Academic literature on the topic 'Axial fan noise'
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Journal articles on the topic "Axial fan noise"
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Lauchle, Gerald C., John R. MacGillivray, and David C. Swanson. "Active control of axial-flow fan noise." Journal of the Acoustical Society of America 101, no. 1 (January 1997): 341–49. http://dx.doi.org/10.1121/1.417979.
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Kang, Jongmin, and Seungchul Park. "Source modeling for the axial fan noise." Journal of the Acoustical Society of America 101, no. 5 (May 1997): 3189. http://dx.doi.org/10.1121/1.419234.
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Capdevila, Hugo. "High efficiency, low-noise axial fan assembly." Journal of the Acoustical Society of America 102, no. 1 (July 1997): 22. http://dx.doi.org/10.1121/1.419532.
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MacGillivray, John R., Gerald C. Lauchle, and David C. Swanson. "Active control of axial‐flow fan noise." Journal of the Acoustical Society of America 98, no. 5 (November 1995): 2885. http://dx.doi.org/10.1121/1.413142.
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Piper, George E., John M. Watkins, and Owen G. Thorp. "Active Control of Axial-flow Fan Noise Using Magnetic Bearings." Journal of Vibration and Control 11, no. 9 (September 2005): 1221–32. http://dx.doi.org/10.1177/1077546305057261.
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In this paper we present a novel approach to reducing blade-rate noise of axial-flow fans. By using magnetic bearings as a noise control actuator, it is possible to collocate the anti-noise source with the disturbance noise source. This approach allows for global noise reduction throughout the sound field. A DC motor connected to a fan by a short rigid shaft was used to demonstrate this approach. The shaft was supported in the radial and axial directions by magnetic bearings. The bearings provide position control of the shaft and fan; this position control can be used to vibrate the fan at a desired frequency and amplitude. Controlled vibration of the fan allows its use as a speaker in an active noise control scheme. Noise control was implemented on a dedicated digital signal processor using a least mean square algorithm. The output of the noise control algorithm supplies the position commands for the magnetic bearing controller. Experimental data showed that by actuating the axial thrust bearing, the noise output of a fan could be reduced by 4 dB at the error microphone, and 3 dB at points away from the error microphone.
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Chun, Guo, Wang Mingnian, and Tang Zhaozhi. "A Study on Surge and Stall under the Interaction of Parallel Axial flow fan in Tunnel." Noise & Vibration Worldwide 42, no. 11 (December 2011): 9–14. http://dx.doi.org/10.1260/0957-4565.42.11.9.
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In the ventilation design for tunnels above 10km, an axial flow fan of great power needs to be set in ventilation shafts. There are few provisions on the setting modes and less discussion of parallel axial flow fan mode in the Specifications for Design of Ventilation and Lighting of Highway Tunnels. All of these bring a lot of difficulties about the axial fan selection, layout and control design. There is no specialized research on axial flow fan for tunnels and no studies on surge and stall under the interaction of parallel axial flow fan in tunnel in spite of the more and more application of parallel axial flow fan. So, this paper conducts a study on surge and stall under the interaction of parallel axial flow fan in tunnels. Through the study on the operating principle and analysis of parallel axial flow fan, we can know that the noise will increase suddenly, which will in turn result in fan vibration and running instability once the stall occurs. When a fan surges, the air volume and pressure, the motor current will fluctuate sharply, which brings significantly increased vibration and noise. At the same time, the rotary blade and the shell are subject to considerable stress effects and the fan will possibly suffer from great damage. The surge will occur in the unstable zone of axial fan performance curve. The strong pulsation and periodic oscillation of the air flow will increase the noise, which is a serious damage to the fan. So an axial fan should avoid this zone in running. With two axial flow fans of the same power parallel, the mutual influence is not very great. Therefore this research will focus on the efficiency in the case of two fans with a high and a low power parallel. Stall will occur if the outside pressure is greater than the outlet pressure. Once the stall happens, the noise will increase suddenly, which will in turn result in fan vibration and running instability. When two fans parallel, i.e. when the power ratio of the parallel fans is over 5.3, the possibility of the small fan's stall is high, otherwise it is small. With regard to the running efficiency of parallel axial flow fans and the starting safety, it is better to parallel two fans, and the fans with adjustable movable vanes or frequency control or the ordinary nonadjustable fans can be used.
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Chang, Cheng-Yuan, Xiu-Wei Liu, Sen M. Kuo, Department of Electrical Engineering, Chung Y, Department of Electrical Engineering, Chung Y, Department of Electrical Engineering, Chung Y, Department of Electrical Engineering, Chung Y, and Department of Electrical Engineering, Chung Y. "Active noise control for centrifugal and axial fans." Noise Control Engineering Journal 68, no. 6 (November 1, 2020): 490–500. http://dx.doi.org/10.3397/1/376840.
