Application of Additive Manufacturing to Rapidly Produce High-Resolution Total Pressure Distortion Screens

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

doi:10.2514/6.2012-929

Cited by 8 publications

(1 citation statement)

References 11 publications

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“…Experimental and numerical investigation by Hah et al [10] have shown that the inlet total pressure distortion increases aerodynamic losses when a strong unsteady interaction between the passage shock and the blade boundary layer develops. Further, experimental research on an S-duct was completed by Ferrar et al [11] and various mass flow rates tested. Results were similar to numerical simulations where curvature in the duct affects the static pressure gradient due to flow separation.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Stability Analysis of a Generic Fan With Distorted Inflow Using Passage-Spectral Method

Romera

Corral

2021

Journal of Turbomachinery

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The dependence of the aerodynamic stability of fan blades with the nodal diameter and amplitude of the inlet perturbations is studied. The analysis is conducted using a block-wise spatial Fourier decomposition of reduced-passages to reconstruct the full-annulus solution. The explicit spatial Fourier approximation is exploited to characterize the relevance of each nodal diameter of the inlet perturbation in the fan stall process and study the nonlinear stability in a harmonic by harmonic basis. This approximation allows studying the contribution to stall of each circumferential mode separately. The methodology has been assessed for the NASA rotor 67. The maximum amplitude of total pressure distortion at which the compressor becomes unstable and triggers a stall process has been mapped. It has been proven that despite the complexity of a screen-induced total pressure distortion the only relevant parameter for the nonlinear stability of the fan is the most unstable nodal diameter. Full-annulus simulations have been conducted to assess the accuracy of the simplified nonlinear stability limit. It is concluded that performing a nonlinear simulation with the proper single harmonic perturbation is enough to assess fan stability. It is shown that for the NASA rotor 67 running at the nominal speed the most unstable nodal diameter is the first. This study not only shows a reduction in computational time to assess nonlinear fan stability by a factor of seven but also creates an efficient methodology for understanding the nonlinear instability of fans due to inlet distortion profiles.

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Section: Introductionmentioning

confidence: 99%

Nonlinear Stability Analysis of a Generic Fan With Distorted Inflow Using Passage-Spectral Method

Romera

Corral

2021

Journal of Turbomachinery

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show abstract

Nonlinear Stability Analysis of a Generic Fan With Distorted Inflow Using Passage-Spectral Method

Romera¹,

Corral²

2021

Preprint

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The dependence of the aerodynamic stability of fan blades with the nodal diameter and amplitude of the inlet perturbations is studied. The analysis is conducted using a block-wise spatial Fourier decomposition of reduced-passages to reconstruct the full-annulus solution. The method represents very efficiently the unsteady flow generated by inlet non-uniformities. The explicit spatial Fourier approximation is exploited to characterize the relevance of each nodal diameter of the inlet perturbation in the fan stall process and study the nonlinear stability in a harmonic by harmonic basis. This approximation allows studying the contribution to stall of each circumferential mode separately. The methodology has been assessed for the NASA rotor 67. The maximum amplitude of total pressure distortion at which the compressor becomes unstable and triggers a stall process has been mapped. It has been proven that despite the complexity of a screen-induced total pressure distortion the only relevant parameter for the nonlinear stability of the fan is the most unstable nodal diameter. The equivalence in terms of stability between realistic distortion screens and single harmonic distortions has been assessed. Full-annulus simulations have been conducted to assess the accuracy of the simplified nonlinear stability limit. It is concluded that performing a nonlinear simulation with the proper single harmonic perturbation is enough to assess fan stability. The total pressure error with respect the full annulus simulation including a screen-induced pressure deficit at the intake is

show abstract

Nonlinear Stability Analysis of a Generic Fan With Distorted Inflow Using Passage-Spectral Method

Romera

Corral

2020

Volume 2A: Turbomachinery

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The dependence of the aerodynamic stability of fan blades with the nodal diameter and amplitude of the inlet perturbations is studied. The analysis is conducted using a block-wise spatial Fourier decomposition of reduced-passages to reconstruct the full-annulus solution. The method represents very efficiently the unsteady flow generated by inlet non-uniformities. The explicit spatial Fourier approximation is exploited to characterize the relevance of each nodal diameter of the inlet perturbation in the fan stall process and study the nonlinear stability in a harmonic by harmonic basis. This approximation allows studying the contribution to stall of each circumferential mode separately. The methodology has been assessed for the NASA rotor 67. The maximum amplitude of total pressure distortion at which the compressor becomes unstable and triggers a stall process has been mapped. It has been proven that despite the complexity of a screen-induced total pressure distortion the only relevant parameter for the nonlinear stability of the fan is the most unstable nodal diameter. The equivalence in terms of stability between realistic distortion screens and single harmonic distortions has been assessed. Full-annulus simulations have been conducted to assess the accuracy of the simplified nonlinear stability limit. It is concluded that performing a nonlinear simulation with the proper single harmonic perturbation is enough to assess fan stability. The total pressure error with respect the full annulus simulation including a screen-induced pressure deficit at the intake is below 10%. It is shown that for the NASA rotor 67 running at the nominal speed the most unstable nodal diameter is the first. This study not only shows a reduction in computational time to assess nonlinear fan stability by a factor of seven but also creates an efficient methodology for understanding the nonlinear instability of fans due to inlet distortion profiles.

show abstract

Application of Additive Manufacturing to Rapidly Produce High-Resolution Total Pressure Distortion Screens

Cited by 8 publications

References 11 publications

Nonlinear Stability Analysis of a Generic Fan With Distorted Inflow Using Passage-Spectral Method

Nonlinear Stability Analysis of a Generic Fan With Distorted Inflow Using Passage-Spectral Method

Nonlinear Stability Analysis of a Generic Fan With Distorted Inflow Using Passage-Spectral Method

Nonlinear Stability Analysis of a Generic Fan With Distorted Inflow Using Passage-Spectral Method

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