Separation Control for Aero Engine Intakes, Part 2: High-Speed Investigations

Wakelam, Christian; Hynes, T. P.; Hodson, H. P.; Evans, Steven W.; Chanez, Philippe

doi:10.2514/1.b34327

Cited by 18 publications

(6 citation statements)

References 4 publications

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“…The plot shows a hysteresis loop in mass flow already discussed in Refs. [4,5], and it is similar to the hysteresis in angle of attack reported in Refs. [9,34].…”

Section: B Air Inlet Flow Without the Abl Grid Installedsupporting

confidence: 89%

“…This causes the airflow to experience a large local acceleration followed by a steep deceleration. These conditions may cause the boundary layer on the lip to separate, therefore creating large flow distortions at fan plane [4,5]. This phenomenon is difficult to numerically simulate in a reliable manner [6].…”

Section: Simulation Of Atmospheric Boundary Layer For Air Inlet Testing In Crossflowmentioning

confidence: 99%

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Simulation of Atmospheric Boundary Layer for Air Inlet Testing in Crossflow

Mouton

2021

AIAA Journal

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“…The plot shows a hysteresis loop in mass flow already discussed in Refs. [4,5], and it is similar to the hysteresis in angle of attack reported in Refs. [9,34].…”

Section: B Air Inlet Flow Without the Abl Grid Installedsupporting

confidence: 89%

Section: Simulation Of Atmospheric Boundary Layer For Air Inlet Testing In Crossflowmentioning

confidence: 99%

Simulation of Atmospheric Boundary Layer for Air Inlet Testing in Crossflow

Mouton

2021

AIAA Journal

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“…Consequently the notable reduction in fan efficiency and fan operability range for 𝐿 𝑖𝑛 /𝐷 𝑓 𝑎𝑛 < 0.25 out-weighted the reduction in nacelle drag at cruise and resulted in a penalty in the overall propulsive efficiency. Wakelam et al [10,11] experimentally investigated two different crosswind regimes within a quasi-3D rig with no ground vortex and no fan-intake interaction. For the transonic regime [11] the ŕow within the sector rig was either attached or grossly separated from the leading edge of the intake lip.…”

Section: Introductionmentioning

confidence: 99%

Effect of Unsteady Fan-Intake Interaction on Short Intake Design

Boscagli,

MacManus,

Christie

et al. 2023

Journal of Engineering for Gas Turbines and Power

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The next generation of ultrahigh bypass ratio civil aero-engines promises notable engine cycle benefits. However, these benefits can be significantly eroded by a possible increase in nacelle weight and drag due to the typical larger fan diameters. More compact nacelles, with shorter intakes, may be required to enable a net reduction in aero-engine fuel burn. The aim of this paper is to assess the influence of the design style of short intakes on the unsteady interaction under crosswind conditions between fan and intake, with a focus on the separation onset and characteristics of the boundary layer within the intake. Three intake designs were assessed, and a hierarchical computational fluid dynamics (CFD) approach was used to determine and quantify primary aerodynamic interactions between the fan and the intake design. Similar to previous findings for a specific intake configuration, both intake flow unsteadiness and the unsteady upstream perturbations from the fan have a detrimental effect on the separation onset for the range of intake designs. The separation of the boundary layer within the intake was shock driven for the three different design styles. The simulations also quantified the unsteady intake flows with an emphasis on the spectral characteristics and engine-order signatures of the flow distortion. Overall, this work showed that is beneficial for the intake boundary layer to delay the diffusion closer to the fan and reduce the preshock Mach number to mitigate the adverse unsteady interaction between the fan and the shock.

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“…The Sector Rig also captured three flow regimes at increasing engine mass flow rates: low-speed separation (with hysteresis), attached flow, and high speed shock-induced separation. Wakelam et al [4,12] further demonstrated the use of different flow-control strategies (passive boundary trips and active vortex generator jets) to reduce fan-face distortion. From the numerical front, Vadlamani and Tucker [13] studied the possibility of using plasma actuators for flow control.…”

Section: Introductionmentioning

confidence: 99%

Quasi 3D Nacelle Design to Simulate Crosswind Flows: Merits and Challenges

Yeung

Vadlamani

Hynes

et al. 2019

IJTPP

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This paper studies the computational modelling of the flow separation over the engine nacelle lips under the off-design condition of significant crosswind. A numerical framework is set up to reproduce the general flow characteristics under crosswinds with increasing engine mass flow rate, which include: low-speed separation, attached flow and high speed shock-induced separation. A quasi-3D (Q3D) duct extraction method from the full 3D (F3D) simulations has been developed. Results obtained from the Q3D simulations are shown to largely reproduce the trends observed (isentropic Mach number variations and high-speed separation behaviour) in the 3D intake, substantially reducing the simulation time by a factor of 50. The agreement between the F3D and Q3D simulations is encouraging when the flow either fully attached or with modest levels of separation but degrades when the flow fully detaches. Results are shown to deviate beyond this limit since the captured streamtube shape (and hence the corresponding Q3D duct shape) changes with the mass flow rate. Interestingly, the drooped intake investigated in the current study is prone to earlier separation under crosswinds when compared to an axisymmetric intake. Implications of these results on the industrial nacelle lip design are also discussed.

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Separation Control for Aero Engine Intakes, Part 2: High-Speed Investigations

Cited by 18 publications

References 4 publications

Simulation of Atmospheric Boundary Layer for Air Inlet Testing in Crossflow

Simulation of Atmospheric Boundary Layer for Air Inlet Testing in Crossflow

Effect of Unsteady Fan-Intake Interaction on Short Intake Design

Quasi 3D Nacelle Design to Simulate Crosswind Flows: Merits and Challenges

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