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Slug frequency for a gas-liquid viscous flow in vertical pipes (2024)
Presentation / Conference Contribution
Magit, K., Hann, D., Hewkandamby, B., & Kisha, W. (2024, August). Slug frequency for a gas-liquid viscous flow in vertical pipes. Paper presented at 10th World Conference on Experimental Heat Transfer, Fluid Mechanics and Thermodynamics, Rhodes Island, Greece

Slug frequency is an important parameter for designing industrial installations with intermittent gas-liquid flows. The literature contains several empirical correlations to predict this parameter, but most studies have focused on air and water, with... Read More about Slug frequency for a gas-liquid viscous flow in vertical pipes.

Characterising Horizontal Two-Phase Flows Using Structured-Planar Laser-Induced Fluorescence (S-PLIF) Coupled With Simultaneous Two-Phase PIV (S2P-PIV) (2024)
Presentation / Conference Contribution
Sherif, A. A., Hann, D. B., & Johnson, K. (2024, July). Characterising Horizontal Two-Phase Flows Using Structured-Planar Laser-Induced Fluorescence (S-PLIF) Coupled With Simultaneous Two-Phase PIV (S2P-PIV). Presented at 21st International Symposium on Applications of Laser and Imaging Techniques to Fluid Mechanics, Lisbon, Portugal

Understanding the physics that underpins the behaviors of two-phase flows is immensely useful for a diverse number of industries, including oil and gas, nuclear, and aerospace. Stratified air-liquid two-phase flows are amenable to the application of two... Read More about Characterising Horizontal Two-Phase Flows Using Structured-Planar Laser-Induced Fluorescence (S-PLIF) Coupled With Simultaneous Two-Phase PIV (S2P-PIV).

Comparative Analysis Of Brightness-Based Laser-Induced Fluorescence (BBLIF) And Structured Planar Laser-Induced Fluorescence (S-PLIF) For Film Thickness Measurement In Two-Phase Flow (2024)
Presentation / Conference Contribution
Sherif, A. A., Johnson, K., & Hann, D. (2024, July). Comparative Analysis Of Brightness-Based Laser-Induced Fluorescence (BBLIF) And Structured Planar Laser-Induced Fluorescence (S-PLIF) For Film Thickness Measurement In Two-Phase Flow. Presented at 21st International Symposium on Applications of Laser and Imaging Techniques to Fluid Mechanics, Lisbon Portugal

Improved understanding of the interactions between gas and liquid phases in gas sheared film flow is crucial for n improved capability to employ computational modelling in the future to optimize systems, thereby reducing environmental impact, increas... Read More about Comparative Analysis Of Brightness-Based Laser-Induced Fluorescence (BBLIF) And Structured Planar Laser-Induced Fluorescence (S-PLIF) For Film Thickness Measurement In Two-Phase Flow.

Experimental investigation into oil film thickness and behaviour near an aero-engine bearing (2022)
Presentation / Conference Contribution
Sinha, A., Hann, D., Johnson, K., & Walsh, M. (2022, June). Experimental investigation into oil film thickness and behaviour near an aero-engine bearing. Presented at ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition, Rotterdam, Netherlands

In an aero-engine transmission system, bearings are used for shaft location and load support. These bearings are housed in bearing chambers and oil is supplied to the chamber for lubrication and cooling. To achieve the targets of ACARE Flightpath 205... Read More about Experimental investigation into oil film thickness and behaviour near an aero-engine bearing.

How Do Interfacial Shear and Gravity Affect the Oil Film Characteristics Near an Aero-Engine Bearing? (2022)
Journal Article
Sinha, A., Brewster, B., Johnson, K., Walsh, M., & Hann, D. (2022). How Do Interfacial Shear and Gravity Affect the Oil Film Characteristics Near an Aero-Engine Bearing?. Journal of Engineering for Gas Turbines and Power, 144(10), Article 101001. https://doi.org/10.1115/1.4055211

Recent demand for reducing carbon emission and for increasing engine efficiency has led aero-engine manufacturers to strive for a better oil flow system. Aero-engine bearing chambers that house the shaft-support bearings are among the most challengin... Read More about How Do Interfacial Shear and Gravity Affect the Oil Film Characteristics Near an Aero-Engine Bearing?.

