In June, Doctoral Researchers Eleanor Borrill and Mahmoud Gadelhaq presented their research at the 13th Mediterranean Combustion Symposium in Corfu, Greece.
The symposium (1-5 June 2025) brought together around 400 researchers in combustion science to explore recent research developments, especially in low-carbon fuels and hydrogen technologies. It also included a Turbulent Combustion of Sprays workshop.
Mahmoud Gadelhaq is a PhD researcher based in the Ella Armitage building at the University of Sheffield, supported by an Engineering and Physical Sciences Research Council Doctoral Training Partnerships (EPSRC DTP) scholarship, and affiliated with the Energy Institute, and is a member of the Energy 2050 research group. His research interests include decarbonisation of the glass industry via a holistic approach, investigating the technical aspects of hydrogen implementation in addition to the effect of using hydrogen on the environment through life cycle analysis (LCA).
Mahmoud presented his work on the submitted paper titled, ‘Insights from the Optimisation of a Pilot Glass Test Furnace Operating Conditions and the Environmental Impacts of Decarbonisation Using Hydrogen’. The presentation examined how hydrogen can decarbonise glass manufacturing. It detailed experimental results from a pilot-scale glass furnace, evaluating:
- Operational variables optimised for hydrogen combustion
- Emission reductions relative to natural gas
- Environmental benefits through life-cycle impact assessment.
Hydrogen usage comes with significant challenges, such as high flame temperatures resulting in more NOx (Nitrogen Oxides) production. Moreover, the hydrogen production technique plays a major role in the environmental effects of glass produced using hydrogen combustion. Mahmoud’s research presented an optimised way of using the fuel in the glass furnace as well as showing the effect of hydrogen usage on the environment, whilst identifying the hot points that need to be addressed to obtain cleaner hydrogen.
Industrial glass production is inherently energy-intensive, traditionally relying on natural gas and contributing heavily to CO₂ emissions. Recent industry trends, such as 100% hydrogen trials at SCHOTT and AGC, and UK HyNet hydrogen firing pilots, show promising pathways to net-zero glass manufacturing. Mahmoud’s research provides experimental evidence on operating parameters and emissions, contributing valuable data toward these emerging global efforts.
Eleanor Borrill is an Engineering and Physical Sciences Research Council (EPSRC)-funded member of the Energy Institute and Energy 2050 research group, based in the School of Mechanical, Aerospace, and Civil Engineering. Her multidisciplinary PhD research focuses on sustainable aviation fuels (SAF), spanning experimental SAF combustion research and SAF supply-chain management. She has also recently joined the South Yorkshire Sustainability Centre as a research associate, where her work centres on SAF lifecycle assessment (LCA), supply-chain resilience modelling, and decision-making science.
At the conference, Eleanor presented her research titled ‘Effect of Primary Dilution Air on Lean Flammability Limits of Turbulent Ethanol Bluff Body Stabilised Swirl Spray Flames’.
Motivated by the global push for cleaner combustion technologies, especially in aviation, reducing emissions and improving fuel efficiency are essential for net-zero goals. Lean combustion is desirable for reducing emissions and improving fuel economy, but it increases the risk of lean blow-out (LBO), where the flame extinguishes due to insufficient heat release. Maintaining flame stability under lean conditions is critical, particularly in gas turbine engines. While prior studies have demonstrated that downstream-injected dilution air can mitigate emissions, especially NOx, its role in flame stabilization—particularly when injected upstream—has not yet been explored.
This paper is the first to systematically investigate the effects of dilution air injection in the primary combustion zone on the LBO behaviour, heat release, and flow dynamics of a turbulent ethanol bluff-body stabilised swirling spray flame. It provides experimental evidence that dilution air can enhance flame stability and improve combustion efficiency through more compact and stable flame structures.
Professor Lenny Koh, a co-supervisor of the researchers from the Sheffield University Management School, said, "Sustainable aviation fuel and hydrogen are two strategically important capabilities to deliver resilient advanced manufacturing, aligning with the net zero goal, energy and industrial strategy. The Energy Institute is playing a key role and being able to share two examples of fundamental research projects on an international stage is fantastic for our researchers. This cutting-edge work also underscores the scalability of new technology based on supply chain sustainability which are directly relevant in the global aerospace, energy and manufacturing industry."