Flooding velocity in a counter-current annular two-phase flow

Abstract Experimental work on flooding has been performed concerning the operation of wetted columns, falling film evaporators, updraft condensers, etc. However, owing to the complexity of the phenomenon of flooding and to numerous factors affecting it, a sufficiently definite theory has not yet emerged. In response to this, the authors performed an experiment whereby the many factors affecting flooding were carried out using four test tubes and four test liquids. It is known that, when the relative velocity of a falling liquid film to a counter-current gas reaches a certain value, a wave occurring on the film surface becomes unstable, its amplitude quickly increases, bridging the test tube and flooding occurs. Taking account of this observation, a theoretical equation was derived by dealing with the instability problem of such waves and an experimental correlation worked out on the basis of the derived theoretical equation and experimental data.