Flooded countercurrent two-phase flow in horizontal tubes and channels

A criterion for flooding in the countercurrent flow of two fluids in horizontal tubes and channels is developed. It exhibits a dependence upon the density ratio of the fluids beyond that present in the criterion of Wallis (1969). Experiments were carried out with air and water in a horizontal tube at atmospheric pressure and these, together with others reported in the literature, are shown to be in fair agreement with the prediction of the criterion, though it is emphasised that more experimental work is desirable.Work reported in the literature with miscible fluids with a density ratio close to unity confirms the extra dependence upon the density ratio.