Design and acoustic shielding prediction of hybrid wing-body aircraft

Recent research and developmental efforts in aircraft design have focused on the growing concerns about the environment impact of aviation and the rising costs of fuel. Under NASA's N+2 subsonics fixed-wing project, hybrid-wing-body (HWB) aircraft are investigated with the goal to meet the N+2 noise, fuel burn, and emissions requirements. As part of the N+2 program, this thesis is focused on the design and assessment of an HWB aircraft and the development of a prediction method for turbomachinery noise shielding. Based on MIT's previous experience in the Silent Aircraft Initiative, the SAX-40 aircraft concept was further developed into the N+2 HWB aircraft. The design effort resulted in two aircraft configurations: the N2A aircraft with conventional podded engines, and the N2B aircraft with a distributed propulsion system embedded in the airframe. The initial performance assessment shows that the N2A and the N2B aircraft can both meet the N+2 fuel burn goal and that the N2A aircraft is 5.7 EPNdB short of the noise goal. Also, the assessment revealed that current noise prediction methods cannot model the advanced propulsion system of the N2B aircraft, requiring the development of noise assessment tools for advanced engine-airframe configurations. NASA's Aircraft Noise Prediction Program employs the barrier shielding method to predict the airframe shielding of engine noise. However, it is an empirical formulation for straight edges and thus it is not appropriate for the planform shape of an HWB aircraft.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Ng, Leo Wai-Tsun

Advisor dc:contributor.advisor

• Zoltán S. Spakovszky.

• Aeronautics and Astronautics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/51635

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/51635