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Fans are widely used in industry for heat dissipation or airflow production. It is achieved by driving a motor of fan to rotate a number of blades. Most industrial fans can be categorized into one of two general types: centrifugal fans and axial fans. However, fan noise is loud when the motor speed is high. This article develops using active noise control (ANC) system to reduce noise from both centrifugal and axial fans. By integrating loudspeakers and microphones, we present multiple-channel feedback ANC structure with the filtered-X least mean square (FXLMS) algorithm to simultaneously reduce noise from the inlet and the outlet of the fans. Several realtime experiments verify that the proposed method and experimental setup not only reduces the narrowband noise but also achieves the global cancellation of the fan noise.
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Gallivan, William P. "High efficiency, low axial profile, low noise, axial flow fan." Journal of the Acoustical Society of America 97, no. 5 (May 1995): 3221. http://dx.doi.org/10.1121/1.411808.
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Hunnaball, P. J. "Control of Axial Flow Fan Noise by Design." Building Acoustics 1, no. 4 (December 1994): 271–78. http://dx.doi.org/10.1177/1351010x9400100402.
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This paper discusses the present methods of controlling tonal noise in axial flow fans and puts forward some basic parameters for use in the design and selection of this product. Descriptions are given of the effects of fan casing geometry, the interaction of fixed duct elements and fan rotating parts, the effect of inlet disturbance and changes in noise level with radial clearance. Finally, guidelines are given for users of axial How fans in order to minimise noise levels.
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Li, Guoqi, Lifu Zhu, Yongjun Hu, Yingzi Jin, Toshiaki Setoguchi, and Heuy Dong Kim. "Influence of Chord Lengths of Splitter Blades on Performance of Small Axial Flow Fan." Open Mechanical Engineering Journal 9, no. 1 (June 25, 2015): 361–70. http://dx.doi.org/10.2174/1874155x01509010361.
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On the basis of small axial fan with five blades, 6 types of small axial flow fans with different chord lengths splitter blades were designed. Numerical simulation of 6 fan models with splitter blades and prototype fan were done by using Fluent. Based on the obtained simulation results, internal flow characteristics and aerodynamic noise were analyzed and compared. It indicates that: splitter blades with suitable chord length have improved significantly on internal flow characteristics, which inhibits backflow from pressure surface to the suction surface at blade tip and leading edge and restrains flow separation. The 6 model fans are better than prototype fan on aerodynamic noise improvement, but too long or too short chord lengths are both disadvantage to improve aerodynamic noise. The results reveal that 2/6, 3/6 and 4/6 chord length model have relatively better acoustic characteristics and internal flow characteristics. The research program will offer a reference for structural improvements and noise reduction on small axial flow fan.
Dissertations / Theses on the topic "Axial fan noise"
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McKinlay, Ryan Neal. "An Investigation into the Performance of Axial Flow Refrigerator Fans." Thesis, University of Canterbury. Mechanical Engineering, 2014. http://hdl.handle.net/10092/9587.
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This work was concerned with the aerodynamic and acoustic performance of small axial flow refrigerator fans. Relevant literature focusing on the principles of fan noise generation and fan system elements that contribute to noise generation was identified and discussed. A plenum chamber test rig was designed and constructed following ISO 10302-1.
A range of 200 mm diameter pressed aluminium Air-Drive fans, commonly used in commercial refrigerator systems, were evaluated using the test rig. It was found that the performance of these fans was highly dependent upon the impedance of the system in which they are installed. Indications of rotating stall under high load were observed and shown to significantly increase the noise output of the fan without greatly affecting the air moving capability. A series of novel colour map plots are presented, which allow for a visual interpretation of fan performance over a wide range of operating conditions.
A fanpack developed by Wellington Drive Technologies Ltd was evaluated. This fanpack was found to generate significant tonal noise. The design of the fanpack was evaluated and improvements are suggested. Prototype fans were developed from the fanpack based on promising concepts presented in the literature. The performance of four prototype fans was evaluated. The results were disappointing, but proof of concept was demonstrated.
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Homma, Kenji. "Compact Integrated Active-Passive Approach for Axial Fan Noise Control." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/29067.
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A new active-passive approach for the control of noise radiated from a small axial fan
was investigated. The approach involved the installation of an axial fan into a short duct
with both passive and active noise control functions. First, a systematic methodology for
the analytical modeling of finite-length ducts with multiple discontinuities was
formulated. The procedure involved the modeling of a duct as a collection of simple duct
sections, which were interconnected at multiple junctions.
