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Experimental Investigation of Inflow-Distortion-Induced Tonal Noise in a Sub-Sonic Fan Test Rig

Klähn, Lukas and Caldas, Luciano and Meyer, Robert and Moreau, Antoine and Tapken, Ulf (2023) Experimental Investigation of Inflow-Distortion-Induced Tonal Noise in a Sub-Sonic Fan Test Rig. In: 29th International Congress on Sound and Vibration, ICSV 2023. 29th International Congress on Sound and Vibration, 2023-07-09 - 2023-07-13, Prag, Tschechische Republik. ISBN 978-801103423-8. ISSN 2329-3675.

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Official URL: https://iiav.org/content/archives_icsv_last/2023_icsv29/indexbd58.html?va=viewpage&vaid=410

Abstract

Experimental investigation on the influence of inflow distortions on fan noise was performed at the low-speed Co-/Counter Rotating Acoustic Fan Test rig (CRAFT). The investigated fan stage is designed such that the dominant interaction modes at the first and second BPF are excited weakly in upstream direction, but strongly in downstream direction, due to the mode propagation angle. Two major tonal source mechanisms are described in the literature and addressed in this work. The first mechanism is the inflow-distortion-rotor interaction, which can generate high sound power levels at the blade passing frequencies at high blade tip mach numbers or low rotor blade counts. For the measurements performed this source seems to be relevant only for extreme inflow distortion cases. The second mechanism is linked to the modulation of the rotor-stator interaction (RSI), which is caused by the periodically fluctuating incidence angle and the resulting fluctuation of the rotor wakes shape. The sources distorted phase and amplitude lead to a less effective constructive interference of the conventional interaction modes and a less a destructive interference of the adjacent modes. As consequence, a broader mode spectrum is propagating to the measurement sections. The overall sound power level for our specific fan stage can be more than 7 dB higher or 1 dB lower than the baseline, depending on the inflow distortion profile and BPF harmonic.

Item URL in elib:https://elib.dlr.de/194810/
Document Type:Conference or Workshop Item (Speech)
Title:Experimental Investigation of Inflow-Distortion-Induced Tonal Noise in a Sub-Sonic Fan Test Rig
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Klähn, LukasUNSPECIFIEDhttps://orcid.org/0000-0002-1425-4453141888811
Caldas, LucianoUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Meyer, RobertUNSPECIFIEDhttps://orcid.org/0009-0005-5241-1818UNSPECIFIED
Moreau, AntoineUNSPECIFIEDhttps://orcid.org/0000-0001-7836-4523UNSPECIFIED
Tapken, UlfUNSPECIFIEDhttps://orcid.org/0000-0002-0870-1253141888812
Date:9 July 2023
Journal or Publication Title:29th International Congress on Sound and Vibration, ICSV 2023
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:No
ISSN:2329-3675
ISBN:978-801103423-8
Status:Published
Keywords:inflow-distortion, fan noise, rotor-stator interaction, radial mode analysis, boundary layer ingestion, CRAFT, fan test rig
Event Title:29th International Congress on Sound and Vibration
Event Location:Prag, Tschechische Republik
Event Type:international Conference
Event Start Date:9 July 2023
Event End Date:13 July 2023
Organizer:International Institute of Acoustics and Vibration
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Clean Propulsion
DLR - Research area:Aeronautics
DLR - Program:L CP - Clean Propulsion
DLR - Research theme (Project):L - Future Engines and Engine Integration, L - Components and Emissions
Location: Berlin-Charlottenburg
Institutes and Institutions:Institute of Propulsion Technology > Engine Acoustic
Deposited By: Klähn, Lukas
Deposited On:07 Sep 2023 10:18
Last Modified:24 Apr 2024 20:55

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