• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.418-422
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• 2001

This paper presents a developed squired cage induction motor for axial flow fan. The developed squirrel cage induction noter for axial flow fan is exchanged the position, rotor and stater. In this method a fan blade is attached to outside rotor. So we can protect the motor from rain and reduce noise, and there is no need to have bending duct to locate the fan motor. Carried out experimental test with this induction motor, and the results were as follows. Starting torque was 21kgㆍcm@120V, maximum efficiency was 0.84@120V. The characteristics of tests were the same as double squirrel-cage type IM.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2440-2443
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• 2008

This paper presents a three dimensional shape optimization procedure for a low-speed axial flow fan blade with a weighted average surrogate model. Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model are discretized by finite volume approximations. Six variables from airfoil profile and lean are selected as design variables. 3D RANS solver is used to evaluate the objective functions of total pressure efficiency. Surrogate approximation models for optimization have been employed to find the optimal design of fan blade. A search algorithm is used to find the optimal design in the design space from the constructed surrogate models for the objective function. The total pressure efficiency is increased by 0.31% with the weighted average surrogate model.

• 한국산업융합학회 논문집
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• 제25권3호
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• pp.379-386
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• 2022

The goal of this research is to verify a performance test system for a low speed, high torque, and harsh reducer at low cost. The reducer rotates a cooling fan with a diameter of 10 meters, in a high temperature (50℃) cooling tower in a geothermal power plant. It requires about 500 kgf·m torque and 47.75 kW power to rotate the fan at a maximum power condition. An expensive dynamometer is commonly used for performance test of a motor or a reducer. In this paper, a low cost system is developed using a hydraulic pump as a load unit to generate torque instead of a dynamometer. We accurately calculated the required power, the flow meter, and the pressure of the pump, and selected to design and optimize the system at minimal cost. The system also applied another reverse reducer and a gearbox to increase the rotational speed and to reduce the torque from the low speed and high torque target reducer. This allows low-cost systems to be built using inexpensive components. The developed system was able to successfully measure the high torque and the low rotational speed of the target reducer at high temperature.

• KIEAE Journal
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• 제14권6호
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• pp.99-104
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• 2014

Recently supply of low energy house is increasing which can enhance energy efficiency and indoor environment comfort. Low energy house have to secure air tightness as well as thermal performance so house become high airtightness and inevitably need heat recovery ventilator to enhance indoor air quality. However, most of current ventilation systems are one-click, controlling the entire space so it causes increasing of heating load and fan power which makes it hard to save energy. Thus, Individual Control system is required which can achieve both enhancing indoor air quality and decreasing heating load and electric fan power. Thereby, in this study, we analyzed the correlation between ventilation and fan power through mock-up experiment and measured ventilation load under individual control system. As a result, under the condition of $24^{\circ}C$ of indoor temperature for 6 month(November to April) in Daejeon, ventilation load by fan speed was $10.9{\sim}19.6kWh/m^2{\cdot}a$ when operated 24 hours and $7.6{\sim}13.7kWh/m^2{\cdot}a$ when operated 12 hours in night time. In addition, it is possible to reduce at most 60% of ventilation load under the individual control system; measured ventilation load was $7.4kWh/m^2{\cdot}a$ when operated 24 hours, and $5.5kWh/m^2{\cdot}$ when operated 12 hours in night time.

• 대한기계학회논문집B
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• 제40권5호
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• pp.321-327
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• 2016

본 연구에서는 고속 회전을 하는 진공청소기용 원심홴의 공력성능 향상을 위해 에어포일 임펠러(Airfoil Impeller)의 적용을 검토 및 연구하였다. 에어포일 최대두께 및 최대두께 위치에 따라 3종의 에어포일 임펠러를 제시하였고, 이때 C4 에어포일 두께분포를 이용하였다. 에어포일 임펠러의 성능 평가는 전산유체역학(Computational Fluid Dynamics) 해석과 흡입일률시험을 통해 수행되었다. 이를 통해 에어포일 형상 적용 시 기존 블레이드 형상에 비하여 임펠러 블레이드 압력면과 디퓨져 블레이드 압력면에서 발생하는 유동박리가 크게 줄어드는 것을 확인하였다. 그리고 이로 인해 기존 원심홴에 비하여 홴 효율이 약 3% 증가 및 비소음이 약 1.3dB(A) 감소되는 것을 확인하였다.

• 대한기계학회논문집A
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• 제41권3호
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• pp.165-172
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• 2017

본 논문에서는 가정용 냉장고의 내부 냉기순환용 원심팬의 고성능/저소음 최적설계를 수행하였다. 최적설계를 위해 여러 독립변수들이 어떠한 종속변수에 영향을 줄 때 용이하게 적용할 수 있는 반응표면법을 사용하였으며, 블레이드의 입구각, 출구각, 내경을 독립변수로 선정하였다. 먼저 이를 통해 팬 블레이드의 유량을 최대화하였으며, 3-D 프린터를 이용해 샘플을 제작하였고, 만들어진 팬의 P-Q곡선을 측정하여 개선된 팬이 유량의 증가를 보임을 확인하였다. 또한 기존 팬과 동일한 유량을 가지도록 새로운 팬의 회전속도를 저감시킬 경우, 1.7 dBA의 소음 저감 효과가 있음을 확인할 수 있었다.