Analytical studies have shown that a short lined duct provides passive noise
reduction effects through the mass-loading effect of the duct air volume at low
frequencies and the sound absorption by a passive liner at high frequencies. It was also
shown that active control can provide further noise attenuations at low-to-mid
frequencies, thereby enhancing the overall noise control performance. Two alternate
designs of active-passive noise control fan duct were considered. One was a simple non-
segmented duct with a 2x2 active control and the other was an internally segmented duct
with an 8x8 active control. It was indicated that the latter design possesses a significantly
higher global noise control potential than the former with respect to both bandwidth and
attenuation level. This was attributed to the reduction of the unwanted pressure
contributions from the duct cross modes through the high frequency shifting of the
associated cut-on frequencies.
The experimental validation of the noise control approach was also carried out.
An active-passive noise control fan duct incorporating the segmented duct design with
8x8 active control was constructed in conjunction with a hybrid feedforward-feedback
control system. Experimental results have shown significant reductions in the total fan noise power associated with the first four BPF tones by the feedforward control and the
broadband fan noise power by the feedback control. The overall active-passive noise
control characteristics were observed to be in accordance with the analytical results.Ph. D.
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Shafer, Benjamin M. "Error Sensor Placement for Active Control of an Axial Cooling Fan." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/1205.
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Recent experimental achievements in active noise control (ANC) for cooling fans have used near-field error sensors whose locations are determined according to a theoretical condition of minimized sound power. A theoretical point source model, based on the condition previously stated, reveals the location of near-field pressure nulls that may be used to optimize error sensor placement. The actual locations of these near-field pressure nulls for both an axial cooling fan and a monopole loudspeaker were measured over a two-dimensional grid with a linear array of microphones. The achieved global attenuation for each case is measured over a hemisphere located in the acoustic far field of the ANC system. The experimental results are compared to the theoretical pressure null locations in order to determine the efficacy of the point source model. The results closely matched the point source model with a loudspeaker as the primary source, and the sound power reduction was greatly reduced when error sensors were placed in non-ideal locations. A weakness of the current near-field modeling process is that a point monopole source is used to characterize the acoustic noise from an axial cooling fan, which may have multipole characteristics. A more complete characterization of fan noise may be obtained using a procedure based on the work of Martin and Roure [J. Sound Vib. 201 (5), 577--593 (1997)]. Pressure values are obtained over a hemisphere in the far field of a primary source and the contributions from point source distributions up to the second order, centered at the primary source, may be calculated using a multipole expansion. The source information is then used in the aforementioned theoretical near-field calculation of pressure. The error sensors are positioned using the complete fan characterization. The global far-field attenuation for the multipole expansion model of fan noise is compared to that of previous experiments. Results show that the multipole expansion model yields a more accurate representation the near field, but is not successful in achieving greater sound power reductions in the far field.
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Van, der Spuy Sybrand Johannes. "The design of a low-noise rotor-only axial flow fan series." Thesis, Stellenbosch : University of Stellenbosch, 1997. http://hdl.handle.net/10019.1/20977.
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ENGLISH ABSTRACT: A design routine was derived for designing a series of rotor-only axial flow fans. The routine was
applied by designing two different series of axial flow fans. The first design was for a general
application rotor-only axial flow fan. This fan series was designed, built and tested in co-operation
with Howden Air Industries for both research and commercial purposes. The second design was for
a low-noise fan series, which was designed, built and tested by the University of Stellenbosch for
research purposes only.
The design theory used the principle of blade cropping, meaning that one blade was designed to fit
all the different fan sizes. The fan series was designed for diameters ranging from 3 15 mm to 1000
mm. The fan rotors were designed to conform to a velocity profile of minimum exit kinetic flux. The
general application fan design was concentrated around the popular fan diameter sizes of 500 rnm,
560 mm and 630 mm and a rotor speed of 1440 rpm, using a commercially available fan series as
reference. The low-noise fan design concentrated on one fan size only, namely 630 mm, while also
making use of the principle of forward blade sweep. The remaining fan design principles stayed the
same as for the general application fan design. The F-series airfoils were used as blade sections for
both fan designs.
