• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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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

• 한국유체기계학회 논문집
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• 제2권1호
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• pp.50-55
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• 1999

The performance of a centrifugal fan depends on the dimensional parameters of impeller, such as the inlet and exit diameter, area ratio, relative flow angles to the blade, and the number of blades. These design parameters, however, are inter-related, so it is very difficult to identify the effect of each parameter on the fan performance. In this experimental study the effects of the design parameters on the performance of a small centrifugal impeller being used for vacuum cleaners are investigated. A total of 30 shrouded impellers with 120mm diameter were tested and the results were non-dimensionalized to compare their performance.

• 한국유체기계학회 논문집
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• 제2권1호
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• pp.22-28
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• 1999

In this study, a preliminary design method of the axial fan was systematically established based on the two-dimensional cascade theory. Flow deviation, lift coefficient, distribution of velocity and pressure coefficient on blade surfaces were predicted by an inviscid flow theory of Martensen method, which was also applied to select an airfoil for required performance in the present design process. The aerodynamic performance of designed blades can be predicted quickly and reasonably by using the through-flow calculation method in the preliminary design process. It would be recommendable to adopt three-dimensional viscous flow calculation at the final design refinement stage.

• 동력기계공학회지
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• 제14권6호
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• pp.20-28
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• 2010

The computational flow analysis using LES technique was carried out to investigate the flow characteristics of a RAC chassis consisting of a rear-guider, a stabilizer and a cross-flow fan. The commercial SC/Tetra software was used in this analysis. In view of the results so far achieved, the distribution trends of static pressure and velocity vector of central region except the edges of a CFFan are similar regardless of the number of revolution, and an eccentric vortex exists around the bottom blade of a CFFan. Also, a reverse flow is found in the region between stabilizer and CFFan. Moreover, near the edges of a CFFan, an eccentric vortex is separated to two vortexes. Also these vortexes increase the velocity near a rear-guider, and guide the flow near a rear-guider into stabilizer inlet. Therefore, the reverse flow region is formed in the bottom of a CFFan.

• 조명전기설비학회논문지
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• 제30권1호
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• pp.44-48
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• 2016

In this paper, we analyzed the operating characteristics of a ventilating fan due to overload and overheating. The experiment assumed the forcible restraint of the blade due to external objects and the aging process. We analyzed the experimental temperature and operating characteristics of the three places in the interior of the ventilating fan. As a result of the analysis, the temperature distribution was highest to lowest in the following order: the thermal fuse, the motor inside, and the above winding. There was smell of burning enamel in the restraint experiment. Following the thermal fuse operation, the insulation of motor winding was good. In the case of rated voltage and new ventilating fan restrained for about 4hours, and the results of restraint experiments in the presence or absence of the thermal fuse, no risk of deformation or fire due to overheating was identified. Henceforward, ignition hazard experiments will be required for additional factors of aging, pollution, and defective insulation.

• 한국소음진동공학회논문집
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• 제16권8호
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• pp.857-863
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• 2006

This paper described the performance test and sound characteristics of helicopter 'Tail-Fan' anti-torque system. In this research, Korea Aerospace Research Institute(KARI) developed 'Tail-Fan' anti-torque system for a helicopter and carried out performance and sound capturing tests of even and uneven tail fans. The performance test is carried out and the noise signals which are generated during the test are saved with microphones at the same time. The performance test's results meet the design requirements. Tone-corrected perceived noise level is reduced by replacing the even product with the uneven one.

• 한국항공우주학회지
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• 제32권1호
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• pp.50-57
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• 2004

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.193.1-193.1
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• 2005

• Journal of Information Processing Systems
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• 제16권4호
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• pp.870-881
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• 2020

Because SCADA monitoring data of wind turbines are large and fast changing, the unbalanced proportion of data in various working conditions makes it difficult to process fault feature data. The existing methods mainly introduce new and non-repeating instances by interpolating adjacent minority samples. In order to overcome the shortcomings of these methods which does not consider boundary conditions in balancing data, an improved over-sampling balancing algorithm SC-SMOTE (safe circle synthetic minority oversampling technology) is proposed to optimize data sets. Then, for the balanced data sets, a fault diagnosis method based on improved k-nearest neighbors (kNN) classification for wind turbine blade icing is adopted. Compared with the SMOTE algorithm, the experimental results show that the method is effective in the diagnosis of fan blade icing fault and improves the accuracy of diagnosis.

• Design & Manufacturing
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• 제13권1호
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• pp.61-67
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• 2019

The cooling unit of the industrial showcase consists of a compressor, a condenser and an evaporator. An axial fan is used to circulate the air to improve the efficiency of the heat exchanger. In the past, aluminum fans have been used, which have problems such as low performance, efficiency, high failure rate, and high noise. This study is to develop high performance, high efficiency plastic fan replacing aluminum fan. A major factor in determining the performance and noise of an axial fan is the angle and cross-sectional shape of the blade, which is suitable for raising the lift force, thereby controlling the vortex, which is the main cause of noise and performance degradation. In order to produce a high efficiency injection molded fan, it is necessary to develop a mold that minimizes the deformation of the injection process for the designed shape. In this study, we developed a high efficiency, low noise plastic injection fan with more than 11% performance improvement and noise reduction compared to conventional aluminum fan.