Delay of wetting propagation during jet impingement quenching for a high temperature surface

Transient heat transfer has been investigated experimentally with a subcooled water jet during quenching of hot cylindrical blocks made of copper, brass and steel for initial surface temperatures from 250 to 400 °C. The jet velocity was from 3 to 15 m/s and jet subcooling from 5 to 80 K with a jet diameter of 2 mm. When the jet strikes the hot surface, the wetting front becomes stagnant for a certain period of time in a small central region before wetting the entire surface. This wetting delay may be described as the resident time which is a strong function of block material and jet subcooling and also a function of initial block temperature and jet velocity. New correlations for the resident time and the surface temperature at the resident time at the wetting front have been proposed.