Both fan series were tested for fan noise and performance in accordance with the BS 848 Standards
part 1 (1980) and 2 (1985). A selection of fan diameter sizes was tested for the general application
fan to verify its perfo!"mance over a range of fan sizes. This indicated a fan series with a wide range
of efficient operation, including excellent noise characteristics. A 630 mm diameter fan was used to
test the low-noise fan series. It showed both high efficiency and low noise characteristics. The
reduction in fan noise achieved with the low-noise fan does not justi1)' the amount of work and costs
involved in the designing process, compared to the general application fan.AFRIKAANSE OPSOMMING: 'n Ontwerpsroetine vir die ontwerp van 'n reeks enkelrotor aksiaalwaaiers is ontwikkel. Die roetine is toegepas deur twee verskillende reekse aksiaalwaaiers te ontwerp. Die eerste ontwerp was vir 'n algemene toepassings enkelrotor aksiaalwaaier. Die waaierreeks is ontwerp, gebou en getoets in samewerking met Howden Air Industries vir beide navorsings - en kommersieIe doeleindes. Die tweede ontwerp was vir 'n lae geraas waaierreeks. Die reeks is ontwerp, gebou en getoets deur die Universiteit van Stellenbosch vir navorsingsdoeleindes. Die onwerpsteorie het gebruik gemaak van die beginsel van lemverkorting, waardeur een lem ontwerp is om op al die groottes waaierdeursnee te pas. Die waaierreekse is ontwerp vir waaierdeursnee tussen 315 mm en 1000 mm. Die rotors is ontwerp om 'n uitlaatsneIheidsprofiel te gee wat 'n minimum verlies in kinetiese energie toelaat. Die algemene toepassings waaierontwerp het gekonsentreer rondom die gewilde waaierdeursnee van 500 mm, 560 en 630 mm. Dit is ontwerp vir 'n rotorspoed van 1440 met 'n kommersieel beskikbare waaierreeks wat as verwysing gebruik is. Die lae geraas waaierreeks het op slegs een waaiergrootte gekonsentreer, naamlik 630 mm. Die lae geraas waaierreeks is ook ontwerp met vorentoe gekurfde lemme. Die res van die ontwerpsbeginsels was dieseIfde as vir die algemene toepassings waaierreeks. Die F-reeks vleuelprofiele is gebruik vir die lemseksies van beide waaierreekse. Beide waaiereekse is getoets vir waaiergeraas en -effektiwiteit deur gebruik te maak van die BS 848 Standaarde deel 1 (] 980) en 2 (] 985). 'n Verskeidenheid van waaierdeursnee van die algemene toepassings waaierreeks is getoets om die waaier se vertoning oor 'n gebied van waaiergroottes te bepaal. Die resuItaat was 'n waaierreeks met 'n wye gebied van effektiewe werking, asook uitstekende geraaseienskappe. 'n 630 mm Deursnee waaier is gebruik om die lae geraas waaier te toets. Die toetse het 'n waaier getoon wat beide hoe effektiwiteit en lae geraaseienskappe het. Die afname in waaiergeraas wat verkry is met die lae geraas waaier, in vergelyking met die algemene toepassings waaier, regverdig egter rue die werk en kostes verbonde aan die ontwerp van die waaierreeks nie.
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Shafer, Benjamin Michael. "Error sensor placement for active control of an axial cooling fan /." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2119.pdf.
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Green, Matthew J. "Feedback Applications in Active Noise Control for Small Axial Cooling Fans." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1539.pdf.
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Khiabani, Amir, and Alanis Daniel Acebo. "Cooling Fan Optimization for Heavy Electrified Vehicles : A study on performance and noise." Thesis, KTH, Flygdynamik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280145.
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Vehicle electrification plays a significant role in the effort to reduce the environmental impact of the automotive industry. Scania is one of the leading manufacturers ofheavy vehicles which is currently moving towards a sustainable transport system by manufacturing a new generation of heavy vehicles powered by batteries. Oneof the major concerns with these vehicles is related to the noise generated by the electric axial fans used in the cooling system. This project was conducted with thepurpose of investigating the factors that positively affect both noise and performance in the electric fans. Based on two different blade design methods and several noisecontrol techniques, 11 fan models were developed. The fan models created with design method 1 are equipped with cambered-plate blades, while the models madewith design method 2 consist of airfoil-shaped blades. Moreover, the performance of these models was analyzed by using theoretical methods and Computational FluidDynamics (CFD). In addition, two empirical approaches were used to estimate the acoustic energy emitted by the fan models. Furthermore, the developed modelswere compared with two commercially available fans. It was found that both design methods provide similar performance in low pressure differences. On the other hand,the efficiency and acoustic energy are influenced by the choice of the noise control methods.Fordonselektrifiering har en väsentlig roll i arbetet med att minska bilindustrins miljöpåverkan. Scania är en av de ledande tillverkarna av tunga fordon som för närvarandegår mot ett hållbart transportsystem, genom att tillverka en ny generation tunga fordon drivna med batterier. Ett stort bekymmer med dessa fordon är relaterattill det ljud som genereras av de elektriska axialfläktarna som används i kylsystemet. Detta projekt genomfördes i syfte till att undersöka de faktorer som positivtpåverkar både buller och prestanda hos de elektriska fläktarna. Baserat på två olika bladdesignmetoder och flera brusstyrningstekniker, utvecklades 11 fläktmodeller.Fläktmodellerna som är utformade med konstruktionsmetod 1 är utrustade med krökformade plattor, medan modellerna som skapades med designmetod 2 bestårav vingprofil blad. Dessutom analyserades prestandan för dessa modeller med användning av teoretiska metoder och strömningsmekaniska beräkningar. Ytterligaretvå empiriska tillvägagångssätt användes för att uppskatta den akustiska energin som släppts ut av fläktmodellerna. Utöver det jämfördes de utvecklade modellernamed två kommersiellt tillgängliga fläktar. Detta visade att båda konstruktionsmetoderna resulterar i liknande prestanda vid lågtrycksskillnader, däremot påverkasverkningsgraden och den akustiska energin av valet av brusstyrningsmetoder.
