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Small bubbles formation and contribution to the overall gas holdup in large diameter columns of very high viscosity oil (2022)
Journal Article
Mohammed, S. K., Hasan, A. H., Dimitrakis, G., & Azzopardi, B. J. (2022). Small bubbles formation and contribution to the overall gas holdup in large diameter columns of very high viscosity oil. International journal of multiphase flow, 152, Article 104104. https://doi.org/10.1016/j.ijmultiphaseflow.2022.104104

A limited number of studies are available in literature on the small bubbles which create from gas-very high viscosity oils interaction and its contribution to the gas holdup in the system. The rate of small bubble formation has an important impact o... Read More about Small bubbles formation and contribution to the overall gas holdup in large diameter columns of very high viscosity oil.

An experimental study on the effect of gas injection configuration on flow characteristics in high viscosity oil columns (2021)
Journal Article
Mohammed, S. K., Hasan, A. H., Ibrahim, A., & Dimitrakis, G. (in press). An experimental study on the effect of gas injection configuration on flow characteristics in high viscosity oil columns. The Canadian journal of chemical engineering, https://doi.org/10.1002/cjce.24312

Gas-viscous liquid bubbly and slug flow are very common in petroleum, chemical, bioengineering, polymer, and food processing. However, there is a major knowledge gap in two-phase flow research in the design of gas injectors/distributers in very high... Read More about An experimental study on the effect of gas injection configuration on flow characteristics in high viscosity oil columns.

Vertical upward and downward churn flow: Similarities and differences (2019)
Journal Article
Bouyahiaoui, H., Azzi, A., Zeghloul, A., Hasan, A. H., Al-Sarkhi, A., & Parsi, M. (2020). Vertical upward and downward churn flow: Similarities and differences. Journal of Natural Gas Science and Engineering, 73, Article 103080. https://doi.org/10.1016/j.jngse.2019.103080

Investigation of downward two-phase flows received less attention compared to the vertical upward flows. Downward flows are found in many industries and facilities including; oil/gas production, nuclear industry and petroleum refinery/production faci... Read More about Vertical upward and downward churn flow: Similarities and differences.

Experimental investigation of the vertical upward single and two-phase flow pressure drops through gate and ball valves (2019)
Journal Article
Zeghloul, A., Bouyahiaoui, H., Azzi, A., Hasan, A., & Al-sarkhi, A. (2020). Experimental investigation of the vertical upward single and two-phase flow pressure drops through gate and ball valves. Journal of Fluids Engineering, 142(2), Article FE-19-1329. https://doi.org/10.1115/1.4044833

This paper presents an experimental investigation of the pressure drop through valves in vertical upward flows. Experiments were carried out using a 1¼" (DN 32) ball and a gate valve. Five opening areas have been investigated from fully open to the n... Read More about Experimental investigation of the vertical upward single and two-phase flow pressure drops through gate and ball valves.

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.

Thin film thickness measurements in two phase annular flows using ultrasonic pulse echo techniques (2019)
Journal Article
Al-Aufi, Y., Hewakandamby, B., Dimitrakis, G., Holmes, M., Hasan, A., & Watson, N. (2019). Thin film thickness measurements in two phase annular flows using ultrasonic pulse echo techniques. Flow Measurement and Instrumentation, 66, 67-78. https://doi.org/10.1016/j.flowmeasinst.2019.02.008

The electric power generation and oil/gas production industries have a strong interest in the physical characterization of conducting and non-conducting liquid films that are formed during the flow of liquids in pipes. Conducting and non-conducting l... Read More about Thin film thickness measurements in two phase annular flows using ultrasonic pulse echo techniques.

Experimental study of the characteristics of an upward two-phase slug flow in a vertical pipe (2018)
Journal Article
Saidj, F., Hasan, A., Bouyahiaoui, H., Zeghloul, A., & Azzi, A. (2018). Experimental study of the characteristics of an upward two-phase slug flow in a vertical pipe. Progress in Nuclear Energy, 108, 428-437. https://doi.org/10.1016/j.pnucene.2018.07.001

Characteristics of the slug flow, mean void fraction, liquid slug and Taylor bubble lengths; and structure frequency were all extracted from the void fraction time series. Average void fractions at nine axial positions have been measured on a 6 m lon... Read More about Experimental study of the characteristics of an upward two-phase slug flow in a vertical pipe.

Experimental investigation of a vertically downward two-phase air-water slug flow (2017)
Journal Article
Bouyahiaoui, H., Azzi, A., Zeghloul, A., Hasan, A., & Berrouk, A. S. (2018). Experimental investigation of a vertically downward two-phase air-water slug flow. Journal of Petroleum Science and Engineering, 162, 12-21. https://doi.org/10.1016/j.petrol.2017.12.028

The present experimental work investigates the vertical downward two-phase slug flow in a transparent vertical pipe of 34 mm internal diameter. The gas and liquid superficial velocities are in the range of 0–3.27 m/s and 0.015–1.4 m/s respectively. T... Read More about Experimental investigation of a vertically downward two-phase air-water slug flow.

