Parametric effects on the onset of flooding in flat-plate geometries

Abstract

Flooding of countercurrent stratified steam-water flow in flat-plate geometries is investigated. Both local and global effects of condensation on the onset of flooding are discussed, based on the results of top and bottom flooding tests. The influence of the channel depth and inclination angle on the flooding velocity is also explored. An envelope model, which considers flooding to be the limiting condition for countercurrent flow, is presented and compared with extensive data at various inclinations. Quite good agreement is shown at the nearly horizontal and moderately steep inclinations, but the onset of flooding in nearly vertical flow is expedited by significant droplet entrainment, and thus takes place earlier than the theory predicts.