Can simultaneous PIV in the gas and liquid phases provide insight into the transfer of momentum between the two phases? (2022)
Presentation / Conference Contribution
Kim, J. H., Hann, D. B., Eastwick, C. M., & Cherdantsev, A. V. (2022, July). Can simultaneous PIV in the gas and liquid phases provide insight into the transfer of momentum between the two phases?. Presented at 20th International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics, Lisbon, Portugal

Understanding the interaction between a gas shearing over a liquid film and the liquid film is essential if we wish to use modeling to optimize systems to decrease environmental impact, increase efficiency and hence productivity. To this end, PIV is... Read More about Can simultaneous PIV in the gas and liquid phases provide insight into the transfer of momentum between the two phases?.

Experimental Investigation Into Oil Film Thickness and Behaviour Near an Aero-Engine Bearing (2022)
Presentation / Conference Contribution
Sinha, A., Hann, D., Johnson, K., & Walsh, M. (2022, June). Experimental Investigation Into Oil Film Thickness and Behaviour Near an Aero-Engine Bearing. Presented at ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition, Rotterdam, Netherlands

In an aero-engine transmission system, bearings are used for shaft location and load support. These bearings are housed in bearing chambers and oil is supplied to the chamber for lubrication and cooling. To achieve the targets of ACARE Flight-path 20... Read More about Experimental Investigation Into Oil Film Thickness and Behaviour Near an Aero-Engine Bearing.

Studying the impacts of droplets depositing from the gas core onto a gas-sheared liquid film with stereoscopic BBLIF technique. (2022)
Journal Article
Cherdantsev, A. V., Sinha, A., & Hann, D. B. (2022). Studying the impacts of droplets depositing from the gas core onto a gas-sheared liquid film with stereoscopic BBLIF technique. International Journal of Multiphase Flow, 150, Article 104033. https://doi.org/10.1016/j.ijmultiphaseflow.2022.104033

In annular gas-liquid flow, the droplets are torn from the liquid film surface by the turbulent gas stream, accelerate due to the gas drag force and eventually deposit back onto the wavy film surface, hitting it with a high speed at a shallow angle.... Read More about Studying the impacts of droplets depositing from the gas core onto a gas-sheared liquid film with stereoscopic BBLIF technique..

How do the liquid properties affect the entrapment of bubbles in gas sheared liquid flows? (2021)
Journal Article
Sinha, A., Cherdantsev, A., Johnson, K., Vasques, J., & Hann, D. (2021). How do the liquid properties affect the entrapment of bubbles in gas sheared liquid flows?. International Journal of Heat and Fluid Flow, 92, Article 108878. https://doi.org/10.1016/j.ijheatfluidflow.2021.108878

A large number of industries use fossil fuels for the purpose of cooling and lubrication utilizing a gas stream that acts as a shearing force on the liquid surface. Decreasing the carbon footprint of these processes needs an improved understanding of... Read More about How do the liquid properties affect the entrapment of bubbles in gas sheared liquid flows?.

Asymmetrically heated multi-stage travelling-wave thermoacoustic electricity generator (2021)
Journal Article
Kisha, W., Riley, P., McKechnie, J., & Hann, D. (2021). Asymmetrically heated multi-stage travelling-wave thermoacoustic electricity generator. Energy, 235, Article 121312. https://doi.org/10.1016/j.energy.2021.121312

Recent developments of thermoacoustic engines have demonstrated that thermoacoustic technology is a viable option for waste heat recovery and low-cost electricity generation, Thermoacoustic technology is capable of converting low-grade heat to electr... Read More about Asymmetrically heated multi-stage travelling-wave thermoacoustic electricity generator.

Numerical Optimisation of the Regenerator of a Multi-stage Travelling Wave Thermoacoustic Electricity Generator (2021)
Presentation / Conference Contribution
Kisha, W., & Hann, D. (2019, September). Numerical Optimisation of the Regenerator of a Multi-stage Travelling Wave Thermoacoustic Electricity Generator. Presented at 16th UK Heat Transfer Conference (UKHTC2019), Nottingham, UK

In a travelling wave thermoacoustic engine, the regenerator is the heart of the engine [1], where the thermal interaction between the working gas and the solid material takes place. Unlike the stack in standing wave engine, the regenerator is more of... Read More about Numerical Optimisation of the Regenerator of a Multi-stage Travelling Wave Thermoacoustic Electricity Generator.

