The Flight Testing of Natural and Hybrid Laminar Flow Nacelles

Barry, B.; Parke, Simon J.; Bown, Nicholas; Riedel, H.; Sitzmann, Martin

doi:10.1115/94-gt-408

Cited by 15 publications

(3 citation statements)

References 5 publications

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“…The control of the laminar flow enables to reduce the friction drag by about 75-80% comparing to the respective value on a solid impermeable plate. It is also stated [19,20] that the laminar form of the flow organized on the engine nacelle alone can reduce the total aerodynamic drag of a subsonic transport aircraft by 1 À2%. Equally important is the fact that the experience in laminar flow controlling is a good start for the development of effective methods of turbulent boundary-layer control.…”

Section: Drag Reduction Conceptmentioning

confidence: 98%

Current state and prospects of researches on the control of turbulent boundary layer by air blowing

Kornilov

2015

Progress in Aerospace Sciences

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Section: Drag Reduction Conceptmentioning

confidence: 98%

Current state and prospects of researches on the control of turbulent boundary layer by air blowing

Kornilov

2015

Progress in Aerospace Sciences

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“…A natural laminar flow nacelle lowers the zero-lift drag of the nacelle. This technology is already in use today in Boeing 787 with prospects to further delay the boundary layer transition in future applications (Norris, 2016; Barry et al , 1994). Due to the high bypass ratio of the engine, the wetted area increases, rendering the application of natural laminar flow on the nacelle necessary and reducing trip fuel on the design mission by 2.4 per cent.…”

Section: Concept Descriptionmentioning

confidence: 99%

Sizing implications of a regional aircraft for inner-city operations

Heinemann

Schmidt²,

Will

et al. 2017

AEAT

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Purpose-The paper aims to assess the potential of aircraft operation from city centres to achieve shortened travel times and the involved aircraft design process. Design/methodology/approach-The paper describes the methodical approach and iterative procedure of the design process. An assessment of potential technologies is conducted to provide the required enhancements to fulfil the constraints following an inner-city operation. Operational procedures were analysed to reduce the noise propagation through flight path optimization. Furthermore a ground based assisted takeoff system was conceived to lower required takeoff field length and to prevent engine sizing just for the takeoff case. Cabin design optimization for a fast turnaround has been conducted to ensure a wide utilization spectrum. The results prove the feasibility of an aircraft developed for inner-city operation. Findings-A detailed concept for a 60 passenger single aisle aircraft is proposed for an Entry-Into-Service year 2040 with a design range of 1,500 nautical miles for a load factor of 90 %. Although the design for STOL and low noise operation had to be traded partly with cruise efficiency, a noteworthy reduction in fuel burn per passenger and nautical mile was achieved against current aircraft. Practical implications-The findings will contribute to the evaluation of the feasibility and impact of the Flightpath 2050 goal of a four hour door-to-door by providing a feasible but ambitious example. Furthermore, it highlights possible bottlenecks and problems faced, when realizing this goal. Originality/value-The paper draws its value from the consideration of the overall sizing effects at aircraft level and from a holistic view on an inner-city airport/aircraft concept.

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“…The assumption of fully turbulent flow on the nacelle possibly leads to conservative nacelle drag estimates, as modern nacelle designs can enable laminar flow over parts of the nacelle or the entire nacelle surface [18,75]. However, the propulsor performance results are consistently evaluated relative to the baseline configuration and absolute nacelle drag results are not used in the short-inlet design process.…”

Section: Cfd Tool Descriptionmentioning

confidence: 99%

Ultra-Short Nacelles for Low Fan Pressure Ratio Propulsors

Peters¹,

Spakovszky²,

Lord³

et al. 2014

Volume 1A: Aircraft Engine; Fans and Blowers

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This thesis addresses the uncharted inlet and nacelle design space for low pressure ratio fans for advanced aeroengines. A key feature in low fan pressure ratio (FPR) propulsors with short inlets and nacelles is the increased coupling between fan and inlet. The thesis presents an integrated fan-nacelle design framework, combining a spline-based tool for the definition of inlet and nacelle surfaces with a fast and reliable body-force-based approach for the fan rotor and stator blade rows. The new capability captures the inlet-fan and fan-exhaust interactions and the flow distortion at the fan face and enables the parametric exploration of the short-inlet design territory. The interaction of the rotor with a region of high streamwise Mach number at the fan face is identified as the key aerodynamic mechanism limiting the design of short inlets. The local increase in streamwise Mach number is due to flow acceleration along the inlet internal surface coupled with a reduction in effective flow area. For a candidate short-inlet design with inlet length to fan diameter ratio L/D = 0.19, the streamwise Mach number at the fan face near the shroud increases by up to 0.16 at cruise and by up to 0.36 at off-design conditions relative to a long-inlet baseline propulsor with L/D = 0.5. As a consequence, the rotor locally operates close to choke, resulting in fan efficiency penalties of up to 1.6 % at cruise and 3.9 % at off-design. For inlets with L/D < 0.25, the benefit from reduced nacelle drag is offset by the reduction in fan efficiency, resulting in propulsive efficiency penalties. Based on a parametric inlet study, the recommended inlet L/D for engine propulsive efficiency benefits is suggested to be between 0.25 and 0.4. A candidate design with L/D = 0.25 maintains the cruise propulsive efficiency of the baseline case without jeopardizing fan and LPC stability at off-design conditions. On the aircraft system level, fuel burn benefits are conjectured to be feasible due to the reductions in nacelle weight and drag compared to an aircraft powered by the long-inlet baseline propulsor.

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The Flight Testing of Natural and Hybrid Laminar Flow Nacelles

Cited by 15 publications

References 5 publications

Current state and prospects of researches on the control of turbulent boundary layer by air blowing

Current state and prospects of researches on the control of turbulent boundary layer by air blowing

Sizing implications of a regional aircraft for inner-city operations

Ultra-Short Nacelles for Low Fan Pressure Ratio Propulsors

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