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Dynamics of flow transitions from bubbly to churn flow in high viscosity oils and large diameter columns (2019)
Journal Article
Mohammed, S. K., Hasan, A. H., Ibrahim, A., Dimitrakis, G., & Azzopardi, B. J. (2019). Dynamics of flow transitions from bubbly to churn flow in high viscosity oils and large diameter columns. International Journal of Multiphase Flow, 120, https://doi.org/10.1016/j.ijmultiphaseflow.2019.103095

The dynamic behaviour of the gas-liquid two phase flows and in particular the flow pattern stability and transition between the flow regimes are influenced significantly by both the properties of the liquid and gas as well as the pipe diameter. The m... Read More about Dynamics of flow transitions from bubbly to churn flow in high viscosity oils and large diameter columns.

Gas rising through a large diameter column of very viscous liquid: flow patterns and their dynamic characteristics (2019)
Journal Article
Hasan, A. H., Mohammed, S. K., Pioli, L., Hewakandamby, B. N., & Azzopardi, B. J. (2019). Gas rising through a large diameter column of very viscous liquid: flow patterns and their dynamic characteristics. International Journal of Multiphase Flow, 116, 1-14. https://doi.org/10.1016/j.ijmultiphaseflow.2019.04.001

Gas-liquid flows are affected strongly by both the liquid and gas properties and the pipe diameter, which control features and the stability of flow patterns and their transitions. For this reason, empirical models describing the flow dynamics can be... Read More about Gas rising through a large diameter column of very viscous liquid: flow patterns and their dynamic characteristics.

Study of bubbles entrapped into a gas-sheared liquid film (2018)
Journal Article
Hann, D. B., Cherdantsev, A. V., & Azzopardi, B. J. (2018). Study of bubbles entrapped into a gas-sheared liquid film. International Journal of Multiphase Flow, 108, 181-201. https://doi.org/10.1016/j.ijmultiphaseflow.2018.07.001

The surface of a thick liquid film under strong gas shear is covered by large-scale disturbance waves and small-scale ripples. Disruption of these ripples on top of disturbance waves by the gas stream leads to the creation of droplets that are entrai... Read More about Study of bubbles entrapped into a gas-sheared liquid film.

Fluid structure behaviour in gas-oil two-phase flow in a moderately large diameter vertical pipe (2018)
Journal Article
Omar, R. A., Hewakandamby, B. N., Azzi, A., & Azzopardi, B. J. (2018). Fluid structure behaviour in gas-oil two-phase flow in a moderately large diameter vertical pipe. Chemical Engineering Science, 187, https://doi.org/10.1016/j.ces.2018.04.075

Intermittent flows in vertical pipes occur in many industrial settings including power generation and downstream oil-and gas production. This type of flows include cap bubble, slug and churn flow regimes. These regimes are of interest as downstream p... Read More about Fluid structure behaviour in gas-oil two-phase flow in a moderately large diameter vertical pipe.

Churn flow in high viscosity oils and large diameter columns (2017)
Journal Article
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, https://doi.org/10.1016/j.ijmultiphaseflow.2017.11.018

Churn flow is an important intermediate flow regimoccurring 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 has been carried out... Read More about Churn flow in high viscosity oils and large diameter columns.

Characterisation of an analogue liquid for hydrodynamic studies of gas-ionic liquid flows (2017)
Journal Article
Azzopardi, B. J., Agunlejika, E. O., Zhao, D., Kaji, R., & Hewakandamby, B. N. (2017). Characterisation of an analogue liquid for hydrodynamic studies of gas-ionic liquid flows. Chemical Engineering Journal, 330, https://doi.org/10.1016/j.cej.2017.07.090

Ionic liquids are liquid salts at low temperatures (normally less than 100°C). They are powerful solvents with very low vapour pressure. They have great potentials in many applications such as gas absorption and chemical synthesis. However, they are... Read More about Characterisation of an analogue liquid for hydrodynamic studies of gas-ionic liquid flows.

Applications of Artificial Neural Network (ANN) method for performance prediction of the effect of a vertical 90° bend on an air-silicone oil flow (2017)
Journal Article
Ayegba, P., Abdulkadir, M., Hernandez-Perez, V., Lowndes, I., & Azzopardi, B. J. (in press). Applications of Artificial Neural Network (ANN) method for performance prediction of the effect of a vertical 90° bend on an air-silicone oil flow. Journal of the Taiwan Institute of Chemical Engineers, 74, https://doi.org/10.1016/j.jtice.2017.02.005

Knowledge of how the presence of a bend can change the flow patterns of a gas–liquid mixture is important for the design of multiphase flow systems, particularly to prevent burn-out and erosion–corrosion. Burn-out and erosion–corrosion both have seri... Read More about Applications of Artificial Neural Network (ANN) method for performance prediction of the effect of a vertical 90° bend on an air-silicone oil flow.

