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Churn flow in high viscosity oils and large diameter columns

Mohammed, Shara K.; Hasan, Abbas; Dimitrakis, Georgios; Azzopardi, Barry J.


Shara K. Mohammed

Georgios Dimitrakis

Barry J. Azzopardi



Churn flow is an important intermediate flow regime occurring in between slug and annular flow patterns in two-phase flow, with profound implications in chemical and petroleum industry. The majority of studies to date in churn flow have been carried out mainly using water or liquids of low viscosities and limited information exists regarding the behaviour of high viscosity liquids which resemble realistic process conditions. In this paper, a study that investigated churn flow and its characteristics in high viscosity oils (360 and 330 Pa.s) and large diameter columns (240 and 290 mm) is presented for a first time. Transition to churn flow regime starts when the structure velocity, length and frequency of the liquid bridges, which appear at the end of slug flow, increase. In churn flow, gas flows at the core of the oil column with a wavy passage, leaving the top surface open to atmosphere with a possibility of creating a very long bubble. The average length of the bubbles seen to decrease with increasing the gas flow rate. While, no considerable change is observed in void fraction, structure velocity and film thickness at this flow pattern.


Mohammed, S. K., Hasan, A., Dimitrakis, G., & Azzopardi, B. J. (2018). Churn flow in high viscosity oils and large diameter columns. International journal of multiphase flow, 100, 16-29.

Journal Article Type Article
Acceptance Date Nov 30, 2017
Online Publication Date Dec 2, 2017
Publication Date 2018-03
Deposit Date Sep 16, 2019
Publicly Available Date Sep 18, 2019
Journal International Journal of Multiphase Flow
Print ISSN 0301-9322
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 100
Pages 16-29
Keywords High viscosity liquids; Transition to churn; Churn flow; Large diameter; Electrical Capacitance Tomography; Volcanic conduits
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Additional Information ©2019, Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license


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