Experimental study on bubbly flow transition in vertical annular gap bubble column
Fahd M. Al-Oufi
Iain W. Cumming
Chris Rielly
2134/8715
https://repository.lboro.ac.uk/articles/conference_contribution/Experimental_study_on_bubbly_flow_transition_in_vertical_annular_gap_bubble_column/9240095
Mean and local gas void fractions in vertical upward, two-phase flows contained within the
annular gap between two concentric tubes are presented. For a given gas superficial velocity, jg, the mean void
fraction, , was found to decrease as the diameter ratio of the two tubes approached unity (i.e. for narrower
gaps). Moreover, was significantly lower than that obtained in an open tube at the same jg. Two explanations
were proposed: (i) large bubbles, generated in the annular gap, destabilised the flow, and (ii) the driftflux
distribution parameter in an open tube was different to that in an annular gap, which results in a different
mean . It was shown that injection of large bubbles into a homogeneous flow led to an early transition.
Furthermore, the void fraction profiles in the annular gaps depended on both jg and the gap geometry
2011-08-15 14:27:36
Homogeneous flow
Local void fraction
Void fraction profile
Double-sensor electrical probe
Chemical Engineering not elsewhere classified