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Rust, Ryan Leonard. "Active Noise Control of a Two-Fan Exhaust-Mounted Array Using Near-Field Control Sources and Error Sensors." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2427.
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Multiple fans are sometimes used in an array configuration to cool various types of electronic equipment. In addition to adding another noise source, using two fans with closely spaced blade passage frequencies (BPF) can create an annoying beat frequency. A two fan array with each fan having a different BPF was considered. The fans were theoretically modeled at the BPF and first harmonics. Each fan has two acoustic paths to the far field. Thus, each fan was modeled as a two source array. The first control configuration consisted of one control filter using six control sources and six error sensors in a fully coupled control system designed to control both fans simultaneously. The second configuration used two independent controllers with three control sources and three error sensors, one controller per fan. Experimentally, the averaged narrow band reduction of the BPFs and the second harmonic of the two independent controllers were 15.6 and 7.4 dB respectively, compared to a reduction of 14.4 and 5.7 dB at the two frequencies using a single control loop. The results suggest that independent controllers perform better than the single control loop for the fan array studied. Optimization of active noise control systems has increased performance but sometimes with decreased robustness. Two control source configurations for the sound power reduction of a simple source were analyzed by modeling the control systems. The two control source configurations were four symmetric control sources surrounding the noise source and an optimized linear array of four control sources. Simulation results show the linear array control source configuration is more sensitive to microphone placement errors, with a 20-33 dB reduction in attenuation for a microphone placement error of 2 mm compared to a 0.8 dB drop in attenuation for the symmetric case. The linear array configuration was found to be more sensitive to the microphone placement errors compared to the symmetric configuration. A 2.5 mm change in one microphone position causes an average of 6 dB loss in attenuation for the linear array configuration compared to a 0.6 dB loss for the symmetric configuration.
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Bouley, Simon. "Modélisations analytiques du bruit tonal d'interaction rotor/ stator par la technique de raccordement modal." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEC007/document.
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Le bruit tonal d’interaction rotor-stator, généré par l’impact des sillages issus des pales d’un rotorsur la grille d’aubes d’un stator redresseur, contribue de manière déterminante au bruit d’origineaérodynamique des turbomachines axiales carénées, qui équipent une large part des systèmes de propulsionaéronautique et de conditionnement d’air. La prédiction du bruit par l’utilisation de simulationsnumériques demeure onéreuse, notamment dans les premières phases de conception lorsque de nombreusesconfigurations doivent être testées. Dans cette optique, l’approche analytique choisie dans cettethèse apporte une alternative tout à fait appropriée. Les modèles analytiques basés sur une fonctionde réponse aéroacoustique de profil isolé ne permettent pas de reproduire l’effet de grille engendrépar le nombre important d’aubes de stator. Inversement, de fortes approximations sont nécessairespour décliner les fonctions de réponse de grilles d’aubes existantes dans des configurations tridimensionnelles.Le formalisme proposé, basé sur la méthode de raccordement modal, permet d’introduiresimplement l’effet de grille dans une géométrie annulaire d’étage rotor-stator. Un modèle de réponse degrille rectilinéaire bidimensionnel est tout d’abord présenté pour la transmission d’ondes acoustiques àtravers le stator ainsi que pour la génération de bruit par l’impact de rafales hydrodynamiques. Dansce cadre, une analyse linéaire et non visqueuse est considérée, pour laquelle les modes acoustique ettourbillonnaire d’un gaz sont couplés par le biais des frontières rigides. Les perturbations de vitessesliées aux sillages sont modélisées comme des rafales convectées. Leur impact sur la grille de statorgénère des ondes acoustiques se propageant en amont, en aval ainsi que dans les espaces inter-aubesdu stator, vu comme un réseau périodique de guides d’ondes. Les sections de bords d’attaque et defuite des aubes sont considérées comme des interfaces sur lesquelles la continuité des fluctuations depression, de vitesse axiale et de vorticité est vérifiée. Un système d’équations est ainsi obtenu, puisrésolu par