| 摘要 |
PROBLEM TO BE SOLVED: To reduce the pneumatic noise, and to improve the blowing efficiency by positively controlling the air flow condition on the blade surface in a blower. SOLUTION: A columnar rotator 10 is embedded for arrangement in any one of a leading edge 2a and a negative pressure surface 2c side of each blade 2 of an impeller 1 so that the columnar rotator 10 forms the nearly same surface with the blade surface and freely to be rotated in the blade span direction. With this structure, when rotating the impeller 1 for blowing operation, the shearing force of the blade surface air flow to be applied to the air flow is reduced to restrict the lowering of the flow speed of the air flow near the blade surface by the rotation of the columnar rotator 10 at a part thereof in comparison with a case that the columnar rotator 10 is not provided, and separation of the air flow becomes hard to be generated. As a result, the pneumatic noise due to the air flow separation near the blade surface is lowered, and the blowing efficiency is improved.
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