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, 16-29. https://doi.org/10.1016/j.ijmultiphaseflow.2017.11.018

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... Read More about Churn flow in high viscosity oils and large diameter columns.

Behavior and pressure drop of an upwardly two-phase flow through multi-hole orifices (2017)
Journal Article
Zeghloul, A., Azzi, A., Hasan, A., & Azzopardi, B. J. (2018). Behavior and pressure drop of an upwardly two-phase flow through multi-hole orifices. Proceedings of the Institution of Mechanical Engineers. Part C, Mechanical engineering science, 232(18), 3281-3299. https://doi.org/10.1177/0954406217736081

Experimental results on hydrodynamic behavior and pressure drop of two-phase mixture flowing upwardly in a pipe containing single- and/or multi-hole orifice plate are presented. It was found from the measurement of the void fraction upstream and down... Read More about Behavior and pressure drop of an upwardly two-phase flow through multi-hole orifices.

An experimental study of a falling liquid film in a vertical pipe (2017)
Conference Proceeding
Hasan, A., Azzopardi, B., Hewakandamby, B., Mohammed, S. K., & AlAufi, Y. (2017). An experimental study of a falling liquid film in a vertical pipe.

The majority of the experimental and theoretical studies in literature on the falling liquid film focus on either small diameter pipes or flat plates. Almost, all these studies provide time series data of the film thickness at a single point on the p... Read More about An experimental study of a falling liquid film in a vertical pipe.

Taylor bubbles at high viscosity ratios: experiments and numerical simulations (2015)
Presentation / Conference
Hasan, A., Hewakandamby, B., Azzopardi, B., Xie, Z., Pain, C., & Matar, O. (2015, November). Taylor bubbles at high viscosity ratios: experiments and numerical simulations. Presented at 68th Annual Meeting of the APS Division of Fluid Dynamics, USA, Boston

The Taylor bubble is a single long bubble which nearly fills the entire cross section of a liquid-filled circular tube, often occurring in gas-liquid slug flows in many industrial applications, particularly oil and gas production. The objective of th... Read More about Taylor bubbles at high viscosity ratios: experiments and numerical simulations.

Experimental study of interfacial structure of a falling liquid film in a vertical pipe (2015)
Presentation / Conference
Hasan, A., Azzopardi, B., & Hewakandamby, B. (2015, November). Experimental study of interfacial structure of a falling liquid film in a vertical pipe. Presented at American Physical Society-Fluid Dynamics Fall Meeting

Many studies in the literature provide time series data of the film thickness at one or two points on the pipe wall. Most of these studies focussed on either flat plates or small diameter pipes. The main aim of this paper is to study the characterist... Read More about Experimental study of interfacial structure of a falling liquid film in a vertical pipe.

Slugs in a large diameter column with air and high viscosity silicone oil (2014)
Presentation / Conference
Hasan, A., & Azzopardi, B. (2014, November). Slugs in a large diameter column with air and high viscosity silicone oil. Presented at 67th Annual Meeting of the APS Division of Fluid Dynamics, San Francisco, USA

Very little information is known about the behaviour of high viscous liquids (> 100 Pa.s) in two phase slug flows. Experiments were carried out to study the behaviour of silicone oil (300 Pa.s) in gas bubble column using electrical capacitance tomogr... Read More about Slugs in a large diameter column with air and high viscosity silicone oil.

Numerical study of Taylor bubbles with adaptive unstructured meshes (2014)
Presentation / Conference
Hasan, A., Xie, Z., Pavlidis, D., Percival, J., Pain, C., Matar, O., & Azzopardi, B. (2014, November). Numerical study of Taylor bubbles with adaptive unstructured meshes. Presented at 67th Annual Meeting of the APS Division of Fluid Dynamics, San Francisco, USA

The Taylor bubble is a single long bubble which nearly fills the entire cross section of a liquid-filled circular tube. This type of bubble flow regime often occurs in gas-liquid slug flows in many industrial applications, including oil-and-gas produ... Read More about Numerical study of Taylor bubbles with adaptive unstructured meshes.

Effect of vibration after filling on mechanical reliability in thin wall investment casting with fillability filling regime—part 1 (2013)
Journal Article
Abdul-Karem, W., Green, N., Al-Raheem, K. F., & Hasan, A. H. A. (2013). Effect of vibration after filling on mechanical reliability in thin wall investment casting with fillability filling regime—part 1. International Journal of Advanced Manufacturing Technology, 67(9-12), 2075-2082. https://doi.org/10.1007/s00170-012-4632-z

A vibration technique is used in this study to explore the effect of low frequency vibration on the mechanical reliability of Al-7Si-Mg castings. The quality of castings is related to the number and the size of porosity and oxide film in thin wall in... Read More about Effect of vibration after filling on mechanical reliability in thin wall investment casting with fillability filling regime—part 1.

