The simplified physical models for falling liquid film breakdown were presented by the flooding mechanisms in annular two phase flow and experiment observations. Under the state of surface evaporation

the forces of gravity

viscosity and capillary pressure in falling liquid film breakdown down vertical dimpled plate play a dominant role. Based on simplified theory analyses

film breakdown criteria Kα1/3 B was obtained. The correlations describing critical states on temporary and permanent breakdown were obtained to predict falling film breakdown conditions. In falling film flow

there were three regions: full wetted region

temporary breakdown region and permanent breakdown region

and two critical states: from fully wetted to temporary breakdown and from temporary breakdown to permanent breakdown.