• Proceedings of the KSME Conference
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• 2001.06e
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• pp.678-683
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• 2001

The present work has carried out experimental study on a cross-flow fan system with a simplified vortex wall scroll casing. A cross-flow fan test rig was constructed to obtain pressure rise and volume flow rate for various fan operating conditions. The performance estimation is using a wind tunnel with a motor driven damper for flow rate control and flows are quantitatively visualized by light scattering system with a pulsed laser. Min focus on the visualization is finding a eccentric vortex inside a fan which is a major factor reducing fan efficiency. Comprehensive engineering data are prepared for industrial applications and show a good agreement with a prior work by experimental measurements.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.583-589
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• 2004

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 fan 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 of the size and position, is the important cause of performance decrease. In this study, experiments are 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 research the application of the general similarity law of the turbomachinery in the cross-flow fan with Archimedes spital, which is the important factor haying an effect on it.

• Journal of Mechanical Science and Technology
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• v.14 no.2
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• pp.226-235
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• 2000

The performance prediction of an airfoil fan using a commerical code, STAR/CD, is verified by comparing the calculated results with measured performance data and velocity fields of an airfoil fan. The effects of inlet tip clearance on performance are investigated. The calculations overestimate the pressure rise performance by about 10-25 percent. However, the performance reduction due to tip clearance is well predicted by numerical simulations. Main source of performance decrease is not only the slip factor but also impeller efficiency. The reduction in performance is 12-16 percent for 1 percent gap of the diameter. The calculated reductions in impeller efficiency and slip factor are also linearly proportional to the gap size. The span-wise distributions of phase averaged velocity and pressure at the impeller exit are strongly influenced by the radial gap size. The radial component of velocity and the flow angle increase over the passsage as the gap increases. The slip factor decreases and the loss increases with the gap size. The high velocity of leakage jet affects the impeller inlet and passage flows. With a larger clearance, the main stream moves to the impeller hub side and high loss region extends from the shroud to the hub.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.862-869
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• 2006

The purpose of this study is to propose the proper vocabularies for evaluating H.D TV set fan noise in residential condition. To achieve this goal, psycho-acoustic experiments were carried out with TV set fan noise modulated at specific frequency band. finally, a correlation analysis between vocabularies, and a factor analysis of psycho-acoustical responses were conducted. As a result of this study, followings are suggested. Analyzing the psycho-acoustical response corresponding to the various sound level, the higher the sound levels, the higher the response values were. It is estimated that the sound level determined psycho-acoustical responses. On the degree of response to fan noise, the initial level of negative feeling is located on $35{\sim}40$ dB(A). The factor of evaluating H.D. TV set fan noise has induced three the appropriate korean adjectives; Irritate, Monotonous, stuffy and dryness. The result of this study may be used to evaluate the acoustic threshold level for indoor noise or a basis for specifying the desired acoustic environment of dwellings.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.10 s.115
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• pp.1014-1023
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• 2006

The purpose of this study is to propose the proper vocabularies for evaluating H.D TV set fan noise. To achieve this goal, psycho-acoustic experiments were carried out with TV set fan noise modulated at specific frequency band. Finally, a correlation analysis between vocabularies, and a factor analysis of psycho-acoustical responses were conducted. As a result of this study, followings are suggested. Analyzing the psycho-acoustical response corresponding to the various sound level, the higher the sound levels, the higher the response values were. It is estimated that the sound level determined psycho-acoustical responses. On the degree of response to fan noise, the initial level of negative feeling is located on $35{\sim}40$ dB(A). The factor of evaluating H.D. TV set fan noise has induced three the appropriate korean adjectives; Irritate, Monotonous, stuffy and dryness. The result of this study may be used to evaluate the acoustic threshold level for indoor noise or a basis for specifying the desired acoustic environment of dwellings.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.256-260
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• 2013

The fan-shroud plays the important role in cooling down the engine heat by the forced convection. As the fan-shroud is made by injection molding, the unbalance of the fan blades is inevitable, and its low frequency characteristics makes it easy to excite the resonances of the environmental structures. So controlling its vibration, specially the dominant vibration source of unbalance vibration, is one of key factor to improve the sound and vibration quality of the modern vehicles. This paper introduces the plane balancing method, the most appropriate way of controlling the fan-shroud by generating the acceleration orbit measured from 2 accelerometers, and proves its balancing effect by the experiment.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.4
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• pp.383-390
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• 2016

In this paper, experiment and dynamics simulations were carried out to identify and reduce the out-of-plane vibration that occurs in a centrifugal fan of an air conditioner installed to a wall. In a wall-installed air conditioner, large space between a case and heat exchanger is often required for the fan to avoid the collision with the case and exchanger. This large space hinders the slim design of the air conditioner even if air conditioner market demands a slim air conditioner. In the present study, in order to determine the cause of the vibration in the centrifugal fan, the out-of-plane vibration and the physical properties were investigated, and the dynamic characteristics of the centrifugal fan were obtained by experiments. Based on these experiments, a dynamic simulation model was established to determine the cause of the out-of-plane vibration of the centrifugal fan. It was found that the main factor of out-of-plane vibration in the centrifugal fan is the axial misalignment between the centrifugal fan and the motor shaft.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.1
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• pp.1-8
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• 2019

In this study, the effect of operating conditions of fan-coil unit with an oval tube type heat exchanger on its non-dimensional performance coefficient has been investigated. Pressure drops and heat transfer rates were measured under heating condition for various water flow rates, inlet temperatures and wind speeds. As a non-dimensional performance coefficient, Colburn j-factor was evaluated. The results show that the most sensitive parameter on heat flux is the inlet temperature, which affects the heat flux 4.7 and 7.2 times more than the wind speed and water flow rate, respectively. On the other hand, the Colburn j-factor as a non-dimensionalized index decreases with the wind speed, and has an maximum when the wind speed is about 1 m/s. the Colburn j-factor increases slowly with the water flow rate and inlet temperature but at a certain range of inlet temperature, the opposite phenomenon is found.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.99-110
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• 2016

This study examined the factors affecting the team identification of professional baseball fans. The factors were divided into the fan factor, game factors, and other factors. For the analysis, two investigators visited stadium three times in total and a total number of 297 spectators were sampled using a convenience sampling method from three baseball teams. For the fan factor, a fan who began supporting his/her team from childhood or after childhood was used as a dummy variable. The interaction effects between the fan factor and other variables were investigated to offer a stereoscopic understanding about the role of kids marketing. In addition, three game factors and four non-game factors were analyzed. The results regarding fan variable and interaction effects were obtained. Fans from their childhood have much stronger team identification, and show interaction effects with the players. Regression analysis revealed player, promotion and fan service, price, and regional connection to have positive relations with team identification. This study is especially meaningful in a sense that it has proposed positive results regarding marketing to children, and the results will contribute to both the academic field and the industry.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.549-551
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• 1999

Recently, Several type of motors are used more widely in Fan system because of their low cost and high reliability. Therefore, the importance of fault detection and isolation of fan system significantly increases. The motor is a important factor bring out the fan system fault. So the problem of a fault detection for motor based on a parameter identification will be considered in this paper. After an introduction into fault detection with parameter estimation, a mathematical model for motor with special emphasis on motor itself. In the fault detection system, current and motor speed are used as parameter. Finally, simulation results are used to demonstrate the efficiency of the fault detection system.