• The KSFM Journal of Fluid Machinery
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• v.8 no.3 s.30
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• pp.26-32
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• 2005

One of noticeable features in the cross flow fan is that a working fluid passes through impeller blade twice without distinction between the inlet and exit angles. Also, it does produce higher circumferential velocity than other types of blade at the same flow rate in accordance with the application of the forward curved shape. However, a design theory for the cross-flow fall has not yet been formed owing to an eccentric vortex, which is the remarkable characteristics, occurred in a cross-flow fan. Furthermore, the eccentric vortex, which is difficult to control the size and position, is the important cause of performance decrease. In this study, experiments we carried out to estimate the similarity of the cross-flow fan with various scales and rotational velocity changes. Pressure coefficients to flow coefficients with various scales of the cross-flow fan are plotted to the application of the general similarity law of the turbomachinery in the cross-flow fan with Archimedes spiral, which is the important factor having an effect on it.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.213-216
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• 2006

This paper was a study about noise reduction through flow stabilization in duct using experimental method and numerical analysis at the same time. To determine the fan's type three kinds of fans(axial fan, centrifugal fan, and axial fan with centrifugal type blades) was examined to investigate the suitability for in-line duct. As a result, under the equal number of rotation 2000 RPM, performance of an axial fan with centrifugal type blades was the most superior by 55dBA at 4.3CMM among other fans. After this, analyzed the results of the numerical analysis to find out the optimum design of pitch angle such as $0^{\circ}$, $10^{\circ}$, $15^{\circ}$ and $20^{\circ}$. The intensity of turbulence was low when pitch angle was $15^{\circ}$ and air volume became peak by 5.08 CMM. It was observed that axis component of velocity increased gradually when pitch angle increased from $0^{\circ}$ to $20^{\circ}$, and embodied noise reduction and improvement of air flow rate through flow stabilization.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.3
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• pp.325-337
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• 2000

A study was done on the numerical and experimental analyses of the aerodynamic characteristics of a counter rotating axial fan. The numerical analysis uses the frequency domain panel method developed for the aerodynamic analysis of interacting rotating systems, which is based on the unsteady lifting surface panel method. Each stage of interaction involves the solution of an isolated rotor, the interaction being done through the Fourier transform of the induced velocity field. Numerical results showed good agreements with other experimental data for single and counter rotating propeller systems. And they were compared with the experimental results of the counter rotating axial fan studied in the present paper. The performance test was carried out based on the Korean Standard (KS B 6311). It was focused on the relative efficiency increase of a counter rotating system for a single rotating one, and effects of the axial distance between the front and rear rotors on overall fan performances were investigated. As a result, it was shown that the counter rotating axial fan has the efficiency 14% higher than the single rotating one at peak efficiency points.

• Journal of Power System Engineering
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• v.9 no.3
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• pp.33-38
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• 2005

The aerodynamic performance of 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 aerodynamic performance of 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. This experiment was carried out with a constant revolution number of 700 rpm in a cross-flow fan installed in the fan tester. The static pressure, flowrate, torque, and revolution number were measured in this paper. Also, the pressure coefficient and the efficiency were analysed according to the various assembly conditions using a stabilizer setup angle, a stabilizer clearance, and a rear-guider clearance in the indoor room air-conditioner.

• Tunnel and Underground Space
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• v.12 no.2
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• pp.92-98
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• 2002

In this study reduced-scale experiments were conducted to analyze smoke movement in tunnel fire with jet fan, The 1/20 scale experiments were carried out under the froude scaling using gasoline pool fire range from 6.6 to 12.5 cm in diameter with total heat release rate from 0.714 to 4.77 kW. In the case of fires under the 2.5kW, backlaying was reduced about 40cm and smoke was effectively controled in downstream of the fan when operating the fan. The smoke layer was moved down and the ceiling temperature was decreased compared to that of without fan case in upstream of the fan, but the temperature in the lower part of the tunnel was increased.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.191-192
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• 2009

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1597-1599
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• 2007

In TFT-LCD, mura is a defect which degrades the display quality. The resistance difference between gate lines is the main cause of H-Block mura. Two methods could eliminate this defect. A thinner gate layer or gate fan-out pattern decrease mura level. H-Block mura has been reduced after implementing the new schemes.

• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.65-69
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• 2019

The cure properties of ethoxysilyl diglycidyl isocyanurate(Ethoxysilyl-DGIC) and ethylsilyl diglycidyl isocyanurate (Ethylsilyl-DGIC) epoxy resin systems with a phenol novolac hardener were investigated for anticipating fan out-wafer level package(FO-WLP) applications, comparing with ethoxysilyl diglycidyl ether of bisphenol-A(Ethoxysilyl-DGEBA) epoxy resin systems. The cure kinetics of these systems were analyzed by differential scanning calorimetry with an isothermal approach, and the kinetic parameters of all systems were reported in generalized kinetic equations with diffusion effects. The isocyanurate type epoxy resin systems represented the higher cure conversion rates comparing with bisphenol-A type epoxy resin systems. The Ethoxysilyl-DGIC epoxy resin system showed the highest cure conversion rates than Ethylsilyl-DGIC and Ethoxysilyl-DGEBA epoxy resin systems. It can be figured out by kinetic parameter analysis that the highest conversion rates of Ethoxysilyl-DGIC epoxy resin system are caused by higher collision frequency factor. However, the cure conversion rate increases of the Ethylsilyl-DGEBA comparing with Ethoxysilyl-DGEBA are due to the lower activation energy of Ethylsilyl-DGIC. These higher cure conversion rates in the isocyanurate type epoxy resin systems could be explained by the improvements of reaction molecule movements according to the compact structure of isocyanurate epoxy resin.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.4
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• pp.551-561
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• 1998

This paper was studied to understand the characteristics of heat transfer coefficients and surface temperature distributions around a circular combustion chamber within the heat-intercept duct of kerosene fan heater. The experiment was carried out in the heat-intercept duct of kerosene fan heater attached to the blow-down-type subsonic wind tunnel with a test section of 240 mm * 240 mm * 1200 mm. The purpose of this paper was to obtain the basic data related with normal combustion for new design from conventional kerosene fan heater, and to investigate the effect of surface temperature, local and mean heat transfer coefficients versus flow-rate of convection axial fan according to the variations of heat release conditions from kerosene fan heater during normal combustion. Consequently it was found that (i) the revolution of convection axial fan during combustion had a smaller value than that of non-combustion because of the thermal resistance due to the high temperature in the heat-intercept duct, (ii) the pressure ratio P$_{2}$/P$_{1}$ had a comparatively constant value of 0.844 according to the revolution increase of turbo fan and the heating performance of kerosene fan heater had a range of 1,494 ~ 3,852 kcal/hr, (iii) the local heat transfer coefficient around a circular combustion chamber had a comparatively larger scale in the range of 315 deg. < .theta. < 45 deg. than that in the range of 90 deg. < .theta. < 270 deg. as a result of heat transfer difference between front and back of a circular combustion chamber, and (iv) the mean heat transfer coefficient around a circular combustion chamber increased linearly like a H$_{m}$=95.196Q+104.019 in condition of high heat release according to the increase of flow-rate of axial fan.n.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.690-695
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• 2006

This paper described the Performance test and sound characteristics of helicopter 'Tail-Fan' anti-torque system. In this research, Korea Aerospace Research Institute(KARI) developed 'Tail-Fan' anti-torque system for a helicopter and carried out performance and sound capturing tests of even and uneven tail fans. The performance test is carried out and the noise signals which are generated during the test are saved with microphones at the same time. The performance test's results meet the design requirements. Tone-corrected perceived noise level is reduced by replacing the even product with the uneven one.