Fan Acoustics Noise Generation And Control Methods Pdf

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Flow and Noise Characteristics of Centrifugal Fan under Different Stall Conditions

This study is an attempt to characterize unsteady flow field and predict flow noise produced by a radial fan installed in a system that has a tiny gap between the fan casing and upper wall similar conditions found in actual products. The large-eddy simulation turbulence model was used to simulate unsteady flow conditions, and an impeller was rotated 13 times in total to sufficiently develop unsteady flow and obtain data for Computational aeroacoustics CAA.

Unsteady flow field due to the radial fan structure and narrow flow channel in a system was verified, and a location wherein flow properties rapidly changed over time due to the complicated flow field was identified. The noise spectrum obtained through CAA was compared with that measured through experiment. Both tonal noise components consisting of blade passing frequency with its harmonic frequencies and broadband noise were matched.

The major source of noise of the radial fan was on the inner surface of the casing. However, the sources of noise in the upper and lower sides of the casing were not equivalent to each other due to the interaction between the flow coming through an inlet located in the upper part of the casing and the flow discharged through an outlet installed at its side, as well as the interaction between impeller rotation and cut-off. Sources of noise located at the upper casing are caused by the flow around impeller tips, whereas sources on the lower casing are related to the interaction of the flow between the impeller and casing.

A low noise model with a modified impeller tip was proposed, and its noise reducing effects were evaluated. The modified model reduced overall sound pressure level by 0. This is a preview of subscription content, access via your institution. Rent this article via DeepDyve. Ren, S. Heo, T. Kim and C. Cheong, Response surface method-based optimization of the shroud of an axial cooling fan for high performance and low noise, Journal of Mechanical Science and Technology, 27 1 33— Cordourier-Maruri and F.

Google Scholar. Minorikawa and H. Jeon, T. Kobayashi, T. Kodama and S. Hamada, Study on the CFD method for noise source identification and aeroacoustic analysis of an axial fan, Proc. Lim, S. Lee, W. Jeon and C. Jang, Characteristics of unsteady flow field and aeroacoustic noise in a regenerative blower, Journal of Mechanical Science and Technology, 29 5 — Lim, W.

Jeon and G. Minorikawa, Characteristics of unsteady flow field and flow-induced noise for an axial cooling fan used in a rack mount server computer, Journal of Mechanical Science and Technology, 30 10 — Lighthill, On sound generated aerodynamically, I. Curle, The influence of solid boundaries upon aerodynamic sound, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, — Lowson, The sound field for singularities in motion, Proc. London, Ser A, — Jeon and D. Lee, An analysis of the flow and aerodynamic acoustic sources of a centrifugal impeller, Journal of Sound and Vibration, 3 — Jeon, S.

Baek and C. Kim, Analysis of the aeroacoustic characteristics of the centrifugal fan in a vacuum cleaner, Journal of Sound and Vibration, 5 — Ffowcs Williams and D.

Hawkings, Sound generation by turbulence and surfaces in arbitrary motion, Phil. Jeon, A numerical study on the effects of design parameters on the performance and noise of a centrifugal fan, Journal of Sound and Vibration , 1 — Scheit, B. Karic and S. Becker, Effect of blade wrap angle on efficiency and noise of small radial fan impellers-A computational and experimental study, Journal of Sound and Vibration, 5 — Ballesteros-Tajadura, S.

Velarde-Suarez and J. Pablo Hurtado-Cruz, Noise prediction of a centrifugal fan: Numerical results and experimental validation, J. Fluids Eng.

Download references. Technical Research Lab. Correspondence to Tae-Gyun Lim. He worked in LG Electronics with a focus on aeroacoustic analysis and low-noise fan design.

He has published over scientific papers in CFD, aeroacoustics, and fan design. Gaku Minorikawa received his Ph. His major research interests are fan noise control, sound quality, microturbomachinery design, standardization work of noise, and vibration measurement for small fans. Reprints and Permissions. Lim, TG. J Mech Sci Technol 31, — Download citation.

Received : 01 March Revised : 27 June Accepted : 20 July Published : 21 November Issue Date : November Search SpringerLink Search. Abstract This study is an attempt to characterize unsteady flow field and predict flow noise produced by a radial fan installed in a system that has a tiny gap between the fan casing and upper wall similar conditions found in actual products.

References [1] G. Author information Affiliations Technical Research Lab. View author publications. Rights and permissions Reprints and Permissions. About this article. Cite this article Lim, TG.

