• Journal of KSNVE
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• v.10 no.5
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• pp.873-879
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• 2000

Experimental investigation was conducted to study the effects of pitch angle maximum camber on the performance and noise of an axial-flow fan used in outdoor-unit of air -conditioner. For this study the axial-flow fan whose pitch angle can be varied was made and the Specific sound Pressure Level and other coefficients were measured using the anechoic fan tester. It is found that pitch angle affects more severly than the maximum camber on the fan performance. On the while the maximum camber affects much on the specific sound power level. Present results show that it is important to choose the optimum pitch angle and maximum camber to design the high-performance and low-noise axial-flow fan and specific noise measured in the anechoic fan tester can be sued effectively for the design of low-noise fan.

• 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.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.37-42
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• 2001

A computerized axial flow fan design system is developed with the capabilities for predicting the aerodynamic performance and the noise characteristics of fan. In the present study, the basic fan blading design is made by combining vortex distribution scheme with camber line design, airfoil selection, blade thickness distribution and stacking of blade elements. With the designed fan blade geometry, the through-flow field and the performance of fan are analyzed by using the streamline curvature computing scheme with spanwise total pressure loss and flow deviation models. Fan noise is assumed to be generated due to the pressure fluctuation induced by wake vortices of fan blades and to radiate as dipole distribution. The vortex-induced fluctuating pressure on blade surface is calculated by combining thin airfoil theory and the predicted flow field data. The predicted performances, sound pressure level and noise directivity patterns of fan by the present method are favorably compared with the test data of actual fans. Furthermore, the present method is shown to be very useful in designing the blade geometry of new fan and optimizing design variables of the fan to achieve higher efficiency and lower noise level.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.5
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• pp.730-736
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• 2008

The purpose of this study is to find out a flow characteristics when a crossflow-fan is installed inside the computer case and to provide information about the preliminary data of cooling efficiency of CPU and a flow inside and outside of a computer case. Under the condition of operating the fan inside the experimental duct we changed the position of a installation of the slot, and the experiment measured with PIV and the results are as follows. Under the influence of the crossflow-fan installed to the air discharging side, mean velocity between 35 to 45 on the point 80 of the Slot 0.2.3 of the case increased and it influences discharging the air inside of the computer case. On the left-upper end. which isn't directly influenced by the suction-discharging fan installed inside the PC, a flow occurs caused by vortex due to the Sirocco-Fan and Slot installed on the center of the right side. We can see that a flow distribution increases when the Sirocco-Fan operates and a whirl appears stronger between the slot and the suction fan. It is thought that this phenomenon is influenced by a flow while it is on the way of entering from the suction-fan and going out to the discharging-fan.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.253-256
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• 2004

Acoustical noise at low frequency range (below 500Hz) of refrigerator result from fans which are inside of the refrigerator. In generally to evaluate and apply to refrigerator it is recommended that acoustical noise and fluidic performance of the fan were measured simultaneously. To do that twin-room type anechoic wind tunnel was needed. But constructing twin room type anechoic wind tunnel was very expensive and estimation of small refrigerator fan performance was not easy. So in this paper we composed anechoic fan tester. A successful noise and performance measurement was performed using the anechoic fan tester. Existing 22 kinds of refrigerator fan were investigated and mapped into one database. Refrigerator duct pressure resistance were measured and reflected into the fan database to find out appropriate fan. Through the application of fan database, the refrigerator became less noise compared to current one and these data shows what is the best way to reduce fan noise.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.83-88
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• 2004

In this study, the flow and thermal performance of the heat sink and fan-sink were experimentally studied to predict the operating condition of the fan-sink. The experiments of the flow and thermal resistance of the heat sink with various inlet blockage, which were occurred by the shapes of the axial fans, were conducted for the proof of the effects of the inlet blockages. The greater the inlet blockage of the heat sink, the higher the pressure drop and lower the thermal resistance of the heat sink will be. The operating point of the fan-sink was predicted by the pressure drop curve with the inlet blockage, which was corresponded to the selected fan and the fan performance curve, and verified by the performance test of the fan-sink. The predicted operating point of the fan-sink had good agreement with the result of the performance test of the fan-sink within $0.7\%$ of the volume flow rates. Measured thermal resistance of the fan-sink was equivalent to that of the heat sink with the same inlet blockage of the fan-sink. It was shown that the heat transfer characteristics of the heat sink were influenced by the flow interaction between the selected fan and the heat sink. To improve the thermal resistance of the heat sink, it is necessary to consider appropriate flow patterns of the fan outlet entering into the heat sink.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.399-404
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• 1999

This study were performed to find the cooling effect and to provide design data during summer season for the Pad& Fan system of greenhouse . The temperature variation along the greenhouse width were analyzed. Also, the effect of the pad location and fan capacity on the cooling of the greenhouse were analyzed. While Pad &Fan systems were operating the temperatures in greenhouse were very different along the meausring locations. It is recommeded that PAD location and FAN capacity should be considered to design the Fan and Pad system in order to provide greenhouse the optimum temperature condition.

• Journal of KSNVE
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• v.10 no.3
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• pp.457-464
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• 2000

Vibrations of a fan are often generated by mechanical unbalance magnetic force and air flow. These vibrations depend on the design of a fan the machining accuracy of each element and assembled conditions. An experimental study is carried out to reduce the vibration and noise of an industrial fan in this paper. In order to identify the vibration sources of a fan the signal analysis and system analysis are performed, It is shown that the industrial fan studied in this paper has a natural frequency at 144 Hz and resonance occurs when the running speed of the fan is 1750 rpm. The results may be helpful to design a fan with low vibration and noise.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.2
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• pp.65-70
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• 2002

The fan stall guard system of boiler airing system of the class of 500MW capacity to protect fan. But because confidence is loosed and operation is influenced by frequent fault of fan stall guard system, confidence is improved by substituting DCS Logic for it.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.924-928
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• 2008

In this paper, The fan stall guard system of boiler airing system of the class of 500MW capacity to protect fan. But because confidence is loosed and operation is influenced by frequent fault of fan stall guard system, confidence is improved by substituting DCS Logic for it.