Assessment of the Performance Potential of Advanced Subsonic Transport Concepts for NASA’s Environmentally Responsible Aviation Project

Nickol, Craig L.; Haller, William

doi:10.2514/6.2016-1030

Cited by 46 publications

(13 citation statements)

References 24 publications

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“…The aspect ratio is chosen considerably lower for the BWB compared to than the TAW aircraft, similar to other BWB design studies. 3,12,25,43 The chosen aspect ratios have been tweaked to achieve good results in terms of wing span for airport gate limits, climb gradients and the resulting sizing of the fuselage and outer wing combination.…”

Section: A Test Case Definition: Design Requirementsmentioning

confidence: 99%

Conceptual Design and Evaluation of Blended-Wing Body Aircraft

Brown

Vos

2018

2018 AIAA Aerospace Sciences Meeting

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Blended wing body (BWB) aircraft represent a paradigm shift in jet transport aircraft design that promise benefits over conventional aircraft. A method is presented to enable the conceptual design of BWB aircraft, enabling comparison studies with tube-and-wing aircraft (TAW) based on the same top-level requirements and analysis fidelity. The aim of this work is to make comparative studies between the blended-wing-body aircraft and its conventional tube-and-wing counterpart based upon the same design requirements at conceptual level. By developing a novel geometric parametrisation of the blended wing body, the design possibilities have been increased while maintaining straightforward shaping manipulation and robustness. The mass estimation methods that have been implemented are verified and validated to be within approximately 5% of reference blended wing bodies. Drag estimations perform less accurately with drag being overpredicted by approximately 20%. The cause of this over prediction was largely due to empirical corrections for miscellaneous and unaccounted drag sources as well as induced drag predicted by a vortex-lattice method. Test-case BWB and TAW aircraft were formed in the 150, 250 and 400 passenger classes. The comparisons of the resulting aircraft show that the blended wing body have reduced mass, improved aerodynamic efficiency and higher fuel economy. Trends also show that the improvements over tube-and-wing aircraft increase with aircraft size.

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Section: A Test Case Definition: Design Requirementsmentioning

confidence: 99%

Conceptual Design and Evaluation of Blended-Wing Body Aircraft

Brown

Vos

2018

2018 AIAA Aerospace Sciences Meeting

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“…These noise sources could be reduced by utilizing a higher bypass-ratio engine. Ultra-high-bypass ratios up to 25 are expected to be available in the 2035 time frame [15], but the physical constraints on maximum engine diameter imposed by the pi-tail again limit the current configuration to a bypass ratio of 16. Fan noise could also be reduced somewhat by modification of the vertical stabilizers to provide more sideline shielding.…”

Section: Resultsmentioning

confidence: 99%

“…Several experimental datasets contribute to the design of the aircraft, as well as the noise source definitions. Integrated Technology Demonstration efforts, summarized by Nickol and Haller [15], were undertaken during the last three years of the ERA project, and those results are used to inform the models for advanced technologies associated with vehicles in the AATT portfolio, including the ND8. Each noise source is predicted individually and follows the flight path for each certification point, which is determined by the unique aircraft design.…”

Section: Noise Prediction Frameworkmentioning

confidence: 99%

“…This design is beyond the current state-of-the-art engines with maximum bypass ratios around 12, but significantly less aggressive than the geared turbofan engines designed for other advanced aircraft concepts with bypass ratios around 25 [14,15,17]. Other aspects of the ND8 engine are given in Table 2 and compared to a similar engine-under-wing aircraft from ERA [15], the 160-passenger tube-and-wing aircraft (T+W160). Key differences include the lower bypass ratio and higher tip speed of the ND8 engine, which lead to higher noise source levels.…”

Section: Fig 4 Design Elements Of the Nd8 Concept With Closeup Viewmentioning

confidence: 99%

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Aircraft System Noise Assessment of the NASA D8 Subsonic Transport Concept

