1998 Fiscal Year Final Research Report Summary
Development of Low Pressure Centrifugal Fan for High Performance and Low Noise
| Project/Area Number |
08650215
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Fluid engineering
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| Research Institution | NAGASAKI UNIVERSITY |
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Principal Investigator |
HAYASHI Hidechito NAGASAKI University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (10173022)
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| Project Period (FY) |
1996 – 1998
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| Keywords | Fluid machine / Aeroacoustics / Fan / Impeller / Airfoil / Noise prediction |
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| Research Abstract |
The low pressure centrifugal fan which is used in the air conditioner is researched for developping the aerodynamic performance and reduce the noise level. And the relationship between the flow pattern around the airfoil and the aeroacoustics was investigated. The following results are obtained.
1. It is important for the performance of a low pressure fan not to increase the efficiency but to obtain the flow patterns to obtain the good performance for the air-conditioner.
2. The leading edge overhang shape or the three dimensional geometry of impeller make the aerodynamic performance being good with small degree. But the noise level of them is almost the same to the ordinary fan.
3. The geometry of bellmouth gives the large influence to the noise of a low pressure fan. The small gap with the impeller and the small curvature at the outlet of bellmouth reduce the noise level of a fan.
4. The ratio of inlet to outlet area is a very important parameter to the aerodynamic and noise performance. The developed impeller which is made with the large aerial ratio gets the good flow condition and the low noise level.
5. The mechanism of the noise generation from the airfoil is cleared with experiments and numerical research. The method to predict the noise level and the frequency is proposed that can be used at the fan design.
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