Theoretical and experimental study of bubbly gas-water two phase flows through a Universal Venturi Tube (UVT) (2012)
Journal Article
Hasan, A. H. A. M., Hadawey, A., Al-Wahaibi, Y., Abdul-Karem, W., & Al-Raheem, K. F. (2012). Theoretical and experimental study of bubbly gas-water two phase flows through a Universal Venturi Tube (UVT). International journal of information and education technology, 2(1), 43-58

Unlike single phase flows, the relationship between the phase flow rate and the pressure drop across a differential pressure device (e.g. Venturi) in multiphase flow measurements is not simple and should include the phase volume fractions or the mass... Read More about Theoretical and experimental study of bubbly gas-water two phase flows through a Universal Venturi Tube (UVT).

Measurement of a void fraction in bubbly gas-water two phase flows using differential pressure technique (2012)
Journal Article
Hasan, A. Measurement of a void fraction in bubbly gas-water two phase flows using differential pressure technique. Applied mechanics and materials, 152-154, 1221-1226. https://doi.org/10.4028/www.scientific.net/amm.152-154.1221

Multiphase flows, where two or even three fluids flow simultaneously in a pipe are becoming increasingly important in industry. In order to measure the flow rate of gas-water two phase flows accurately, the void fraction (gas volume fraction) in two... Read More about Measurement of a void fraction in bubbly gas-water two phase flows using differential pressure technique.

Experimental and theoretical study of the gas–water two phase flow through a conductance multiphase Venturi meter in vertical annular (wet gas) flow (2010)
Journal Article
Hasan, A. H., & Lucas, G. (2011). Experimental and theoretical study of the gas–water two phase flow through a conductance multiphase Venturi meter in vertical annular (wet gas) flow. Nuclear Engineering and Design, 241(6), 1998-2005. https://doi.org/10.1016/j.nucengdes.2010.09.006

Annular gas-liquid two phase flow widely occurs in nuclear industry. Various combinations of techniques have been employed in annular gas-liquid two phase flows to measure the flow parameters (e.g. liquid film thickness, gas volume fraction and the p... Read More about Experimental and theoretical study of the gas–water two phase flow through a conductance multiphase Venturi meter in vertical annular (wet gas) flow.

Simulation and static measurement of the gas volume fraction in a separated flow model using a conductance multiphase Venturi meter (CMVM) (2008)
Conference Proceeding
Hasan, A., & Lucas, G. (2008). Simulation and static measurement of the gas volume fraction in a separated flow model using a conductance multiphase Venturi meter (CMVM). In Proceedings of Computing and Engineering Annual Researchers' Conference 2008: CEARC’08 (69-74)

The assumption of equal mixture densities at the inlet and the throat of the Venturi is only valid in a homogenous flow. This assumption is no longer valid for a separated flow and therefore, the measurement of the gas volume fraction at the throat m... Read More about Simulation and static measurement of the gas volume fraction in a separated flow model using a conductance multiphase Venturi meter (CMVM).

Modeling of a homogenous gas-water two phase flow through a Venturi and vertical pipe; (A prediction of pressure drop sign change in two phase flow) (2007)
Conference Proceeding
Hasan, A., & Lucas, G. (2007). Modeling of a homogenous gas-water two phase flow through a Venturi and vertical pipe; (A prediction of pressure drop sign change in two phase flow). In Proceedings of Computing and Engineering Annual Researchers' Conference 2007: CEARC’07

In two phase flow, differential pressures technique can be used to measure the volume fraction of the gas phase. In the case where no restriction is available in the pipeline, the differential pressure technique can be used only in vertical or incl... Read More about Modeling of a homogenous gas-water two phase flow through a Venturi and vertical pipe; (A prediction of pressure drop sign change in two phase flow).

Experimental characterization of interfacial wave structure of a falling liquid film in a vertical large pipe diameter
Conference Proceeding
Hasan, A., Azzopardi, B., Hewakandamby, B., AlAufi, Y., Watson, N., & Mohammed, S. (2016). Experimental characterization of interfacial wave structure of a falling liquid film in a vertical large pipe diameter.

There is considerable literature on the thicknesses of falling liquid films, much of which is focussed on either flat plates or small diameter pipes. Many studies provide time series data of the film thickness at one or two points on the pipe wall. T... Read More about Experimental characterization of interfacial wave structure of a falling liquid film in a vertical large pipe diameter.

Modelling and measurement of the gas flow rate in vertical annular gas-water flow using a conductance multiphase Venturi meter
Conference Proceeding
Hasan, A., & Lucas, G. (2009). Modelling and measurement of the gas flow rate in vertical annular gas-water flow using a conductance multiphase Venturi meter.

Separated flow in a Venturi meter is highly complex and the application of a homogenous flow model could not reasonably be expected to lead to highly accurate results. If this is the case, a gas volume fraction measurement technique at the throat mus... Read More about Modelling and measurement of the gas flow rate in vertical annular gas-water flow using a conductance multiphase Venturi meter.