Global ETD Search
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 20 of 33 for “"Aero-engine"”.
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Multidisciplinary Optimization of Next-Generation Aero-Engine Fans
… The role of sustainability in the modern aeronautics has gained a growing importance, and has been identified as a key challenge facing the aviation industry. Today, sustainability is one of the main agents pushing jet engine manufacturers towards the design of machines that consume less …
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Lead Time Reduction in the Aero Engine Overhaul Industry
… times of the strip to detail inspection of an aero engine overhaul facility. To achieve this, various methods were used. Initially dealing with the justification and construction of a simulation model followed by an examination of various scenarios to achieve the required reduction.<br/><br/>On …
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Advances in tunable diode laser spectroscopy for aero engine research
… of CO2 in the harsh environment of a gas turbine engine (GTE). The work is part of a much larger initiative called Fibre Laser Imaging of gas Turbine Exhaust Species (FLITES) aimed at obtaining concentration distributions of gas species such as CO2 and NO, unburnt hydrocarbons, and soot in a gas …
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Forced Response System Identification of Full Aero-Engine Rotordynamic Systems
… challenges have surfaced in advanced turbofan engine designs where there are opportunities for dynamical coupling between rotor shafts and support structures, requiring entire system-level assessment. Addressing such vibration challenges relies on knowledge of damping levels in the system, but …
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Near infrared tunable diode laser spectroscopy for aero engine related applications
… harsh detection environments, particularly for aero engine diagnostics, are considered. For stand-alone instrumentation, calibration-free direct absorption measurements are highly advantageous yet calibrated techniques employing wavelength modulation spectroscopy are often favoured due to their …
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Numerical Modelling of Shock Wave Boundary Layer Interactions in Aero-engine Intakes at Incidence
Aero-engine intakes play a critical role in the performance of modern high-bypass turbofan engines. It is their function to provide uniformly distributed, steady air flow to the engine fan face under a variety of flow conditions. However, during situations of high incidence, high curvature of the …
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System theoretic framework for assuring safety and dependability of highly integrated aero engine control systems
… of complex, safety-critical systems for aero-engine control is subject to the, often competing, demands for higher safety and reduced development cost. Although the commercial aerospace industry has a general good safety record, and has placed much emphasis on process improvement within a …
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A systems engineering approach to aero engine development in a highly distributed engineering and manufacturing environment
Engineering and Manufacturing firms face increasing pressure to continuously improve product development performance in terns of time to market, development cost, and customer satisfaction. The product development organization continues to evolve, first from a strictly functional focus to a product …
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Flow and Thermal Field Measurements in a Combustor Simulator Relevant to a Gas Turbine Aero-Engine
… to the well-known Brayton cycle is key to higher engine efficiencies. The desire for increased turbine inlet temperatures creates an extremely harsh environment for the combustor liner in addition to the components downstream of the combustor. Shear layers between the dilution jets and the …
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A Study of the Effects of Laser Shock Peening on Residual Stress, Microstructure and Local Properties of IN718 Ni-Base Superalloy
… effects of Laser shock peening (LSP) on two aero engine alloys, IN718 and IN718 SPF were studied. The primary goal of the program was to secure required fundamental knowledge of e impact of LSP process parameters on these two aero engine alloys and thereby advance the science and application …
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Characterization of cavitation instabilities in rocket engine turbopump inducers
… of cavities around the periphery of rocket engine turbopump inducers, rotating cavitation is the primary cavitation instability considered in this thesis. A recently developed hypothesis for rotating cavitation onset is assessed through novel experimental analysis and a previously developed …
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Experimental design to determine the effect of temperature and Mach number on entropy noise
… The apparatus simulates entropy noise in an aero engine. In the test rig, compressed air enters an anechoic labyrinth, flows through a settling chamber that straightens airflow, and then goes to the entropy wave generator. The entropy wave generator forms entropy waves through electric …
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Net-shape hot isostatic pressing of a nickel-based powder superalloy
… assess Net Shape HIPping as a process-route for aero engine components. HIPping led to (Hf,Zr)-rich oxides and carbides on prior particle boundaries (PPBs) which could be coarsened, but not eliminated by changing the HIP procedure. HIPping above the γ′ solvus resulted in coarser grains with …
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Development of a Concept for Forced Response Investigations
… improve performance and lower weight of aircraft engines, modern compressor blades become thinner and lighter but higher loaded resulting in an increased vulnerability towards flutter. This trend is further aggravated through blisk designs that diminish structural damping and therewith flutter …
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Development and application of transition detection using infrared thermography for characterization of fan blade waviness effects
… transition in the regime of operation of civil aero engine fan blades. Surface waviness on fan blades arises from the carbon composite manufacturing process. The waviness results in transition point movement due to receptivity amplification between the surface wavelength and Tollmien-Schlichting …
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Model-based approaches to support process improvement in complex product development
… is thus a strategic imperative for many engineering companies — the aero-engine is one example of a complex product for which market pressures necessitate ever-shorter development times. This thesis argues that process modelling and simulation can support the improvement of complex …
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Effect of gas path heat transfer on turbine loss
… i.e., streamtube-to-streamtube, heat transfer on aero engine turbine loss and efficiency. The assessment, based on the concept of mechanical work potential [19], was carried out for two model problems to introduce the ideas. Three-dimensional RANS calculations were also conducted to show the …
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L1 Adaptive Control of Uncertain Nonlinear Systems with Dynamic Constraints: As Applied to Commercial Aircraft Engines
… control for a turbofan commercial aircraft engine is developed and applied in the presences of constraint limits. Turbofan engines are a highly complex system, with a wide variety of dynamics, operating under constantly changing environmental conditions. In aircraft turbofan operation many …
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Adaptive mesh refinement for computational aeroacoustics
UNIVERSITY OF SOUTHAMPTON ABSTRACT FACULTY OF ENGINEERING, SCIENCE & MATHEMATICS SCHOOL OF ENGINEERING SCIENCES Doctor of Philosophy ADAPTIVE MESH REFINEMENT FOR COMPUTATIONAL AEROACOUSTICS by Xun Huang<br/>This thesis describes a parallel block-structured adaptive mesh refinement (AMR) method that …
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Turbulent combustion simulation in realistic gas-turbine combustors
… retained all essential features of a modern aero-engine rich burn combustor and thus the turbulence combustion within this combustor is much more complicated than those observed in the combustor-like burners typically considered in laboratory experiments. A comparative study of two combustion …
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