• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.381-382
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1223-1224
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• 2013

• Journal of Korean Medical classics
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• v.32 no.1
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• pp.29-48
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• 2019

Objectives : The purpose of this study is to investigate which system the FanQie notation of "Taisu(太素)" followed by comparing FanQie notation appearing in "Taisu", with the Sound button(聲紐) and Rhyme system(韻類) of the FanQie notation appearing in the "Qieyun(切韻)" system phonology book and "Guangyun(廣韻)". Methods : Followed by organizing the FanQie list in "Taisu", in comparing this list with the top and bottom characters of FanQie in the "Qieyun" system phonology book and "Guangyun", this study explores the similarity of the system after noting the Sound button and the Rhyme system. Results & Conclusions : 1. Compared to FanQie of "Taisu" with that of "Qieyun" system, the Sound button and Rhyme system were 61.54% identical, and when comparing FanQie of "Taisu" with that of "Guangyun", the Sound button and Rhyme system were 55.45% identical. 2. Comparing FanQie top and bottom letters themselves of the "Taisu" and "Qieyun" system, of the 217 FanQie sound notation Chinese characters, FanQie top and bottom letters of 18 characters were the same, accounting for 8.29%, and when compared to the "Taisu" with the FanQie top and bottom characters of "Guangyun", 15 FanQie top and bottom characters were the same, accounting for 6.91%. 3. Of the total 11,500 characters in "Qieyun", the ratio of FanQie notation Chinese characters in "Taisu" was 1.89%, and among them, nine characters came out in "Taisu" FanQie notation while there was none in "Qieyun". This accounted for 4.15% of 217 FanQie notation sound Chinese characters in "Taisu", demonstrating that this represented a relatively high ratio. 4. Conclusionally "Taisu" was more closely related to "Qieyun" system phonology book than "Guangyun" in FanQie notation, and there is also a possibility that Yang Shangshan has created some FanQie notation by himself or additionally referred to other phonology books that are not "Qieyun" system phonology book.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.5
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• pp.381-390
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• 2016

In this study, aeroacoustic characteristics of combined fan are investigated and noise was reduced by applying Serrated Trailing Edge which is known as the method to reduce fan noises. Unsteady CFD (Computational Fluid Dynamics) analysis was carried out using Lattice Boltzmann Method(LBM) to figure out the combined fan's aeroacoustics and experimental results was used to verify simulation results. Results show that different BPFs are generated at the each inner fan and outer fan on the different frequency while Blade Passing Frequency(BPF) of general fans is constant on the entire frequency range. Boundary vortex and vortex shedding are suppressed or dispersed by applying the Serrated Trailing Edge to the inner fan. Furthermore, broadband noise and fan's torque are reduced.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.5 no.1
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• pp.42-49
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• 1987

This paper describes test-pattern generation and it;s sequence for fan out-free Combinational logic network with multiple faults. The method for detecting multiple faults, in systematic way, is established by using characteristic graphs. This method is applied even in the case of fan out-reconvergent combinational logic networks. In this case, the network is decomposed into a set of fan out-free sybnetworks so as to use the characteristic graphs, and minimal test patterns are generated seperately. The each test set is combined and the test pattern for fan out-reconvergent networks are derived. According to corresponding characteristic graph, additional test patterns to detect multiple faults are simply derived.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.123-128
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• 2002

Over the range(OTR) has been applied for cooking and ventilation functions especially in northern Amarica. Because flow rate and operating rpm of the double sided sirocco fan for ventilation are much higher and than the microwave oven system, the major noise source is the sirocco fm. Recently, the quiet fan development is one of very important issues for amenity. In this study, the noise source identification using multi-microphone array system was carefully carried out and numerical simulations for understanding the aerodynamic and aeroacoustic of the fan were peformed. The sound level of tonal noise is predicted with a good accuracy but that of the broadband shows some discrepancy. In order to reduce the broadband noise, the inlet region of sirocco fan have to be modified that the secondary flow should be suppressed. Based on these results, new low noise fan and OTR is now developing.

• Journal of Industrial Technology
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• v.29 no.B
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• pp.41-45
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• 2009

The new cooling fan for various parts & equipments of KTX is developed and evaluated to improve fan performance and durability. The characteristic curve of the developed fan is obtained according to KSB 6311 of performance test regulation. 70 degree of the installation angle of blade makes the fan to produce a maximum flow rate. This angle is found out through trial-error and is confirmed through the verification test. In order to improve the blade strength, the blade is produced by a draw forming. The adoption of AL50 reduces a fan weight by 6 kg. The new blade makes a static pressure 170 (mmAq), a discharge rate $140(m^3/min)$, a rotational speed 2886 (rpm) at the power 10 kw. which results 54% of the static pressure improvement relative to the original blade.

• The KSFM Journal of Fluid Machinery
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• v.13 no.3
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• pp.59-64
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• 2010

To analyze the three-dimensional flow in tunnel caused by operation of jet fan, both experimental and computational studies have been conducted. The experimental analysis of tunnel flow induced by jet fan is conducted on a real-scale apparatus with jet fan and tunnel, and air velocity at the monitoring points is measured for variation of fan's RPM. The three-dimensional numerical analysis including tunnel and jet fan is carried out for the same geometric configuration as the experimental analysis. The experimental and computational results are compared to examine the applicability of the numerical method.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.245-250
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• 1999

In order to design micro-fan appropriately, flow chacracteristics and mechanics should be carefully considered. The present work concerns with design procedure for a micro-fan using NACA(National Advisory Committee for Aeronautics) airfoil series. The generation of fan profiles is carried out automatically by defining related parameters, which is also converted to CAD/CAM data automatically. The optimal parting surface for the mold of micro-fan is also calculated by analyzing the geometric data numerically. As a consequence, the high capacity micro-fan can be developed successfully with a high-quality and an improved efficiency.