EPSRC ICASE/Rolls Royce - Hydrogen Fuel Flow Control for Zero Carbon propulsion systems

Project Description This project falls within the EPSRC Engineering research area. The studentship is jointly offered by the University of Oxford and Rolls-Royce under the EPSRC iCase award scheme.

Hydrogen as a fuel in aircraft propulsion is one potential avenue in achieving carbon reduction. One of the big challenges for hydrogen fuelled aerospace propulsion is the use of liquid hydrogen to enable higher payload/range aircraft. Liquid Hydrogen requires compression and heating before being metered ahead of introduction in the combustion chamber.

Aerospace requirements for accurate steady and transient fuel flow metering in challenging operating temperature and vibration environments drives the need for bespoke innovative reliable low weight solutions. There is also a potential need for modulated metering of individual combustor burner flows where there are few technological solutions present due to high temperature environment.

The main objective of this project is to investigate novel fluidic valve concept with the application to hydrogen fuel flow metering. Fluidic devices utilize fluid mechanic phenomena to control the behaviour of a subject fluid (such as hydrogen fuel) while removing the need for any moving parts. Previous work has looked at fluidic diverters and switched vortex valves. This work will research the working principle of a novel opposed jet amplifier device

The Opposed Jet Amplifier theoretically works by pointing two jets of the same fluid at each other, using one small but powerful jet to cut off a less powerful jet coming from a larger inlet. While it is known that a smaller jet can in fact cut off the flow of a larger one (as long as the jet velocities are different), the exact relationship between the size of the jets and what jet velocities are required is not yet known and will likely determine the viability of such class of devices.

The first aim of this research is to characterise performance of a canonical version of the device under series of conditions. As the device utilises opposing jets that are inherently unstable and so detailed computational and experimental studies will be carried out to understand optimum performance. Finally a more engine scale geometry will be developed and tested.

Throughout this research a multitude of engineering methodologies are being used to determine and improve the performance of the device. 3D printing is being used to prototype the device and evaluate initial performance. This is being used in conjunction with computational fluid dynamics to simulate performance at conditions that can't be tested with a prototype device (such as at very high pressures).

Analytical predictions are also being carried out to compare with experiments and computational studies. The research project will therefore include: Research into fluid dynamics of opposed jets Investigation into analytical modelling of the device operation Computational modelling of the canonical device behaviour and experimental validation on low pressure facilities.

Preliminary design of a suitable engine scale device and testing This project falls within the EPSRC Fluid dynamics, aerodynamics and control research areas.