Propulsion installation characteristics for turbofan transports

Henderson, W. P.; Patterson, James C.

doi:10.2514/6.1983-87

Cited by 10 publications

(5 citation statements)

References 2 publications

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“…Although available computational budget constraints precluded further studies, we believe a logical extension to the optimization would be to relax the axisymmetric nacelle requirement. In fact, recall that Henderson and Patterson [9] found that nacelle contouring was a major factor in reducing interference drag. They found that a non-axisymmetric nacelle had around half the interference drag of symmetric nacelle.…”

Section: Resultsmentioning

confidence: 99%

“…Henderson and Patterson [9] revisited this configuration using a fully metric model and found that, indeed, nacelle penalties did outweigh the previously reported benefits for the wing-body; but they also found that interference drag could be reduced significantly just by re-contouring the nacelles. Later, Szodruch and Kotschote [10] conducted a fully metric wind-tunnel study with powered nacelles and concluded that the OWN configurations yield higher maximum lift-to-drag ratios than the UWN configuration; however, the optimum nacelle positions were dependent on the wing configurations.…”

Section: Introductionmentioning

confidence: 99%

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Sensitivity Analysis of the Overwing Nacelle Design Space

Ahuja

Renganathan

Mavris

2022

Journal of Aircraft

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The over-wing nacelle (OWN) concept refers to aircraft designs where the engine is installed above the wing. The OWN configuration offers several advantages over conventional under-wing nacelle (UWN) vehicles, which include improved fuel-burn and propulsive efficiencies due to the feasibility of ultra high bypass ratio turbofans, and reduced noise. However, a non-optimal OWN design can result in large transonic drag penalties that can potentially outweigh the aforementioned benefits. We study the OWN design problem from an aerodynamics and propulsion perspective, using the NASA common research model, a notional 90,000 pound thrust class turbofan model, and Reynolds-Averaged Navier-Stokes simulations. We first quantify the sensitivity of drag, lift, and pressure recovery to variations in engine location and power setting, and identify trends. Then, we perform aerodynamic design optimization of the wing and nacelle to determine OWN performance improvement from outer mold line refinement at a favorable engine installation location. A 20% reduction in drag is achieved for the optimized OWN configuration, highlighting the sensitivity of OWN aerodynamics to airframe contours. However, compared to the UWN baseline, the optimized OWN drag is 5% higher at the same lift and worsens significantly at higher lift.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Sensitivity Analysis of the Overwing Nacelle Design Space

Ahuja

Renganathan

Mavris

2022

Journal of Aircraft

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“…Analytical shaping using streamline tracing techniques in [8], Euler CFD in [4], and Navier-Stokes CFD in [9] resulted in significant flow quality and drag improvements to the OWN configurations studied, although the installation penalties were not always entirely eliminated. Aside from these studies, however, this sensitivity has generally not be fully exploited in much of the OWN wind-tunnel research because of hardware fabrication costs.…”

Section: Introductionmentioning

confidence: 89%

Aerodynamic Investigations of an Advanced Over-the-Wing Nacelle Transport Aircraft Configuration

Hill

Kandil

Hahn

2009

Journal of Aircraft

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The transonic aerodynamics of an advanced, over-the-wing nacelle, subsonic transport configuration are assessed using both Euler and Navier-Stokes computational fluid dynamics and results are compared to a similar configuration with an under-the-wing nacelle installation and a similar wing-body configuration. The over-the-wing nacelle configuration is designed with a novel inboard wing channel section between the nacelle and the fuselage that produces favorable aerodynamic interference and reduces the overall drag. Qualitative observations and quantitative drag computations are performed for the three configurations at a cruise Mach number of 0.78. It was found that, at the cruise point, the inboard wing channel section of the over-the-wing nacelle configuration effectively produces a favorable pressure distribution but that the overall drag, compared to the under-the-wing nacelle configuration, is higher. This excess drag, however, was found to be largely localized in the nacelle interior. Euler and Navier-Stokes computational fluid dynamics solutions were obtained for additional Mach numbers to assess the transonic drag-rise characteristics. The computational fluid dynamics solutions showed that the over-the-wing nacelle configuration has higher drag at lower Mach numbers than the under-the-wing nacelle configuration but experiences a milder overall drag rise and has lower drag at higher Mach numbers.

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“…Nacelle incidence and toe-in angle can minimise the lift induced drag of the nacelle. Further drag reductions of usually second order can be achieved by pylon shape, twist and camber in order to reduce circulation losses due to a lateral loading of the pylon* 17 '. Additional fairings on pylon LE and TE, following some empirical area ruling, were successfully applied to alleviate the drag rise characteristics oftheConvair990(i»)( Fig.…”

Section: Wing-engine Integration Aspects On Previous Jet Transportsmentioning

confidence: 99%

Integration of high bypass ratio engines on modern transonic wings for regional aircraft

et al. 1993

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Changing airline scenarios and aggravated congestion have led to an increasing demand for new regional aircraft which will cover ranges of more than 1500 nm and accommodate 80 to 130 passengers. These far exceed the capability of today's commuter types. In the required thrust range of 15-5-20 klb only a very limited number of older engines with high SFC is available. Recently the manufacturers have begun offering new turbofans based on modern core technology and internal mixing (long duct) with lower SFC.The underwing turbofan installation aspects are well understood from earlier wide and narrowbody aircraft but installing a long-duct nacelle on such a small aircraft means a significant increase in interference problems which may lead to close coupling and new methods for minimisation of the mutual interference.After a survey of installation problems on previous jet transports up to the Airbus family the state of the art of experimental and theoretical methods for interference analysis is discussed. By means of an inverse design method a local lofting change on a given wing design confined to 20% span area was derived in order to sustain the isobar pattern of the clean wing with the pod/pylon on.The design modification was checked by means of a 3D-Euler code and verified on a large half-model in the NLR-HST wind tunnel. From the analysis of the resulting conclusions concerning the feasibility of such a lofting change, further improvements are made.

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Propulsion installation characteristics for turbofan transports

Cited by 10 publications

References 2 publications

Sensitivity Analysis of the Overwing Nacelle Design Space

Sensitivity Analysis of the Overwing Nacelle Design Space

Aerodynamic Investigations of an Advanced Over-the-Wing Nacelle Transport Aircraft Configuration

Integration of high bypass ratio engines on modern transonic wings for regional aircraft

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