Clark

Thomas

Guo³

2018

2018 AIAA/CEAS Aeroacoustics Conference

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A vehicle-level noise assessment has been performed for the NASA D8 concept aircraft (ND8) in the NASA Advanced Air Transport Technology Project portfolio. The NASA research-level Aircraft NOise Prediction Program (ANOPP-Research) was used to predict the noise from each source component on the ND8 to build up a noise estimate for the full aircraft. The propulsion airframe aeroacoustic (PAA) effects of the ND8, namely boundary layer ingestion (BLI) with its influence on fan noise, and the noise shielding, reflection, and diffraction mechanisms of the unconventional airframe, were empirically modeled using experimental data. Noise reduction technologies appropriate to the 2025-2035 time frame were included in this study. Including all technologies and PAA effects, the ND8 is predicted to have a cumulative margin to the Stage 4 certification metric of only 7.4 EPNdB. Boundary layer ingestion is predicted to have a detrimental impact on cumulative noise levels on the order of 15 EPNdB. Fan noise is seen to be the primary noise source at all three certification points, even if the BLI noise impact could be entirely suppressed. The impact of engine noise shielding by the airframe is limited by a lack of aft shielding and the presence of horizontal tail reflections in the aft direction. The physical constraint on engine size by the pi-tail is seen as a potential barrier to engine noise reduction through the corresponding limitation on fan bypass ratio. Mildly reduced climb performance (compared to similar reference aircraft) does not provide any benefit through increased noise propagation distance. If the boundary layer ingestion noise penalty could be suppressed such that BLI would have no effect on noise, the cumulative margin to Stage 4 would increase to 22.4 EPNdB, still below the NASA Mid Term goal of 32-42 EPNdB.

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“…The uncertainty quantification described in this paper is focused on a hybrid wing body (HWB) in the large twin aisle aircraft class, sized for 301 passengers [10]. An artist's rendering of the aircraft is shown in Fig.…”

Section: Aircraft Configurationmentioning

confidence: 99%

Aircraft System Noise Prediction Uncertainty Quantification for a Hybrid Wing Body Subsonic Transport Concept

June

Thomas

Guo³

2018

2018 AIAA/CEAS Aeroacoustics Conference

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Aircraft system level noise prediction for advanced, unconventional concepts has undergone significant improvement over the past two decades. The prediction modeling uncertainty must be quantified so that potential benefits of unconventional configurations, which are outside of the range of empirical models, can be reliably assessed. This paper builds on previous work in an effort to improve estimates of element prediction uncertainties where the prediction methodology has been improved, or new experimental validation data are available, to provide an estimate of the system level uncertainty in the prediction process. In general, the uncertainty of the prediction will be strongly dependent on the aircraft configuration as well as which technologies are integrated. While the quantitative uncertainty values contained here are specific to the hybrid wing body design presented, the underlying process is the same regardless of configuration. A refined process for determining the uncertainty for each element of the noise prediction is detailed in this paper. The system level uncertainty in the prediction of the aircraft noise is determined at the three certification points, using a Monte Carlo method. Comparisons with previous work show a reduction of 1 EPNdB in the 95 % coverage interval of the cumulative noise level. The largest impediment for continued reduction in uncertainty for the hybrid wing body concept is the need for improved modeling and validation experiments for fan noise, propulsion airframe aeroacoustic effects, and the Krueger flap, which comprise the bulk of the uncertainty in the cumulative certification noise level.

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Assessment of the Performance Potential of Advanced Subsonic Transport Concepts for NASA’s Environmentally Responsible Aviation Project

Cited by 46 publications

References 24 publications

Conceptual Design and Evaluation of Blended-Wing Body Aircraft

Conceptual Design and Evaluation of Blended-Wing Body Aircraft

Aircraft System Noise Assessment of the NASA D8 Subsonic Transport Concept

Aircraft System Noise Prediction Uncertainty Quantification for a Hybrid Wing Body Subsonic Transport Concept

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