• The KSFM Journal of Fluid Machinery
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• v.5 no.3 s.16
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• pp.72-77
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• 2002

• The KSFM Journal of Fluid Machinery
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• v.12 no.3
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• pp.84-89
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• 2009

• The KSFM Journal of Fluid Machinery
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• v.7 no.6 s.27
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• pp.83-87
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• 2004

• The Monthly Technology and Standards
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• s.41
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• pp.50-53
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• 2005

• Journal of Drive and Control
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• v.16 no.1
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• pp.62-65
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• 2019

• The KSFM Journal of Fluid Machinery
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• v.5 no.2 s.15
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• pp.36-42
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• 2002

A new method to calculate the aeroacoustic pressure of a centrifugal fan that is used in a vacuum cleaner has been developed. The centrifugal fan consists of the impeller, the diffuser, and the circular casing. Due to the high rotating speed of the impeller and the small gap distance between the impeller and diffuser, the centrifugal fan makes very high noise levels at BPF and its harmonic frequencies. In order to calculate the sound pressure of a centrifugal fan, the unsteady flow field data is needed. This unsteady flow field is calculated by the vortex method. The sound pressure is then calculated by acoustic analogy. In this paper, only dipole term is considered in the equation. The noise generated by moving impeller and stationary diffuser is calculated separately. The predicted acoustic pressures agree very well with the measured data. The difference between the two is less than 4dB

• 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.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1138-1145
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• 2011

The internal broadband noise of a centrifugal fan in a household refrigerator is predicted using hybrid CAA techniques based on stochastic turbulent synthetic model. First, the unsteady flow field around the centrifugal fan is predicted using computational fluid dynamics(CFD) method. Then, the turbulent flow field is synthesized by applying the stochastic turbulent synthetic technique to the predicted flow field. The aerodynamic noise sources of the centrifugal fan are modeled on a basis of the synthesized turbulent field. Finally, the internal broadband noise of the centrifugal fan is predicted using the boundary element method(BEM) and the modeled sources. The predicted noise spectrum is compared with the experimental data. It is found that the predicted result closely follows the experimental data. The proposed method can be used as an effective tool for designing low-noise fans without expensive computational cost required generally for the LES and DNS simulations to resolve the turbulence flow field responsible for the broadband noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.209-212
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• 2005

Recently, since structures have become extremely airtight with the development of high-rise apartments, mixed use residential and commercial buildings and offices, large capacity range hoods have become commonly implemented. However, the high noise level caused by this range hood system made of thin plate is the cause of increased complaints among users. In this study, the level of noise emitted from this type of range hood was measured by height at the user's location in the kitchen. It was confirmed that a great deal of noise was emitted in the downward direction of the hood. In order to minimize the noise emitted from this type of range hood, a new type of fan was manufactured. This was done by changing only the material and shape of the fan, since it was determined to be the primary source of noise emission. Then a comparison and evaluation were carried out regarding the noise characteristics between the new type of fan and the existing type of fan. As a result, it was confirmed that the noise from the new fan was reduced by more than 2 dB compared to the existing fan without noise interference at the discharge end.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.5
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• pp.509-515
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• 2009

This paper proposes an optimal design scheme to reduce the noise of the engine cooling fan by adapting Kriging with two meta-heuristic techniques. An engineering model has been developed for the prediction of the noise spectrum of the engine cooling fan. The noise of the fan is expressed as the discrete frequency noise peaks at the BPF and its harmonics and line spectrum at the broad band by noise generation mechanisms. The object of this paper is to find the optimal design for noise reduction of the engine cooling fan. We firstly show a comparison of the measured and calculated noise spectra of the fan for the validation of the noise prediction program. Orthogonal array is applied as design of experiments because it is suitable for Kriging. With these simulated data, we can estimate a correlation parameter of Kriging by solving the nonlinear problem with genetic algorithm and find an optimal level for the noise reduction of the cooling fan by optimizing Kriging estimates with simulated annealing. We notice that this optimal design scheme gives noticeable results. Therefore, an optimal design for the cooling fan is proposed by reducing the noise of its system.