Aircraft Electrical Propulsion for High-Speed Flight: Rim Driven Fan (RDF) Technology
AuthorsBolam, Robert C.
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AbstractThe aim of this programme of studies is to research and develop electrical Rim Driven Fan (RDF) technology for high-speed aircraft propulsion and to provide knowledge to support Society’s efforts to combat climate change using zero-emission technologies. The objectives were to conduct research into the state-of-the-art of aircraft electrical propulsion, to estimate the performance of single and dual stage contra-rotating fans over a range of diameters, to provide a methodology to enable the aerodynamic design and detailed Computational Fluid Dynamic (CFD) analyses of small contra-rotating fans and to create a conceptual design for an RDF device suitable to power an unmanned aircraft. In completing this work, literature reviews were carried out on electrically powered propulsion for aircraft, electrical motor technologies and rim drive technology for aircraft propulsion. Original research was undertaken in the form of aerodynamic analyses, using derived numerical and CFD techniques, to determine the optimum performance of single and dual stage (contrarotating) rim driven fans for high-speed electric aircraft applications. Original research was also undertaken in the form of electrical analyses using Motor-CAD finite element software to analyse the feasibility of novel rim-drive concepts such as slotless stator designs, aluminium windings and iron-less rotors with Halbach magnet arrays in an RDF context. The results of these studies have contributed new knowledge that has been peer-reviewed and internationally published. An original RDF design concept, suitable to power an unmanned aircraft, was devised and a UK patent application filed. The main findings of this work are that RDF technology offers a viable means of high-speed aircraft propulsion with a dual-stage contrarotating, air-cooled fan arrangement. That optimum RDF power density is achieved with slotless windings and iron-less rotors configured with Halbach magnet arrays which reduce their rotating mass. These findings have enabled a feasible novel RDF design to be created which is a significant contribution in the field of electrical aircraft propulsion. The results of this work also contribute the significant new knowledge that dual stage contra-rotating RDF configurations provide the potential for an increase in thrust per frontal area, and higher exhaust-air velocities, when compared with existing hub-driven fan technologies. This work has established a novel fan design technique, that can be used by technologists to analyse and design future electrical fan concepts, and offers a significant contribution towards Society’s efforts to combat climate change with zero-emission technologies. Opportunities for further areas of study in this field are in the analyses of large diameter high thrust versions of RDFs suitable for large manned aircraft and hovercraft applications.
CitationBolam, R. C. (2021). Aircraft electrical propulsion for high-speed flight: Rim driven fan (RDF) technology [Unpublished doctoral thesis]. University of Chester & Wrexham Glyndŵr University
PublisherUniversity of Chester
TypeThesis or dissertation
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