Advanced Turbofan Duct Liner Concepts

Advanced Turbofan Duct Liner Concepts PDF

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-06-27

Total Pages: 238

ISBN-13: 9781721928361

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The Advanced Subsonic Technology Noise Reduction Program goal is to reduce aircraft noise by 10 EPNdB by the year 2000 relative, to 1992 technology. The improvement goal for nacelle attenuation is 25% relative to 1992 technology by 1997 and 50% by 2000. The Advanced Turbofan Duct Liner Concepts Task work by Boeing presented in this document was in support of these goals. The basis for the technical approach was a Boeing study conducted in 1993-94 under NASA/FAA contract NAS1-19349, Task 6, investigating broadband acoustic liner concepts. As a result of this work, it was recommended that linear double layer, linear and perforate triple layer, parallel element, and bulk absorber liners be further investigated to improve nacelle attenuations. NASA LaRC also suggested that "adaptive" liner concepts that would allow "in-situ" acoustic impedance control also be considered. As a result, bias flow and high-temperature liner concepts were also added to the investigation. The major conclusion from the above studies is that improvements in nacelle liner average acoustic impedance characteristics alone will not result in 25% increased nacelle noise reduction relative to 1992 technology. Nacelle design advancements currently being developed by Boeing are expected to add 20-40% more acoustic lining to hardwall regions in current inlets, which is predicted to result in and additional 40-80% attenuation improvement. Similar advancements are expected to allow 10-30% more acoustic lining in current fan ducts with 10-30% more attenuation expected. In addition, Boeing is currently developing a scarf inlet concept which is expected to give an additional 40-80% attenuation improvement for equivalent lining areas. Bielak, Gerald W. and Premo, John W. and Hersh, Alan S. Langley Research Center NAS1-20090; RTOP 538-03-12-02

Tailored Light 2

Tailored Light 2 PDF

Author: Reinhart Poprawe

Publisher: Springer Nature

Published: 2023-11-05

Total Pages: 894

ISBN-13: 3030983234

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This book covers the application technology of lasers, focusing more on the vast range of processes than on individual applications, in order to motivate and enable future innovations. The physical basics are presented in the first half of the book. The following examination of application categories and their processes is documented by experts from their practical points of view but always refers back to the underlying physical principles. In this way, readers are free to choose their own individual level of depth in understanding this globally relevant field of innovation. This new edition of Tailored Light 2: Laser Applications birings the book up to date with the latest applications of laster technology.

Green Aviation

Green Aviation PDF

Author: Ramesh Agarwal

Publisher: John Wiley & Sons

Published: 2016-09-20

Total Pages: 536

ISBN-13: 1118866509

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Green Aviation is the first authoritative overview of both engineering and operational measures to mitigate the environmental impact of aviation. It addresses the current status of measures to reduce the environmental impact of air travel. The chapters cover such items as: Engineering and technology-related subjects (aerodynamics, engines, fuels, structures, etc.), Operations (air traffic management and infrastructure) Policy and regulatory aspects regarding atmospheric and noise pollution. With contributions from leading experts, this volume is intended to be a valuable addition, and useful resource, for aerospace manufacturers and suppliers, governmental and industrial aerospace research establishments, airline and aviation industries, university engineering and science departments, and industry analysts, consultants, and researchers.