Journal of Visualization

, Volume 21, Issue 4, pp 585–596 | Cite as

Visualisation of gas–liquid bubbly flows in a large diameter pipe with 90\(^{\circ }\) bend

  • Safari Pour Sirous 
  • Krishna MohanarangamEmail author
  • Sara Vahaji
  • Sherman C. P. Cheung
  • Jiyuan Tu
Regular Paper


Two-phase gas–liquid flows are prevalent in many industries and understanding their behaviour would have significant impact on the efficiency of the systems in which they occur. However, information on two-phase gas–liquid flows in \(90^\circ\) bends is limited in the literature and their flow behaviour is not fully understood. One technique that could assist researchers in exploring flow behaviour is visualisation. Accordingly, in this study a two-phase flow experimental investigation was carried out in a large pipe of diameter 150 mm, using water and air at different superficial velocities in order to visualise the effect of \(90^\circ\) bend on two-phase flow behaviour. As optical methods are not suitable for visualising dense bubbly flows due to overlapping of bubbles, in this study, bubble size distribution and void fraction results were obtained using wire-mesh sensors before and after the bend. The results were then post-processed to visualise the flow field. The instantaneous visualisation of flow shows that gas hold-up migrates from the bottom to top wall of the pipe at the bend when the liquid superficial velocity increases for a fixed superficial gas velocity. An increase in superficial gas velocity shows insignificant influence on the gas hold-up at locations beyond the bend for the investigated conditions. This may be due to the centrifugal force imparted by the bend and hence needs further investigation. Bubble size distribution results before and after the bend indicate that the bend has influence on bubble breakup and coalescence.

Graphical Abstract


Two-phase flow Wire-mesh sensor Void fraction 3D bubble Bubble size distribution Instantaneous flow 



The author acknowledges the support received through the provision of an Australian Government Research Training Program in form of a Ph.D. scholarship and RMIT university support. The author also appreciates CSIROs experimental facilities and technical support received from Mr. Andrew Brent.


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Copyright information

© The Visualization Society of Japan 2018

Authors and Affiliations

  1. 1.School of EngineeringRMIT University, Bundoora East CampusBundooraAustralia
  2. 2.CSIRO Mineral ResourcesClaytonAustralia

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