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.
Results
Showing 1 to 20 of 33 for “"Turbofan engines"”.
-
Acoustic Tomography and Thrust Estimation on Turbofan Engines
… order to accurately estimate the thrust of two turbofan engines (1.0-1.5%). In the second, it is shown that acoustic tomography methods that only use the first ray paths to arrive cannot distinguish some relevant propulsion flow fields (i.e., different flow fields can have the same times of …
-
Detection filters for fault-tolerant control of turbofan engines
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1981.
-
Analytical investigation of active control of radiated inlet noise from turbofan engines
… for reducing radiated tonal inlet noise from turbofan engines. The analytical model consists of multiple control sources placed in the periphery of the engine inlet duct which inject anti-noise into the duct to destructively interfere with the sound field generated by the fan. The development …
-
Advanced modeling of active control of fan noise for ultra high bypass turbofan engines
… control of fan noise for ultra high bypass turbofan engines has been developed. This model is based on a boundary integral equation method and simulates the propagation, radiation and control of the noise generated by an engine fan surrounded by a duct of finite length and cylindrical shape, …
-
Influence of system architecture changes on organizational work flow and application to Geared turbofan engines
… P&W designed, built and flew a large "Geared Turbofan" engine which was a demonstrator for a new product architecture being developed, the first of the new product family being the PWl 524G. This new engine architecture is different from the more traditional turbofan engine architecture in the …
-
Improvement In Acoustic Liner Attenuation In Turbofan Engines By Means Of Plasma Synthetic Jet Actuator
… continually striving to reduce noise emissions. Turbofan engine acoustic liners are efficient attenuators of engine noise. Plasma actuators have been used as flow control devices in other settings and will now be studied as an enhancement for acoustic liners. A plasma actuator can excite …
-
Investigation of the Herschel-Quincke Tube Concept as a Noise Control Device for Turbofan Engines
… tubes concept for the reduction of noise from turbofan engines is proposed here. The approach consists of installing circumferential arrays of Herschel-Quincke (HQ) tubes or waveguides in the inlet of the turbofan engine. An analytical technique was developed to predict the effects of HQ tubes …
-
Modeling of Herschel/Quincke-Liner Systems for the Control of Aft Fan Radiation in Turbofan Engines
… development of more effective ones. In terms of turbofan generated noise, the most widely used technology is that of absorbent materials or liners. In recent investigations Alonso et al. have combined Herschel/Quincke (HQ) tubes with liners. This combination has the potential of effectively …
-
Influence of Turbofan Engine Design Parameters on Aircraft Environmental Impact
… carriers and propulsion systems architectures, turbofan engines power the majority of commercial aircraft. Therefore, aviation’s environmental impacts are significantly influenced by the design of these turbofan engines. Hence, we should drive the design of modern turbofan engines, informed with …
-
Experimental Investigation of Fan Rotor Response to Inlet Swirl Distortion
… boundary layer ingestion which locates the turbofan engine inlet near enough to the lifting surface of the aircraft skin that the boundary layer is ingested and reenergized. This process reduces overall aircraft drag and associated required thrust, resulting in fuel savings and decreased …
-
Design of a model propulsor for a boundary layer ingesting aircraft
… propulsors represent the ultra-high bypass ratio turbofan engines on a full-scale conceptual aircraft previously designed at MIT. Powered models will use these propulsors in both podded and boundary layer ingesting configurations to allow back-to-back assessment of BLI benefit. The thesis gives a …
-
Assessment of propfan propulsion systems for reduced environmental impact
… In addition, a comparable aircraft with advanced turbofan engines was defined for performance and noise comparisons.
-
Parametric Scramjet Analysis
… of the ramjet, turbojet, and fanjet ideal engines. The objective of this work is to explore material operating temperatures and fuel possibilities for the combustion chamber of a scramjet propulsion system to show how they relate to scramjet performance and the seven scramjet engine …
-
Advanced Trailing Edge Blowing Concepts for Fan Noise Control: Experimental Validation
… to 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 …
-
Application of multiple information sources to prediction of engine time on-wing
The maintenance and operation of commercial turbofan engines relies upon an understanding of the factors which contribute to engine degradation from the operational mission, environment and maintenance procedures. A multiple information source system is developed using the Pratt & Whitney engine to …
-
Development of an engine model for an integrated aircraft design tool
… ratio, small-core, geared and direct-drive turbofan engines. The engine weight surrogate model was built as separate engine component weight surrogate models using least squares and Gaussian Process regression techniques on data data generated from NPSS/WATE++ and then combined to estimate a …
-
Filtered Rayleigh Scattering with an Application to Force Component Decomposition
… measurements on the ground with mini turbojet engines as well as full-scale turbofan engines. A data grouping technique is derived such that the total measured force using FRS can be divided into individual contributions from different parts of the engine. These developed techniques have laid …
-
Propulsion system concepts for silent aircraft
… system concepts of ultra-high bypass ratio turbofan engines, a distributed propulsion system, and silent engine air-brakes are evaluated in light of their noise signatures and propulsion system performance. These propulsion system concepts are assessed using simple analytic models and …
-
Aeroacoustic computation of sound radiation from ducts
Modern high-bypass turbofan engines produce high levels of nuisance noise that has a significant impact on the environment near airports as well as the crew and passengers inside the aircraft. Significant research is being undertaken to understand the aeroacoustic noise source mechanisms and to …
-
Computational investigation of the effects of casing treatments on the performance of a turbofan
… and increasing the stall margin of a model turbofan stage in transonic operating conditions. The study is divided into three phases. During the first phase two types of casing treatments, inward protruding rings and circumferential grooves, were tested with relatively coarse grids. In the …
Page 1 of 2