scholarly journals Reactive control of subsonic axial fan noise in a duct

2014 ◽  
Vol 136 (4) ◽  
pp. 1619-1630 ◽  
Author(s):  
Y. Liu ◽  
Y. S. Choy ◽  
L. Huang ◽  
L. Cheng
Keyword(s):  
Reactive Control ◽  
Axial Fan ◽  
Fan Noise

COMPUTATIONAL AERO-ACOUSTIC STUDY ON AXIAL FAN NOISE AND ITS CHARACTERISTICS

2017 ◽  
Vol 22 (2) ◽  
pp. 15-20
Author(s):  
I.Y. Jang ◽  
C.K. Han ◽  
Y.J. Moon
Keyword(s):  
Axial Fan ◽  
Fan Noise ◽  
Acoustic Study

A Ring Silencer Design for Reducing Noise of Axial Fan

2003 ◽  
Vol 03 (03) ◽  
pp. L259-L264
Author(s):  
Jian-Da Wu ◽  
Mingsian R. Bai
Keyword(s):  
Helmholtz Resonator ◽  
Boundary Region ◽  
Acoustic Analogy ◽  
Axial Fan ◽  
Noise Sources ◽  
Fan Noise ◽  
Fluctuating Pressure ◽  
Axial Fans ◽  
Fan Blade ◽  
Broadband Frequency

In this paper, a ring silencer design for reducing the noise of axial fans is presented. The noise sources on axial fans are usually caused by the fluctuating pressure distribution on the surface of fan blade. Most of the sources are near the trailing edge of blades or boundary region of blades. The ideation of proposed design is based on the principle of Helmholtz resonator for reducing the noise around the fan. The electro-acoustic analogy of this design is presented and simply discussed. Experimental measurement is carried out to evaluate the proposed design for reducing the axial fan noise. The result of experiment indicated that the ring silencer achieved 17 dB in blade passing frequency and 10 dB in other broadband frequency of power spectrum level.

A Velocity Parameter for the Correlation of Axial Fan Noise

1982 ◽  
Vol 19 (1) ◽  
pp. 17 ◽  
Author(s):  
T. Wright
Keyword(s):  
Axial Fan ◽  
Fan Noise ◽  
Velocity Parameter

Prediction of axial fan noise by linearized perturbed compressible equations with large eddy simulation.

2010 ◽  
Vol 127 (3) ◽  
pp. 1837-1837
Author(s):  
Young J. Moon ◽  
Hoyeon Kim ◽  
Youngmin Bae ◽  
Florent Ravelet ◽  
Sofiane Khelladi ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Axial Fan ◽  
Fan Noise ◽  
Eddy Simulation ◽  
Large Eddy

Noise Characteristics of Automobile Cooling Fan Based on Circumferential Mode Analysis

2021 ◽  
Author(s):  
Pengfei Chai ◽  
Zonghan Sun ◽  
Zhiqiang Chang ◽  
Zhigang Peng ◽  
Jie Tian ◽  
...  
Keyword(s):  
Automobile Industry ◽  
Cooling System ◽  
Tip Clearance ◽  
Mode Analysis ◽  
Far Field ◽  
Axial Fan ◽  
Fan Noise ◽  
Cooling Fan ◽  
Noise Characteristics ◽  
Cooling Fans

Abstract The fan is the main component of the cooling system of an automobile engine. A typical automobile cooling fan consists of a shrouded axial fan, stator vanes, a deflector, and a cover. With recent developments in the automobile industry, the increase in the speed of rotation and blade load of cooling fans has increased the noise generated by them. To reduce it, it is important to analyze the characteristics of this noise. This paper uses an acoustic test to examine the characteristics of flow and noise of automobile cooling fans. The frequency spectrum and far-field radiation of the noise of the fan are first analyzed through far-field measurements, and the influence of the single rotor, tip clearance of the blade, and cover on fan noise is studied. The distribution of the mode spectrum and characteristics of sound propagation of discrete tonal noise are then examined using the circumferential mode test. The influence of the flow structure on fan noise is also studied. The flow characteristics and distribution of the source of noise of the automobile cooling fan are then used to analyze the influence of the structure of the fan on the noise generated by it. The results can help develop designs to reduce the noise of automobile cooling fans.

