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Abstract

Innovations in propulsion systems have been a main driver of progress in aviation. The current dependence on fossil fuels and their increasing use due to the continuous growth of air transport suggest that alternative solutions must be considered to reduce emissions as well as alleviate shortage issues that may arise in the future. To tackle these issues, innovative solutions including novel cycle arrangements for higher efficiency and the use of alternative, potentially zero emissions fuels have been investigated in recent years.

With regards to the low cycle efficiency affecting small power rating gas turbines, recovery of waste heat from the exhaust gases represents a possible remedy, typically used in ground applications. Further remedies have been identified: the adoption of an intercooler, for instance. The implementation of these remedies has the potential to improve the efficiency of the power plant. However, they usually lead to reduce the specific installed power, mainly due to the added weight of extra components needed. As the weight is a key parameter for aeroengines, an analysis that addresses the performance trade-off between t he improved power plant efficiency and its larger weight on the fuel economy is required to determine if the added complexity is justified f or typical flight missions.

As far as alternative fuels are concerned, liquid hydrogen is considered an appealing energy carrier for aeronautical applications. In fact, its amount of energy per unit mass is about three times greater than jet fuel. Moreover, the non-pressurized liquid state allows hydrogen the highest amount of energy per unit volume, which results in relatively moderate size and weight of the storage tanks. These aspects suggest there could be a case to take advantage of this weight saving to introduce cycles that can reach higher efficiency despite a more complex, thus heavier configuration.

During the upcoming months of this research project, part of the European project NextMGT, trade-off studies will be conducted to assess the multi-fuel performance of propulsion systems based on novel cycles obtained by modification of a simple cycle micro gas turbine. To this extent, a numerical model simulating design and off-design steady state operation of an aeronautical engine will be developed and integrated with aircraft performance and mission analysis tools. This simulation framework enables the calculation of the fuel consumption of the different engine arrangements, under a set of defined realistic flight missions.

Finally, the results obtained could be used to provide recommendations for the most beneficial cycles innovations to the overall efficiency of MGT-based aeronautical propulsion systems, improving engine performance and minimizing environmental impact.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TJ Mechanical engineering and machinery T Technology > TL Motor vehicles. Aeronautics. Astronautics
Departments:	School of Science & Technology > Engineering > Mechanical Engineering & Aeronautics School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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