• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.809-812
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• 2006

This article shows the study on the arresting sound occurrence due to the interaction of the centrifugal Fan and bellmouth suction flow with bellmouth height as variable. It has accomplished to measure of inlet noise and also to analysis suction pressure distribution through experiment and also using CFD. The main cause of sound occurrence was judged with the effect due to static pressure change of bellmouth surface.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.6
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• pp.29-35
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• 2021

Bell mouth inlet is applied in various industries due to the advantage of little pressure loss and accurate flow measurement. In this study, the configuration of the bell mouth intake is designed in a long radius shape, and a suitable grid size was selected to minimize the pressure drop and to prevent the engine damage by foreign objects at outdoor operating conditions. It was able to present a modified pressure drop coefficient equation from two data obtained from the computational simulation and experimental results for the total pressure loss by inlet screen installation.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.4
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• pp.70-79
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• 2012

For an aerodynamic test facility, it is very important to get the precise measurement data of pressure, temperature and mass flow rate at the upstream to the test article. Hence, a new measurement method using a bellmouth and rakes was studied for the large scale system of which the corrected mass flow is between 5 kg/s and 8 kg/s. The bellmouth was designed by ISO standard for 0.5% accuracy, and the rakes were designed by using the equal area method. From the results of 9 test trials, it is found that the Reynolds number of rakes and the mass flow rate ratio can be simply formulated by an one-dimensional equation. The mass flow rate of rakes was calibrated by this equation. By the result of calibration, The maximum error rate was -0.507%, and the average error rate was -0.000274%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.737-742
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• 2011

Because of complex structure of inlet and outlet flows, the performance of centrifugal fans used in a household refrigerator is affected by many parameters of duct system surrounding the fans. In this paper, the performance of a centrifugal fan is numerically analysed according to shapes of inlet bell-mouth. To improve performance of the centrifugal fan, some design parameters are selected for comparison. On a basis of these comparison, optimum shape of inlet bell-mouth is proposed to maximise the flow rate of the fan.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.183-184
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• 2006

• Journal of Power System Engineering
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• v.17 no.6
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• pp.73-78
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• 2013

A Small-size axial fan(SSAF) has widely been utilized to circulate a cooling air in a refrigerator, etc. Generally, the aerodynamic performance of SSAF is strongly dependent upon the depth between SSAF and bellmouth, and it includes axial, partially stalled, mostly stalled and radial flow regions according to the flow coefficient. In this study, four kinds of bellmouth depths were considered to analyze the aerodynamic performance of SSAF. As a bellmouth depth increases, a maximum flowrate decreases, but a maximum static pressure increases. Also, stall region includes an inflection point in all aerodynamic performance curves. Finally, a static pressure efficiency shows the maximum value of 37%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.93-96
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• 2004

A turbo-fan for the 4-way cassette indoor units of air-conditioners has been investigated. The main purpose of this investigation is the reduction of the turbo-fan noise. In order to reduce the noise level, many design parameters of turbo-fans such as blade section, blade thickness, geometry of blade leading edge, blade width, blade angle and bellmouth depth have been studied. With the experimental data of these parameters, a new turbo-fan was made for our system. The noise level of the new system was at least 3 dB(A) lower than that of the current in use.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.11
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• pp.972-981
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• 2000

Comprehensive work is done for flows by an axial fan by experimental research. The present model fan is used for air handling device for out-door unit of an air conditioner in home appliance. PIV(Particle Image Velocimetry) system and wind tunnel are adopted for measurements of flows and performance evaluation, respectively. Major experimental conditions are the installation depth of a fan into a bellmouth of it. Optimal position of a fan in an inlet guide tube is observed by examination of fan-performance and flows in both upstream and downstream of the fan. Consequently, in the case of the fan inserted in half depth into the inlet tube, the efficiency of fan shows its maximum value and flow patterns is also streamlined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.11-15
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• 1994

헤어드라이기, 자동차용 진공청소기, 면도기, 쥬서/믹서기등과 같은 소형 가 전제품은 사용시, 제품과 소비자사이의 거리가 짧아 진동/소음에 관한 인식이 대형 가전제품에 비해 크다. 과거에는 가전제품의 경우, 기본성능 및 각 회사만이 갖고 있는 독자적인 성능과 디자인을 최우선적으로 고려하여 설계하였다. 소음/진동에 관한 문제는 제품이 제작된 후에 필요에 따라 고려되었기 때문에 주어진 조건하에서 저진동/저소음을 위한 대책에는 한계가 있었다. 근래에는 진동/소음에 대한 관심이 증가하면서 제품의 설계단계부터 저진동/저소음 제품을 설계하기 위한 노력이 점차로 증가하고 있다. 본 연구는 이러한 추세의 한 예로서 헤어드라이기에 대해 결정된 디자인 및 성능이 크게 변경되지 않는 범위내에서 진동/소음이 적은 구조를 설계하는데 목적이 있다. 먼저, 헤어드라이기의 소음원 및 특성을 간단히 규명한 뒤, 벨마우스(bellmouth) 이용등과 같이 일반적으로 잘 알려진 소음저감법을 소음원에 대해 적용하였다. 헤어드라이기의 경우 소음원이 몸체에 삽입되는 순간 특정 주파수대역에서 소음이 증가하는 현상이 발생하는데, 헤어드라이기의 몸체에 대한 음향학적 특성을 수치해석 및 실험을 통해 파악함으로써 이에 대한 원인을 규명하였다. 이를 바탕으로 몇가지의 변경된 구조에 대해 소음에 관련된 현상을 고찰해 봄으로써 저소음을 위한 헤어드라이기의 설계방법을 제안하였다.

• Journal of Power System Engineering
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• v.19 no.6
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• pp.19-25
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• 2015

The unsteady-state, incompressible and three-dimensional large eddy simulation(LES) was carried out to analyze the aerodynamic performance of three-dimensional small-size axial fan(SSAF) with the different depth of bellmouth. The static pressure coefficients analyzed by LES predict a little bit larger than measurements except stall region regardless of the installation depth between SSAF and bellmouth. Moreover, static pressure efficiencies analyzed by LES show about maximum 30% at the actual operating point ranges, but measurements do not. Therefore, if the blades of conventional SSAF have some more rigidity and complete dynamic balance, the aerodynamic performance of SSAF will be some more improved. In consequence, LES shows the best prediction performance in comparison with any other Reynolds averaged Navier-Stokes(RANS) method.