NASA Technology for Next Generation Vertical Lift Vehicles

Gorton, Susan A.

doi:10.2514/6.2015-0949

Cited by 8 publications

(10 citation statements)

References 9 publications

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“…This turbine stage was selected to operate at application specific conditions to meet FVL requirements [1,2,[4][5][6][7]9]. These conditions include two off-design operating speeds of 50% (22,350 RPM) and 75% (33,525 RPM) as well as a design speed of 100% (44,700 RPM).…”

Section: Fig 3 Illustration Of Stator and Rotor Blade Geometries Andmentioning

confidence: 99%

“…These conditions include two off-design operating speeds of 50% (22,350 RPM) and 75% (33,525 RPM) as well as a design speed of 100% (44,700 RPM). These operating speeds effectively replicate different engine conditions that are seen during cruise, takeoff, and hover [1,2,[4][5][6][7]9]. Furthermore, the computational model operates under theoretical gas-turbine combustor exit flow conditions.…”

Section: Fig 3 Illustration Of Stator and Rotor Blade Geometries Andmentioning

confidence: 99%

“…Innovative engines are in high demand because of the ever-higher power and efficiency requirements needed to advance today's propulsion systems [1][2][3][4][5][6][7][8]. Different engine modifications have been proposed to meet those requirements.…”

Section: Introductionmentioning

confidence: 99%

“…Particularly, one promising design is the variable speed power turbine (VSPT). A VSPT would have the capability of operating at several different conditions without facing the substantial performance losses seen in traditional gas turbine engine [1,2,[4][5][6][7][8][9][10][11][12]. This capability would enable VSPT to meet the requested power and efficiency levels.…”

Section: Introductionmentioning

confidence: 99%

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Computational Finite Element Analysis of Adaptive Gas Turbine Stator-Rotor Flow Interactions for Future Vertical Lift Propulsion

Kozak

Bravo

Murugan

et al. 2019

AIAA Propulsion and Energy 2019 Forum

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The objective of this work is to computationally investigate the impact of an incident-tolerant rotor blade concept on gas-turbine engine performance under off-design conditions. Currently, gas-turbine engines are designed to operate at a single condition with nearly fixed rotor speeds. Operation at off-design conditions, such as during hover flight or during takeoff, causes the turbine blade flow to excessively separate introducing performance degradations, excessive noise, and critical loss of operability. To address these issues, the benefits of using an incidence-tolerant rotor blade concept is explored based on a novel concept that articulates the rotating turbine blade synchronously with the stator nozzle vanes. This concept is investigated using a novel CFD/FSI framework based on finite element analysis. The model considers a complex single stage highpressure turbine geometry with 24 stator and 34 rotor blades operating under combustor exit flow conditions. The rotor speeds investigated are 44,700 rpm, 33,525 rpm, and 22,350 rpm corresponding to the design point at 100% speed down to 51% speed during off-design flight mode. This study focuses on determining the optimal performance benefits possible by exploring the limits of rotor blade articulation angles, as well as reporting its impact over a broad range of rotor speeds at Army relevant conditions. The key variables of interest include moments on the blade suction surface, torque, power, and turbine stage adiabatic efficiency. Further, sensitivity analysis of the uncertainties in boundary conditions is conducted to determine its influence on turbine efficiency. The results show that it is possible to increase efficiency increases of up to 10% by articulating rotor blades at off-design conditions thereby providing critical leap ahead design capabilities for the US Army Future Vertical Lift (FVL) program.

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Section: Fig 3 Illustration Of Stator and Rotor Blade Geometries Andmentioning

confidence: 99%

Section: Fig 3 Illustration Of Stator and Rotor Blade Geometries Andmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Computational Finite Element Analysis of Adaptive Gas Turbine Stator-Rotor Flow Interactions for Future Vertical Lift Propulsion

Kozak

Bravo

Murugan

et al. 2019

AIAA Propulsion and Energy 2019 Forum

View full text Add to dashboard Cite

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“…For new Vertical Take-Off and Landing (VTOL) aircraft manufacturers, especially those engaged with non-traditional configurations, in-house discipline tools appropriate for rotary wing vehicles are rarely available. Formal optimisation tools and analyses are needed now to incorporate the growing number of design constraints and complex system trades needed to assess future rotorcraft designs (1) .…”

Section: Introductionmentioning

confidence: 99%

A handling qualities analysis tool for rotorcraft conceptual designs

et al. 2018

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Over the past decade, NASA, under a succession of rotary-wing programs, has been moving towards coupling multiple discipline analyses to evaluate rotorcraft conceptual designs. Handling qualities is one of the component analyses to be included in such a future Multidisciplinary Analysis and Optimization framework for conceptual design of Vertical Take-Off and Landing (VTOL) aircraft. Similarly, the future vision for the capability of the Concept Design and Assessment Technology Area of the U.S Army Aviation Development Directorate also includes a handling qualities component. SIMPLI-FLYD is a tool jointly developed by NASA and the U.S. Army to perform modelling and analysis for the assessment of the handling qualities of rotorcraft conceptual designs. Illustrative scenarios of a tiltrotor in forward flight and a single-main rotor helicopter at hover are analysed using a combined process of SIMPLI-FLYD integrated with the conceptual design sizing tool NDARC. The effects of variations of input parameters such as horizontal tail and tail rotor geometry were evaluated in the form of margins to fixed- and rotary-wing handling qualities metrics and the computed vehicle empty weight. The handling qualities Design Margins are shown to vary across the flight envelope due to both changing flight dynamics and control characteristics and changing handling qualities specification requirements. The current SIMPLI-FLYD capability, lessons learned from its use and future developments are discussed.

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