The upward vertical flow of air‐water mixtures: II. Effect of tubing diameter on flow‐pattern, holdup and pressure drop

Abstract

AbstractResults of visual observations and measurements of holdup and pressure drop are reported over a range of air‐water ratios for the upwards vertical flow of air‐water mixtures in four tubes with diameters ranging from 0.630 in. to 2.50 in. Tests were conducted under conditions of constant air density corresponding with an average pressure of 36 psia and at 10 constant superficial water velocities ranging from 0.0695 to 7.35 ft./sec.The data are analyzed by the method previously suggested by Govier, Radford and Dunn involving the separation of the unit pressure drop curves into four regimes to aid in flow pattern description and the separation of the unit pressure drop itself into two components to facilitate correlation.Tubing diameter is found to have little or no effect on the border between Regimes I and II or on the transition from the bubble to the slug flow pattern. The borders between Regimes II and III and between Regimes III and IV are markedly affected by tubing diameter as by consequence are the transitions from slug to froth and from froth to ripple flow.Tubing diameter is found to have an important effect on the superficial friction factor and the holdup. The pressure drop data for each of the diameters have been successfully brought together in a single friction factor‐Reynolds number correlation. The holdup data are separately correlated for pressure drop Regimes I and II and for Regime III and Regime IV.