Numerical Assessment of Pneumatic Devices on the Wing/Fuselage Junction of a Tiltrotor

Simioni, Nicola; Ponza, Rita; Benini, Ernesto

doi:10.2514/1.c031911

Cited by 6 publications

(11 citation statements)

References 12 publications

(13 reference statements)

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“…The shear stress transport (SST) k-ω turbulence model developed by Menter [14,15] was selected. The semi implicit method for pressure linked equations (SIMPLE) scheme was used to resolve the pressure-velocity coupling with the second order discretization for the pressure equation, the third order monotonic upstream-centered scheme for conservation laws (MUSCL) for the momentum, turbulent kinetic energy and turbulent dissipation rate [10]. Unsteady calculations (URANS) were performed.…”

Section: Boundary Condition and Simulation Setupmentioning

confidence: 99%

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Numerical Study of Transition of an Annular Lift Fan Aircraft

Jiang

Zhang

2016

Aerospace

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The present study aimed at studying the transition of annular lift fan aircraft through computational fluid dynamics (CFD) simulations. The oscillations of lift and drag, the optimization for the figure of merit, and the characteristics of drag, yawing, rolling and pitching moments in transition are studied. The results show that a two-stage upper and lower fan lift system can generate oscillations of lift and drag in transition, while a single-stage inner and outer fan lift system can eliminate the oscillations. The characteristics of momentum drag of the single-stage fans in transition are similar to that of the two-stage fans, but with the peak of drag lowered from 0.63 to 0.4 of the aircraft weight. The strategy to start transition from a negative angle of attack −21 • further reduces the peak of drag to 0.29 of the weight. The strategy also reduces the peak of pitching torque, which needs upward extra thrusts of 0.39 of the weight to eliminate. The peak of rolling moment in transition needs differential upward thrusts of 0.04 of the weight to eliminate. The requirements for extra thrusts in transition lead to a total thrust-weight ratio of 0.7, which makes the aircraft more efficient for high speed cruise flight (higher than 0.7 Ma).

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Section: Boundary Condition and Simulation Setupmentioning

confidence: 99%

“…CFD simulations were performed using ANSYS Fluent 17.0 (ANSYS, Inc., Canonsburg, PA, USA), which has been extensively used in various studies [9][10][11][12][13]. Steady and unsteady Reynolds-averaged Navier-Stokes (RANS) equations for the mean flow quantities were solved.…”

Section: Boundary Condition and Simulation Setupmentioning

confidence: 99%

Numerical Study of Transition of an Annular Lift Fan Aircraft

Jiang

Zhang

2016

Aerospace

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“…The shear stress transport (SST) k-ω turbulence model developed by Menter [20,21] was selected. The semi-implicit method for pressure linked equations (SIMPLE) scheme was used to resolve the pressure-velocity coupling with the second order discretization for the pressure equation, the third order monotonic upstream-centered scheme for conservation laws (MUSCL) for the momentum, turbulent kinetic energy and turbulent dissipation rate [22]. Multiple reference frames were used for the fan fluid zone and the stationary zone.…”

Section: Boundary Condition and Simulation Setupmentioning

confidence: 99%

CFD Study of a New Annular Lift Fan Configuration with High Lift Efficiency

Jiang

Zhang

2017

Aerospace

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Abstract:A new annular lift fan configuration that has very high lift efficiency is explored by using a numerical scheme. The inlet lip radius and diffuser angle are maximized by semicircle duct walls and the location of the lift fan is moved from the throat to the diffuser area to maximize the diffusion effect of the ducted fan. The improved lift fan achieves the figure of merit of 0.772 and the power loading of 9.03 lbs/hp without ground effect, very close to the theoretical limit. Under the ground effect, the figure of merit reaches 0.822 with the power loading of 9.62 lbs/hp. The improved lift efficiency deteriorates the transition characteristics with higher momentum drag and pitching moment. However, with the aid of jet thrusts directly providing part of the lift during transition, the peak of momentum drag and pitching moment can be lowered. A total thrust to weight ratio of 0.7 is enough for all of the requirements in transition and in hover and for the maximum speed of 0.75 Mach in cruise flight.

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“…The unstructured mesh technique has been successfully applied to solve CFD problems [6][7][8][9]. CFD methods based on unstructured grids have an advantage of easily handling complex geometries and can improve the solution accuracy by refining cells locally as required [7].…”

Section: Computational Meshmentioning

confidence: 99%

“…In the last two decades, as a result of continuing efforts spent in computational fluid dynamics (CFD) calculations and more diffuse access to adequate computational resources, many aerodynamic researches have moved into the branch of CFD, which is more affordable, practical, systematic and reliable [6]. A numerical investigation of the novel annular-ducted fan system before expensive experiments is necessary to provide insights for future studies.…”

Section: Introductionmentioning

confidence: 99%

CFD Study of an Annular-Ducted Fan Lift System for VTOL Aircraft

2015

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Abstract:The present study aimed at assessing a novel annular-ducted fan lift system for VTOL aircraft through computational fluid dynamics (CFD) simulations. The power and lift efficiency of the lift fan system in hover mode, the lift and drag in transition mode, the drag and flight speed of the aircraft in cruise mode and the pneumatic coupling of the tip turbine and jet exhaust were studied. The results show that the annular-ducted fan lift system can have higher lift efficiency compared to the rotor of the Apache helicopter; the smooth transition from vertical takeoff to cruise flight needs some extra forward thrust to overcome a low peak of drag; the aircraft with the lift fan system enclosed during cruise flight theoretically may fly faster than helicopters and tiltrotors based on aerodynamic drag prediction, due to the elimination of rotor drag and compressibility effects on the rotor blade tips; and pneumatic coupling of the tip turbine and jet exhaust of a 300 m/s velocity can provide enough moment to spin the lift fan. The CFD results provide insight for future experimental study of the annular-ducted lift fan VTOL aircraft.

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Numerical Assessment of Pneumatic Devices on the Wing/Fuselage Junction of a Tiltrotor

Cited by 6 publications

References 12 publications

Numerical Study of Transition of an Annular Lift Fan Aircraft

Numerical Study of Transition of an Annular Lift Fan Aircraft

CFD Study of a New Annular Lift Fan Configuration with High Lift Efficiency

CFD Study of an Annular-Ducted Fan Lift System for VTOL Aircraft

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