• Journal of Power System Engineering
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• v.17 no.1
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• pp.58-63
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• 2013

The aerodynamic performance of double inlet sirocco fan is strongly dependent upon the design factors of impeller and scroll. In this paper, the change of scroll size was adopted to investigate the aerodynamic performances of double inlet sirocco fan and indoor PAC. Especially, a scroll expansion angle and a cut-off clearance ratio were considered to change the scroll size. In addition, the installation depth between double inlet sirocco fan and indoor PAC was considered. As a result, the total pressure efficiency of double inlet sirocco fan shows about 62%~73% according to the change of scroll expansion angles. Moreover, the flowrate performance of indoor PAC is the best at the condition of a scroll expansion angle of 8°, an installation depth of 15 mm and a cut-off clearance ratio of 8%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.402-406
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• 2000

In the Over-The-Range, the outlet size is limited by the industrial standards. Therefor to enlarge the volume of cavity, the installation height of ventilation fan is become small, the system resistance is higher than before. For that reason, the important design variables such as the diameter of a fan, the scroll expansion angle, etc. which play the significant role on flow rate and noise, are confined. In this study, we made an experiment of the diameter of fans relation to scroll expansion angle and investigated flow rate of the length of fans in enlarged cavity volume of OTR, and then we designed the new scroll to improve the flow rate and noise level. As a result, flow rate increased to 110% compared to current scroll and the blade passing frequency of a fan is disappeared by inclined cut-off shapes.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.11
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• pp.954-963
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• 2002

For the optimal design of an automotive blower system, effects of the scroll cut-off starting angle, the clearance between blade tip and bellmouth, and the scroll expansion angle on the performance of sirocco fan are investigated experimentally. Best performance is achieved at fan exposure ratio $\Deltae/r_c$,/TEX> =1.0, and clearance ratio $\DeltaeC/C=0.62. Flow characteristics inside sirocco fan are also studied by using LDV. Flow patterns in the inside of fan can be classified into three regions. Velocity vector has the same direction as rotational direction of fan at 0~$120^{\circ}$, toward the fan blades at 150～$180^{\circ}$, and opposite direction at 210~$330^{\circ}$. Turbulent intensity is relatively high near the cut-off edge in the scroll housing.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.179-180
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• 2009

본 논문은 웨어러블 플랫폼 구성 기술로써 e-Textile Fabric Area Network (e-FAN) 시스템을 소개하고, e-FAN 시스템에서의 브릿지 노드를 이용한 네트워크 확장 방법을 제안한다. E-FAN 은 직물 소재의 제품에 센서, 엑츄에이터, 프로세서 등의 다양한 정보 처리 유닛이 전도성사로 연결되는 구성되는 네트워크이다. 본 논문은 이러한 e-FAN 시스템에서의 e-FAN 브릿지 노드 (e-FAN Bridge Node; eFANBN)을 활용한 네트워크 확장 방법을 제시한다. E-FAN 브릿지 노드를 활용한 네트워크 확장 방법을 통하여 다양한 종류의 전도성사를 통신 매질로 하는 네트워크 세그먼트를 통합하여 내고장성을 지원하는 네트워크로 확장한다.

• The KSFM Journal of Fluid Machinery
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• v.13 no.2
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• pp.18-23
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• 2010

This paper presents a procedure for the aerodynamic and aeroacoustic characteristics of a sirocco fan. For the aerodynamic and aeroacoustic analyses of the sirocco fan, three-dimensional steady and unsteady Reynolds-averaged Navier-Stokes equations are solved with a shear stress transport turbulence model for turbulence closure. The flow analyses were performed on a hexahedral grid using a finite-volume solver. The validation of the numerical results is performed by comparing with experimental data for the pressure, efficiency and power. The internal flow analyses of the sirocco fan are performed to understand the unstable flow phenomenon on the casing for the wall pressure and internal flow characteristics at each position. It was found that fluctuation of pressure and locally concentrated noise source are observed near the cut-off and expansion regions of the casing.

• Journal of Power System Engineering
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• v.9 no.3
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• pp.50-57
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• 2005

A cross-flow fan is strongly influenced by the various design factors of a rear-guider and a stabilizer. The purpose of this paper is to investigate the effects of a rear-guider and a stabilizer on the surface pressure of a rear-guider in an indoor room air-conditioner using a cross-flow fan. The design factors considered in this paper are a rear-guider clearance, a stabilizer clearance, and a stabilizer setup angle, respectively. The operating condition of a cross-flow fan was controlled by changing the static pressure and flowrate using a fan tester. All surface pressures of a rear-guider are differently distributed according to the stabilizer setup angle, and show a zero value in the flow coefficient, ${\Phi}{\fallingdotseq}0.5$ only of a stabilizer setup angle, $45^{\circ}$. Especially, they show a big negative value in the expansion angle larger than $34^{\circ}$ regardless of a rear-guider clearance, a stabilizer clearance, and a stabilizer setup angle. On the other hand, surface pressures for various stabilizer cutoff clearances are better than those for various rear-guider clearances.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.4
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• pp.71-77
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• 2021

Several cooling techinques have been studied for protecting gas turbine blades from hot gas. In terms of film-cooling techniques, various shapes of film cooling holes have been studied including fan shaped holes, which are used on gas turbine blades. However, owing to increasing demands on smaller gas turbines, a research on film-cooling holes on thin walls is required. This study was conducted at blowing ratios of 1 and 2, using numerical analysis. Through the numerical analysis, the effect of geometrical parameters on the effectiveness of fan-shaped hole film cooling was studied. Moreover, optimization was performed on three geometrical parameters: metering length, lateral expansion angle and forward expansion angle. As a result, we realized that the optimal fan-shaped holes on each blowing ratio were found to have very similar geometry and cooling performance.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.525-528
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• 1988

In this paper, a new multi-output logic minimization algorithm is presented. A base minterm is selected in the given function and the prime implicant is obtained by expanding it in the order of the expansion set that is decided by heuristic method. Input-oriented expansion procedure is used to reduce fan-in and fan-out number. To show the effectiveness of this algorithm, comparative run time with other minimization algorithm is given.

• Journal of the Korean Society of Safety
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• v.10 no.2
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• pp.32-38
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• 1995

The silencers are used to attenuate noise generated by the exhaust fan for industrial processes. The types of silencers applied in this study are absorptive duct silencer, expansion chamber, absorptive chamber and resonator. This study was carried out to verify the attenuation by the various silencers and elements. As a result, the difference of attenuation between the calculation and the measurement was about 1-7㏈. The attenuation by absorptive duct silencer and absorptive chamber was negligible at frequencies below 250Hz. The expansion chamber should be used for low frequency applications where the absorptive duct silencer was Ineffective. The attenuation by resonator may be realised when the ratio of frequency to resonant frequency approaches 1.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.1-11
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• 2004

Numerical analyses on the aerodynamic characteristics of a counter rotating axial flow fan were conducted for the development of an axial type in-line duct fan. The counter rotating fan has a front rotor and a rear rotor which are counter rotating each other. Blade design of the counter rotating fan was done by extension of design method for axial flow fan which consists of rotor and stator blades. Through flow analysis was performed using matrix method which is applied for flow fields prediction of compressors or turbines. Aerodynamic characteristics and characteristic curves of the counter rotating fan were analyzed by expansion of the frequency domain panel method with duct modeling. Pressure losses were higher at leading edge and hub region of rotor blades. Characteristic curve of the counter rotating fan was overpredicted without consideration of viscous effect.