Some Consideration on the Edge Condition of a Finite-Size Horizontal Downward-Facing Plate in Subcooled Pool Film Boiling

Reliability and usability of the analytical results regarding vapor film thickness, vapor velocity, and the mass flow rate of vapor at the plate edge and Nusselt number averaged over the surface are examined to clarify vapor outflow conditions at the plate edge which has not been clarified by conventional experiments. For analysis, we adopt the two-phase boundary layer theory and the integral method which can determine the variation of vapor film thickness in the vapor flow direction to set a velocity profile in a vapor film and a temperature profile in a liquid boundary layer reasonably. In the calculation of the analysis, the inclination angle of the vapor-liquid interface at the plate edge is varied ranging from 0 to 90 degrees. The results of the analysis provide useful guides to future studies in observing the vapor flow conditions in detail and measuring the vapor flow velocity at the plate edge.