Flow Film Boiling From a Sphere to Subcooled Freon-11

The boiling curves for flow boiling of freon-11 from a fluid-heated 3.81-cm-dia copper sphere showed dual maxima. One maximum corresponded to the nucleate peak heat flux while the other was caused by transitory behavior of the wake behind the sphere. Film boiling data were predicted well by the theory of Witte and Orozco. A semi-empirical correlation of the film boiling data accounting for both liquid velocity and subcooling predicted the heat transfer to within +/− 20 percent. The conditions at which the vapor film became unstable were also determined for various sub-coolings and velocities.