Improved Prediction Method for the Design of High-Resolution Total Pressure Distortion Screens

Schneck, William C.; Ferrar, Anthony M.; Bailey, Justin M.; Hoopes, Kevin; O’Brien, Walter F.

doi:10.2514/6.2013-1133

Cited by 14 publications

(10 citation statements)

References 5 publications

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“…Following on from the work of Giuliani, this current study quantifies the characteristics of the unsteady swirl and velocity distortion for S-duct intakes with a non-uniform pressure distribution at the inlet. Recent studies demonstrated the use of devices to impose non-uniform inlet conditions, including swirl [30], boundary layers [19] and, more generally, total pressure distortion screens [21] for the application in model-scale research engine testing. In this work, 3Dprinted honeycomb screens are used to generate a boundary layer at the of S-duct inlet.…”

Section: Inlet Total Pressure Profilesmentioning

confidence: 99%

“…More recently, 3D printing techniques have been used for the generation of pressure profiles, to simulate the operation of the intake with a thick boundary layer profile [19]. Methods with CFD and experimental calibrations showed the possibility to reproduce swirl patterns [20], generalized pressure distortions [21] and combined pressure and swirl distortion [22]. There is little previous work on the effect of the different inlet boundary layer heights to the unsteady flow distortion at the aerodynamic interface plane of an S-duct intake.…”

Section: Introductionmentioning

confidence: 99%

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The impact of inlet boundary layer thickness on the unsteady aerodynamics of S-duct intakes

Migliorini

Zachos

MacManus

2019

AIAA Propulsion and Energy 2019 Forum

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The need to reduce aero-engine emissions and direct operating costs is driving the civil aerospace sector towards considering more integrated propulsion systems. Many of the proposed novel aircraft architectures employ convoluted intakes for either the aero-engine or propulsion system. These intakes are characterized by unsteady distortion that can hinder the performance and operability of the propulsion system. This work assesses the impact of the inlet boundary layer on the unsteady aerodynamics of an S-duct intake using time-resolved particle image velocimetry at the aerodynamic interface plane. An increase in the boundary layer thickness at the intake inlet increases the flow unsteadiness on the swirl angle by up to 40% relative to the baseline case. The azimuthal orientation of the inlet boundary layer modifies the intensity and topology of the most frequent swirl distortion pattern. For a relatively thick inlet boundary layer, the reduction of the dominant frequencies associated with the unsteady swirl angle is postulated to be beneficial for the engine stability. Overall, this works gives guidelines for the integration between the intake and the engine across the range of potential inlet operating conditions.

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Section: Inlet Total Pressure Profilesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The impact of inlet boundary layer thickness on the unsteady aerodynamics of S-duct intakes

Migliorini

Zachos

MacManus

2019

AIAA Propulsion and Energy 2019 Forum

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“…The performance of turbofan engines depends on the characteristics of the flow entering the engine. While the effects of total pressure and total temperature distortions in engine inlets have been studied and well-characterized for decades [2][3][4][5], swirl distortions are still not fully understood by the turbomachinery community. Swirl distortions are angular non-uniformities in the flow, which can be caused by several phenomena, such as boundary layer ingestion, ingestion of ground/fuselage vortices, the presence of cross wind, and adverse pressure gradients [6].…”

Section: Introductionmentioning

confidence: 99%

Vortical flow development in round ducts across scales for engine inlet applications

2019

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Turbofan engine performance depends highly on the characteristics and conditions of the inlet flow. Swirl distortions, caused by non-uniformities in flows arising from boundary layer or ground/fuselage vortex ingestion are of concern and need to be fully understood to guarantee efficiency and safety of propulsion systems. To investigate a fundamental single-vortex distortion development in a duct at different Reynolds numbers, a StreamVane distortion generating device was designed and experimentally analyzed in a small-scale low-speed wind tunnel (Re D 500 × 10 3 ) and in a full-scale engine testing rig (Re D 3 × 10 6 ). Stereoscopic particle image velocimetry was used to measure the three-component velocity fields at discrete measurement planes downstream of the distortion device. Results show that the secondary flow is generated and develops very similarly in both scales, and is mostly driven by two-dimensional (2D) vortex dynamics. Induced velocities arising from the proximity of the vortex to the duct wall causes the vortex center to convect circumferentially around the duct, in the same sense as the vortex rotation, as it travels downstream. Small-scale turbulence results show small-scale instabilities related to the development of the vortex. This work shows that the development of this vane-generated, vortex-dominated flow is largely Reynolds number independent for the covered range, so that details of similar duct-bounded flows can be analyzed in depth in small-scale experiments, decreasing development efforts and cost. arXiv:1808.07273v1 [physics.flu-dyn]

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“…5 Distortion screens are commonly used for simulating distorted inlet total pressure flow field in test facilities. The design of screens to simulate a target flow field is discussed in Overall, 6 Anderson, 7 and Schneck et al 8 In the present study, a distortion screen designed using the methodology of Sankaranarayanan et al 9 is employed. A series of systematic experiments were conducted to characterize the screen meshes of various porosities in terms of their loss coefficients and distortion parameters, and a comprehensive database was generated.…”

Section: Introductionmentioning

confidence: 99%

Flow field behind a complex total pressure distortion screen

Sivapragasam

2019

Proceedings of the Institution of Mechanical Engineers, Part G:

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The flow field behind a complex total pressure distortion screen is investigated experimentally and numerically. The distortion screen is designed using an established design methodology and fabricated by water-jet cutting technique. The distorted total pressure field behind the screen is quantified by a distortion index parameter, which is evaluated from computations and experiments for several values of inlet Mach number. The root-mean-square error between the target total pressure values and that achieved by the screen design at the aerodynamic interface plane is 4.75%. The evolution of the distorted total pressure field downstream of the screen is presented in detail in terms of radial and circumferential total pressure distributions and their gradients. An alternative interpretation of the distorted total pressure field is made by means of defining a total pressure flux existing behind the screen and expanding it using derivative-moment transformation technique. It is seen that the circumferential vorticity is a major contributing factor to the total pressure flux.

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Improved Prediction Method for the Design of High-Resolution Total Pressure Distortion Screens

Cited by 14 publications

References 5 publications

The impact of inlet boundary layer thickness on the unsteady aerodynamics of S-duct intakes

The impact of inlet boundary layer thickness on the unsteady aerodynamics of S-duct intakes

Vortical flow development in round ducts across scales for engine inlet applications

Flow field behind a complex total pressure distortion screen

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