Unsteady Three-Dimensional Simulation Research of Fan-OGV-Strut-Pylon Interaction in Japanese ECO Engine Project

Ooba, Yoshinori; Murooka, Takeshi; Yamada, Takashi; Nozaki, Osamu; Ishiyama, Takeshi

doi:10.2514/6.2011-979

Cited by 3 publications

(2 citation statements)

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“…Depending on the design of the fan stage, the loss generation in the rotor and stator blade rows due to the presence of a pylon can be substantial, as demonstrated for example by Unno et al [32] or Ooba et al [83]. An example for the optimization of the stator stagger circumferential distribution in the presence of two bifurcations is presented by Milli and Bron [78].…”

Section: Mitigating the Pylon Upstream Influencementioning

confidence: 99%

“…Rotor blade losses increase whenever the local operating point is shifted away from the design point, with rotor incidence i = i des . Thus, non-axisymmetric FEGV designs with circumferentially-varying vane spacing to offset the pylon upstream influence offer a potential for improved propulsor performance [32,78,83]. This approach is discussed in more detail in Chapter 8.…”

Section: Dissection Of Distortion Transfer Mechanismsmentioning

confidence: 99%

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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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Section: Mitigating the Pylon Upstream Influencementioning

confidence: 99%

Section: Dissection Of Distortion Transfer Mechanismsmentioning

confidence: 99%