Low-Speed Fan Noise Reduction with Trailing Edge Blowing

Sutliff, Daniel L.; Tweedt, Daniel L.; Fite, E. Brian; Envia, Edmane

doi:10.2514/6.2002-2492

Cited by 20 publications

(8 citation statements)

References 6 publications

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“…The maximum tonal noise reduction was observed at a blowing rate of 0.68% of the overall fan mass flow rate. At this blowing rate, a total attenuation of 6.8 dB was achieved, which is in comparable order to the results of Sutliff et al [16]. However, the required TEB mass flow was half compared to the previously mentioned experiment.…”

Section: Fig 4 Teb Blade Design Of Sutliff Et Al [3]supporting

confidence: 89%

“…Sutliff et al [16] focuses on the acoustic benefit of the TEB technique. Blowing was applied on a low-speed fan (DA = 1.219 m, n = 1700 -1900 rpm, 16 blades and 14 stator vanes) by implementing 19 blowing passages per fan blade.…”

Section: Fig 3 Teb Fan Rotor and Schematic Of The Teb Fan Blade By Bmentioning

confidence: 99%

“…This change increase the performance of acoustic liners used in conjunction with TEB. The experimental part of this study was performed at NASA Glenn using the same test rig as Sutliff et al [3], [16]. The blade design was a bit different.…”

Section: Fig 4 Teb Blade Design Of Sutliff Et Al [3]mentioning

confidence: 99%

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Active Control of Fan Tones by means of Trailing Edge Blowing

Enghardt

Kausche

Moreau

2015

21st AIAA/CEAS Aeroacoustics Conference

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At DLR in Berlin, a series of experiments was performed on a laboratory scale fan rig to explore the potential of trailing edge blowing (TEB) for the attenuation of tonal noise of an axial fan stage. The model fan consisted of 18 blades, each of which was equipped with five internal flow channels, commonly provided with pressurized air through the rotor hub. In configuration 1, all five channels were utilized for noise control. In configuration 2, the outmost two internal channels were blocked by means of aluminum tape. The latter case provided substantial tonal noise reduction, whereas the former led to no acoustic impact. In order to reproduce the experimental result, an analytical acoustic model based on the flow field measured by the hot wires was utilized. The model considers the interaction of the rotor wakes with the stator and substitutes the real sources by a spatial distribution of dipoles on the blades. Thus, the impact of the trailing edge blowing is modelled via the wake velocity perturbations and the unsteady lift they induce on the stator blades. The predicted noise reductions achieved by the TEB approach are in fairly good agreement with the experiments. Moreover, the model provides helpful indications about the reason for the failure of conf. 1 to provide a noise reduction and the success of conf. 2 to do so.

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Section: Fig 4 Teb Blade Design Of Sutliff Et Al [3]supporting

confidence: 89%

Section: Fig 3 Teb Fan Rotor and Schematic Of The Teb Fan Blade By Bmentioning

confidence: 99%

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Active Control of Fan Tones by means of Trailing Edge Blowing

Enghardt

Kausche

Moreau

2015

21st AIAA/CEAS Aeroacoustics Conference

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“…Morinushi studied the influence of five major geometric parameters on noise and aerodynamic performance of forward curved centrifugal fans [24]. Sutliff et al conducted an experimental proof of concept test to demonstrate rotor stator interaction tone noise reduction through rotor trailing edge blowing [25]. Li et al studied that the deviation of installation angle may cause deformation of total pressure and acoustic distribution based on Reynolds time-averaged equation and realizableturbulent model [26].…”

Section: Introductionmentioning

confidence: 99%

Simulation of Broadband Noise Sources of an Axial Fan under Rotating Stall Conditions

Zhang

Wang

2014

Advances in Mechanical Engineering

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Study on the influence of rotating stall on the aerodynamic noise of axial fan has important value to warn of the occurrence of stall through monitoring the noise variations. The present work is to analyze the aerodynamic noise before and after the phenomenon of rotating stall by solving Navier-Stokes equations, coupled with the throttle condition and the broadband noise sources model. The impeller exit rotational Mach number and rotational Reynolds number are separately 0.407 and 8.332 × 106 . The results show that the aerodynamic noise source of the fan is mainly the rotation noise under the design condition. The vortex noise accounts for the major part of fan noise after the occurrence of stall, and the maximum acoustic power level of the fan appears in the rotor domains. In the evolution process from the stall inception to the stall cell, the high noise regions of the rotor develop along the radial, circumferential, and axial directions, and the area occupied by high noise regions increases from 33% to 46% impeller channels area. On rotating stall condition, the high noise regions occupying about 46% impeller channels area propagate with the stall cell along the circumferential direction at a half of rotor speed.

