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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"aeroengine"”.
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Predicting fan noise propagation in aeroengine bypass ducts
This thesis explores the prediction of rearwards fan noise propagation within the bypass duct and its radiation into the far feld. Two recently developed models: B-induct and GXMunt, are exploited in application to real engine bypass ducts and their performance is evaluated. These methods are an …
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Parametric dependencies of aeroengine flutter for flutter clearance applications
… the effects of operational parameters upon aeroengine flutter stability. The study is composed of three parts: theoretical development of relevant parameters, exploration of a computational model, and analysis of fully scaled test data. Results from these studies are used to develop a …
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Fuel Droplet Optical Diagnostic Techniques for Lean Premixed Prevaporized Aeroengine Combustors
Recent advancements in civil supersonic transport (CST) have sparked interest in developing new technologies aimed at reducing the environmental impact of CST jet engines. Because these engines require lower pressure and bypass ratios, they tend to consume more fuel and produce higher emissions …
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In-duct measurement techniques for the characterisation of broadband aeroengine noise
The focus of this thesis is the measurement of broadband fan noise, which due to reductions in tonal and jet noise, is now the dominant source at approach, and a major contributor at takeoff. This thesis proposes three new in-duct measurement techniques for the characterisation and measurement of …
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Design Optimisation and Flow Characterisation for Future Aeroengine Axial Fan Blades
The increased need to design higher performing aerodynamic shapes has led to design optimisation cycles requiring high-fidelity CFD models and high-dimensional parametrisation schemes. The computational cost of employing global search algorithms on such scenarios has typically been prohibitive for …
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Laser Induced Incandescence for Volume Fraction and Relative Particle Size Measurements in a Rich-Quench-Lean Jet A Combustor
… mostly of soot, is an important goal for modern aeroengine combustors. Not only does soot production reduce engine performance, but it also creates unwanted pollution. In order to understand soot production in realistic environments, this thesis focuses on the measurement of soot volume fraction …
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Mathematical modelling of noise generation in turbofan aeroengines using Green’s functions
… level. One of the key noise components is the aeroengine. Building and designing an aeroengine costs millions of pounds and furthermore, to prove the aeroengine is safe, it has to be tested to destruction. Engineers and mathematicians are employed to design aeroengines that will not only be …
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The machinability of a gamma titanium aluminide intermetallic
… and low pressure (LP) turbine sections of an aeroengine due to the alloys high temperature (~800C) and low weight properties. Following a literature review, the thesis details the results from two phases of experimental work. The first focused on high speed milling trials using coated tungsten …
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Design of a High Specific Power Electric Machine for Turboelectric Propulsion
… pressure compressor of a low fan pressure ratio aeroengine. The specific power of the integrated compressor generator is estimated to be 14.8 kW/kg, exceeding the NASA 2030 goal for aviation applications of 13 kW/kg for a standalone electric machine for aviation applications. Relative to a …
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Characterization and mitigation of blade waviness effects on fan performance
… from carbon composite manufacturing process, on aeroengine fan blade performance is characterized. The mechanisms for laminar-turbulent transition are assessed numerically and experimentally over relevant range of aerodynamic and geometric parameters. The governing mechanism (natural transition …
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Finite element analysis of combined fracture and delamination on coated substrate under normal and tangential loading
… pressure and sliding contact. In this thesis, aeroengine brittle material has been modelled to simulate coating failure under combined fracture and delamination failure. Hard brittle coatings modelled are subjected to normal and tangential loads through a finite element (FE) based methodology. …
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The acoustics of curved and lined cylindrical ducts with mean flow
… This is aimed at modelling a surge event in an aeroengine with a convoluted intake.
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The Effects of Shrouded Rotor Tip Leakage Flow on the Downstream Stator Aerodynamics in Turbines
In modern civil aeroengines the fan is driven by the low pressure turbine. In order to match the low rotational speed of the fan, the low pressure turbine consists of large diameter components and several stages, up to six or seven. An individual stage of a low pressure turbine consists of a row of …
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Shape Optimization of Annular Combustors with an Open Source Parallelized Thermoacoustic Helmholtz Solver
… simple demonstration cases, and an industrial aeroengine combustor geometry, which is more complicated. We use the same analysis as in the cases with NURBS parametrization, but for FFD control points. We modify the FFD control point positions in order to reduce the thermoacoustic growth rates …
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A Low Order Aerodynamic Model of Embedded Total Temperature Probes
… downstream of fans is of primary importance to aeroengine development. Historically, these measurements have been acquired with the use of traditional total condition probes mounted to the guidevanes or engine cowling; however, such a setup can have significant impact on the flow. Difficulties …
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Microstructural Evolution in Refractory Metal Multi-Component Alloy Systems
Aeroengine and power-generation efficiency targets demand higher operating temperatures than those tolerated by current Ni-based superalloys, motivating the search for alternative high temperature materials. Refractory superalloys based on AlTaTiZr and AlMoNbTaTiZr have attracted particular …
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The use of air assisted atomised water spray systems for controlled cooling of high temperature forgings
… of air assisted atomised water sprays to quench aeroengine components from temperatures of approximately 850°C. New data were obtained at high temperatures for air assisted atomised water sprays operating over a wide range of water mass fluxes, (8.01>w 0 >0kg/m2 .s).<br/>In practice the geometry …