ABSTRACT
Among various two-phase flow regimes the post critical heat flux region is relatively less well understood due to its special heat transfer conditions. For confined flow conditions the boiling curve beyond the dryout point may differ greatly from the classical boiling curve due to two-phase flow hydrodynamics. In the analytical study by R. T. Jensen, break-up lengths of the inverted annular flow liquid core were calculated, along with surface wavelengths. Data on liquid core stability, core break-up mechanisms, and dispersed-core liquid slug and droplet sizes can be obtained. At low relative velocities, drag-induced break-up is characterized by asymmetric waves, resulting in sinuous jet deformation, while at high relative velocities atomizations occurs. Some understanding of the film boiling mechanisms has been obtained from high speed motion pictures and flash photography. In addition, jet core diameter and surface smoothness under these high velocity flows were observed to remain relatively constant until very near the break-up point, when large amplitude deformations occurred rapidly.