des projections sur les bases modales du conduit et des inversions matricielles. Le champacoustique rayonné est ainsi déterminé uniformément dans tout le domaine. Les résultats issus de cesmodélisations sont comparés à ceux des fonctions de réponse de grilles d’aubes rectilinéaires issues dela littérature, montrant un très bon accord avec les modèles basés sur la technique de Wiener-Hopf. Leformalisme est par la suite étendu aux grilles annulaires par l’ajout de fonctions de Bessel comme fonctionsde forme radiale exprimant les effets tridimensionnels. Finalement, une procédure est présentéepour rendre compte de l’hétérogénéité des aubes de stator, caractéristique des nouvelles architecturesde turbomachines. Cette méthodologie est basée sur l’emploi conjoint du principe du dipôle de bordd’attaque et de la fonction de réponse aéracoustique de la grille de stator à l’aide de la technique deraccordement modal. Le principe de dipôle de bord identifie le chargement instationnaire des aubesinduit par l’impact de rafales hydrodynamiques, calculé par le formalisme d’Amiet, avec la trace duchamp de pression acoustique produit par un dipôle placé au voisinage du bord de l’aube. Les prédictionsissues de ce modèle, appliqué dans un cadre bidimensionnel, sont ensuite comparées à des mesuresobtenues pendant la campagne d’essais du projet SEMAFORThe rotor-stator wake-interaction tonal noise, generated by the impingement of rotor wakes onoutlet guide vanes, plays a crucial role in the aerodynamic noise of axial-flow ducted fan stages. Thelatter are widely used in most aeronautic propulsion and air-conditioning systems. The noise predictionby means of numerical simulations remains expensive, especially at the preliminary design stage whennumerous configurations must be tested. In this respect, the analytical approach chosen in this thesisprovides a well suited alternative. The analytical modeling based on an isolated-airfoil response functioncan not reproduce the cascade effect introduced by the large number of stator vanes. Conversely, drasticapproximations are required to extend the current cascade response functions to three-dimensionalconfigurations. The proposed modeling based on the mode-matching technique simply introduces thecascade effect in an annular rotor-stator stage. A rectilinear cascade response function is firstly presentedto account for the acoustic transmission through the stator along with the wake-interaction noise.In this context, a linearized and non-viscous analysis is carried out, in which the acoustic and vorticalmodes of a gas are coupled at rigid physical boundaries. The velocity perturbations issued from thewakes are written as a sum of convected gusts. Their impingement on the cascade of vanes generatesacoustic waves propagating upstream, downstream of the cascade, as well as inside the inter-vane channelsof the stator, seen as a periodic array of bifurcated waveguides. The duct cross sections at theleading-edge and the trailing-edge of the vanes are seen as interfaces on which the continuity of thefluctuating pressure, axial velocity and vorticity is fulfilled. A system of linear equations is obtained,then solved by means of modal projections and matrix inversions. The acoustic field is then uniformlycalculated in the whole domain. Comparisons with rectilinear cascade response functions show a verygood agreement with predictions based on the Wiener-Hopf technique. The configuration of an annularcascade is addressed by introducing the Bessel functions as radial shape functions, expressing threedimensionaleffects. Finally, a procedure is presented to account for the heterogeneity of the statorvanes, typical of modern fan architectures. This approach is based on the combinaison of the leadingedgedipole principle and the cascade response function derived from the mode-matching technique.The edge-dipole principle identifies Amiet’s solution for the unsteady loading and the radiation of adipole approached very close to the edge of a half plane. The predictions provided by this modeling,applied in a two-dimensional configuration, are finaly compared to measurements performed in the testcampaign of the SEMAFOR project
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Monson, Brian B. "Optimization of Active Noise Control for Small Axial Cooling Fans." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1495.pdf.
Full textBooks on the topic "Axial fan noise"
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Actuator feasibility study for active control of ducted axial fan noise: Under contract NAS3-26618. [Washington, DC: National Aeronautics and Space Administration, 1994.
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Actuator feasibility study for active control of ducted axial fan noise: Under contract NAS3-26618. [Washington, DC: National Aeronautics and Space Administration, 1994.