Numerical modelling of the rise of Taylor bubbles through a change in pipe diameter (2017)
Journal Article
Ambrose, S., Lowndes, I. S., Hargreaves, D., & Azzopardi, B. (2017). Numerical modelling of the rise of Taylor bubbles through a change in pipe diameter. Computers and Fluids, 148, https://doi.org/10.1016/j.compfluid.2017.01.023

The rise of Taylor bubbles through expansions in vertical pipes is modelled using Computational Fluid Dynamics. The predictions from the models are compared against existing experimental work and show good agreement, both quantitatively and qualitati... Read More about Numerical modelling of the rise of Taylor bubbles through a change in pipe diameter.

Study of the impacts of droplets deposited from the gas core onto a gas-sheared liquid film (2016)
Journal Article
Cherdantsev, A. V., Hann, D. B., Hewakandamby, B. N., & Azzopardi, B. J. (2017). Study of the impacts of droplets deposited from the gas core onto a gas-sheared liquid film. International Journal of Multiphase Flow, 88, 69-86. https://doi.org/10.1016/j.ijmultiphaseflow.2016.09.015

The results of an experimental study on droplet impactions in the flow of a gas-sheared liquid film are presented. In contrast to most similar studies, the impacting droplets were entrained from film surface by the gas stream. The measurements provid... Read More about Study of the impacts of droplets deposited from the gas core onto a gas-sheared liquid film.

The control and maintenance of desired flow patterns in bends of different orientations (2016)
Journal Article
Zhao, D., Omar, R., Abdulkadir, M., Abdulkareem, L. A., Azzi, A., Saidj, F., …Azzopardi, B. J. (in press). The control and maintenance of desired flow patterns in bends of different orientations. Flow Measurement and Instrumentation, 53(B), https://doi.org/10.1016/j.flowmeasinst.2016.09.003

Multiphase flows are common in industrial settings and bends in pipe lines cannot be avoided due to space limitations. Gas-liquid two phase flows could form material discontinuities that could have adverse effect on productivity and the pipe network... Read More about The control and maintenance of desired flow patterns in bends of different orientations.

Subatmospheric boiling study of the operation of a horizontal thermosyphon reboiler loop: Instability (2016)
Journal Article
Agunlejika, E. O., Langston, P. A., Azzopardi, B. J., & Hewakandamby, B. N. (2016). Subatmospheric boiling study of the operation of a horizontal thermosyphon reboiler loop: Instability. Applied Thermal Engineering, 109(A), 739-745. https://doi.org/10.1016/j.applthermaleng.2016.08.135

Distillation and chemical processing under vacuum is of immense interest to petroleum and chemical industries due to lower energy costs and improved safety. To tap into these benefits, energy efficient reboilers with lower maintenance costs are requi... Read More about Subatmospheric boiling study of the operation of a horizontal thermosyphon reboiler loop: Instability.

Flow instabilities in a horizontal thermosyphon reboiler loop (2016)
Journal Article
Agunlejika, E. O., Langston, P., Azzopardi, B. J., & Hewakandamby, B. N. (2016). Flow instabilities in a horizontal thermosyphon reboiler loop. Experimental Thermal and Fluid Science, 78, https://doi.org/10.1016/j.expthermflusci.2016.05.013

Thermosyphon systems have been the subject of several studies due to instability issues negating their attractive high heat fluxes, low temperature gradients requirement, reduced weight and simple, pump-less system. There is a dearth of design data f... Read More about Flow instabilities in a horizontal thermosyphon reboiler loop.

Global and local hydrodynamics of bubble columns – Effect of gas distributor (2015)
Journal Article
Sharaf, S., Zednikova, M., Ruzicka, M. C., & Azzopardi, B. J. (2016). Global and local hydrodynamics of bubble columns – Effect of gas distributor. Chemical Engineering Journal, 288, 489-504. https://doi.org/10.1016/j.cej.2015.11.106

Global (level swell) and local (WMS – Wire Mesh Sensor) measurements were made on waters of different purities and air, in a cylindrical laboratory bubble column (2 m tall, 0.127 m dia) using two different gas distributors: a perforated plate (to pro... Read More about Global and local hydrodynamics of bubble columns – Effect of gas distributor.

