Modeling the growth of a vapor film formed in contact between a hot metal sphere and water in pressure vessels

Abstract

The contact between a hot object such as the particles of a molten metal and a cool and relatively volatile fluid such as water likely takes place in metal casting, paper manufacturing industries, and nuclear reactors. The highly intensive and quick heat transfer caused by the contact may increase the pressure in the vapor film formed on a hot particle within a short period leading to the vapor explosion followed by a strong pressure wave in a vessel containing a volatile matter. The present study aims to provide a mathematical model for contacting between a small hot copper metal sphere and water and explain the effect of pressure change in water vessel on the vapor film radius, pressure inside vapor film, as well as the saturation temperature at the interface. In addition, it examines the results of vapor film growth and the internal pressure of the film for such a phenomenon in nuclear power plants with fuel rod coolant pressures ranged between 60 and 150 bar. The results of the extremely high pressures of the vessels indicated an increase in the pressure pulse inside the vapor film within a short period which raised the likelihood of vapor explosion.