• International Journal of Fluid Machinery and Systems
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• v.9 no.2
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• pp.175-181
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• 2016

Contra-rotating rotors have been adopted for some of the cooling fans to meet the demand for the high pressure and large flow rate. Therefore, it is important to clarify its inlet and outlet flows by experiments for the high performance and stable operation. PIV measurements were conducted at the design and partial flow rates. In the present paper, the inlet and outlet flow conditions of the contra-rotating small-sized cooling fan with a 40mm square casing are studied by using PIV measurement. Furthermore, improvements of the flow condition and design guideline to increase the performance were discussed based on the experimental results.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.8
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• pp.957-968
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• 1999

Performance tests of an airfoil fan and measurement of flow fields at the impeller exit are carried out to investigate the effects of the tip clearance between the rotor and inlet casing on the impeller performance. The impeller is twelve bladed of NACA 65-810 airfoils and tested with 3 different size of gap; 1, 2, 4mm. The relative decrease of pressure rising performance of the fan is 15 percent for the design flow rate when the gap size is 1 percent of the impeller diameter. The reduction of performance becomes large as the flow rate increases. The leakage flow through the clearance affects the through flow of the impeller, which results in decrease of the slip factor as well as the impeller efficiency. The data base obtained in the present study can be used for the design and flow analysis of the airfoil fans.

• 유체기계공업학회:학술대회논문집
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• 1998.12a
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• pp.57-63
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• 1998

The performance of a centrifugal fan depends on the dimensional parameters of impeller, such as the inlet and exit diameter, area ratio, relative flow angles to the blade, and number of blades. These design parameters, however, are inter-related, so it is very difficult to identify the effect of each parameter to the fan performance. In this experimental study the effect of the design parameters on the performance of a small centrifugal impeller being used for vacuum cleaners are investigated. Total 30 shrouded impellers with 120mm diameter were tested and the results were non-dimensionalized to compare their performance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.8 s.251
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• pp.715-721
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• 2006

In the present work, nozzle shape of a jet fan is optimized numerically using three-dimensional Reynolds-averaged Navier-Stokes analysis. Standard $k-{\epsilon}$ model is used as a turbulence closure. Response surface method is employed as an optimization technique. The objective function is defined as maximum throw distance. Three geometric variables, i.e., length and angle of nozzle, and interval between two nozzles, are selected as design variables. As the main result of the optimization, the throw distance has been improved effectively.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.365-370
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• 2001

In order to minimize unstable flow occurred at a multiblade fan/scroll system, optimal angle and shape of cut-off was determined by using two-dimensional turbulent fluid field analyses and neural network. The results of CFD analyses were used for learning as data of input and output of neural network. After learning neural network optimization process was accomplished for design variables, the angle and the shape of cut-off, in the design domain. As a result of optimization, the optimal angle and shape were obtained as 71 and 0.092 times the outer diameter of impeller, respectively, which are very similar values to previous studies. Finally, it was verified that the fluid field is very stable for optimal angle and shape of cut-off by two-dimensional CFD analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.242-243
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• 2010

The cooling system, including a fan is a one of the major sources to generate the radiated noise of construction equipment. Therefore, it is required to reduce the flow noise induced by a fan in order to reduce the noise level. In this study, we made an engine room model to carry out a variety of experiments. And then, the flow noise analysis technique using the CFD code was applied to the cooling system of construction equipment. These analyses results agree well with the measurement results. These results make it possible to understand the flow noise characteristics and to design the low noise cooling system in the design stage.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.6
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• pp.529-535
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• 2011

Indoor noise is very important related to the morale and fighting power of the crew as well as environmental condition for them in a navel vessel. Especially, the crew members working in CIC (combat information center) and sonar equipment room require much more quiet environment condition. One of the most serious noise source in CIC is the cooling fan noise installed in the console of the combat system. Therefore, in this paper, the design of the plenum chamber is studied to reduce the noise of the fan from these consoles by numerical analysis and experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.77-82
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• 2011

Indoor noise is very important related to the morale and fighting power of the crew as well as environmental condition for them in a navel vessel. Especially, the crew members working in CIC(Combat Information Center) and sonar equipment room require much more quiet environment condition in order to increase the performance of their combat system. One of the most serious noise source in CIC is the cooling fan noise installed in the console of the combat system. Therefore, in this paper, the design of the plenum chamber is studied to reduce the noise of the fan from these consoles by numerical analysis.

• The KSFM Journal of Fluid Machinery
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• v.2 no.1 s.2
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• pp.50-55
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• 1999

The performance of a centrifugal fan depends on the dimensional parameters of impeller, such as the inlet and exit diameter, area ratio, relative flow angles to the blade, and the number of blades. These design parameters, however, are inter-related, so it is very difficult to identify the effect of each parameter on the fan performance. In this experimental study the effects of the design parameters on the performance of a small centrifugal impeller being used for vacuum cleaners are investigated. A total of 30 shrouded impellers with 120mm diameter were tested and the results were non-dimensionalized to compare their performance.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.214-216
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• 1999

This paper discussed an optimal designs of 2 pole fan motors in refrigerator using a Niching Algorithm. We applied a Niching method to multi-objective optimal design of air gap construct. This Niching genetic algorithm is called "Restricted Competition Selection"(RCS) that is suitable for real world problem such as shape or structural optimization of electromagnetic device. The finite element method being used for nonlinear numerical characteristic analysis is provided exact solution in the system. Through this process is reduced the cogging torque ripple in air gap.