Void fraction development in gas-liquid flow after a U-bend in a vertically upwards serpentine-configuration large-diameter pipe

Almabrok A. Almabrok, Aliyu M. Aliyu, Yahaya D. Baba, Liyun Lao, Hoi Yeung

Research output: Contribution to journalArticle

1 Citation (Scopus)


We investigate the effect of a return U-bend on flow behaviour in the vertical upward section of a large-diameter pipe. A wire mesh sensor was employed to study the void fraction distributions at axial distances of 5, 28 and 47 pipe diameters after the upstream bottom bend. The study found that, the bottom bend has considerable impacts on up-flow behaviour. In all conditions, centrifugal action causes appreciable misdistribution in the adjacent straight section. Plots from WMS measurements show that flow asymmetry significantly reduces along the axis at L/D = 47. Regime maps generated from three axial locations showed that, in addition to bubbly, intermittent and annular flows, oscillatory flow occurred particularly when gas and liquid flow rates were relatively low. At this position, mean void fractions were in agreement with those from other large-pipe studies, and comparisons were made with existing void fraction correlations. Among the correlations surveyed, drift flux-type correlations were found to give the best predictive results.

Original languageEnglish
Pages (from-to)209-226
Number of pages18
JournalHeat and Mass Transfer/Waerme- und Stoffuebertragung
Issue number1
Early online date1 Aug 2017
Publication statusPublished - 1 Jan 2018
Externally publishedYes


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