209 低騒音クロスフローファンの開発(生産技術及び製品開発III)

概要

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It is difficult to minimize fan noise when the flow rate of the cross-flow fan is increased. In order to decrease fan noise, the shape of casing has been optimized and the pitch angle between fan blades has been set to be random. On the other hand, noise in the low-frequency region increases in some cases with random pitch-pattern. As low-frequency noise is very disturbing to the ear, it is very important to keep it low. We developed a simulation model to estimate the sound character. Using this model, we simulated a noise spectrum and compared the calculated results with the experimental ones. Further, we studied the relation between blade profile and blade passing frequency noise level. We made flow simulation about 2 types of blades and discovered that the change of sound character is related with the change of pressure fluctuation on stabilizer suction side.
2000-06-23