Noise Characteristics of Automobile Cooling Fan Based On Circumferential Mode Analysis

2021 ◽  
Author(s):  
Pengfei Chai ◽  
Zonghan Sun ◽  
Zhiqiang Chang ◽  
Zhigang Peng ◽  
Jie Tian ◽  
...  
Keyword(s):  
Automobile Industry ◽  
Cooling System ◽  
Tip Clearance ◽  
Mode Analysis ◽  
Far Field ◽  
Axial Fan ◽  
Fan Noise ◽  
Cooling Fan ◽  
Noise Characteristics ◽  
Cooling Fans

Abstract The fan is the main component of the cooling system of an automobile engine. A typical automobile cooling fan consists of a shrouded axial fan, stator vanes, a deflector, and a cover. With recent developments in the automobile industry, the increase in the speed of rotation and blade load of cooling fans has increased the noise generated by them. To reduce it, it is important to analyze the characteristics of this noise. This paper uses an acoustic test to examine the characteristics of flow and noise of automobile cooling fans. The frequency spectrum and far-field radiation of the noise of the fan are first analyzed through far-field measurements, and the influence of the single rotor, tip clearance of the blade, and cover on fan noise is studied. The distribution of the mode spectrum and characteristics of sound propagation of discrete tonal noise are then examined using the circumferential mode test. The influence of the flow structure on fan noise is also studied. The flow characteristics and distribution of the source of noise of the automobile cooling fan are then used to analyze the influence of the structure of the fan on the noise generated by it. The results can help develop designs to reduce the noise of automobile cooling fans.

scholarly journals Axial fan noise reduction by improved inlet conditions

1991 ◽  
Vol 89 (4B) ◽  
pp. 1970-1970
Author(s):  
K. Anthony Hoover
Keyword(s):  
Noise Reduction ◽  
Axial Fan ◽  
Fan Noise ◽  
Inlet Conditions

Development of an Ultra-Quiet Fan for Computer Cooling Applications

2014 ◽  
Author(s):  
Zhenyu Wang ◽  
Hui Hu
Keyword(s):  
Flow Field ◽  
Noise Reduction ◽  
Sound Pressure ◽  
Field Measurements ◽  
Vortex Structures ◽  
Tip Clearance ◽  
Axial Fan ◽  
Fan Noise ◽  
Piv Measurements ◽  
Cooling Fan

We report the progress made in our recent study to develop an ultra-quiet axial fan for computer cooling applications. By using a commercially-available cooling fan as the baseline, a number of acoustically tailored modifications are implemented in order to reduce the noise level of the cooling fan, which includes optimizing the rotator blades and guide vanes according to axial fan design theory, adding an intake cone in the front of the hub to guide the airflow into the axial fan smoothly, and reducing the tip clearance to lower the noise generation due to tip vortex structures. A comparison study is conducted to measure the sound pressure level (SPL) of the reformed axial fan in an anechoic chamber, in comparison to that of the prototype fan, in order to assess the effects of the modifications on the fan noise reduction. The measurement results of our preliminary study reveal that, at the same flow rate, the SPL of the reformed fan would be up to 5 dB lower than that of the prototype fan. In addition to measuring the sound pressure levels (SPLs) of the fans, a digital particle image velocimetry (PIV) system is also used to conduct detailed flow field measurements to reveal the changes of the flow characteristics and unsteady vortex structures associated with the modifications. Besides conducting “free-run” PIV measurements to determine the ensemble-averaged statistics of the flow quantities such as mean velocity, Reynolds stress, and turbulence kinetic energy (TKE) distributions at the exit of the axial fan, “phase-locked” PIV measurements are also performed to elucidate further details about evolution of the unsteady vortex structures in fan exhaust in relation to the position of the rotating fan blades. The detailed flow field measurements are correlated with the SPL measurements in order to elucidate underlying physics associated with the fan noise reduction.

Development and Application of Fan Noise Prediction Method to Axial and Centrifugal Fan

2002 ◽  
Author(s):  
Duck-Joo Lee ◽  
Wan-Ho Jeon ◽  
Ki-Hoon Chung
Keyword(s):  
Flow Field ◽  
Free Field ◽  
Sound Field ◽  
Solid Boundary ◽  
Centrifugal Fan ◽  
Acoustic Analogy ◽  
Axial Fan ◽  
Fan Noise ◽  
Scattering Effect ◽  
Numerical Predictions

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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