• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.973-974
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• 2014

대형 전동기의 주요 소음원은 전자기 소음과 냉각/통풍 시스템 소음이며, 이 중 냉각/통풍 시스템이 전체 소음에 큰 영향을 미친다. 본 논문에서는 대형 전동기의 저소음 냉각/통풍 시스템 개발을 위해 저소음 냉각 팬을 개발하고 팬 커버 내부의 유로를 개선하였다. 유동해석은 상용 CFD 소프트웨어를 이용하였으며 팬 커버 내의 scroll 형상 및 air guide, baffle 의 유무에 따라 팬 커버의 압력손실을 계산하였다. 해석을 통해 팬 커버 내부의 난류 유동과 압력손실이 가장 작은 팬 커버 형상을 도출하였으며 개선된 냉각/통풍 시스템이 기존 냉각/통풍 시스템보다 6.5dB 감소된 것을 확인하였다.

• Journal of Bio-Environment Control
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• v.12 no.3
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• pp.127-131
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• 2003

This study was conducted to establish the ventilation fan operation schedule to be able to provide satisfactory environment for colonies in thc wintering honey bee house. The simulation and practical measuring test were conducted to verify the applicability of an existing simulation program to thc calculation of inside thermal environment condition of the house, and the environment control performance was compared between the two types of fan operation schedule to find the proper schedule. It was concluded that the program could be used to design thc materials of the enclosure and the fan operation schedule and decide the number of accommodation hives. Inside temperature of bee house controlled by the fan operation schedule B was lower than the schedule A under the similar high outside temperature condition. In the presence of the high outside temperature condition, inside air temperature of bee house could be decreased by changing fan operation schedule A to schedule B. The humidity variation in bee house controlled by the tan operation of schedule B was smaller than that by schedule A. These results indicated that the schedule B was superior in the aspect of the environment control performance.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.313-318
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• 2011

도로터널은 반지하 공간으로서 환기에 많은 설비와 구조에 대한 연구가 진행되고 있으며 특히 제트팬의 경우 평상시에는 환기를 담당하고 있다. 또한 화재시에는 화재연기의 유독가스를 효과적으로 차단하는 제연역할을 함으로서 피난에 대한 중요한 역할을 담당한다. 이러한 제트팬의 특성을 정량적으로 유추하고 공학적인 QRA의 수행을 위한 기초적 연구로서 터널내부의 제트팬의 환기특성을 알아보기 위하여 모형실험체의 내부측정을 2/3까지한 전보에 이어 이번 연구에서는 터널내부전체를 측정하여 제트팬이 모형터널내에 미치는 영향을 CFD와 비교한 연구이다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.4
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• pp.335-344
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• 2006

The domestic standards which used the standards of Road Association of Japan standards presents the distances of between jet-fans by the caliber of jet-fan. However, the Permanent International Association of Road Congress (PIARC) encourages it to be ten times a diameter of the tunnel. The distance of jet-fans installed in bases of two standards differs as much as two times, as so the proper basis after analysis of internal air current is needed since such difference can lead to disadvantage for selection of ventilation configuration. Based on Froude modeling theory, 1/40 scale acrylic model of a tunnel (215mm in diameter and 6.9m in length) and jet-fan (26.3mm and 31.6mm in caliber) was made for the measurement of changes in pressure and velocity due to the extension of tunnel for analysis of internal air current. And we measured the changes in pressure of surroundings of a jet-fan for confirmation of recirculation due to the exterior airs when the jet-fan is on. The results of the model test show that internal air current was not influenced by the caliber of jet-fan and its changes in pressure and velocity were stable in the point where it was nine times of diameter of the tunnel. Also the recirculation when the jet-fan is on could be verified. According to such results, in the cases of installing jet-fan in tunnels, the distances between jet-fans needs to be more than nine times the diameter.

• The Journal of the Acoustical Society of Korea
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• v.33 no.1
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• pp.40-47
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• 2014

Interaction between the unsteady flow emitted from the blade of the centrifugal fan and the volute tongue region of fan duct is known as the main noise source of the centrifugal fan. In this paper, the relative contributions of the volute tongue region of the centrifugal fan is analyzed to utilize as the foundation data of low noise design. The internal hybrid CAA (Computational Aero-Acoustics) method is used to predict noise radiated from the main noise source. This method is the noise prediction technique using CFD (Computational Fluid Dynamics), Acoustic analogy, and BEM(Boundary Element Method). The relative contributions of the centrifugal fan volute tongue region using the hybrid CAA method show that the region between the cut-off and the scroll has high contribution than the region between the cut-off and the outlet and the hub region of blade has high contribution than the shroud region of blade. These results is utilized as the important data for the development of low noise centrifugal fan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.896-902
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• 2018

