Condensation on the Dynamics of Thin Liquid Films for the Porous Wetted Wall Protection Scheme in IFE Reactors

A numerical investigation has been conducted to analyze the fluid dynamic aspects of the porous wetted wall protection scheme for IFE reactor first walls. A level contour reconstruction method has been used to track the three-dimensional evolution of the liquid film surface on porous downward facing walls with different initial film thickness, liquid injection velocity through the porous wall, surface disturbance amplitude, configuration and mode number, liquid properties, and surface inclination angle. Here, we report on the effects of evaporation and condensation at the liquid film surface on the dynamics of film flow, the free surface topology, the frequency of liquid droplet formation and detachment, the minimum film thickness between explosions, and the equivalent diameter of detached droplets. Generalized charts, which allow designers of conceptual IFE reactors to identify appropriate "windows" for successful operation of the wetted wall protection concept for different coolants are presented.