An aircraft system noise assessment was performed for the hybrid wing body aircraft concept, known as the N2A-EXTE. This assessment is a result of an effort by NASA to explore a realistic HWB design that has the potential to substantially reduce noise and fuel burn. Under contract to NASA, Boeing designed the aircraft using practical aircraft design princip0les with incorporation of noise technologies projected to be available in the 2020 timeframe. NASA tested 5.8% scale-mode of the design in the NASA Langley 14- by 22-Foot Subsonic Tunnel to provide source noise directivity and installation effects for aircraft engine and airframe configurations. Analysis permitted direct scaling of the model-scale jet, airframe, and engine shielding effect measurements to full-scale. Use of these in combination with ANOPP predictions enabled computations of the cumulative (CUM) noise margins relative to FAA Stage 4 limits. The CUM margins were computed for a baseline N2A-EXTE configuration and for configurations with added noise reduction strategies. The strategies include reduced approach speed, over-the-rotor line and soft-vane fan technologies, vertical tail placement and orientation, and modified landing gear designs with fairings. Combining the inherent HWB engine shielding by the airframe with added noise technologies, the cumulative noise was assessed at 38.7 dB below FAA Stage 4 certification level, just 3.3 dB short of the NASA N+2 goal of 42 dB. This new result shows that the NASA N+2 goal is approachable and that significant reduction in overall aircraft noise is possible through configurations with noise reduction technologies and operational changes. XXXX In this paper, the full system noise assessment of the N2A-EXTE vehicle using ANOPP2 will be reported. The data from the aerodynamic and acoustic testing of the N2A-EXTE are utilized in ANOPP2 in the predicting cum noise margin relative to Stage 4. The processing of model-scale acoustic data to full-scale results that are appropriate to determine certification noise will be presented. The use of the scaled results within the noise prediction process will be detailed along with complete descriptions of the computational methods employed. The noise assessment will be presented as the result of a series of updated strategies from a defined baseline N2A-EXTE configuration (to which variations of noise reduction technologies are added). The effect of each noise reduction technology/configuration will be evaluated at the component and system level.
Noise Scaling and Community Noise Metrics for the Hybrid Wing Body Aircraft
2014
22 pages
Report
Keine Angabe
Englisch
Hybrid Wing–Body Aircraft Slat Noise
AIAA | 2013
|Hybrid Wing-Body Aircraft Slat Noise
Online Contents | 2013
|