Find full textBook chapters on the topic "Axial fan noise"
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Wang, C., W. Zhang, and L. Huang. "Noise Source Analysis and Control for Two Axial-Flow Cooling Fans in Series." In Fluid-Structure-Sound Interactions and Control, 57–62. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-48868-3_9.
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Bianchi, Stefano, Alessandro Corsini, and Anthony G. "Synergistic Noise-By-Flow Control Design of Blade-Tip in Axial Fans: Experimental Investigation." In Noise Control, Reduction and Cancellation Solutions in Engineering. InTech, 2012. http://dx.doi.org/10.5772/26682.
Full textConference papers on the topic "Axial fan noise"
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Faverjon, Beatrice, Jeoffrey R. Fischer, Con J. Doolan, Danielle Moreau, and Zebb Prime. "Characterisation and modelling of axial fan noise." In 22nd AIAA/CEAS Aeroacoustics Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2016. http://dx.doi.org/10.2514/6.2016-3002.
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Swienty, Andreas, Evgenii Palamarchuk, Raja Abou Ackl, and Paul Uwe Thamsen. "Noise Reduction Measures for an Axial Fan." In ASME 2017 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/fedsm2017-69287.
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The aim of this work is to investigate how a reduction of the noise emissions can be achieved by means of an irregular arrangement of the blades of the fan impeller and an additional blade skewing. For this purpose a fan impeller with a defined operating point is designed. Preliminary investigations have shown that a volumetric flow rate of 18 m3/h at a pressure of 200 Pa is required for cooling. Due to structural restrictions, only one axial impeller with a diameter of 68 mm can be used. The rotational speed of the electric motor is 10000 rpm. In a further step, the influences of the blade skewing and irregular arrangement of the blades are examined. These impellers are manufactured in a rapid prototyping process, which is a cost-effective and fast process. Thus, various variants can be examined to find the most suitable impeller. The study of the impellers is divided into two phases. Firstly, the fluid mechanical data of the impeller is measured. For this purpose, a chamber test stand is used to measure the characteristic curves of fan impellers. Thus, on the one hand, it can be examined whether the designed impeller reaches the operating point and, on the other hand, the influence of the noise reduction measures on the characteristic curves can also be evaluated. It is, of course, not desired that the noise reduction measures result in a deterioration of the pressure increase or in the volumetric flow rate. In the second phase, the noise generation of the impeller is measured in an installed state on an acoustic test stand. For this purpose, the impellers are installed in the electric motor and then acoustically examined in enveloping surface method according to DIN 45635. It can be seen that the sound load can be reduced by 5.6 dB by a sufficient design of the impeller compared to a reference impeller. The further measures taken, such as the irregular arrangement of the blades and the blade skewing, have shown a further improvement of 1.6 dB. The influence of the implemented measures on the characteristic curve lies in a small area. It is measured that the pressure increase has fallen due to the irregular arrangement of the blades and the blade skewing by 10 Pa with a constant remaining flow rate.
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Fedala, Djaafer, Smaïne Kouidri, Robert Rey, Thomas Carolus, and Marc Schneider. "Incident Turbulence Interaction Noise from an Axial Fan." In 12th AIAA/CEAS Aeroacoustics Conference (27th AIAA Aeroacoustics Conference). Reston, Virigina: American Institute of Aeronautics and Astronautics, 2006. http://dx.doi.org/10.2514/6.2006-2477.
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Roy, Subrata, Phillip Cho, and Fred Périé. "Designing Axial Flow Fan for Flow and Noise." In International Off-Highway & Powerplant Congress & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1999. http://dx.doi.org/10.4271/1999-01-2817.
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Sommerfeldt, Scott D., and Kent L. Gee. "Active control of axial and centrifugal fan noise." In ICA 2013 Montreal. ASA, 2013. http://dx.doi.org/10.1121/1.4799648.
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Lee, Duck-Joo, Wan-Ho Jeon, and Ki-Hoon Chung. "Development and Application of Fan Noise Prediction Method to Axial and Centrifugal Fan." In ASME 2002 Joint U.S.-European Fluids Engineering Division Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/fedsm2002-31209.
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Numerical predictions of fan noise have not been studied extensively. This is due to the scattering effect of the fan casing, duct and the difficulty in obtaining aerodynamic acoustic source. New method to predict the fan noise and performance is developed and used to calculate various fan noise problems. A vortex method is used to model the fan and to calculate the flow field. Acoustic pressures are obtained from the unsteady force fluctuations of the blades using an acoustic analogy. But the acoustic analogy can be applied only in the free field in general. In order to consider the solid boundary effects of the casing, the newly developed Kirchhoff-Helmholtz BEM (Boundary Element Method) is introduced. With the above-mentioned method, the flow field and sound field of centrifugal and axial fan were calculated. Reasonable results are obtained not only for the peak frequencies but also for the amplitudes of the tonal sound. Also, in the predicted sound field, we can see the scattering effect of duct and casing.
