| 摘要 |
PROBLEM TO BE SOLVED: To attempt compatibility between lowering of aerodynamic noises and improvement of aerodynamic performance. SOLUTION: While a plurality of small holes 4, 4,... through which the front surface of a negative pressure surface and a hollow chamber part are communicated with each other is formed in the front edge part 2a of the negative pressure surface side of hollow blades 2, 2,... having the hollow chamber part, an oblong hole 5 communicating the front surface with the hollow chamber part and extended in a circumferential direction is formed in the rear edge part 2b of the negative pressure surface side. By this structure, suction force by a blade end vortex 10 is applied to the oblong hole 5, and a part of air led to flow into the front edge part 2a by this suction force is sucked from the small holes 4, 4,... to the hollow chamber part, passed through the oblong hole 5 and led to flow out to the rear edge part 2b side. As a result, while separation of air flow is suppressed as much as possible on the front edge part 2a side by suction action in the small holes 4, 4,..., growth of a blade surface boundary layer on the front surface is suppressed on the rear edge part 2b side by air flow led to flow out from the oblong hole 5 to the front surface side of the negative pressure surface, therefore, by these synergistic effects, this impeller for a blower having low aerodynamic noises and excellent aerodynamic performance can be obtained.
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