| 摘要 |
PROBLEM TO BE SOLVED: To reduce the collision/separation phenomenon in a blade inlet at a working point in a large flow rare/low static pressure region, widen the main flow region partial to a region apart from a suction port to a region near to the suction port, moderate increase in flow between blades in the region apart from the suction port, and reduce turbulent flow noise attendant on the separation. SOLUTION: A vent hole 2 for passing air is formed in a main plate 107, an inlet angleβ1 of an upper blade 1a and a lower blade 1b is made different from an outlet angleβ2, and in the large flow rate/low static pressure region, since the inlet angleβ1 of the upper blade can be made small, difference between inlet angles can be made small, the effective work region of the blade is widened, and the collision/separation phenomenon in a blade inlet part 4 can be reduced. A restriction part of the main plate is eliminated, a ventilation passage is widened, flow in the blade is made easy, and since a flow speed is reduced, the collision/separation phenomenon in the blade inlet part 4 and the blade surface is reduced, and noise can be reduced.
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