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Heinemann, Till, Sven Münsterjohann, Florian Zenger, and Stefan Becker. "Cross Wind Influence on Noise Emission and Computed Vibrational Noise of an Axial Fan." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-42444.
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The total noise emissions of two commercial axial fans were measured in a semi-anechoic fan test rig in comparison. The total sound pressure levels and the respective spectra were found to change with the fans’ operating points. Increasing fan flow rates lowered the total acoustic pressure, with a broadband shift towards higher frequencies, keeping perceived (A-weighted) sound pressure levels approximately constant over a wide range of operating points. In a second step, Laser Scanning Vibrometry measurements of the fan blades’ axial motion were conducted in comparison inside a wind tunnel fan test rig. Rotating blade surface vibration data was used as sole input to a Ffowcs Williams and Hawkings algorithm, to estimate noise emission from vibration. The computed noise from surface vibration was found to be hardly affected by the change of fan flow rate. In the application of an axial fan subject to natural wind or induced cross flow at its inlet, the flow field and possible noise emission of the fan changes. Microphone measurements of the cross flow influence inside a semi-anechoic wind tunnel revealed increasing broadband noise with ambient flow field velocity, and an amplification of the sound at the blade passing frequency harmonics. Similar excitations of the blade passing frequency harmonics under cross flow influence were also found in sound pressure spectra computations based on the Laser Scanning Vibrometry measurement data captured in the wind tunnel fan test rig. Blade vibration is considered to contribute to the low frequency tonal noise emission of axial fans operating under cross flow conditions.
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Luo, Bo, Wuli Chu, Wei Dong, and Xiangyi Chen. "Aerodynamic Characteristics and Noise Analysis of a Low-Speed Axial Fan." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-76079.
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Axial fans are widely used in modern industry and new regulations and stringent environmental concerns are prompting manufacturer to design efficient low-noise axial fans. This paper is focused on improving the aerodynamic performances and reducing the tonal noise at BPF and its harmonics by the optimum choice of lean-swept blade and the stacking line for the low-speed axial fan. The aerodynamic characteristics of the axial fan with a shroud are explored by CFD with ANASYS CFX. A hybrid method, SST turbulence model for flow and FW-H equation for acoustics, is chosen to predict the radiated noise. The accuracy and reliability of predicted aerodynamic and aeroacoustics results are verified by comparing both computation and experimental data. A number of modified blades with different leaned angle, swept angle and the stacking lines are modeled and analyzed, and the investigation into the optimum choice of lean-swept blade and the stacking line is conducted according to aerodynamic performances and tonal noise. Q-criterion which can visualize the major flow disturbances is applied for the purpose of identification of acoustic sources. The turbulent flow structures on the leading edge, tip and suction side of the blade are main noise sources. An optimal modification is determined through the analysis of the aerodynamic performances and noise, which is to achieve the desired performances by blade sweep and lean and adjusting the stacking line. The results show that aerodynamic and acoustic performances of the optimized fan are better than that of the original fan and the improvement is more obvious to change the stacking line with centre of gravity compare to blade sweep and lean for the low-speed axial fan.
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Zenger, Florian, Clemens Junger, Manfred Kaltenbacher, and Stefan Becker. "A Benchmark Case for Aerodynamics and Aeroacoustics of a Low Pressure Axial Fan." In 9th International Styrian Noise, Vibration & Harshness Congress: The European Automotive Noise Conference. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2016. http://dx.doi.org/10.4271/2016-01-1805.
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Bae, Il-Sung, Hooi-Joong Kim, and Seungbae Lee. "Computation of Turbulent Flows and Aero-Acoustics From an Axial Fan." In ASME 2002 Joint U.S.-European Fluids Engineering Division Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/fedsm2002-31327.
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LES formulation was applied to simulate the flow fields around rotating fan blades tested by DLR. The turbulent flows around fan blade rotating with 500 RPM were simulated and the far-field noise was exactly computed by using the Ffowcs Williams and Hawkings equation with an inclusion of quadrupole source formulation. Variations of lift forces and deviation angles in the spanwise direction were analyzed to correlate flow parameters with acoustics parameters and identify noise sources. The dipole noise computed at the far-field by computed drag and lift forces was in good agreement with experimental data and the dipole source was also found to be the major contributor to overall far-field noise from unsteady calculation.