Film-Boiling Drag And Heat Transfer On A Flat Surface

Stable film-boiling flow along a vertical flat plate is analyzed theoretically for a water-steam system at atmospheric pressure. This numerical study indicates that skin friction drag on the plate in a film-boiling flow may increase or decrease relative to the single-phase (all liquid) flow level and that the wall heat transfer coefficient always deteriorates in a film-boiling flow. Subcooling promotes wall heat transfer but may increase or decrease the wall skin friction beyond the single-phase flow level. Adverse streamwise buoyancy force (simulated by downward film-boiling flow) acting on the vapor film will separate the vapor flow. © 1991 by Hemisphere Publishing Corporation