Structures in gas–liquid churn flow in a large diameter vertical pipe (2015)
Journal Article
Sharaf, S., van der Meulen, G. P., Agunlejika, E. O., & Azzopardi, B. J. (2016). Structures in gas–liquid churn flow in a large diameter vertical pipe. International Journal of Multiphase Flow, 78, 88-103. https://doi.org/10.1016/j.ijmultiphaseflow.2015.09.005

Gas–Liquid two phase co-current flow in a vertical riser with an internal diameter of 127 mm was investigated in the churn flow pattern. This paper presents detailed experimental data obtained using a Wire Mesh Sensor. It shows that the most obvious... Read More about Structures in gas–liquid churn flow in a large diameter vertical pipe.

Electrocoalescence of water drop trains in oil under constant and pulsatile electric fields (2015)
Journal Article
Vivacqua, V., Mhatre, S., Ghadiri, M., Abdullah, A., Hassanpour, A., Al-Marri, M., …Kermani, B. (2015). Electrocoalescence of water drop trains in oil under constant and pulsatile electric fields. Chemical Engineering Research and Design, 104, https://doi.org/10.1016/j.cherd.2015.10.006

This study addresses the effectiveness of constant and pulsed DC fields in promoting coalescence of dispersed water drops in an oil-continuous phase. For this purpose, a train of drops of relatively uniform size is injected into a stream of flowing s... Read More about Electrocoalescence of water drop trains in oil under constant and pulsatile electric fields.

Comparison of experimental and Computational Fluid Dynamics (CFD) studies of slug flow in a vertical riser (2015)
Journal Article
Abdulkadir, M., Hernandez-Perez, V., Lo, S., Lowndes, I., & Azzopardi, B. J. (in press). Comparison of experimental and Computational Fluid Dynamics (CFD) studies of slug flow in a vertical riser. Experimental Thermal and Fluid Science, 68, https://doi.org/10.1016/j.expthermflusci.2015.06.004

This paper presents a comparison of the results obtained from experiments and CFD studies of slug flow in a vertical riser. A series of two experimental investigations were carried out on a 6 m vertical pipe with a 0.067 m internal diameter charged w... Read More about Comparison of experimental and Computational Fluid Dynamics (CFD) studies of slug flow in a vertical riser.

Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior (2015)
Journal Article
Zeghloul, A., Azzi, A., Saidj, F., Azzopardi, B. J., & Hewakandamby, B. N. (2015). Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior. International Journal of Multiphase Flow, 74, https://doi.org/10.1016/j.ijmultiphaseflow.2015.04.013

Experiments are reported on an air–water mixture flowing through an orifice in a vertical pipe. Time series of cross-sectionally averaged void fractions have been measured at nine axial positions by using a conductance probe technique. A series of si... Read More about Interrogating the effect of an orifice on the upward two-phase gas–liquid flow behavior.

Characterization Of oil/ gas flow pattern in vertical pipes using electrical capacitance tomography (2015)
Journal Article
Abdulkareem, L. A., Azzopardi, B. J., Hamid, S. A., & Abdulkahdir, M. (2015). Characterization Of oil/ gas flow pattern in vertical pipes using electrical capacitance tomography. European Journal of Scientific Research, 130(1),

Electrical Capacitance Tomography provides the opportunity to visualize the contents of a process of many applications such as pipeline and obtain information on the flow configuration. Multiphase flow is an extremely complex field of fluid mechanics... Read More about Characterization Of oil/ gas flow pattern in vertical pipes using electrical capacitance tomography.

Electrostatic phase separation: a review (2015)
Journal Article
Mhatre, S., Vivacqua, V., Ghadiri, M., Abdullah, A., Al-Marri, M., Hassanpour, A., …Kermani, B. (2015). Electrostatic phase separation: a review. Chemical Engineering Research and Design, 96, https://doi.org/10.1016/j.cherd.2015.02.012

The current understanding and developments in the electrostatic phase separation are reviewed. The literature covers predominantly two immiscible and inter-dispersed liquids following the last review on the topic some 15 years. Electrocoalescence kin... Read More about Electrostatic phase separation: a review.

The properties of large bubbles rising in very viscous liquids in vertical columns (2014)
Journal Article
Azzopardi, B. J., Pioli, L., & Abdulkareem, L. (2014). The properties of large bubbles rising in very viscous liquids in vertical columns. International Journal of Multiphase Flow, 67, https://doi.org/10.1016/j.ijmultiphaseflow.2014.08.013

Very viscous liquids (>100 Pa s) are found in form of heavy oils and polymers in industry as well as in the natural environment (silicatic magma). Little is known of their behaviour as gas bubbles up through them in vertical columns. Using advanced t... Read More about The properties of large bubbles rising in very viscous liquids in vertical columns.