Effects of area and radius of curvature of downward-facing curved surfaces on pool boiling

Quenching experiments were performed to investigate the effects of surface area and radius of curvature on pool boiling from downward-facing, curved copper surfaces in saturated water. The maximum heat flux (q{sub MHF}) was highest at the lowermost position and decreased with increasing local inclination (or elevation) on the surface. A higher vapor release angle reduced vapor accumulation on the boiling surface, which enhanced surface coolability and shortened the quenching time. The surface area, however, insignificantly affected the local values of q{sub MHF}. Transient pool boiling from downward-facing convex surfaces in water is of interest in many applications. One example is in nuclear reactor safety for assessing the coolability of the lower head of the reactor pressure vessel, following a core meltdown accident.