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 25 for “"fan blade"”.
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Fan blade damage detection using on-line vibration monitoring
Please read the abstract in the section 00front of this document
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Experimental studies in a supersonic through-flow fan blade cascade
… of the flow in a supersonic through-flow fan blade cascade. The blade shapes are those of the baseline supersonic through-flow fan (STFF) under investigation at the NASA Lewis Research Center. Measurements were made at an inlet Mach number of 2.36 over a 15° range of incidence. Flowfield …
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Modal Response of a Transonic Fan Blade to Periodic Inlet Pressure Distortion
A new method for predicting forced vibratory blade response to total pressure distortion has been developed using modal and harmonic analysis. Total pressure distortions occur in gas turbine engines when the incoming airflow is partially blocked or disturbed. Distorted inlet conditions can have …
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Modifications of Coherent Structures in Fan Blade Wakes for Broadband Noise Reduction
… on the wakes of a linear cascade of idealized fan blades was investigated experiments with a view to the likely effects on broadband aircraft engine interaction noise. Single and three-component hotwire velocity measurements were made downstream of the cascade for a chord Reynolds number of …
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Design Optimization of the First Stage Fan Blade of a Low Bypass Turbofan Engine
… analyzing the aerodynamics, thermodynamics, and blade geometry across the first stage rotor blade under an extreme set of conditions, while altering several design parameters, has been developed and applied. The conditions for which the analyses have been developed were designed for the use of, …
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An Automated Optimal Design of a Fan Blade Using an Integrated CFD/MDO Computer Environment
… case study is the optimal design of a low speed fan for an industrial air-conditioning application using the Response Surface Optimization (RSO) algorithm.</p> <p>The optimization algorithm controls the variations of parameters that describe the three-dimensional geometry of the blade while …
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Development and application of transition detection using infrared thermography for characterization of fan blade waviness effects
… 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 wavelength, …
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An Investigation of the Mechanical Properties of Aircraft Engine Fan Casing Abradable Materials at Different Temperatures and Strain Rates
Certification of an aircraft turbofan engine requires the demonstration of its ability to contain a fan blade should the blade accidentally separate under critical operating conditions. Significant efforts have been made by the industry in creating high-fidelity full-engine numerical models for …
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Characterization and mitigation of blade waviness effects on fan performance
… 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 triggered by …
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Design Optimisation and Flow Characterisation for Future Aeroengine Axial Fan Blades
… efficiency optimisation of a modern jet engine fan blade with constrained pressure ratio. This outcome is compared against a state-of-the-art adjoint-based approach. Results indicate the strategy proposed achieves comparable improvements to its adjoint counterpart with a reduced computational …
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Computer-aided design of axial-flow fans
… of designing low- to medium-speed, axial-flow fans and blowers is discussed, and a Fortran program called FANJD is introduced. The first purpose of F AN3D is to perform the aerodynamic and mechanical calculations needed to establish the basic geometry of an axial-flow fan blade. Next, geometric …
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Diagnostic test and analytical methods for resolving fan/motor vibration problems in air-conditioning units
… Standard for small (<36 in. diameter) propeller fans. Test and analysis procedures also need to be used to convert AHRAE Standard 87.1 - 1992 test results where the fan hub mobility is zero to corresponding results that will exist with a finite (nonzero) hub mobility; In this project, the …
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Body Force Modeling for Engine Inlet Fan System
… throughflow method to analyze aircraft nacelle/fan systems. The method adopts the body force concept using source terms to model the effects of fan blades. The method is designed to capture interaction effects between bypass fan and nacelle at off-design conditions, especially for …
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Vibration Analysis of a Fan/Compressor Blade
<p>The vibration of blades in gas turbine engines has become an important issue during the last decade because of its significant impact on high cycle fatigue failure due to resonant vibrations. The main objective of this thesis is the vibration analysis of compressor/fan blade using …
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Flow Control Optimization for Improvement of Fan Noise Reduction
The study of the flow of a fan blade was conducted to improve tonal fan noise reduction by optimizing an existing flow control configuration. The current configuration consisted of a trailing edge Slot with a flow control area of 0.045 in² per inch span with an exit angle of -3.3° with respect to …
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The Behavior Of A Macroscopic Granular Material In Vortex Flow
… auto-transformer, and a power-meter. A fixed fan blade was attached to the duct's inner wall to create a tornado-like vortex airflow from straight flow. As the airflow velocity was increased gradually, the behavior of a set of same-diameter granular materials was observed. The observed …
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Advanced Trailing Edge Blowing Concepts for Fan Noise Control: Experimental Validation
… reduce rotor / stator interaction noise in turbofan engines. The existing technique of filling every velocity deficit requires a large amount of air and is therefore impractical. The purpose of this research is to investigate new blowing configurations in order to achieve noise reduction with …
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The Role of Twinning in the Plastic Deformation of Alpha Phase Titanium
The optimisation of compressor stage aerofoil and fan blade design remains an important area of titanium alloy research and development for aerospace gas turbines. Such research has important implications for critical and sensitive component integrity and efficiency. In particular, a better …
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A Predictive Methodology for Soft Impact Damage in Jet Engines Incorporating Hybrid Composite Structures
… subjected to soft impact. Bird strike onto the fan assembly is chosen as the impact event to be studied. The aim is to develop a numerical methodology capable of accurately capturing the full range of multifaceted damage in hybrid and composite structures as they evolve throughout the forward …
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Effects of blade damage on low pressure ratio fan windmill aerodynamics
… can occur after the in-flight shutdown of a turbofan, when the fan continues to spin due to the aircraft forwards speed. This condition leads to high levels of drag, and the fan operates at very low rotational speeds. Windmill often follows damage to the fan, which will lead to large …
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