Renewable Fuels Combustion – Sustainable route for the future?

Elisa Wylie is our second PhD candidate, working under the umbrella of the Advanced Engineering Centre. She is both an ardent environmentalist, and, also, a petrol head, so she’s investigating the feasibility of renewable chemical fuels in advanced engines for a sustainable transportation sector.

Elisa says, in order to address the root cause of the emissions problem, I am using a combustion focused approach (Fig 1), facilitated by numerical methods. This generates three themes of focus for my work: the fuel, the technique and the engine (Fig 2).

Firstly, the fuel. This research is focused on chemical fuels in engines. Hydrogen carrier e-fuels, (H2, NH3, CH4), have the potential to bridge the transition to a sustainable future for hard to electrify heavy-duty applications. The question is, what e-fuel mixture can match or exceed diesels performance whilst also meeting net zero emissions targets? To answer this question, I will map out the combustion chemistry of renewable fuels and their blends and undertake parameter studies of fuel blends validated against experimental data. My work so far has shown that hydrogen and hydrogen/methane mixtures can match performance and emissions targets of best in class.

Secondly, the technique.  Engaging in numerical combustion chemistry requires the use of a software tool. Ansys Chemkin-Pro has been extensively validated in a range of environments and enables the rapid solution of chemically reacting mixtures. As with any software application, the output is only as accurate as the input allows. With Chemkin Pro, an important input is the gas phase kinetics mechanism. This mechanism describes the interactions and reaction rates of a fuel and oxidiser mixture and requires validation against experimental data. So far, project output includes a novel kinetic mechanism for hydrogen/air mixtures in high pressure, low temperature conditions, relevant to low emissions engine operation. Further refinement of this, and extension to other e-fuels, particularly NH3 for marine applications, is a part of future work and I am seeking collaboration in this area.

Finally, the engine. This research is focused on heavy-duty engines, which have relied on diesel compression ignition engines. Despite development including innovative valve timings, lean homogenous ignition and energy recuperation, these engines are reaching their limits in terms of efficiency and emissions, a catch phrase for sustainable development. Alternative approaches, such as a recuperated split cycle engine or double compression expansion engine, offer potential step changes in terms of efficiency, whilst also taking advantage of mature and familiar platforms. The question is, what engine architecture is compatible with hydrogen carrier fuels? In this project experimental data from our team is also being analysed. This data can then be used as experimental validation points for the numerical simulation model allowing us to produce a digital twin of the engine, and subsequent parameter studies will push the limits of operation.

These three areas of focus aim to map out a route to a sustainable future for heavy-duty engines. If you are interested, want to collaborate on, from modelling to experimental approaches for implementation of renewable fuels, then contact me at E.G.Wylie@brighton.ac.uk.

Also, check out the below recording, during the early stages of the works. This was used to set the scene for the main topic of Renewable Fuels Combustion.

Want to know more about the ‘renewable fuel combustion’ themed PhD research? Contact Elisa Wylie