Countercurrent gas–liquid flow in inclined and vertical ducts — II: The validity of the Froude–Ohnesorge number correlation for flooding

A number of flooding correlations have been proposed in the past. These correlations often succeed in predicting the researcher’s own data but fail to correlate data of other investigations, limiting the use of the correlations. The validity of the correlation method proposed in part I is discussed in part II in the context of data generated in previous investigations by other researchers. The correlation method consisting of a combination of the phase Froude numbers and the Ohnesorge number succeeds in correlating the data of two previous investigations. A critical discussion of other dimensionless groups used in the past for the purpose of correlating flooding data is presented. The well known Kutateladze-type equation appears not to be valid for flooding in vertical tubes of diameters in the region of 30 mm.