Thermoacoustic Electricity Generator for Rural Dwellings in Developing World (2021)
Presentation / Conference Contribution
Kisha, W., & Hann, D. (2019, September). Thermoacoustic Electricity Generator for Rural Dwellings in Developing World. Presented at 16th UK Heat Transfer Conference, Nottingham, UK

Thermoacoustic seems to be a promising technology for waste heat recovery (Blok in J. Acoust. Soc. Am. 123:3541–3541, 2008;Abdoulla-Latiwish et al. in Energy 134:1107–1120, 2017;) and are subject to steadily growing interest, particularly in the fiel... Read More about Thermoacoustic Electricity Generator for Rural Dwellings in Developing World.

The use of POD filtering to study the transition from 2D to 3D in stratified two- phase flow (2018)
Presentation / Conference Contribution
Hann, D. B., Loizou, K., Vasques, J., Tokarev, M. P., & Cherdantsev, A. V. (2018, July). The use of POD filtering to study the transition from 2D to 3D in stratified two- phase flow. Presented at 19th International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics, Lisbon, Portugal

The understanding of the velocity profile beneath waves in sheared flow can have implications for the understanding of heat transfer in many applications. In this paper an analysis of the velocity field beneath 2D and 3D waves is performed to underst... Read More about The use of POD filtering to study the transition from 2D to 3D in stratified two- phase flow.

The Influence of Heat Input Ratio on Electrical Power Output of a Dual-Core Travelling-Wave Thermoacoustic Engine (2018)
Presentation / Conference Contribution
Kisha, W., Riley, P. H., Mckechnie, J., & Hann, D. (2018, September). The Influence of Heat Input Ratio on Electrical Power Output of a Dual-Core Travelling-Wave Thermoacoustic Engine. Presented at The 8th Heat Powered Cycles Conference, The University of Bayreuth, Bayreuth, Germany

This paper presents an analytical and experimental investigation of an electricity generator that employs a two-stage looped tube travelling-wave thermoacoustic prime-mover to deliver acoustic power from heat energy, a loudspeaker to extract electric... Read More about The Influence of Heat Input Ratio on Electrical Power Output of a Dual-Core Travelling-Wave Thermoacoustic Engine.

Development of a low-cost, electricity-generating Rankine Cycle, alcohol-fuelled cooking stove for rural communities (2018)
Presentation / Conference Contribution
Kisha, W., Riley, P. H., & Hann, D. (2018, September). Development of a low-cost, electricity-generating Rankine Cycle, alcohol-fuelled cooking stove for rural communities. Presented at The 8th Heat Powered Cycles Conference, University of Bayreuth, Bayreuth, Germany

This article describes a novel design and construction of a helical tube flash boiler that uses a 2kW nominal methylated spirit burner to heat an approximately 2.5m long coil of copper pipe fed by a nominal 8 bar electrically operated solenoid water... Read More about Development of a low-cost, electricity-generating Rankine Cycle, alcohol-fuelled cooking stove for rural communities.

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.

Comparison of disturbance wave parameters with flow orientation in vertical annular gas-liquid flows in a small pipe (2018)
Journal Article
Vasques, J., Cherdantsev, A. V., Cherdantsev, M., Isaenkov, S., & Hann, D. B. (in press). Comparison of disturbance wave parameters with flow orientation in vertical annular gas-liquid flows in a small pipe. Experimental Thermal and Fluid Science, 97, https://doi.org/10.1016/j.expthermflusci.2018.03.020

The interfacial wave structure of the liquid film in both upward and downward annular gas-liquid flows in an 11.7 mm pipe were investigated using the Brightness Based Laser Induced Fluorescence technique (BBLIF). Film thickness measurements were carr... Read More about Comparison of disturbance wave parameters with flow orientation in vertical annular gas-liquid flows in a small pipe.

Experimental investigation of oil shedding from an aero-engine ball bearing at moderate speeds (2017)
Presentation / Conference Contribution
Santhosh, R., Hee, J. L., Simmons, K., Johnson, G., Hann, D., & Walsh, M. (2017, June). Experimental investigation of oil shedding from an aero-engine ball bearing at moderate speeds. Presented at ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition, Charlotte, North Carolina, USA

In civil aero-engine transmission system bearings are used for shaft location and load support. An experimental test facility in the University of Nottingham's Gas Turbine Transmissions Research Centre (G2TRC) was designed and commissioned to investi... Read More about Experimental investigation of oil shedding from an aero-engine ball bearing at moderate speeds.