This study examined the flow and noise inside a sirocco fan for ventilation as a commercial program. To confirm only the location and power of the noise source, flow analysis was performed with steady state flow analysis. Through flow analysis, the flow was observed in the sirocco fan and the velocity vector. The pressure distribution inside was observed with contours. From the results of steady analysis, the position and size of the noise source could be seen using the 'Curle surface acoustic power' and 'Proudman acoustic power'. The Curle surface acoustic power can be used to observe the noise from the surface. The Proudman acoustic power can be used to detect noise generated in the flow region because the position and size of the noise source generated inside the sirocco fan can be seen only in the steady state. Therefore it is necessary to further analyze the unsteady state to check the frequency of the noise generated. This study provides basic data for improving the performance of the Sirocco fan and reducing the noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.602-607
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• 1997

원심팬의 소음해석 기법은 Lighthill 방정식을 풀어야 하는 어려운 작업이기 때문에 아직 해석된 예가 드물다. 그래서 본 연구에서는 이미 개발한 움직이는 쌍극에 의한 소음 계산 기법을 이용해서 원심팬의 소음을 자유공간에서 계산한다. 닫힌 공간내의 음장은 경계요소법 혹은 유한요소법으로 많이 연구가 되어 왔다. 본 연구도 일반적으로 많이 사용되는 경계요소법을 이용한다. 이 세가지 방법은 원심팬에 의한 유동/음원 특성을 계산하고, 계산된 음원특성을 이용해서 경계요소법으로 전체 음향장을 계산하는 순서로 수행된다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.11a
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• pp.93-97
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• 1997

본 연구는 새로운 부하(고온의 저장물)가 냉장실 내부에 인입됨에 따라 발생하는 온도불균형을 해소하기 위해 채택된 집중냉각 방식에 있어서의 회전날개의 정지각도 결정 알고리즘 관한 것으로, 특히 냉장실내의 온도에 직접적인 영향을 미치는 압축기 (Compressor) 및 냉기팬(냉기를 냉장실내에 불어넣기 위한 팬)의 운전상황을 입력으로 냉장실내 여러 영역에서의 온도를 추정하는 퍼지적응모델을 이용하여 온도불균형 영역을 검지하고, 이에 따라 회전날개의 각도를 제어함으로서 냉장실 내부의 온도평형을 신속히 이루게하는 특징을 가지고 있다.

• Journal of Mushroom
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• v.15 no.1
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• pp.14-20
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• 2017

The oyster mushroom cultivation house typically has multiple layers of growing shelves that cause the disturbance of air circulation inside the mushroom house. Due to this instability in the internal environment, growth distinction occurs according to the area of the growing shelves. It is known that minimal air circulation around the mushroom cap facilitates the metabolism of mushrooms and improves their quality. For the purpose of this study, a CFD analysis FLUENT R16 has been carried out to improve the internal environment uniformity of the oyster mushroom cultivation house. It is found that installing a section of the working passage towards the ceiling is to maintain the internal environment uniformity of the oyster mushroom cultivation house. When all the environment control equipment - including a unit cooler, an inlet fan, an outlet fan, an air circulation fan, and a humidifier - were operated simultaneously, the reported Root Mean Square (RMS) valuation the growing shelves were as follows: velocity 23.86%, temperature 6.08%, and humidity 2.72%. However, when only a unit cooler and an air circulation fan operated, improved RMS values on the growing shelves were reported as follows: velocity 23.54%, temperature 0.51%, and humidity 0.41%. Therefore, in order to maintain the internal environment uniformity of the mushroom cultivation house, it is essential to reduce the overall operating time of the inlet fan, outlet fan, and humidifier, while simultaneously appropriately manage the internal environment by using a unit cooler and an air circulation fan.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.383-392
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• 2021

It has been known that oyster mushrooms cultivated in facilities with thermal insulation have been strongly affected by inner environments. Forced air-circulation fans exert much direct influence on disturbing air inside the facility so the matter is of particular interest. This study is carried out to investigate the measured levels of air uniformity in a cultivation facility for oyster mushroom in the various cases that reversibly controlled air-circulation fans which drove the flow in the upward and reverse direction by turn and unidirectional fans by which the wind blew upwards only were operated from July 1 to 10. The actual survey for the selection of ongoing operation cases presented that farmers, even though there were some discrepancies, have made use of fans in a way that it paused for 5-30min after running for 5-15min by turn. The level of air uniformity in the case of adopting reversible fans revealed a slight difference of 1.4-1.8℃ (Temp.) and 7.8-8.7% (R.H.) under the condition of not using a cooler during the investigation period. By contrast, unidirectional fans showed a noticeable difference of 3.2-3.7℃ and 14.0-15.4%, which meant that air uniformity driven by reversible fans much more increased compared to that for unidirectional fans. Among the twenty operational applications considered for reversible fans, the circumstance that the wind blew upwards for 10-15min and ceased for 5-10min and blew again in the reverse direction for 10-15min in succession gave minor improvements at the level of air uniformity, but at present there was somewhat difficult to make decision on which cases were optimally best. It seems necessary that the effects of reversible fans on air uniformity as well as qualities of oyster mushrooms have to be appraised in the cultivation period and the flow visualization needs to be done to ascertain the performance of air mixture.