Cyclostationary Analysis of Fan Noise Influenced by an Inflow Control Device

Grizewski, Larisa; Behn, Maximilian; Funke, Stefan; Siller, H.

doi:10.2514/1.j059493

Cited by 5 publications

(3 citation statements)

References 13 publications

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“…At subsonic blade tip speeds BPF amplitudes were significantly reduced if the facility is operated with TCS while at supersonic tip Mach numbers the influence of the TCS on the acoustic spectra is small. Broadband noise levels are hardly affected by TCS for all operating conditions [20,25,21,24,26]. In addition, novel mode decomposition methods yield that no additional propagating modes were introduced due to the use of TCS and that cut-on modes can be stabilized (i.e.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, novel mode decomposition methods yield that no additional propagating modes were introduced due to the use of TCS and that cut-on modes can be stabilized (i.e. they are more prominent in the spectra) through TCS [24,26]. Besides a detailed acoustic characterization Caldas et al [24] investigated the flowfield upstream of the rotor via hot-wire anemometry.…”

Section: Introductionmentioning

confidence: 99%

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Influence of a Turbulence Control Screen on the Aerodynamic and Aeroelastic Behavior of a UHBR Fan

Schneider

Paoletti

Ottavy

et al. 2022

Volume 8A: Structures and Dynamics — Aerodynamics Excitation and Damping; Bearing and Seal Dynamics; Emerging Methods in Engine

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A composite fan stage representative of a modern Ultra High Bypass Ratio (UHBR) architecture has been investigated experimentally on a novel test facility at Ecole Centrale de Lyon. For these experiments, a turbulence control screen (TCS), a hemisphere, consisting of honeycomb and wiremesh panels, was installed in front of the rig in order to ensure homogeneous, disturbance-free inflow conditions. This kind of screen was developed in the early 1970 years to investigate flight-noise on static test beds. Today, they are commonly used in aero-engine and fan tests, because they improve the accuracy of acoustic measurements and provide more reproducible performance tests. However, the influence of such screens has been investigated only from an acoustic point of view in the past. This study presents a back-to-back comparison of measurements with and without the TCS, which allows a characterization of the effects on aerodynamic and aeroelastic behavior of the fan stage. The investigation was carried out for multiple stable operating points on two different speed lines to obtain a global image of the influence at part and design speed. The utilization of steady and unsteady instrumentation in different axial and circumferential duct positions allows a detailed analysis of similarities and differences of the configuration without and with the TCS and provides insight into underlying physical mechanisms.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of a Turbulence Control Screen on the Aerodynamic and Aeroelastic Behavior of a UHBR Fan

Schneider

Paoletti

Ottavy

et al. 2022

Volume 8A: Structures and Dynamics — Aerodynamics Excitation and Damping; Bearing and Seal Dynamics; Emerging Methods in Engine

View full text Add to dashboard Cite

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“…19 Signals are subsequently split with the help of a cyclostationary analysis into: one part with a locked phase relative to the rotor, and a second with the fluctuating component. 20,21 Through this averaging procedure in the time domain, only pure tones remain in the rotor-locked spectrum. It is therefore also referred to as tonal spectrum.…”

Section: Introductionmentioning

confidence: 99%

Advanced analysis of fan noise measurements supported by theoretical source models

Klähn

Moreau

Caldas

et al. 2022

International Journal of Aeroacoustics

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With the objective to improve the understanding of the dominant fan noise source mechanisms, a comprehensive experimental study was conducted at a low speed fan test rig. The aerodynamic fan map as well as the acoustic characteristics of the fan was measured for a new blade integrated disk (Blisk) rotor with systematic variation of the shaft speed and throttling. The interpretation of the results is supported by simulations of the experiment with a physics-based analytical in-house tool for fan noise prediction. For the acoustic measurements, an array of wall-flushed microphones was used in the inlet section. By means of radial mode analysis techniques, the broadband and tonal sound powers are calculated for each operating point. In the obtained comprehensive database, systematic variations of the tonal and broadband sound power with the flow rate are found. These patterns can only partly be correlated to the varying incidence angle of the rotor blades. Comparing the mode distributions of the measured noise and the analytical models then allows conclusions on the predominant noise sources of rotor–stator interaction and inflow-rotor interaction.

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