• 농업생명과학연구
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• 제50권2호
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• pp.187-194
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• 2016

본 연구는 무창돈사에서 최적 환경조절이 가능한 시스템을 구축하고자 환경조절이 가능한 모형돈사를 제작하여 온도분포특성을 분석하고 ICT 융합기술을 활용한 온도센서 위치 최적화 및 컨트롤 일체형 환기팬을 개발하고자 하였다. 팬 상부에 부착된 센서에 의해 측정된 온도는 다른 측점온도보다 1℃ 내의 낮은 온도차를 나타내어 측정오차를 고려할 때 온도센서가 팬 상부에 위치하여도 문제가 없을 것으로 판단되었다. 환기팬 성능은 최대 출력일 때 회전수 1920rpm, 송풍량 125㎥/min로 나타났으며, 최대 효율은 개방면적비 약 70%를 고려할 경우 사용된 환기팬의 적정 송풍량은 75㎥/min에 60pa로 나타났다. 댐퍼의 개방면적비가 약 70%일 때 환기팬의 동력과 상관없이 최대효율을 나타내었다. 팬의 출력별 회전수는 출력 100%일 때 최대 1,920rpm으로 나타났으며, 컨트롤러의 펄스 듀티비를 변화시킴에 따라 AC 출력 위상이 지연 없이 변화하는 것으로 나타나 빠른 응답속도로 팬 속도조절이 가능한 것으로 판단되었다.

• Journal of Biosystems Engineering
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• 제13권3호
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• pp.32-43
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• 1988

This study was attempted to investigate the pneumatic separation on separating unit of a combine harvester. The aerodynamic characteristics of threshed materials were analyzed by experiments. The air velocity distribution within the separation chamber was measured for various speeds of the winnower and suction fans to find out the operational and design conditions of the separating unit which would serve for reducing the grain loss from chaff outlet. The results of study arc summarized as follows: 1. Based on the separation curve of threshed materials analyzed, it was shown that three different kind. of materials-kernels, straw chaff, and leaf chaff were as a whole able to be separated pneumatically, regardless of varieties. However, a small amount of the separation grain loss may be expected to occur if the complete separation between kernels and straw chaff would be undertaken because some portion of their separation curve were overlapping. 2. The analysis of air velocity distribution showed that the separation chamber may be divided into two regions, the discharging and separating. The air velocity of the discharging region was 5-15 m/s and that of the separating region 2-5 m/s. 3. The air movement of the separation chamber may be a turbulence flow, being its speed became greater as it moves from the left to the right section of the separation chamber. The equi-speed line. of air flow had a steep gradient in between the discharging and the separation regions. The air velocity in the discharging region was much higher than the terminal velocity of kernels, because of which those kernels appearing in the region could be possibly exhausted as the grain loss from the chaff outlet. 4. The motion trajectory of threshed material in the separating region was dominantly affected by the winnower fan, on the other hand, its motion in the discharging region was affected by suction fan. 5. The grain loss from the chaff outlet was affected greatly by the winnower fan and the trace of kernel movement. It was observed that the optimum working speed to give minimum grain loss from chaff outlet for the combine tested should be maintained at 950~1,150 rpm for the winnower fan and 1,850 rpm for the suction fan. 6. It was shown that a large portion of grain loss from chaff outlet may occur when the kernels may bump against a portion of separation chamber wall and those kernels thus scattered into the discharging region were sucked by the suction fan. It was accordingly recommended that a new design of the wall of separation chamber so as to bump down kernels may be necessary to reduce grain loss from the chaff outlet.

• 한국수소및신에너지학회논문집
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• 제28권4호
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• pp.369-376
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• 2017

Temperature and humidity regulations of an open-cathode PEM fuel cell with balance of plant (BOP) are developed in this study. The axial fan, a bubble humidifier, set of solenoid valves and a controller are used to perform temperature and humidity control simultaneously. A fuzzy controller is designed, and it shows its superiority in real-time controlling for strong non-linear dynamical fuel cell system. The axial fan speed is used for temperature control and solenoid valve on/off signal of the bubble humidifier is used for humidity control. The axial fan speed is controlled to keep the fuel cell temperature within the desired point. Meanwhile, the bubble humidifier is utilized to moisture hydrogen to manage the water content of membrane. The results show that the proposed fuzzy controller effectively increases the output power of 10% for a PEM fuel cell.

• Journal of Biosystems Engineering
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• 제26권4호
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• pp.355-362
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• 2001

Uniform application of agri-chemicals will improve orchard pest management. An air-blast(orchard) sprayer designed for vineyards has been used: however, few research on the uniformity and coverage of the sprays has been reported. Distributions of spray coverage were measured with artificial targets and analyzed to enhance the efficiency of spray application. A structure was built to place water sensitive papers, sampling spray droplets blasted from the orchard sprayer. The sampling cards were collected from five directions at three distances (2.5, 3.0 and 3.5m) for two fan speeds (2,075 and 3,031 rpm), and analyzed using an image analysis system. The distribution of the coverage percent area did not follow the wind velocity pattern. The coverage by the low fan speed was more uniform and higher than that by the higher fan speed. The coverage percent area decreased with an increase of distance. The distribution of droplet density was similar to that of coverage. However, the coverage contribution by smaller droplets became more significant as the distance increased. The upward blasting distance was limited within 3m, but the limit to the ground level was expanded the distance more than 3.5m because of the concentrated droplets.