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“…Esse efeito pode ser notado no estudo experimental feito por Sutliff et al (2002), que mostrou uma redução entre 8 e 20 dBs nos primeiros 3 tonais do espectro quando aplicada injeção de massa na esteira do rotor, reduzindo o déficit de velocidade da esteira que atinge as pás do estator.…”

Section: Modelos De Previsão De Ruídounclassified

Aeroacústica de motores aeronáuticos: uma abordagem por meta-modelo

Cuenca¹

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Desde a última década, as autoridades aeronáuticas dos países membros da ICAO vem, gradativamente, aumentando as restrições nos níveis de ruído externo de aeronaves, principalmente nas proximidades dos aeroportos. Por isso os novos motores aeronáuticos precisam ter projetos mais silenciosos, tornando as técnicas de predição de ruído de motores cada vez mais importantes.Diferente das técnicas semi-analíticas, que vêm evoluindo nas últimas décadas, as técnicas semiempíricas possuem suas bases lastreadas em técnicas e dados que remontam à década de 70, como as desenvolvidas no projeto ANOPP. Uma bancada de estudos aeroacústicos para um conjunto rotor/estator foi construída no departamento de Engenharia Aeronáutica da Escola de Engenharia de São Carlos, permitindo desenvolver uma metodologia capaz de gerar uma técnica semi-empírica utilizando métodos e dados novos. Tal bancada é capaz de variar a rotação, o espaçamento rotor/estator e controlar a vazão mássica, resultando em 71 configurações avaliadas. Para isso, uma antena de parede com 14 microfones foi usada. O espectro do ruído de banda larga é modelado como um ruído rosa e o ruído tonal é modelado por um comportamento exponencial, resultando em 5 parâ-metros: nível do ruído, decaimento linear e fator de forma da banda larga, nível do primeiro tonal e o decaimento exponencial de seus harmônicos. Uma regressão superficial Kriging é utilizada para aproximar os 5 parâmetros utilizando as variáveis do experimento e o estudo mostrou que Mach Tip e RSS são as principais variáveis que definem o ruído, assim como utilizado pelo projeto ANOPP.Assim, um modelo de previsão é definido para o conjunto rotor/estator estudado na bancada, o que permite prever o espectro em condições não ensaiadas. A análise do modelo resultou em uma ferramenta de interpretação dos resultados. Ao modelo são aplicadas 3 técnicas de validação cruzada: leave one out, monte carlo e repeated k-folds e mostrou que o modelo desenvolvido possui um erro médio, do nível do ruído total do espectro, de 2.35 dBs e desvio padrão de 0.91. Since the last decade, the countries members of ICAO, via its aeronautical authorities, has been gradually increasing the restrictions on external aircraft noise levels, especially in the vicinity of airports. Because that, the new aero-engines need quieter designs, so noise prediction techniques for aero-engines are getting even more important. Semi-analytical techniques have undergone a major evolution since the 70th until nowadays, but semi-empirical techniques still have their bases pegged in techniques and data defined on the 70th, developed in the ANOPP project. An Aeroacoustics Fan Rig to investigate a Rotor/Stator assembly was developed at Aeronautical Engineering Department of São Carlos School of Engineering, allowing the development of a methodology capable of defining a semi-empirical technique based on new data and methods. Such rig is able to vary the rotation, the rotor/stator spacing and mass flow rate, resulting in a set of 71 configurations tested.To measure...

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Low-Speed Fan Noise Reduction with Trailing Edge Blowing

Cited by 20 publications

References 6 publications

Active Control of Fan Tones by means of Trailing Edge Blowing

Active Control of Fan Tones by means of Trailing Edge Blowing

Simulation of Broadband Noise Sources of an Axial Fan under Rotating Stall Conditions

Aeroacústica de motores aeronáuticos: uma abordagem por meta-modelo

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