Why and How to Control Fan Speed for Cooling Electronic Equipment

JavaScript is disabled for your browser. Some features of this site may not work without it. Advanced modeling of active control of fan noise for ultra high bypass turbofan engines. Date Author Hutcheson, Florence Vanel. Metadata Show full item record. Abstract An advanced model of active control of fan noise for ultra high bypass turbofan engines has been developed.

Description The papers in this four-book set are an outgrowth of the Second International Symposium on Aeroacoustics held in Skip to main content. Description Description The papers in this four-book set are an outgrowth of the Second International Symposium on Aeroacoustics held in No Access Table of Contents pp. Full Access Index of Contributors pp.

Volume 2A: Turbomachinery. June 16—20, The tonal noise source and the sound propagation in the nacelle duct and in the nacelle near field are simultaneously predicted, starting from the engine geometry and parameters, with a single CFD analysis based on an efficient Nonlinear Harmonic NLH method. The present method provides to a gain of close to two orders of magnitude compared to standard approaches, based on full unsteady flow simulations, followed by a near-field FEM based approach and a BEM method for the far-field noise propagation. The final comparison between the numerical results and the measurements highlights the capability of the methodology to efficiently predict the unsteady flow field and the radiated sound field. Sign In or Create an Account. Sign In.

Why and How to Control Fan Speed for Cooling Electronic Equipment

With the development of civil aero-engines, the noise emission is now an essential issue to be considered during engine design. In this study, the preliminary design for a model fan, which was used for the fan noise estimation, was carried out. The fans with different bypass ratios, different tip speed as well as different aspect ratio were designed and the rough dimensions of the fan were obtained. Based on the dimension and performance of the fan, the effect of fan bypass ratio, tip speed, rotor blade numbers, and rotor—stator spacing on noise generation was investigated. However, lower tip speed does not achieve the noise reduction as expected.

Examines the problem of noise level of civil aircraft engines. Focuses on two aspects of aircraft fan noise: cabin noise and community noise. Outlines the FANPAC programme launched in to assess techniques to control fan noise and describes two of the most promising liner designs. Hutchinson, J. Report bugs here.

This study is an attempt to characterize unsteady flow field and predict flow noise produced by a radial fan installed in a system that has a tiny gap between the fan casing and upper wall similar conditions found in actual products. The large-eddy simulation turbulence model was used to simulate unsteady flow conditions, and an impeller was rotated 13 times in total to sufficiently develop unsteady flow and obtain data for Computational aeroacoustics CAA. Unsteady flow field due to the radial fan structure and narrow flow channel in a system was verified, and a location wherein flow properties rapidly changed over time due to the complicated flow field was identified. The noise spectrum obtained through CAA was compared with that measured through experiment. Both tonal noise components consisting of blade passing frequency with its harmonic frequencies and broadband noise were matched.

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Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. Although noise can be generated by turbulence in highspeed flows, most noise is generated by mechanical motion caused by forces acting on structures.

Why and How to Control Fan Speed for Cooling Electronic Equipment

The human ear is more sensitive to some frequencies than others. In particular low frequency noises sound quieter than high frequency noises. In fact, most legislation regarding noise is written using dB A s, in addition nearly all manufacturers of fans and other noise generating machines quote their noise levels in dB A s at 1, 1. This test standard describes methods that may be applied to calculate the sound power level of fans.

Description The AIAA Aeroacoustics Technical Committee planned and organized the first Aeroacoustics Specialists Conference held in October for the purpose o f presentation and discussion of recent research and engineering results on aeroacoustic phenomena for different types of flight vehicles. The papers given at this conference are contained in these two volumes. In Volume 37 the papers are grouped into three sections: jet noise, combustion and core engine noise, and duct acoustics. Volume 38 contains the following five sections: fan noise and control, STOL and rotor noise, boundary layer noise and response of structure, sonic boom, and aeroacoustic instrumentation.

3 Response
  1. PehuГ©n S.

    Interest has been growing in integrated circuits for controlling the speed of cooling fans in personal computers and other electronic equipment.

  2. Mara1769

    Download full-text PDF · Read full- method for controlling BPF tonal noise by carefully positioning obstructions in. a duct in concern in the generation of fan noise. noise, one can also try to minimize the acoustic propa-.

  3. Teodequilda C.

    Fluid-Structure Interaction as a Noise Generation Mechanism. – Modeling of Fan Noise Computational Methods:Aeroacoustics and UnsteadyAerodynamics​.

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