Over Wing Nacelle Installations for Improved Energy Efficiency

Hooker, John R.; Wick, Andrew; Zeune, Cale; Agelastos, Anthony Michael

doi:10.2514/6.2013-2920

Cited by 47 publications

(31 citation statements)

References 12 publications

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“…Additionally, D i is the lift-induced drag of the airframe without propulsion system, and ∆D i is the change in lift-induced drag due to thrust, that is, the difference between the drag of the complete aircraft with the propulsor at a determined thrust setting, and the drag that would exist at T dp = 0 for the same total lift value. Although different drag breakdowns exist [30,36,37], this simplified approach has been selected because it clearly identifies the contribution of the installation effects. All lift and drag contributions can be expressed as non-dimensional coefficients by dividing them by the reference area of the wing S and the dynamic pressure of the freestream q ∞ .…”

Section: Thrust Lift and Drag Decompositionmentioning

confidence: 99%

A Preliminary Sizing Method for Hybrid-Electric Aircraft Including Aero-Propulsive Interaction Effects

Vries

Brown

Vos

2018

2018 Aviation Technology, Integration, and Operations Conference

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The potential benefits of hybrid-electric propulsion (HEP) have led to an increased interest in this topic over the past decade. One promising advantage of HEP is the distribution of power along the airframe, which enables synergistic configurations with improved aerodynamic and propulsive efficiency. The purpose of this paper is to present a generic sizing method suitable for the first stages of the design process of hybrid-electric aircraft, taking into account the powertrain architecture and associated propulsion-airframe integration effects. To this end, the performance equations are modified to account for aero-propulsive interaction. A powerloading constraint-diagram is used for each component in the powertrain to provide a visual representation of the design space. The results of the power-loading diagrams are used in a HEP-compatible mission analysis and weight estimation to compute the wing area, powerplant size, and takeoff weight. The resulting method is applicable to a wide range of electric and hybrid-electric aircraft configurations and can be used to estimate the optimal power-control profiles. For demonstration purposes, the method is applied a HEP concept featuring leadingedge distributed-propulsion (DP). Three powertrain architectures are compared, showing how the aero-propulsive effects are inlcuded in the model. The results confirm the method is sensitive to top-level HEP and DP design parameters, and indicate an increase in wing loading and power loading enabled by DP.

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Section: Thrust Lift and Drag Decompositionmentioning

confidence: 99%

A Preliminary Sizing Method for Hybrid-Electric Aircraft Including Aero-Propulsive Interaction Effects

Vries

Brown

Vos

2018

2018 Aviation Technology, Integration, and Operations Conference

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“…The GasTurb results were loaded into the DMS via an interface program and were immediately available to all modules for application in the overall process. In addition to reducing the noise signature, the unconventional engine position behind the wing (see Figure 1) also improved the drag in cruise due to flow interactions between the wing and the propulsion unit, as shown in American studies by Hooker et al (2013). The investigations show a possible aircraft drag reduction of −5%.…”

Section: Preliminary Aircraft Designmentioning

confidence: 80%

Evaluation of ultra-high bypass ratio engines for an over-wing aircraft configuration

Giesecke

Lehmler

Friedrichs

et al. 2018

J. Glob. Power Propuls. Soc.

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Today, main hub airports are already at their capacity limit and hence, smaller airports have become more interesting for providing point-to-point connections. Unfortunately, the use of regional airports induces an increased environmental footprint for the population living around it. In an attempt to solve the related problems, the research project Coordinated Research Centre 880 aims to examine the fundamentals of a single-aisle aircraft with active high-lift configuration powered by two geared ultra-high bypass turbofan engines mounted over the wing. Low direct operating costs, noise shielding due to the over-wing configuration, and short runway lengths are the main advantages. Highlighting the performance, economical and noise benefits of a geared ultra-high bypass engine is the key aim of this paper. This assessment includes a correspondingly adjusted aircraft. Open literature values are applied to design the two investigated bypass ratios; a reference engine with a bypass ratio of 5 and 17 respectively. This study shows that a careful selection of engine mass flow, turbine entry temperature and overall pressure ratio determines the desirable bypass ratio. The aircraft direct operating costs drop by 5.7% when comparing the designed conventional with a future ultra-high bypass ratio engine. Furthermore, the sound at source for a selected mission and operating condition can be reduced by 7 dB. A variable bypass nozzle area for the ultra-high bypass ratio engine is analysed in terms of performance and operability. An increase of safety margin is shown for the turbofan engine with a variable bypass nozzle. It is concluded that this unconventional aircraft configuration with ultra-high bypass ratio engines mounted over the wing has the potential to relieve main hub airports and reduce the environmental impact.

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“…They were obtained using a workstation running 12×2 GHz Intel Core i7 processors, which took approximately 1.5 min per flow and adjoint solution, respectively. Finally, the test problem was selected because it shared similarities with an OWN study previously reported, 24 and whose trends were later found to agree with a more advanced study by Hooker et al 25 A comparison of the test problem and the OWN problem is shown in Figs. 5 and 6.…”

Section: Test Problemmentioning

confidence: 92%

Dimensionality Reduction In Aerodynamic Design Using Principal Component Analysis With Gradient Information

Berguin

Mavris

2014

10th AIAA Multidisciplinary Design Optimization Conference

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The cost of dimensionality reduction in aerodynamic design applications involving highdimensional design spaces and CFD is often prohibitive. In an attempt to overcome this challenge, a new method for dimensionality reduction is presented that scales as p log(p), where p is the number of design variables. It works by taking advantage of adjoint design methods in order to collect gradient observations, which are then used to compute the covariance matrix of the design variables. Dimensionality is then reduced by using principal component analysis to develop a linear transformation that allows an aerodynamic optimization problem to be re-formulated in a new coordinate system of lower dimensionality. In order to demonstrate it's feasibility, the method is tested on a 2D staggered airfoil problem, intentionally chosen as an abstraction of a more realistic over-wing nacelle integration problem, and shown to exhibit similarities with the latter. Results show that the method outperforms typical screening methods used in aerospace engineering, either in terms of effectiveness, cost or the ability to capture nonlinear effects. Furthermore, the method is found to improve convergence during gradient-based optimization. Overall, results offer strong evidence in support of the proposed method, paving the way for larger analytical efforts such as design space exploration, where dimensionality reduction is unavoidable to cope with the necessity of gradient-free approaches.

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Over Wing Nacelle Installations for Improved Energy Efficiency

Cited by 47 publications

References 12 publications

A Preliminary Sizing Method for Hybrid-Electric Aircraft Including Aero-Propulsive Interaction Effects

A Preliminary Sizing Method for Hybrid-Electric Aircraft Including Aero-Propulsive Interaction Effects

Evaluation of ultra-high bypass ratio engines for an over-wing aircraft configuration

Dimensionality Reduction In Aerodynamic Design Using Principal Component Analysis With Gradient Information

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