• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.762-767
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• 2001

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 Focus Williams and Hawkings equation with an inclusion of quadrapole source formulation. The dipole noise computed at the far-field by predicted drag and lift forces at steady state was in good agreement with experimental data and the dipole source was also found to be the major factor than other sound sources from unsteady calculation.

• The KSFM Journal of Fluid Machinery
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• v.2 no.1 s.2
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• pp.43-49
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• 1999

Flow field and near-field noise of a centrifugal fan has been studied with an efficient compressible method and STAR-CD. The flow field of the centrifugal fan is assumed to be two-dimensional. Most of the compressible studies have been done by inviscid solver because viscous simulation shows little difference. The near field noise is estimated in terms of sound pressure level in frequency domain transformed from the computed pressure fluctuations using FFT. The simulation has been done on various design elements such as impeller blade shapes, the number of blades and cut-off clearance. The comparison shows that the number of blades has a significant effect on near-field noise without losing aerodynamic performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1090-1094
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• 2007

The aim of this study is to estimate the cause of Cooling Tower vibration and eliminate the faults of fan with high vibration in spite of overhaul. The cause of high vibration was that the natural frequency of fan blade coincide with second blade pass frequency. To achieve reduction of Cooling Tower vibration, change motor speed from 1784rpm to 1714rpm, and then the vibration has reduced conspicuously.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.355-355
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• 2007

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.17-22
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• 2001

Tube axial fans were designed to provide effective cooling for a personal computer by using $DasignFan^{TM}$ software. With basic input parameters of flow rate, pressure rise, rotating speed, and fan diameter, three dimensional geometry of blade is automatically generated and its performance and overall sound pressure level are predicted. In this steady, the newly developed fans of 60 mm and 80 mm diameters were proved to provide a very promising mode of low noise, compared with manufactured products.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.286-289
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• 2002

This paper proposes wireless fan system as noise measurement system. It is easy to combine measurement system(Hardware) and analytic system(software) to the Wireless tan system. Thus wireless fan system can be applied to noise mapping system and noise monitoring system. This paper show noise measurement experiment and result using wireless lan system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.366.1-366
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• 2002

It is addressed that the turbulent broadband sound power from a sirocco fan can be modeled by the trailing edge noise. The trailing edge noise is usually influenced by inflow turbulence, separation, and boundary layer on the blade. The design parameters such as solidity(c/s) and stagger angle are specified to predict performance and noise level because the separation and slip velocity are strong1y affected by them along with the flow coefficient. (omitted)

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.6
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• pp.529-535
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• 2011

Indoor noise is very important related to the morale and fighting power of the crew as well as environmental condition for them in a navel vessel. Especially, the crew members working in CIC (combat information center) and sonar equipment room require much more quiet environment condition. One of the most serious noise source in CIC is the cooling fan noise installed in the console of the combat system. Therefore, in this paper, the design of the plenum chamber is studied to reduce the noise of the fan from these consoles by numerical analysis and experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.77-82
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• 2011

Indoor noise is very important related to the morale and fighting power of the crew as well as environmental condition for them in a navel vessel. Especially, the crew members working in CIC(Combat Information Center) and sonar equipment room require much more quiet environment condition in order to increase the performance of their combat system. One of the most serious noise source in CIC is the cooling fan noise installed in the console of the combat system. Therefore, in this paper, the design of the plenum chamber is studied to reduce the noise of the fan from these consoles by numerical analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1011-1014
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• 2006

Turbo blower generates high peaks when it operates at high pressure region. The fan of the air-cleaner system, operates especially high pressure region due to several filters, generates high noise level. In this case, the tonal sound of BPF makes people annoyance. The blower of air-cleaner has several high resistance filters in its inlet area and rotates above 900rpm Moreover, for the compact design, the size of the blower should be reduced 10%. The reduced diameter of blower makes low flow rate and high noise level. In order to reduce the noise, new blade shape was suggested and optimized